This PDF file contains the front matter associated with SPIE Proceedings Volume 6703, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

The transient evolution of X-ray emission from high density plasmas usually terminates with a recombination regime at low density. For matter irradiated by short pulses (< 1 ps) the accumulation of x-ray emission at low density cannot be suppressed by streak camera techniques as current time resolution is limited (> 0.5 ps). We propose intrinsically fast x-ray signals realized by the radiation emission from hollow ion states K⁰Lⁿ to temporally isolate high density information from the low density radiative recombination regime. Simulations carried out for short pulse (100 fs) intense x-ray free electron laser radiation (XFEL) interacting with dense plasmas demonstrate that the hollow ion x-ray emission "switch" has a time scale faster than 50 fs. Moreover, the time of the hollow-ion emission signal is related to the interaction time and is thus directly related only to the highest density regimes even if the usual time integrated spectroscopic techniques are employed.

LASERIX is a high power laser facility intended to realise and use for applications transient collisional excitation (TCE) X-ray lasers (XRLs) at various wavelengths, using grazing incidence pumping (GRIP) configuration with 10 Hz repetition rate. In addition new types of XRL schemes giving rise to emission at short wavelengths will be developed using the high energy LASERIX driver with 0.1 HZ rep-rate. Thus, this laser facility will both offer Soft X-ray lasers in the 40-10 nm range and synchronised auxiliary IR beam that could be also used to produce XUV sources. This experimental configuration highly enhances the scientific opportunities of the facility. Indeed it will be possible to realise both X-ray laser experiments and more generally pump/probe experiments, mixing IR and XUV sources. Then, this facility will be useful for the community, opening a large scale of investigations, including imagery and irradiation as illustrated in the case of laser Interaction with matter investigations using XUV interferometry.

A summary of recent developments of modern x-ray sources based on university-scale 1 MA z-pinch generators is given. Wire array z-pinches are a powerful x-ray source that was found during the last decade to be promising for inertial confinement fusion and radiation physics. Applications of novel and traditional wire-array configurations, such as X-pinches, planar and compact cylindrical wire arrays, to high energy density science are observed and analyzed. After a general introduction to wire array sources, new results are discussed along with numerous experiments.

Within a National Project on nanotechnologies, a Micro-Exposure Tool (MET) for projection lithography at 14.4 nm, based on a laser-produced plasma source, is being developed at the Frascati ENEA Center. The choice of this "exotic" wavelength is due to the higher efficiency of a Debris Mitigation System (DMS) working in the interval of approximately 14 nm < λ < 15 nm. It has to be noted that Mo/Si multilayer mirrors (MLM) can still have a high reflectivity also at these wavelengths. The solid-tape-target laser-generated plasma is driven by a XeCl excimer laser, with an optimized intensity of about 3•10¹⁰ W/cm², generating an extreme ultraviolet (EUV) source with a diameter of about 0.2 mm. Clearly, this kind of source emits a lot of debris (both atomic and particulate types) and the 7-cm-far collector mirror must be protected against them. The paper is mostly devoted to the accurate and systematic study of these debris and to their reduction. The results of mitigation efficiency obtained with a DMS prototype are very encouraging and lead to the design and patenting of its improved version.

We are developing a laser produced plasma light source for high volume manufacturing (HVM) EUV lithography. The light source is based on a short pulse, high power, high repetition rate CO₂ master oscillator power amplifier (MOPA) laser system and a Tin droplet target. A maximum conversion efficiency of 4.5% was measured for a CO₂ laser driven Sn plasma having a narrow spectrum at 13.5 nm. In addition, low debris generation was observed. The CO₂ MOPA laser system is based on commercial high power cw CO₂ lasers. We have achieved an average laser power of 7 kW at 100 kHz by a single laser beam with good beam quality. In a first step, a 50-W light source is under development. Based on a 10-kW CO₂ laser, this light source is scalable to more than 100 W EUV in-band power.

Dynamics of laser-produced Sn-based plasmas were investigated for a monochromatic EUV lithography (EUVL) source. A hollow plasma density in a Sn plasma driven by Nd:YAG laser was observed in the late time within the laser pulse. The possible reason comes from the distributed laser energy deposition in the expanding corona. This distributed absorption results in a temperature gradient in the corona and a broad EUV spectrum. It was shown that for CO₂ laser most of the laser energy deposition is localized around the critical density, a narrower EUV x-ray spectrum and a higher conversion efficiency from laser to monochromatic 13.5 nm EUV emission can be expected. It was found that 0.5% Sn-doped foam targets show an almost the same electron density as compared with that of solid density Sn targets. The same n_e enables efficient absorption of laser energy, and at the same time much lower Sn ion number density results in less re-absorption of the in-band 13.5 nm EUV emission induced by the plasma itself, so high CE can be expected with a low concentration of Sn.

Extreme ultraviolet lithography (EUVL) requires an emission of soft x-rays around a wavelength region of 13.5 nm. EHYBRID simulation was made under the laser operation at 1064 nm with a pulse duration of 6 ns. Intensity was changed between 1 x 10 ¹² W/cm² and 5 x 10 ¹² W/cm². Soft X-rays emitted from Sn XII and Sn XIII ions were simulated by using the EHYBRID code. Ion fractions of the tin ions and the line intensities for different electron temperatures were calculated by using the collisional radiative code NeF.

Results on micro- and nanoprocessing of organic polymers with extreme ultraviolet (EUV) radiation from a compact laser plasma EUV source based on a gas puff target are presented in the paper. Processing of polymers is connected with non-thermal ablation under the influence of energetic EUV photons. The process can be useful for practical applications as it makes possible to produce structures with sub-micron spatial resolution that is not possible using the thermal ablation. The new technology will be used for production of photonic microstructures and for modification of polymer surfaces for biomedical applications.

We present here a laser based time resolved ultrafast XANES beam line operating with the 100 Hz ALLS facility laser system (100 mJ and 35 fs at 800 nm wavelength). This system is based on a broadband soft x-ray plasma source, produced with a tantalum solid target, and a grazing flat field incidence grating designed to work in the 1-5 nm range. This femtosecond x-ray absorption spectroscopy experimental set up is used to study ultrafast phase transition in vanadium dioxide (VO₂). In this model system we are probing the electronic dynamics occurring during semiconductor to metal phase transition following excitation by a femtosecond laser pulse.

We report on the first experiments of high-order harmonic generation done with the 100 Hz high-energy optical parametric amplifier (OPA) of the Advanced Laser Light Source. Using krypton and argon as targets, we show that the OPA's signal beam − with a wavelength range from 1200 nm to 1600 nm, 1.3 mJ to 0.8 mJ of pulse energy and 100 fs pulse duration − can generate fully tunable XUV radiation down to a wavelength of 15 nm. We have also started to investigate the use of the OPA pulses for molecular imaging. Inducing molecular alignment with 800 nm, 70 fs pulses, we have measured the high harmonics spectra generated with 1300 nm pulses from nitrogen molecules oriented at various angles with respect to the ionizing field, in order to study for the first time the technique of molecular orbital tomography with a laser wavelength different than 800 nm.

We report on our high speed camera designed for temporal characterization of attosecond pulses (1as =10^-18s) generated with the polarization gating technique. The uniform external magnetic field applied on the time-of-flight spectrometer enlarges the acceptance angle (up to 65° for ~20-eV photoelectrons). By collecting two-dimensional momentum images of the photoelectrons, which are ejected by the XUV pulses and streaked directly by the co-propagating polarization gating electric field, we expect to derive the information about the XUV pulses. After the characterization of XUV pulses, the same setup can be used to study complex dynamics of electrons in atoms and molecules with time-resolved spectroscopy.

Polarization gated high harmonic generation in argon gas was phase matched to produce a single or double pulses with 10⁴ photons. It was accomplished by optimizing the argon gas pressure. The spectrum interference of the two pulses is affected by the carrier-envelope phase like in Young's experiments. The XUV flux is sufficient for measuring the single shot XUV spectrum in the 33eV-55eV photon energy range. The spectral profile was a super-continuum for some shots and showed discrete high harmonics peaks for other shots. The carrier-envelope phase of pulses from grating-based chirped pulse amplification was also varied smoothly to cover a 2π range by controlling the grating separation. It is demonstrated that XUV spectra measures both the absolute value of the phase and the stability of the phase by measuring the phase with an f-to-2f setup and by the variation of XUV spectra from polarization gated high harmonics generation.

The Advanced Laser Light Source (ALLS) infrastructure is a new state-of-the-art multi-beams femtosecond laser facility currently in operation at INRS near Montreal, Canada. The use of a wide range of energy radiation from hard x-ray up to infrared light on the ultrafast time scale requires the development of ultrafast detector diagnostics tools to study the emission spectrum of these sources. To fulfill these requirements, new streak cameras have been developed for ALLS facility. We present the new FXR streak camera which has been specifically developed for ALLS and which is dedicated to x-ray spectroscopy with sub-picosecond time resolution combined with a very high spatial resolution.

The Axis-Photonique PX1 fast X-ray streak camera records the temporal structure of events with picosecond accuracy. Using a potassium iodide photocathode the streak camera has been characterised for the effects of space charge. In a recent grazing incidence pumping X-ray laser experiment the streak camera was coupled to the output of a flat field spectrometer to observe first order diffraction. The second order was observed using a CCD camera. In this paper data is presented from this experiment comparing the brightness of the X-ray laser emission with the dispersion of the streaked image both temporally and spectrally (non temporal direction). Consequently measurements of the dynamic range of the streak camera are made. The results are compared with data from previous experiments.

We will discuss our attempts to measure of the absolute gain and its variation across the face of fast gated multichannel plate [MCP] detectors for 4.75 keV x-rays. We found that some of the gated strips had variations in the gain along and perpendicular to the direction of travel, and significant variation along the time axis that requires these calibrations to obtain the correct time history of gated events. We will also present some of the results on the linearity of such gain with input x-ray signal amplitude.

We have studied the current voltage and X-ray detection using front and back side processed, unintentionally doped bulk GaAs Schottky detectors. GaAs detectors with large enough thickness and low enough doping could be used for X-ray imaging, especially for medical applications. GaAs Schottky detectors were fabricated using front and back side photolithographic processing with Ti/Au for Schottky and Ge/Au/Ni/Au for Ohmic contacts. A number of detectors of size 2 mm² were tested. The breakdown voltage reached 600- 800 V in semi insulated (SI) GaAs Schottky front and back side processed detectors. For these detectors the dark current was found to be between 2- 90 nA. These detectors were also characterized with 150 keV, 3mA X-ray radiation and they responded well by showing more than a hundred fold increase in photocurrent due to production of electron hole pairs by the ionization processes. The processing of the detectors and the I-V and X-ray characterization is presented in this report.

An imaging Pixel Array Detector (PAD) is being developed to record x-ray scattering images from single particles at the SLAC Linac Coherent Light Source (LCLS) x-ray free electron laser. The LCLS will deliver x-ray pulses of 5-200 femtosecond duration 120 times per second. Proposed experiments require that the scatter from each pulse be independently recorded. This necessitates a detector with a charge integrating front-end because the high instantaneous arrival rate of photons (> 1000 photons per pixel in femtoseconds) exceeds the processing speed capabilities of digital counting detectors. Other capabilities of the PAD are a frame rate >120 Hz, a full-well depth in excess of 2000 8-keV photons, a detective quantum efficiency near unity, and the ability to readily differentiate between 0 and 1 photons per pixel. The detector will be a 4x4 array of subunit tiles. Each tile consists of two silicon chips solder-bump bonded together. A pixelated 500 micron thick, fully depleted silicon chip converts x-ray energy into charge carriers. The charge created is conveyed by solder connecting bumps to a CMOS ASIC in which each pixel has its own signal processing electronics. Each tile has ~190 x 190 pixels, resulting in a detector of > 760 x 760 pixels. Tests of prototype 16x16 readout pixel arrays show a read noise equivalent to 0.14 8-keV photons. Features of the detector include an in-pixel parallel 14-bit digitization scheme, and the capability to be configured with an adaptable, 2-level, 2D gain profile. The development of the read-out electronics and the effects of tiling on dead area are also discussed.