This PDF file contains the front matter associated with SPIE Proceedings Volume 11454, including the Title Page, Copyright Information, and Table of Contents.

Teledyne e2v continues to develop silicon sensors for ground and space-based Astronomy applications. Multiple new BSI CMOS sensors are presented, which use a patented back-bias structure to achieve NIR and soft x-ray quantum efficiency comparable to a deep depletion CCD. These include NIR-enhanced variants of Capella space imager and a predevelopment for THESEUS in collaboration with the OU with large x-ray sensitive pixels. Two new extremely large BSI CMOS sensors, the first in a buttable format suitable for focal plane arrays also incorporating the back-bias structure and the second a high speed, ultra-low noise sensor for use in the Teledyne Princeton Instruments COSMOS camera. A range of BSI CCD developments are presented. These include development work towards a curved CCD231-84, the HiRho CCDs used in the huge 3.2 Gigapixel Vera Rubin focal plane array and the Space telescope projects: Euclid, Plato and WSO-UV.

With the increase of human activities in space, a large number of space artifacts have been generated around the Earth which called Near Earth Objects (NEO), most of which are space debris. CMOS image sensor can achieve very high frame rate by electronical shutter and suitable for NEO observation with its fast moving. For space objects observation, key technologies of a large-format and high-rate scientific CMOS camera were studied, including low-noise readout and low-interference refrigeration technology, real-time processing algorithm, high-speed data transmission technology, system integration technology and high precision timing technology , etc. A 4K*4K pixel scientific CMOS camera is introduced in this paper with 24fps rate in full frame mode and high timing accuracy of exposure synchronization with 10ns, which has great advantages for the initial orbit positioning of the space objects. The overall size of the camera is 143mm * 160mm * 168mm. The readout noise of the camera is about 4.4e^-. At present, the camera has been installed and running at Xinglong Observatory.

Pyxel is a novel python tool for end-to-end detection chain simulation i.e. from detector optical effects to readout electronics effects. It is an easy-to-use framework to host and pipeline any detector effect model. It is suited for simulating both Charge-Coupled Devices, CMOS Image Sensors and Mercury Cadmium Telluride hybridized arrays. It is conceived as a collaborative tool to promote reusability, knowledge transfer, and reliability in the instrumentation community. We will provide a demonstration of Pyxel’s basic principles, describe newly added capabilities and the main models already implemented, and give examples of more advanced applications.

The aim of this work is to investigate the degradation induced by radiation on the Dark Count Rate in a monolithic SPADs detector manufactured in a 150-nm CMOS process. Two irradiation campaigns have been carried out with 16 MeV protons and 2 MeV electrons. Samples have been exposed to different displacement damage dose. Differences between the effects induced by the two irradiation particle types have been observed. The Dark Count Rate characterization as a function of the delivered fluence has been reported, providing the limits of operability of such devices in a radiation environment. Finally, possible Dark Count Rate mitigation techniques have been investigated.

For the MWIR channel of the spectrometer of the ESA Ariel mission, ESA has procured a dedicated MCT detector from TeledyneE2V with a cut-off of 8µm at 42K.A test bench has been designed, manufactured and commissioned to measure the performances of the detector at cryogenic temperature. The detector was tested before, during and after proton radiation performed at 42K up to a level of 2.50E+10 p+/cm².The results of the impact of the proton radiation on the detector performances are presented as well as a description of the test bench.

Charge-coupled devices (CCDs) currently constitute the standard detector for precision astronomical telescopes such as the Large Synoptic Survey Telescope (LSST) due to their high linearity, sensitivity and dynamic range. Charge transfer properties can however be degraded by the presence of defect levels in the silicon band-gap, which can act as trapping centers for signal charge. The technique of single trap-pumping can be used as a tool to probe the underlying properties of relevant defect levels and potentially mitigate against their effects. In this paper we present a single trap-pumping study of the LSST E2V CCD250 across a temperature range of ^-30◦ to ^-110◦, a much larger range than previously studied using this approach. The predominant defect level of relevance for CCDs appearing at these temperatures is shown to be the single-acceptor level of the silicon divacancy. Using experimental data and a basic Monte-Carlo model of the trap-pumping process we examine the defect level properties, with an attempt made to account for both the capture and emission of signal charge.

CMOS image sensors (CIS) have several significant advantages for NASA missions. Among the challenges for larger NASA payloads, including flagship mission concepts such as LUVOIR and Habex, are requirements for CIS detectors with small pixels, single photon sensitivity, and integration into large area mosaic focal planes. Key to these challenges is the emerging technology of 3D stacked CMOS image sensors. In this paper, we report the latest results from a collaboration between JPL and SNL to develop 3D-stacked, superlattice-doped CIS detectors for imaging and spectroscopy of high intensity, pulsed X-ray sources. JPL’s MBE-grown surface passivation layers are two orders of magnitude thinner and more highly doped than the ion-implanted layers in Sandia’s previous generation of detectors. JPL and Sandia demonstrated 3D-stacked, superlattice-doped photodiodes with 10x higher efficiency, marking a key milestone on the road toward gigapixel focal planes with single photon sensitivity.

An optical bench setup for quantum efficiency (QE) measurements across the 350 nm to 1100 nm range has been developed at the Open University’s Centre for Electronic Imaging (CEI). Here we use it to measure the performance of a monolithic silicon CMOS image sensor (CIS), the CIS115. This sensor was selected for the JANUS camera, due to launch on board ESA’s JUpiter ICy moons Explorer (JUICE) spacecraft in 2022. The CIS115 sensors tested here have high quantum efficiency (QE) over the optical band, due to their backside illumination and multi-layer anti-reflective coating. Here we validate the QE measurements against manufacturer reported performance and compare the QE for unirradiated (beginning of life) and gamma-irradiated devices, indicating that no significant change in performance should be expected after a total ionizing dose (TID) of 200 krad(Si). This is important for the JANUS application, where the sensor is predicted to accumulate up to 44 krad(Si) TID. We also demonstrate that the measurement setup has excellent repeatability. We conclude by discussing the limitations of the setup, including the key systematic error sources that have been understood and investigated. Optional improvement to the setup for reducing these errors are presented and will be considered for follow-on activities.

A new method for minimizing image lag due to charge spill-back has been developed for pinned photodiode CMOS image sensors. The proposed method involves the use of multi-level transfer gate voltage during a single charge transfer period. Measurement results show that the new transfer process maintains the lower values for image lag at low signal levels that a high transfer gate voltage grants, whilst simultaneously preserving the later onset of spill-back dominated lag that a lower transfer gate voltage allows.

Scientific CMOS image sensors are a modern alternative for a typical CCD detectors, as they offer both low read-out noise, large sensitive area, and high frame rates. All these makes them promising devices for a modern wide-field sky surveys. However, the peculiarities of CMOS technology have to be properly taken into account when analyzing the data. In order to characterize these, we performed an extensive laboratory testing of Andor Marana sCMOS camera. Here we report its results, especially on the temporal stability and linearity, and compare it to the previous versions of Andor sCMOS cameras. We also present the results of an on-sky testing of this sensor connected to a wide-field lens, and discuss its applications for an astronomical sky surveys.

Curved and freeform sensors are now a reality and are about to become very beneficial for wide field imaging system. By directly correcting the field curvature of imagers and spectrographs in the focal surface, curved sensors allow to get rid of one third to half of the optics. This leads to a reduction of the volume and mass of the instruments, simplification of the optics prescriptions, while drastically improving the image quality. The ERC-ICARUS team and the SME CURVE developed a nondestructive, high quality shaping process. This paper provides details on the electro-performance of curved and freeform CMOS sensors made in house. We will also present results on the curvature and shape quality of these sensors and talk about future developments for astronomical instruments such as rovers cameras and spectrographs. We will describe the goals and the development of projects using curved sensors, that are today considered as technological demonstrators for the next five years. We will browse on-going projects that consider using curved sensors as a base line, such as CASTLE (wide field telescope) for Calar Alto or BlueMUSE (spectrograph) for the Very Large Telescope. Optical designs and specifications for the focal surfaces are presented, and compared to the existing performance. We will also detail our proposition to the ESA Space Weather Department of a design for a wide field/curved-sensor-based UV camera dedicated to in-orbit survey of Aurora and electromagnetic storms.

THESEUS (Transient High Energy Sky & Early Universe Surveyor) is one of the three candidates for the M5 mission of the European Space Agency. The favoured mission will be announced in 2021 for an expected launch in 2032. THESEUS will be equipped with a Soft X-ray Imager (SXI) composed of a set of two telescopes using micro-pore optics offering an overall field of view of 0.5 sr (<2’ accuracy) for X-ray energies between 300 eV and 5 keV. The focal plane of each SXI telescope has a 16 x 16 cm² cooled detector area. However, the limited radiator accommodation on the spacecraft prohibits the use of CCDs since cooling the focal planes to an optimal temperature for radiation hardness (<-100 ◦C) is not feasible. Therefore, the development of a suitable CMOS Image Sensor (CIS), capable of handling the expected levels of radiation at higher operating temperatures (approximately -30 ◦C) has been proposed. To demonstrate the performance required for the THESEUS SXI detector, a 2 x 2 cm² prototype is under development using Open University pixel designs in a Teledyne-e2v digital CMOS platform. The pixel design will allow full depletion over silicon thickness of 35 µm for optimal soft X-ray quantum efficiency and instrument background suppression, and will be capable of near-Fano-limited spectral resolution that will also be of prime interest for synchrotron and Free Electron Lasers (FEL) applications. In this paper, we will present the design considerations and simulations leading to the implemented structures complying with THESEUS’ SXI requirements.

We report development status of an X-ray imaging spectrometer for scientific micro satellite mission GEO-X that aims for imaging of Earth’s magnetosphere from the vicinity of the Moon (∼40 R_E). The planned direction for the observations includes proximity of the day-side Earth. Therefore the primary requirement for the detector is the fast frame rate to decrease the visible light background. In this regard we will apply complementary MOS (CMOS) sensor that is originally fabricated for the visible light and/or infrared spectroscopy. Faster readout speed improves time resolution and decrease the contribution from visible light compared with the conventional CCD detectors. We evaluate imaging and spectroscopic performances of backside illumination type scientific CMOS sensors with low noise performance. Most of the signals produced by X-rays distributes within 2 by 2 pixels. Spectra of monochromatic X-rays exhibit significant difference of pulse height between the event within single pixel and that spreads across multiple pixels, which indicates that a part of the signal charges are lost around the pixel edges. Then we adopt another type of the sensor that have been updated in terms of the incident surface treatment. We found that the amount of the lost charges are substantially decreased with the new sensor. Another measure to improve the spectroscopic performance is the dark level determination. Gradual or discontinuous change of the dark level in orbit might it difficult to evaluate the appropriate dark level especially for the high frame rate and the limited resources of onboard computer. Then we take the average of pulse heights for the outermost pixels in a event (5 by 5 pixels) and correct the pulse height of all pixels with the average value. With these measures the energy resolution improved successfully.

Experimental study of the influence of the CdZnTe substrate thickness on the response of IR detectors under irradiation has been performed. Two detectors, with different substrate thickness 800 μm and 50 μm, were submitted to low flux 62 MeV proton irradiation.Images acquired under irradiation were analyzed. Whereas the detector with 800 μm substrate thickness has shown background signal increase under irradiation, the detector with the substrate partially removed has not shown any background signal elevation. The elevation of the background signal under irradiation in the detector with intact substrate is attributed to the large extension of one transient event as reveal by the derivation of one transient event. The results of the irradiation campaign are further compared to simulations. This comparison shows very good agreement and highlights the role of emission of low energy photons inside the substrate which are in turn detected by the light sensitive layer.

We are developing an X-ray SOI pixel detector “XRPIX” for the next generation X-ray astronomical satellite “FORCE”. XRPIX is the detector using SOI (Silicon-On-Insulator) technology which makes it possible to integrate a high-resistivity Si sensor part and a low-resistivity Si CMOS circuit part. The CMOS circuit is equipped with the trigger function, which can read out only the output signal of the pixel where the X-ray is incident. This function realizes high throughput and high time resolution, enabling the background rejection with anticoincidence technique. A new series of XRPIX named XRPIX6E, we developed, with a Pinned Depleted Diode (PDD) structure improves the spectral performance by suppressing the interference between the sensor layer and the circuit layer. When semiconductor X-ray detectors are used in space, it is known that their spectral performance is degraded due to radiation damage caused by high-energy protons. Therefore, before using XRPIX in space, it is necessary to evaluate how much the spectral performance will be degraded by radiation damage. Then we performed proton irradiation experiment for XRPIX6E for the first time at HIMAC in National Institute of Radiological Sciences. We irradiated XRPIX with high-energy protons up to a total dose of 40 krad, equivalent to 400 years irradiation in orbit. As a result, the energy resolution in full width half maximum at the 5:9 keV degrades by 25 ± 3%, however, is better than the required performance of FORCE, 300 eV at 6 keV. It was also found that the PDD structure XRPIX has better radiation hardness than the previous XRPIX series. In addition, We investigated about the degradation of the energy resolution; it was found that the degradation would be due to increasing energy independent components, for example, readout noise.

The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer mission (SMILE) aims to develop a global scale understanding of the interaction between the solar weather and the Earth’s magnetosphere-ionosphere. The soft X-ray imager (SXI) is one of the instruments on board and will observe photons emitted in the 200 eV to 2000 eV energy range from the solar wind charge exchange process using two large 4510 x 4510 pixel CCD370s as a focal plane. The CCD370s take their design and qualification heritage from similar sensors being used in the PLATO mission, with specific modifications to optimize their performance in this soft X-ray energy range. SMILE will orbit Earth in a highly elliptical orbit and will pass through the radiation belts every 52 hours. The trapped and solar protons present will gradually damage the CCDs throughout the 3-year mission and degrade their performance. To understand the impact the damage has on the devices a series of proton radiation campaigns are being undertaken. These campaigns are being performed with flight-like SMILE CCDs, and functionally similar PLATO devices, with follow-up characterization across from -130 to -85 °C. The most recent irradiation campaign has been completed using a PLATO CCD280 kept below -85 °C for irradiation and characterization, and the results show that the measured parallel charge transfer inefficiency varies with temperature between 1x10^-4 and 4x10^-4 in unbinned full-frame readout mode. The effect of temperature annealing up to -85 °C on the parallel charge transfer inefficiency has also been assessed and shows that no temperature-dependent annealing of the radiation-induced damage has been observed. A similar behavior is expected to be seen in the SMILE devices, albeit with an anticipated improvement by a factor 3-4 due to the modifications made to the design. Thus, results indicate the SMILE CCD370s will meet the performance requirements of the SMILE SXI instrument.

The European Space Agency’s Gaia spacecraft was launched in December 2013 and has been in orbit at the Earth-Sun Lagrange point 2 (L2) for over 6 years. The spacecraft measures the positions, distances, space motions and many other physical characteristics of around one billion stars in the Milky Way and beyond. It has a focal plane of 106 Charge-Coupled Devices (CCDs) which have all been performing well but have been measuring a small but quantifiable degradation in performance in time due to Non-Ionizing Energy Loss (NIEL) damage from interstellar radiation. This NIEL damage produces trap defects which can capture charge from signals and reduces the quality of the data. Gaia’s original mission lifetime was planned to be around 5 years and the pre-flight testing and radiation damage analysis was tailored around those timescales as well as with the projected solar activity before launch. Closer to the time of launch and during Gaia’s years of orbit, it has been noted that the solar activity was lower than what was initially predicted. From the previous analysis of in-flight data in 2016, it was calculated that Gaia was experiencing an order of magnitude less radiation damage than was predicted. This paper describes the analysis of charge calibration data and corresponding Charge Transfer Inefficiency (CTI) measurements from the in-flight CCDs, both near the beginning of the mission and after more than 5 years in orbit to quantify the radiation damage impact. These sets of results can be compared with those from the pre-flight tests which can be used to evaluate and understand the differences between the on-ground and in-flight results.

SMILE (Solar Magnetosphere Ionosphere Link Explorer) is a collaborative mission between the European Space Agency and the Chinese Academy of Sciences that is scheduled to be launched in 2024 and will be placed in a highly elliptical, inclined, orbit. The on-board instrumentation will study interactions between the solar wind and the Earth’s magnetosphere-ionosphere system by imaging the soft X-ray emission that results from solar wind charge exchange whilst simultaneously collecting information about the northern aurora with a UV imager and investigating the solar wind and magnetosheath plasma and magnetospheric field conditions using a Light Ion Analyzer and a magnetometer. The SXI (Soft X-ray Imager) is a wide field ‘lobster-eye’ telescope that is equipped with two 4510 x 4510 pixel CCDs with 18 μm pixel pitch. It will image X-rays (300 eV-2000 eV) through focusing optics that consist of an array of Micro Pore plates. The predicted X-ray event rate is expected to be low and the instrument will operate in photon counting mode so the SXI is designed to maximize the useful information returned to earth by identifying and storing individual events on board the spacecraft before transmitting the relevant information back to earth. This study investigates the baseline methods that will be implemented on-board to isolate and extract these events from the images amongst a more complicated particle background. The detector response is modelled and verified with calibration data from the CCD270. The work presented here by the Centre for Electronic Imaging at the Open University demonstrates the proposed method for isolating individual soft X-rays from images taken using the SMILE SXI and subsequently sorting these X-rays into data packets suitable for transmitting to earth. Different methods are tested with simulated and real data to optimize the proportion of useful events transmitted.

The DePFET is an active pixel sensor utilized or suggested for several experiments. For future applications, it is desirable to improve the signal to noise ratio of the DePFET. The DePFET is essentially a pMOSFET built on a high resistive, fully depleted bulk. A deep-n implant beneath the MOS-gate forms a positive potential. Electrons collected in this internal gate modulate the transistors conductivity. This charge gain is influenced by the geometry and operational parameters of the DePFET. To study all influences, we utilized Sentaurus TCAD based simulations to investigate the DePFETs characteristics and compared the results from simulations and measurements. Using the simulations, we studied possible improvements of the DePFET, optimizing its charge gain and noise. From these simulations, it becomes evident, that especially impact ionization poses a problem. We developed an optimized technology that can overcome this limitation.

The Soft X-ray Imager (SXI) on-board the joint ESA-CAS SMILE mission is a wide-field lobster-eye telescope designed to characterize the Earth's magnetospheric boundaries, by observing emission from the solar wind charge exchange (SWCX) process in the soft X-ray band. It has two large CCD370 (Teledyne-e2v) detectors, derived from the CCD-Bruyeres for ESA’s PLATO mission, with minor optimizations for soft X-ray detection, related to higher responsivity and increased radiation hardness. We present the first performance results under X-ray illumination of the CCD370 in SXI-specific operating conditions, including 6x6 on-chip pixel binning, over a range of pixel readout rates and operating temperatures.

Superconducting Nanowire Single Photon Detectors (SNSPDs) are the most advanced detectors available for time-resolved single photon counting from the UV to the mid-infrared. We will discuss recent progress in SNSPD development for the ground terminal in NASA’s Deep Space Optical Communication (DSOC) project as well as recent performance advances in other metrics, including the development of kilopixel SNSPD arrays, single-photon sensitivity at mid-infrared wavelengths as long as 10 microns, and SNSPDs with sub-3ps timing jitter. I will discuss a range of new potential scientific applications for SNSPDs, including exoplanet transit spectroscopy, dark matter detection, fluorescence lifetime imaging microscopy, and quantum information science.

We are developing an x-ray imaging spectrometer for Super DIOS satellite mission, a future x-ray observatory, planned by JAXA, to be launched in 2030’s. Super DIOS will reveal the nature of the missing baryon in the warm-hot intergalactic medium because of its fine energy and angular resolution, large effective area and large field of view. A main detector on-board Super DIOS consists of a transition-edge sensor (TES) microcalorimeter array of over 30,000 pixels working at a temperature below 100 mK and it poses a considerable technical difficulty to the readout. A microwave superconducting quantum interference device (SQUID) multiplexing is promising technique and expected to achieve a large scale readout of more than 30,000 pixels. We describe our development of a 40-channel microwave SQUID multiplexer with low-noise characteristics∗ and a demonstration of simultaneously reading out 40-pixel TESs. Finally, we discuss a future prospect and a feasibility of reading out an array of more than 30,000 pixels.

With its first flight in 2018, Micro-X became the first program to fly Transition-Edge Sensors and their SQUID readouts in space. The science goal was a high-resolution, spatially resolved X-ray spectrum of the Cassiopeia A Supernova Remnant. While a rocket pointing error led to no time on target, the data was used to demonstrate the flight performance of the instrument. The detectors observed X-rays from the on-board calibration source, but a susceptibility to external magnetic fields limited their livetime. Accounting for this, no change was observed in detector response between ground operation and flight operation. This paper provides an overview of the first flight performance and focuses on the upgrades made in preparation for reflight. The largest changes have been upgrading the SQUIDs to mitigate magnetic susceptibility, synchronizing the clocks on the digital electronics to minimize beat frequencies, and replacing the mounts between the cryostat and the rocket skin to improve mechanical integrity. As the first flight performance was consistent with performance on the ground, reaching the instrument goals in the laboratory is considered a strong predictor of future flight performance.

Incom Inc. is developing and commercializing a new type of microchannel plate (MCP) electron multiplier, as well as MCP-based photodetectors such as the Large-Area Picosecond Photodetector, LAPPD(TM), and the High-Resolution Picosecond Photodetector, HRPPD. This new class of MCPs is called “ALD-GCA-MCPs” because these are MCPs that are made from glass capillary arrays (GCA) – glass plates with a regular array of hollow glass capillaries – that are functionalized using atomic layer deposition (ALD) thin film coating technology. ALD-GCA-MCPs are a technology advancement that affords MCPs with significantly improved performance, as compared to conventional MCPs. We will provide a brief ALD-GCA-MCP technology overview highlighting the current state of the art of Incom’s ALD-GCA-MCP technology, as well as ongoing developments addressing the GCA glass substrate, the resistive and secondary-electron-emissive ALD coatings, and their implications for detectors used in astronomical applications.

A noiseless, photon counting detector is desired for low light applications in astronomy. We study superconducting Microwave Kinetic Inductance Detectors (MKIDs) in which the intrinsic energy resolution eliminates the conventional dark current. A visible/near-IR photon creates thousands of quasiparticles through electron-phonon interaction. Phonons lost in this process limit the energy resolution to E/dE<20 (10) for aluminium MKIDs on solid substrate, measured with a 402 (1545) nm laser. When fabricated on a 120 nm SiN membrane, E/dE increases to 55 (25), which demonstrates that phonons are more effectively trapped, and that the promises on resolving power for MKIDs are realistic.

We have developed a photo-sensor for an optical photon counting imager for astronomy with high timing resolution. We customize a Multi Pixel Photon Counter as a monolithic Geiger avalanche photodiode array with a pixel size of 100 micro-meter. The prototype model consists of 4x4 pixels. Excellent timing response is achieved as fast as an order of nanosecond. We evaluate the basic performance of the sensor and confirm the gain linearity, uniformity and low dark count rates. We observe the Crab pulsar using this system with a 35-cm telescope, and successfully detected periodic pulses with a frequency consistent with that reported by radio observatory.

We characterize the response of a novel 250 µm thick, fully-depleted Skipper Charged-Coupled Device (CCD) to visible/near-infrared light with a focus on potential applications for astronomical observations. We achieve stable, single-electron resolution with readout noise σ 0.18 e⁻ rms/pix from 400 non-destructive measurements of the charge in each pixel. We verify that the gain derived from photon transfer curve measurements agrees with the gain calculated from the quantized charge of individual electrons to within < 1%. We also perform relative quantum efficiency measurements and demonstrate high relative quantum efficiency at optical/near- infrared wavelengths, as is expected for a thick, fully depleted detector. Finally, we demonstrate the ability to perform multiple non-destructive measurements and achieve sub-electron readout noise over configurable sub- regions of the detector. This work is the first step toward demonstrating the utility of Skipper CCDs for future astronomical and cosmological applications.

A germanium charge-coupled device (CCD) offers all of the advantages of silicon CCDs – notably excellent uniformity, high energy resolution, and noiseless on-chip charge summation – but covers an even broader spectral range, extending into the hard X-ray band. MIT Lincoln Laboratory has been developing germanium CCDs for applications in astrophysics, with the goal of realizing megapixel-class arrays with read noise less than a few electrons, sensitivity to both soft and hard X-rays, and high energy resolution. We recently realized our first small pixel arrays and have since been working to increase both the format and performance of these devices. In this article, we discuss performance improvements, identification of yield-limiting process steps in fabrication of frontside-illuminated devices, fabrication and analysis of our first backside-illuminated detectors, and design of prototypes which includes a 512 × 512 pixel frame-transfer CCD with 24 µm pixel pitch.

NASA is currently studying a mission concept called Lynx for the next generation X-ray telescope to follow up on highly successful Chandra observatory that has been in operation since 1999. Detector technology for the main instruments focal planes has not been selected at this time, with several different options under consideration (see¹). Charge Coupled Devices (CCDs) have been traditionally the detectors of choice for space X-ray instruments, and, while new technologies, such as CMOS image sensors and hybrid detectors made huge progress in recent years, CCDs still have a combination of features that make them difficult to replace as soft X-ray detectors. To enhance these advantages, MIT Lincoln Laboratory has in recent years designed several versions of a CCD with single level polysilicon gates which can be controlled by low voltages compatible with CMOS driving circuitry, and could be an attractive option for Lynx and other X-ray space missions due to its higher speed and lower power consumption. In this work we investigate their parameters at higher speed and lower voltage amplitudes and report some of the results of testing those new detectors. We describe new techniques that we developed to study physical mechanisms that limit device performance.

Effective and continuous monitoring of space debris in satellite orbit is an important issue in resolving potential threats to aerospace equipment. The SDM (Space Debris Monitoring)-16803 is a front-illuminated high-readout-speed, low-noise scientific CCD camera designed for the needs of space debris monitoring telescopes. The camera is designed with drift scanning function in which mode the moving target will be presented as a static image, so that a fixed telescope can track the moving space target. The electronics of the camera provides driving signals for the CCD, samples the video signals of the CCD, and also communicates with the host computer. The maximum readout speed of the CCD is 10Mpixels. The mechanics structure of the camera is designed with a sealed chamber in which a TEC (Thermo Electric Cooler) is used for cooling the sensor and provide a stable temperature.

Charge coupled devices (CCDs) have been the detector of choice for large-scale space mission for many years. Although dominant in this field, the charge transfer performance of the technology degrades over time due to the harsh space- radiation environment. Charge transfer performance can be optimized however, but it is often time consuming and expensive due to the many operating modes of the CCDs. A new technique is presented and developed here, which uses new measurements of the trap landscape present in a CCD, to predict changes in charge transfer inefficiency as a function of different variables. By using this technique, it is possible to focus experimental lab testing on key device parameters, potentially saving many months of laboratory effort. Due to the generality of the method, it can be used to optimize the charge transfer performance of any CCD, and as such has many uses across a wide range of fields. Future CCDs variants that will be used in potential space missions (EMCCD and p-channel CCDs) can use this technique to feedback key device performance to the wider mission consortium before devices are available for experimental testing.

Teledyne-e2v’s sensors and wafer-scale processing are widely used for high performance imaging across soft X-ray and optical bands. In the ultraviolet spectral range, the combination of short absorption lengths (below 10 nm) and high reflectance (up to 75 %) can strongly limit the quantum efficiency. Direct detection capability relies on back-illumination and back-thinning processes to be applied to a sensor to remove dead layers from the optical path. As the thinning process leaves an unacceptably thick backside potential well as well as a highly reflective surface, in-house ultraviolet-specific (e.g. for WUVS) or third-party processes (e.g. delta-doping for FIREBall) are required. We have calibrated Teledyne-e2v’s latest in-house wafer-scale proprietary processes with monochromatic synchrotron radiation over a wide spectral range in the ultraviolet domain (λ=40 nm – 400 nm) at the Metrology Light Source of the Physikalisch-Technische Bundesanstalt. The first process is a shallow p+ implantation that permits the thinning of the backside potential well. It is available in two different levels: basic and enhanced. The second type of enhancement is a specific anti-reflective coating to increase the back-surface transmittance for distinct spectral ranges. In this paper, we will present comparative quantum efficiency calibration of both passivation stages and of two different ultraviolet specific anti-reflective coatings (applied on enhanced passivation devices). Also, their stability after intense ultraviolet illumination will be shown. These measurements will permit Teledyne-e2v to extend the quantum efficiency data of their most recent processes across the soft X-ray to near-infrared spectrum.

Microchannel plate based detectors are widely used for photon counting spectroscopy and imaging in astronomical, high energy physics and remote sensing applications^1-15. We present progress in the development of imaging cross strip readout detectors using novel microchannel plates functionalized by atomic layer deposition (ALD). ALD microchannel plates have established formats of 10 cm with 10 μm pore sizes and 20 cm with 20 μm pores. ALD MCPs show with high quantum efficiency (>50% @115 nm) using opaque alkali halide photocathodes and very low background levels (0.05 events cm^-2) have been achieved. Readout systems have also evolved and now cross-strip anodes and encoding electronics enable high spatial resolution (<20 μm) at low gain (10⁶) and over large formats (10 cm) with high dynamic range (>5 MHz). These characteristics are essential for UV instrument concepts currently under study for NASA including the Large UV/Optical/IR Surveyor (LUVOIR)¹⁶, the Habitable Exoplanet Imaging Mission (HABEX)¹⁶, and Cosmic Evolution Through UV Spectroscopy (CETUS)¹⁶.

Scientists are constantly pushing the boundaries, discovering new frontiers of exploration of the Universe; as space missions pursue these challenges it places a greater demand on detector technology advancement. I will present the status of our delta-doped Electron Multiplying CCD (EMCCD) for a UV multi-object spectrograph, the Faint Intergalactic Redshifted Emission Balloon (FB-2). FB-2 demonstrates this new technology, in a low risk suborbital environment, to prove the performance of EMCCDs for future space missions and Technology Readiness Level (TRL) advancement. It uses a new generation controller for counting photons from Nuvucameras. Part of this endeavor will be testing EMCCDs in a radiation environment; initial results will presented in this paper. EMCCDs have proven to be a versatile technology due to its photon counting (PC) capabilities to achieve extremely low readout noise (<< 1 electron). I will present results from the most recent flight and recent noise optimization.

Linked by ESA’s Astronomy Large Format Array for the near-infrared ("ALFA-N") technology development program, CEA and Lynred aim at setting up the fabrication of very large IR focal plane arrays (FPA) for astronomy needs. Prior to this project, dark current and image persistence are under investigation for achieving the high level of performance needed by astronomers. During previous characterization of this kind of detector, the FPA appeared particularly sensitive to ROIC electro-luminescence, preventing to observe fainter effects such as persistence. With the mitigation of the glow, the first measurements showed that dark current was dominated by persistence instead of classical diffusion, Auger or ShockleyRead-Hall mechanisms. We propose a dedicated test protocol in order to electrically characterize persistence and an empirical modelling tool to describe it in terms of amplitude and characteristic time constant. The first step consists in removing the residual persistence, allowing to characterize the intrinsic photodiode’s dark current, down to 0.03e-/s at 90K on four tested devices. From this reference, the persistence contribution is dramatically minimized and experimental conditions are reproducible, enabling further investigation on persistence to be carried out. Applied on detectors manufactured in the CEA-LETI clean rooms, this protocol aims at a better understanding of the phenomenon. Using an array containing different diode flavours (ie variations in the technological parameters such as diode geometry, passivation…), the characterization scheme described above should bring information about technological contributions on persistence.

We present analysis of James Webb Space Telescope (JWST) near infrared H2RG detectors ul{with a 5$upmu$m cutoff} showing that at temperatures below 60K there is no measurable dark current. Instead, the observed signal in dark exposures is almost entirely due to multiplexer glow that arises as each pixel is selected. We are able to separate the per sample glow from the time dependent dark current by comparing the observed signal in both continuous and sparsely sampled dark exposures. We show that the glow is lower within the regions of the detector that are missing the epoxy back fill (voids). We also show that the magnitude of the glow is affected by the pixel source follower current, the pixel clocking rate, and the number of outputs running in parallel. Our measurement of an insignificant dark current shows that the detector noise is no longer limited by the quality of the HgCdTe layer but instead by the multiplexer and readout electronics.

MOONS is a multi-object spectrograph for the ESO VLT covering a simultaneous wavelength range of 0.6-1.8 microns using approximately 1000 fibres. It uses four Teledyne Imaging Systems H4RG-15 4K x 4K detectors with 2.5 μm cut-off material for the two longer wavebands (YJ and H). Since the spectrographs utilize an extremely fast modified Schmidt camera design, then the detectors are situated in the optical beam and hence required the development of a novel 64- channel cryogenic differential cryogenic preamplifier, minimized for optical footprint which will be reported on. We have operated the Engineering Grade H4RG detector at a range of temperatures from 90K to 40K and we will report on the advantages of the lower operational temperature. We have completed a full persistence analysis and are able to model it reasonably well and will offer a correction for it in our data pipeline. We have also configured the detector for use with both unbuffered and buffered outputs and report on the differences in performance between the two output types. We have also seen some programming issues with the detector type and will report on our work-around for this, we will also describe the use of the column-deselect feature and row skipping to minimize the effects of PEDs. We have also measured charge injection per read and report on this, likewise we have also measured the inter-pixel capacitance in different regions of the detector. We will present all these results together with a summary of the complete performance characteristics of this detector family.

The Mid-Infrared Instrument MIRI on-board the James Webb Space Telescope uses three Si:As impurity band conduction detector arrays. MIRI medium resolution spectroscopic measurements (R~3500-1500) in the 5 μm to 28 μm wavelength range show a 10-30% modulation of the spectral baseline; coherent reflections of infrared light within the Si:As detector arrays result in fringing. We quantify the shape and impact of fringes on spectra of optical sources observed with MIRI during ground testing and develop an optical model to simulate the observed modulation. We use our optical model in conjunction with the MIRI spectroscopic data to show that the properties of the buried contact inside the MIRI Si:As detector have a significant effect on the fringing behavior.

EMCCDs are capable of operating in both a standard CCD mode with high dynamic range and a low-light mode with single photon sensitivity. Standard CCD mode benefits from maximizing the image area FWC, while in photon counting mode passing large signals through the EM register should be avoided. Here, we present customized clocking schemes that enhance the image area FWC of 2-phase EMCCDs by nearly a third. Serial clocking schemes are presented that provide a user configurable level of control over the register FWC for the CCD201. This dynamic control of serial FWC provides a convenient and powerful means to control the signal passing through the EM register at high at high gain values, limiting the size of cosmic ray “tails”, reducing background detector noise while also acting as a means of protection against device ageing.

High precision Doppler spectroscopy hinges on an accurate understanding of the wavelength-to-pixel mapping (wavelength solution) of the spectrograph, including particularly systematics related to the detector. Herein, we describe the uniformity and stability of the wavelength solution of the Habitable-zone Planet Finder (HPF), a near-infrared spectrograph that utilizes a Hawaii-2RG (H2RG) hybrid CMOS detector. We focus on time-varying discontinuities equivalent to approximately 10 m/s in the otherwise-smooth wavelength solution, corresponding to the boundaries between H2RG readout channels. This behavior is revealed by calibration with dedicated laser frequency comb and white light-illuminated Fabry-Perot systems over a ~1 year baseline. These findings will inform the usage of similar near-infrared CMOS devices for high-precision applications including Doppler exoplanet and gravitational lensing WFIRST surveys.

Electron Multiplying Charge Coupled Devices, EMCCD are used as x-ray detectors. The NSLS-II Soft Inelastic x- ray Scattering (SIX) beam line uses two EMCCDs for x-ray detection. Electrons drift and diffuse from generation point toward pixel gates and are collected there. The diffused electrons form a charge cloud distributed over several neighboring pixels. This charge sharing enables coordinate measurements with accuracy better than the pixel pitch. The charge distribution shape has to be taken into account to achieve ultimate accuracy in coordinate measurements. In this paper, we present a method of the charge distribution shape analysis and demonstrate its applications. The number of electrons collected under a pixel is proportional to the shape function integral. These electron packets get transferred to the sense node of the output amplifier. The transfer process could introduce distortions to the original charge distribution. For example, during transfers, electrons in the packet could be exposed to traps if they are present in the sensor. The trapping and later the release processes distort the apparent shape of the charge distribution. Therefore, deviations of the charge distribution shape from the originally symmetrical form can indicate the presence of trap centers in the sensor and can be used for sensor diagnostics.

The Euclid mission aims to image the far galaxies of our universe to better understand and characterise the structure of dark matter and energy. This galactic survey requires highly accurate images to document the effects of dark matter via weak lensing on the shapes of galaxies. Over the course of the mission, radiation damage to the CCDs will cause an increase in detector Charge Transfer Inefficiency (CTI) reducing the accuracy of measurements [2]. To analyse this, we undertook a long-term study on the evolution of CTI on the CCDs in the Euclid VIS focal plane, after a cryogenic irradiation campaign at 153 K. Following the irradiation, the device has been monitored for 12 months of operation under mission representative conditions. We present the CTI evolution as measured by Extended Pixel Edge Response (EPER) over this time.

The scientific detector systems for the ESO ELT first-light instruments, HARMONI, MICADO, and METIS, together will require 27 science detectors: seventeen 2.5 μm cutoff H4RG-15 detectors, four 4K x 4K 231-84 CCDs, five 5.3 μm cutoff H2RG detectors, and one 13.5 μm cutoff GEOSNAP detector. This challenging program of scientific detector system development covers everything from designing and producing state-of-the-art detector control and readout electronics, to developing new detector characterization techniques in the lab, to performance modeling and final system verification. We report briefly on the current design of these detector systems and developments underway to meet the challenging scientific performance goals of the ELT instruments.

The timing-based localization, which utilize the triangulation principle with the different arrival time of gammaray photons, with a fleet of Cubesats is a unique and powerful solution for the future all-sky gamma-ray observation, which is a key for identification of the electromagnetic counterpart of the gravitational wave sources. The Cubesats Applied for MEasuring and Localising Transients (CAMELOT) mission is now being promoted by the Hungarian and Japanese collaboration with a basic concept of the nine Cubesats constellations in low earth orbit. The simulation framework for estimation of the localization capability has been developed including orbital parameters, an algorithm to estimate the expected observed profile of gamma-ray photons, finding the peak of the cross-correlation function, and a statistical method to find a best-fit position and its uncertainty. It is revealed that a degree-scale localization uncertainty can be achieved by the CAMELOT mission concept for bright short gamma-ray bursts, which could be covered by future large field of view ground-based telescopes. The new approach utilizing machine-learning approach is also investigated to make the procedure automated for the future large scale constellations. The trained neural network with 10⁶ simulated light curves generated by the artificial short burst templates successfully predicts the time-delay of the real light curve and achieves a comparable performance to the cross-correlation algorithm with full automated procedures.

The Wide Field Survey Telescope (WFST) is being developed by University of Science and Technology of China and Purple Mountain Observatory. The camera of WFST is proposed to image with a mosaic Charge-coupled devices (CCD) array, which consists of 9 CCD290-99 detectors. It has requirements of decreasing the size and reducing total power dissipation for electronics system. Considering the demands of CCD290-99, two chips Application-specified Integrated Circuits (ASIC) were designed, called Second Version of Bias-Clock-Driver ASIC (BCDA2) and Second Version of CCDVideo- Readout ASIC(CVRA2) respectively. These chips have been upgraded and optimized based on the BCDA and CVRA. BCDA2 provides multi-channel clocks and biases to drive CCD290-99 and CVRA2 is used for the readout circuits of CCD signal processing. BCDA2 integrates 5 channels low noise biases with adjustable voltage and 9 channels low power dissipation clocks with adjustable driving capability. CVRA2 integrates 4 channels low noise readout circuits. Serial Peripheral Interface (SPI) was designed for configuration of BCDA2. BCDA2 and CVRA2 were designed with the Global Foundries 180 nm BCDlite technology. The area of bare chip is 3.1mm × 6mm.

We characterized the S14160-3050HS Multi-Pixel Photon Counter (MPPC), a high efficiency, single channel silicon photomultiplier manufactured by Hamamatsu Photonics K.K. All measurements were performed at a room temperature of (23.0 ± 0.3)°C. We obtained an I-V curve and used relative derivatives to find a breakdown voltage of 38.88 V. At a 3 V over voltage, we find a dark count rate of 1.08 MHz, crosstalk probability of 21 %, photon detection efficiency of 55 % at 450 nm, and saturation at 1.0x10¹¹ photons per second. The S14160- 3050HS MPPC is a candidate detector for the Ultra-Fast Astronomy (UFA) telescope which will characterize the optical (320 nm - 650 nm) sky in the millisecond to sub-microsecond timescales using two photon counting arrays operated in coincidence on the 0.7 meter Nazarbayev University Transient Telescope at the Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) located near Almaty, Kazakhstan. We discuss advantages and disadvantages of using the S14160-3050HS MPPC for the UFA telescope and future ground-based telescopes in sub-second time domain astrophysics.

X-ray Charge Coupled Devices (CCDs) have been the workhorse for soft X-ray astronomical instruments for the past quarter century. They provide broad energy response, extremely low electronic read noise, and good energy resolution in soft X-rays. These properties, along with the large arrays and small pixel sizes available with modern-day CCDs, make them a potential candidate for next generation astronomical X-ray missions equipped with large collecting areas, high angular resolutions and wide fields of view, enabling observation of the faint, diffuse and high redshift X-ray universe. However, such high collecting area (about 30 times Chandra) requires these detectors to have an order of magnitude faster readout than current CCDs to avoid saturation and pile up effects. In this context, Stanford University and MIT have initiated the development of fast readout X-ray cameras. As a tool for this development, we have designed a fast readout, low noise electronics board (intended to work at a 5 Megapixel per second data rate) coupled with an STA Archon controller to readout a 512 512 CCD (from MIT Lincoln Laboratory). This versatile setup allows us to study a number of parameters and operation conditions including the option for digital shaping. In this paper, we describe the characterization test stand, the concept and development of the readout electronics, and simulation results. We also report the first measurements of read noise, energy resolution and other parameters from this set up. While this is very much a prototype, we plan to use larger, multi-node CCD devices in the future with dedicated ASIC readout systems to enable faster, parallel readout of the CCDs.

Recent astronomical discoveries of temporally varying objects can be attributed to advances in detection systems for High Time Resolution Astrophysics (HTRA). We present our lab results including the use of analog memories to save bursts of data at subnanosecond resolution. We identify the most efficient detection systems for discovering astrophysical objects with time variability on the order of 1 microsecond to 1 nanosecond. A ground based architecture utilizes an SiPM detection system. For space, vacuum tube photocathode detectors are used to mitigate the effects of space radiation while an analog memory readout system is used to reduce SWaP.

Using the high-resolution OLED screen of a smartphone to project arbitrary scenes and patterns can open a complete new dimension for testing sensors in the visible. Based on an original concept from JPL (Jet Propulsion Laboratory), this contribution describes a new experimental setup designed to achieve the demanding performance of its first application by ESA (European Space Agency): the evaluation of radiation-induced CTI (Charge Transfer Inefficiency) on Euclid’s weak lensing measurement. We show that pushed to its limits especially in terms of calibration such a simple experiment can deliver a level of optical performance high enough to be applied in the verification of high-precision astronomy instrument performance.

The High Definition X-ray Imager (HDXI) for the proposed Lynx X-ray Observatory will require much larger (16 Mpixel) and faster (around 100 fps) imaging detectors than have been developed to date. One engineering solution to meet these requirements is to combine substantial parallelization with fast readout speeds. Stanford University and MIT are collaborating in the development of such detectors. The work involves the design of a new ASIC, the MIT CCD Readout Chip MCRC-V1, developed to read out MIT Lincoln Laboratory CCDs using MOSFET or JFET outputs. The architecture of the MCRC-V1 involves eight low-noise, fully differential amplifiers, each coupled to a fully differential output driver to support waveform sampling with a commercial ADC. The chip also includes an experimental current readout capability to support fixed-bias potential operation of single-electron sensitive readout (SiSeRo) CCD output stages. We will present both the readout concept and circuit details for the MCRC-V1 ASIC.

We present a new development for the measurement of the Quantum Efficiency (QE) of a Mercury Cadmium Telluride (HgCdTe or MCT) detector array in the long wave infrared (LWIR) spectral band. To measure the incident photon flux on the detector, CEA-LETI has designed and produced a calibrated MCT photodiode which, under the test setup conditions used for the QE measurement, delivers a total (dark plus photonic) current of 1nA at 60K. The readout of such a low level of current makes a standard room temperature amplifier inconvenient due to the length of the wires between the focal plane (FP) at cold and the outside of the cryostat (>2m in the current cryostat). A much better approach is to use High Electron Mobility Transistors (Cryo-HEMTs), optimized by CNRS/C2N laboratory for ultra-low noise at very low temperatures (<1K). We have developed a Cryo-HEMT-based transimpedance amplifier to readout the photonic current of the calibrated MCT chip. The paper describes the calibrated photodiode, the Cryo-HEMT amplifier and the test setup, and shows the results of the QE measurements of the LWIR detector.

The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload achieved its third successful flight on September 7, 2018. FOXSI uses glancing-incidence Wolter-I mirrors combined with fine-pitch Si and CdTe detectors to perform direct solar Hard X-Ray (HXR) imaging spectroscopy. For FOXSI’s latest flight, several upgrades were made to the instrument, including updating the optics and detectors as well as adding new honeycomb type collimators to reduce Ghost rays background. We provide an overview of these updates as well as a discussion of their measured performance.

As the precision frontier of large-area survey astrophysics advances towards the one millimagnitude level, flux calibration of astronomical instrumentation remains an ongoing challenge. We describe initial testing of silicon solar cells as large-aperture precise calibration photo- diodes. We present measurements of dark current, linearity, frequency response, spatial response uniformity, and noise characteristics of the Sunpower C60 solar cells, an interdigitated back-contact 125mm x 125mm monocrystalline solar cell. We find that these devices may hold promise as large-area flux calibration sensors, and that further analyses over a broader range of operating conditions are necessary. Flux calibration remains a primary source of systematic uncertainty in the use of type Ia supernovae (SNe Ia) as probes of the history of cosmic expansion [1, 2, 3, 4]. The wavelength-dependent throughput of the observing instrument is the most immediately accessible and separable contribution to this systematic error. One approach for flux calibration is to invoke models of photon emission spectra vs. wavelength for a simple stellar atmosphere, white dwarf stars being the most popular [5]. This calibration method includes contributions from the instrument throughput, but is also affected by uncertainties in Galactic and atmospheric extinction, and other systematic effects. A supplemental approach that isolates the instrument throughput is to use well-characterized sensors as the metrology standard for relative flux determination [6, 7, 8, 9, 10]. In this approach a well-calibrated photodetector, known to better than a part per thousand, [11] is used to map out the instrument’s relative sensitivity vs. wavelength. Conventional photon- detectors (photodiodes, CCDs, etc) have collection areas no larger than a few square centimeters. Such small collection areas are inadequate for some mod- ern imaging applications that depend on the calibration of a large-diameter optical beam. The Large Synoptic Survey Telescope [12] (LSST) project intends to use a collimated, monochromatic beam (a Collimated Beam Projector, or CBP), to sequentially illuminate portions of the optics, and a calibrated silicon photodiode to monitor the flux [13, 14]. The LSST team plans to use the CBP to measure instrument transmission as a function of photon wavelength and source position. One metrology challenge of this approach is to measure the flux emanating from the CBP, which has an exit pupil diameter of 240 mm, about twenty times larger than the diameter of typical silicon photodiodes. The LSST team is considering several solutions to this unsolved problem, including changing the projector beam focus to reduce the spot size, collecting the light with a focusing concentrator, using an integrating sphere with a 250mm port, or scanning the exit beam across one or more standard calibrated photodiodes. Each of these approaches, all suboptimal, are born of a perceived need to measure a large light source with a small detector. In this paper we consider the possibility of using an array of high-efficiency solar cells as a full-aperture sensor for calibrating the LSST CBP and other large-diameter internal calibration light sources. In Section 1, we describe the general architecture of an interdigitated back-contact monocrystalline silicon solar cell and introduce the C60 solar cells that we study. In Section 2, we describe the methods and results of our measurements. We conclude in Section 3, where we summarize the results of our experiments and discuss what additional steps should be taken to fully assess the prospect of creating a precision photometric calibrator composed of solar cells.

The LSST project (Large Survey for Space and Time), Vera Rubin Observatory is designed to observe the deep and wide Universe addressing the questions about dark matter as well as the near Universe with the study of the Milky Way. These observations are conducted by a high-resolution camera, which is made up of 189 4k×4k CCD sensors observing from the UV to the near-infrared. Some sensors supplied by ITL (Imaging Technology Laboratory), present a layer of cleaning residue or non-stoichiometric oxidized silicon adhering the surface after etching and create some non-uniformity in backside charging and irregularities inducing a variation of counting in UV and imprecise photometry. In this paper, we will present the camera and the particularities of the ITL sensors, then, the impact of this layer on the performances of the sensors and finally on the observed astronomical object.

The Single Pixel Feed Receiver (SPFRx) is a Sub-Element of the Square Kilometer Array (SKA) Dish Element. Its main function is receiving RF signals captured by the SKA-mid Dish (DSH) and pre-amplified by the Single Pixel Feed (SPF) Sub-Element components. The main tasks of the SPFRx hardware, firmware, and software is to perform analog to digital conversion on the incoming RF signals and to send the digital RF samples to the SKA Central Signal Processing (CSP) Element as 100G Ethernet packets. For analog to digital conversion, of SKA-mid Bands 1-3 a 12-bit Analog to Digital Converter (ADC) is used. The ADC and its supporting electronics reside on an electronic board placed within a metal box on the telescope’s indexer. A number of measures are taken to minimize Radio Frequency Interference (RFI) created by the switching elements on the board. One of the major measures is using an optical link for performing monitor and control function of the internal electronics by the Local Monitor Control (LMC) module residing within the telescope’s base.

In the search for exoplanets, the TESS mission shifts much of the focus in transit detection towards observing nearby cool stars.¹ Many of the M-dwarf systems identified can be followed up from the ground with meter class telescopes or smaller to confirm the presence of rocky planets.^{2, 3} However, while space-based missions can easily justify the expensive mercury cadmium telluride (HgCdTe) detectors that perform well at the emission peaks of M-dwarfs, ground based searches at small facilities with modest budget need an alternative.4 Deep depletion charged-coupled devices (CCDs) are commercially available, but do not have good sensitivity beyond 1000 nm. Commercial off the shelf (COTS) indium gallium arsenide (InGaAs) detectors offer an alternative, but work needs to be done to characterise them, and adapt them to astronomical use. Towards this effort, we code automation software in Python for a commercially available unit and test the performance for typical use in astronomical instruments. We also integrate a unit into a spectroscopy instrument and demonstrate it on sky at near-infrared (NIR) ranges.

PANIC¹ , the PAnoramic Near-Infrared Camera for the Calar Alto Observatory in Spain, was successfully commissioned in late 2014 with a mosaic of four 2K x 2K HAWAII-2RG arrays covering a field of view of approximately 30 arcmin at the 2.2 m telescope. Unfortunately, two of its science detectors suffered from extreme degradation² along the years of operation making the instrument unsuitable for science observations. In the light of new technologies and constant innovations, it was decided to upgrade the instrument with a monolithic state of the art 4K x 4K HAWAII-4RG array. With as minimum mechanical and optical impact as possible for the instrument, the MPIA is the responsible institute for the challenging upgrade. Besides presenting the results of the initial operation of the HAWAII-4RG array in 64-Channel mode, the newly in-house designed detector mount will also be highlighted. In order to take as much advantage as possible of the new detector readout capabilities, and thanks to the modularity and flexibility of the in-house readout electronics, all 64 channels of the detector are read out in parallel. This allows for shorter integration times, which is very advantageous for a wide field imager with high background conditions.

The focal planes of X-ray astronomy missions are at risk of particulate impacts from both micrometeoroids and orbital debris due to the open aperture of the narrow-angle incidence optics. Silicon micro-pore optics (MPOs) have seen significant development due to their wide-angle observing capabilities and are planned for use in future X-ray instruments such as SMILE and THESEUS. Although previous missions have seen sporadic events in detectors which are attributed to particulate impacts, the number of particulates that can traverse the new micro-pore optics and affect detector performance is not currently known. By using relevant micrometeoroid and orbital debris models, the number of particulates incident on the optics over the course of both missions can be predicted. The transmission rate of particulates through the MPOs has been calculated using a bespoke Monte Carlo simulation, based upon the method of ray-tracing with known physical mechanisms such as low angle scattering incorporated. For validity, an analytical solution is derived, which shows good agreement with the Monte Carlo simulation. Using the incident flux on the optics and the simulated mirror transmission rates, the probability of a focal plane impact can be estimated. This work, in combination with experimental micrometeoroid impact campaigns, aims to predict the overall detector performance loss as a result of the micrometeoroid environment for both the SMILE and THESEUS missions.

We report on the impact of proton and gamma irradiation on an MCT detector. The main result is the proton irradiation prevents the increase of the dark current due to the later total ionizing dose.

We present the InGaAs detector system of the Wide-Field Infrared Transient Explorer (WINTER), a new infrared instrument operating on a 1 meter robotic telescope at the Palomar Observatory. These commercially produced sensors are cooled to -50 °C by a thermo-electric cooler integrated into a room temperature package. These warm InGaAs sensors represent a dramatic reduction in cost and complexity over HgCdTe systems and achieve sky background-limited performance across our science bands for exposures greater than a few seconds. We present the design and implementation of the WINTER detector system and readout electronics.

We report the testing results of the Teledyne e2v CIS 113 CMOS sensor at temperatures from room temperature down to 168K. The CIS 113 sensor is a customized device for the Transneptunian Automatic Occultation Survey (TAOS II) project. The sensor has 1920 × 4608, 16 μm pixels with 8 outputs. The pixels have a 5T design to provide anti-blooming capability with 18 μm thick high resistivity epitaxial silicon. The sensor provides two parallel and eight serial registers so the region of interests can be addressed and rapidly read out separately through different output channels. More than one thousand 8 × 8 star boxes can be sampled at a frame rate higher than 20 Hz. With a package similar to large format Teledyne e2v CCDs, the CIS 113 is three-side buttable. The device shows peak QE about 77% in 500-600 nm, readout noise around 3eand dark current lower than 2 e^-/s/pix at -40 ℃. The linear full well for the device is higher at lower temperature and it is about 14400 e^- at temperature lower than 210K. The device performance meets the science requirements with the operation temperature around 200K for TAOS II.

At DIAS, in collaboration with Trinity College Dublin, we are developing visible and near-infrared Microwave Kinetic Inductance Detectors (MKIDs) for astronomical applications. By designing an array of MKIDs with different resonant frequencies, an array of thousands of detectors can be readout with inherent frequency domain multiplexing (FDM). The Xilinx ZCU111 Radio Frequency System on Chip (RFSoC) Evaluation Kit is a very promising option not only for Microwave Kinetic Inductance Detector (MKID) readout systems, but also for any application relying on frequency domain multiplexing. The board's on-chip data converters provide ample bandwidth for reading out up to 8,000 MKID resonators, with 2 MHz spacing, at a 1 MHz pixel sampling rate. Without additional resources, we roughly estimate the ZCU111’s field programmable gate array (FPGA) can analyse ~ 4,000 MKID pixels, at a cost of about €4.75 per pixel. We present initial progress from developing firmware for this MKID readout system.

Cerium-doped Lanthanum Bromide [LaBr₃(Ce)] is a relatively newly developed inorganic scintillator with high performance for X/gamma-rays. It has high light yield, good energy resolution, and suitable time response for X/gamma- ray spectroscopy in comparison with NaI(Tl) conventionally used for spaceexperiments. Although NaI(Tl), especially using a cleaved surface forthe entrance window, was regarded as the most suitable scintillatorfor the spectroscopy of photons in the hard X-ray to gamma-ray band, a large amount of induced background from radio-activated iodinepolluted observed spectra, which were caused by charged particleirradiation in a high radiation region such as South Atlantic Anomalyin space experiments (e.g., Murakami et al. 1989). LaBr₃(Ce) could have comparable or even better performance toNaI(Tl). There is, however, very limited knowledge about radio-activated LaBr₃(Ce) estimated in a low-earth orbit. To verify the degradation of performance by high charged particle radiation field estimated in a low-earth orbit, we performed proton irradiation experiments using a synchrotron accelerator at TheWakasa Bay Energy Research Center. We performed irradiation experiments of LaBr₃(Ce) using proton beams with 20, 70, 140 MeV. The crystal has the size of 0.5 inch in diameter and a thickness of 0.5 inch; the thickness is the same as the gamma-ray burst detector flown after for the CALET experiment (Yamaoka et al. 2013). The measurement has been done to take gamma-ray spectra from the radio-activated LaBr3(Ce) crystal during the period from 7 minutes to 3.8 days after the proton irradiation. As a result, we detected 24 gamma-ray peak sand identified 19 nuclides by activation. We also found that the nuclides generated by the proton irradiation can be divided into two types; short-lived nuclides (half-life shorter than 24 hours) and long-lived nuclides (half- life longer than a day). From the results, we estimated that the background rate of LaBr₃(Ce) in a low-earth orbitexpected for such as the International Space Station was several counts per second, which was smaller than that for Cosmic X-ray background from an opening angle of about a pi steradian. The contamination suffered from radio-activation of LaBr₃(Ce) crystal was sufficiently small for spectroscopy with a large field-of-view taken forsuch as gamma-ray transient observations.

The Antarctic Plateau is one of the best places for infrared and submillimeter observations in the world, which has the advantages of high altitude, low water vapor and low atmospheric thermal radiation. It is indispensable for the design of instruments to know the environment of the observatory site in advance, especially the infrared sky background brightness. It determines the ultimate magnitude of infrared observation of the equipment, which is an important reference to evaluate whether a candidate site is suitable for constructing corresponding equipment. We have designed a NIR sky brightness monitor (NISBM) based on InGaAs photodiode, which is used to monitor the J, H and Ks bands of sky background brightness at the Dome A. In the Ks band the signal is sensitive to thermal radiation and temperature fluctuations. So, it needs to be calibrated in real time by a surface source blackbody. According to this requirement, we have designed a surface source blackbody that has the property of low temperature resistance, high emissivity, and high temperature uniformity. The device has a compact structure. The control system and the radiation surface are packaged in the same square house, which is suitable for outfield installation and calibration with low ambient temperature.

The Wide Field Survey Telescope (WFST) is a proposed 2.5m-aperture wide field survey telescope intended for dedicated wide field sciences in China. The focal-plane instrument is a mosaic CCD camera comprising 9 pieces of 9K×9K pixels CCD chips. In order to verify the WFST mosaic solution, we designed a 2×2 mosaic camera test system using CCD303- 88. The mechanical design of vacuum chamber, cryogenic refrigeration of CCD, mosaic CCD technique and multi CCD control electronic have been implemented on this system. We design a CCD controller capable of controlling two pieces of CCDs and a power supply module for the controller. The cryogenic refrigeration control is implemented with a refrigerator and temperature control electronics.

In this paper, we present our concept of an on-the-fly image processing pipeline for ground-based telescopes. Our focus lies on the correction of undesired but unavoidable detector effects like persistence. State of the art systems like ESO’s NGC perform operation of detectors and acquisition of science data. Instrument operators monitor the science data stream during measurement. Detector issues like persistence worsen the image quality and impair the inspection tasks. To overcome these difficulties, we develop the real-time data processing system EIDAS (Enhanced Infrared Detector Acquisition System) as an add-on to the NGC. Therewith, detector effects in the raw image stream are corrected on-the-fly and astronomical objects are visualized more clearly for direct inspections. EIDAS accompanies CPU, FPGA and GPU as well as algorithms optimized for this hardware architecture. The system is designed generically, matching various types of detectors and their respective science data output

Many specs of scientific CMOS cameras characterize the performance of camera, which can help developers analyze the quality of cameras. In order to test the performance of sCMOS cameras, we designed and built a test platform for performance test of sCMOS cameras which has been developed. The test platform includes a group of test devices and a automatic test software system. The software system is designed based on remote controllable WEB technology and EPICS-based real-time control framework, making the test platform flexible and convenient. According to the features of sCMOS camera, in the test platform four test procedures are designed to test various specs of sCMOS camera, including FPN test, dark current test, gain, noise, linear error, full well capacity test and dead pixel test. Users can perform automatic tests on camera through web UI, including the control of test platform device, data acquisition and data processing. At the same time, the test platform also provides users with various functions such as test data query and test report generation.

Microwave Kinetic Inductance Detector (MKID) arrays are currently being developed and deployed for astronomical applications in the visible and near infrared and for sub-millimetre astronomy. One of the main challenges of MKIDs is that large arrays would exhibit a pixel yield, defined as the percentage of individually distinguishable pixels to the total number of pixels, of 75 80 %.¹ Imperfections arising during the fabrication can induce an uncontrolled shift in the resonance frequency of individual resonators which end up resonating at the same frequency of a different resonator. This makes a number of pixels indistinguishable and therefore unusable for imaging. This paper proposes an approach to individually re-tune the colliding resonators in order to remove the degeneracy and increase the number of MKIDs with unique resonant frequencies. The frequency re-tuning is achieved through a DC bias of the resonator since the kinetic inductance of a superconducting thin film is current dependent and its dependence is non linear. Even though this approach has been already proposed,² our innovative pixel design may solve two issues previously described in literature such as non-negligible electromagnetic losses to the DC bias line, and the multiplexibility of multiple resonators on a single feed-line.

In recent years, CCD-in-CMOS TDI image sensors are becoming increasingly popular for many small satellite missions to assure a fast and affordable access to space for Low Earth Observation. Our monolithic CCD-inCMOS TDI imager features a specifically developed technology which combines the benefits of a classical CCD TDI with the advantages of CMOS System-On-a-Chip (SoC) design. Like CCD, this detector is also controlled by a large number of clock voltages. Optimizing these voltages allows to increase the performance of the detector by improving multiple characteristic parameters, such as full well capacity (FWC), dark current, linearity, dark signal non-uniformity (DSNU) and charge transfer efficiency (CTE). Traditionally, it has been the standard practice to adjust the CCD voltages by trial and error methods to get a better image. Because of the large parameter space, such subjective procedures may yield far from the optimum performance. This paper reports a design of experiments (DOE) technique applied on the clock voltages to improve the multiple performance parameters of the detector. This method utilizes the Taguchi’s orthogonal arrays of experiments to reduce the number of experiments with different voltage combinations. Finally, optimal combination of clock voltages is obtained by converting the multiple performance parameters of the detector into a single Grey relational grade. In this process, the sequences of obtaining parameter values are categorized according to the performance characteristics. The condition Higher-the-better is used for parameters like FWC and CTE whereas condition Lower-the-better is applied for parameters, such as dark current, linearity error and DSNU.

CEA and Lynred develop very large focal plane arrays (FPA) in the short wave infrared range (SWIR) with ultra-low dark current for space and astronomy applications. The structure of such arrays is based on a HgCdTe sensitive layer flipchipped onto a Si ROIC. This ROIC is based on a source follower per detector input and output stage giving access to very high gains for very low flux (below 1ph/s) and very low noise (11.5e-) measurements. However, during previous characterisations, these FPAs appeared particularly sensitive to electro-luminescence emitted by ROIC source follower output stage transistors in the saturation regime. Indeed, the emitted photons are in the sensitive wavelength range of the HgCdTe layer (2.1 μm cut-off). They are then collected by the photodiodes thus degrading the measured dark current. This phenomenon, called ROIC glow, is the limiting mechanism of dark current at low temperature for such arrays. We describe here a solution to reduce to ground level this ROIC glow. MOSFET drain to source voltage is a major parameter for limiting glow and our results show good agreement with hot electrons light emission models. Transfer function characterisation of the ROIC was also performed to highlight the limits of the proposed procedure, which is that the source follower MOSFETs must stay in the saturated regime. Measurements carried out on different characterisation benches and several detectors at CEA-LETI and CEA-DAP show dark currents below 0.03e/s/pixel after glow mitigation.

ASTRONIRCAM is an infrared camera-spectrograph installed at the 2.5-meter telescope of the CMO SAI. The instrument is equipped with the HAWAII-2RG array. A bad pixels classification of the ASTRONIRCAM detector is proposed. The classification is based on histograms of the difference of consecutive non-destructive readouts of a flat field. Bad pixels are classified into 5 groups: hot (saturated on the first readout), warm (the signal accumulation rate is above the mean value by more than 5 standard deviations), cold (the rate is under the mean value by more than 5 standard deviations), dead (no signal accumulation), and inverse (having a negative signal accumulation in the first readouts). Normal pixels of the ASTRONIRCAM detector account for 99.6% of the total. We investigated the dependence between the amount of bad pixels and the number of cooldown cycles of the instrument. While hot pixels remain the same, the bad pixels of other types may migrate between groups. The number of pixels in each group stays roughly constant. We found that the mean and variance of the bad pixels amount in each group and the transitions between groups do not differ noticeably between normal or slow cooldowns.

The Nancy Grace Roman Space Telescope (Roman) formerly known as the Wide-Field Infrared Survey Telescope will answer fundamental questions about the evolution of dark energy over time and expand the catalog of known exoplanets into new regions of parameter space. Using a Hubble-sized mirror and 18 newly developed HgCdTe 4K × 4K photodiode arrays (H4RG-10), the Roman Space Telescope will measure the positions and shapes of hundreds of millions of galaxies, the light curves of thousands of supernovae, and the microlensing signals of over a thousand exoplanets toward the bulge of the Galaxy. These measurements require unprecedented sensitivity and characterization of the Wide Field Instrument, particularly its detectors. The Roman project undertook an extensive detector development program to create focal plane arrays that meet these science requirements. We present the performance characteristics of these TRL-6 demonstration devices.

The depletion region around each p-n junction in HgCdTe HAWAII-2RG detector arrays decreases in volume as charge is collected, causing the pixel capacitance to change continuously throughout an integration period. This changing capacitance manifests as a steadily decreasing measured signal rate while observing a constant flux. Ignoring this nonlinear response to signal accumulation can lead to underestimating the number of detected pho- tons by as much as 10%. Presented here are two methods, one simple and one complex, of measuring this signal nonlinearity and a theoretical framework behind a nonlinearity correction method. Additionally, experimental data are compared with simulations to explain methods to reduce noise in the nonlinearity measurement and identify deviations from the expected behavior that merit further study.

NRC has been involved in the ongoing development of the SAPHIRA infrared APD arrays from Leonardo MW. We present results from our characterization testing on the original 320x256 pixel device, including response speed at frame rates up to 1 kHz. We have also been working on the support electronics, including cryogenic preamplifiers and a readout system that is capable of operating a new 512x512 pixel, 64-output SAPHIRA device at 10 Mpx/s.

We developed an X-ray imaging spectrometer with a high timing resolution. CMOS image sensors, widely used in optical imaging, have an excellent time resolution with considerably low readout noise. We performed experiments using a Zyla CMOS image sensor manufactured by Andor Technology pic. (UK). It employs a front illuminated(FI) scientific CMOS (sCMOS) with each pixel size of 6.5×6.5μm². We found that nearly all X-ray events spread more than 5×5 pixels and obtained good energy resolution of 260 eV at 5.9 keV at room temperature. The spectrum shows no degradation at lower energy, which imply that there is negligibly small charge loss. We report photon counting performance for a broad range of X-rays from 3-25keV at room temperature.

Electro-optical testing and characterization of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) Camera focal plane, consisting of 205 charge-coupled devices (CCDs) arranged into 21 stand-alone Raft Tower Modules (RTMs) and 4 Corner Raft Tower Modules (CRTMs), is currently being performed at the SLAC National Accelerator Laboratory. Testing of the camera sensors is performed using a set of custom-built optical projectors, designed to illuminate the full focal plane or specific regions of the focal plane with a series of light illumination patterns: the crosstalk projector, the flat illuminator projector, and the spot grid projector. In addition to measurements of crosstalk, linearity and full well, the ability to project realistically-sized sources, using the spot grid projector, makes possible unique measurements of instrumental signatures such as deferred charge distortions, astrometric shifts due to sensor effects, and the brighter-fatter effect, prior to camera first light. Here we present the optical projector designs and usage, the electro-optical measurements and how these results have been used in testing and improving the LSST Camera instrumental signature removal algorithms.

The Panoramic SETI (Search for Extraterrestrial Intelligence) experiment (PANOSETI) aims to detect and quantify optical transients from nanosecond to second precision over a large field-of-view (∼4,450 square-degrees). To meet these challenging timing and wide-field requirements, the PANOSETI experiment will use two assemblies of ∼45 telescopes to reject spurious signals by coincidence detection, each one comprising custom-made fast photon-counting hardware combined with (f/1.32) focusing optics. Preliminary on-sky results from pairs of PANOSETI prototype telescopes (100 sq.deg.) are presented in terms of instrument performance and false alarm rates. We found that a separation of >1 km between telescopes surveying the same field-of-view significantly reduces the number of false positives due to nearby sources (e.g., Cherenkov showers) in comparison to a side- by-side configuration of telescopes. Design considerations on the all-sky PANOSETI instrument and expected field-of-views are reported.

The brighter-fatter effect is a well known phenomenon in thick, back illuminated CCDs, causing asymmetric increase in the observed size of point sources via correlated charge collection with higher signal levels. Over recent years, the effect of various operating parameters (such as the back bias applied) on the size of measured correlations has been well established. Less well studied is the consequence of changing the effective collection gate width of the CCD, which is of limited accessibility to experiment though several values are available in 3 or 4 phase devices. In this proceeding we present collection gate width experiments using both flat field and spot projection illuminations on a thick back illuminated device as used for the LSST project. We report on the size of the variation of measured correlations with gate width as compared with backside bias voltage, and find that gate width constitutes a small but significant contribution. In light of these results, we give comment on device optimisation when minimising correlated charge collection effects is desired.

We present our laboratory tests of a commercial near-infrared camera, the C-RED One, which was built by First Light Imaging. The camera uses a high-speed, low-noise, HgCdTe avalanche photo-diode (APD) array from Leonardo. We used the photon transfer technique to measure the gain and read noise. In early 2019, we identified the source of a fluctuating sensor bias, which limited the noise performance of the camera. We also measured the effect of the cryo-cooler on vibration of the array, which limited its performance as a tilt sensor. We sent the camera back to the FLI, where they installed a redesigned power-supply board to address the issue with the fluctuating sensor bias. FLI also installed passive damping to reduce the vibration of the sensor array. Here we present the performance characteristics of the camera before and after the repair of the camera by the manufacturer.

The Teledyne HxRG detectors have versatile and programmable output options to allow operation of them in a variety of configurations such as slow unbuffered, slow buffered, fast buffered or unbuffered modes to optimise the detector performance for a given application. Normally at ESO, for low noise operation, the detectors are operated in slow unbuffered mode. Whilst the slow unbuffered mode offers a simple interface to the external preamplifier electronics, the detector operation in this mode can suffer from reduced pixel frequency response and higher electrical crosstalk between the readout channels. In the context of the detector systems required for the first generation instruments of the ELT (MICADO, HARMONI and METIS), an exercise was undertaken to evaluate the noise, speed and crosstalk performance of the detectors in the slow buffered mode. A test preamplifier has been designed with options to operate a H2RG detector in buffered or unbuffered and with or without using the reference output, so a direct performance comparison can be made between different modes. This paper presents the performance advantages such as increased pixel frequency response, elimination of electrical crosstalk between the readout channels and the noise performance in the buffered mode operation. These improvements allow us to achieve the same frame readout time using half the detector cryogenic electronics and detector controller electronics for the ELT instruments, which significantly reduces the associated cryomechanical complexities in the instrument.

The infrared astronomy is a very important branch of astronomy. Imaging observation is the basic approach to conduct infrared astronomy observation. Therefore, infrared Focus Plane Array (FPA) detector is needed for an infrared telescope. Detection toward celestial body need the detector to have high performance like extremely low dark current and low readout noise. Therefore, we designed a test equipment based on a 640 × 512 InGaAs array detector with a cryocooler which can cool the detector down to 77K. The detector is InGaAs of SITP-Hu-I type which is sensitive to 0.9us ~ 1.7um band. The test equipment is composed of a vacuum cryocooling system, a mechanical system and an electronical system. The vacuum cryocooling system can provide a low-temperature vacuum environment for the detector, and the mechanical system provides firm supporting. The electronic system provides the driver and readout of the detector.