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Proceedings Paper

An efficient, FPGA-based, cluster detection algorithm implementation for a strip detector readout system in a Time Projection Chamber polarimeter
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Paper Abstract

A fundamental challenge in a spaceborne application of a gas-based Time Projection Chamber (TPC) for observation of X-ray polarization is handling the large amount of data collected. The TPC polarimeter described uses the APV-25 Application Specific Integrated Circuit (ASIC) to readout a strip detector. Two dimensional photo- electron track images are created with a time projection technique and used to determine the polarization of the incident X-rays. The detector produces a 128x30 pixel image per photon interaction with each pixel registering 12 bits of collected charge. This creates challenging requirements for data storage and downlink bandwidth with only a modest incidence of photons and can have a significant impact on the overall mission cost. An approach is described for locating and isolating the photoelectron track within the detector image, yielding a much smaller data product, typically between 8x8 pixels and 20x20 pixels. This approach is implemented using a Microsemi RT-ProASIC3-3000 Field-Programmable Gate Array (FPGA), clocked at 20 MHz and utilizing 10.7k logic gates (14% of FPGA), 20 Block RAMs (17% of FPGA), and no external RAM. Results will be presented, demonstrating successful photoelectron track cluster detection with minimal impact to detector dead-time.

Paper Details

Date Published: 4 May 2016
PDF: 9 pages
Proc. SPIE 9853, Polarization: Measurement, Analysis, and Remote Sensing XII, 98530Z (4 May 2016); doi: 10.1117/12.2222800
Show Author Affiliations
Kyle J. Gregory, NASA Goddard Space Flight Ctr. (United States)
Joanne E. Hill, NASA Goddard Space Flight Ctr. (United States)
J. Kevin Black, NASA Goddard Space Flight Ctr. (United States)
Rock Creek Scientific (United States)
Wayne H. Baumgartner, NASA Goddard Space Flight Ctr. (United States)
Univ. of Maryland Baltimore County (United States)
Keith Jahoda, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 9853:
Polarization: Measurement, Analysis, and Remote Sensing XII
David B. Chenault; Dennis H. Goldstein, Editor(s)

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