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Proceedings Paper

First results from the 128x128 pixel mixed-mode Si x-ray detector chip
Author(s): W. Vernon; M. Allin; R. Hamlin; T. Hontz; D. Nguyen; F. Augustine; S. M. Gruner; Ng. H. Xuong; D. R. Schuette; M. W. Tate; L. J. Koerner
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Paper Abstract

A Mixed-Mode Pixel Array Detector has been developed to measure protein crystallographic diffraction patterns. X-rays are stopped in a 500 μm thick layer of silicon diodes, and collected charge is processed by an attached ASIC. Goals of the project are high flux (108 x-rays/s/pixel) capability and fast readout (< 0.5 ms dead time between frames). "Mixed-Mode" refers to a readout method whereby integrated signal accumulating in each pixel is compared against a threshold value. When the threshold is reached, a digital count is added to an 18-bit in-pixel counter and a set quantity of charge is removed from integrator. At the end of the x-ray exposure, analog signal left in the integrator is separately processed. Thus, one obtains mixed digital and analog data where the counter bits are a high order word and the analog residual provides higher precision. Typically, each count is equivalent to 100 10 keV x-rays, for a well-depth >107 10 keV x-rays/ pixel. The analog residual is digitized to 9-bit precision allowing measurement of the residual charge to better than a quarter of the charge from single 10 keV x-rays. Measurements are presented on x-ray tests at the Cornell High Energy Synchrotron Source (CHESS). Dynamic range, linearity, point-spread function and noise properties are shown. Status will be is reported on five different approaches for ASIC-diode hybridization. Progress toward bonding of a 128 x 512 pixel device is also presented.

Paper Details

Date Published: 21 September 2007
PDF: 11 pages
Proc. SPIE 6706, Hard X-Ray and Gamma-Ray Detector Physics IX, 67060U (21 September 2007); doi: 10.1117/12.738663
Show Author Affiliations
W. Vernon, Area Detector Systems Corp. (United States)
M. Allin, Area Detector Systems Corp. (United States)
R. Hamlin, Area Detector Systems Corp. (United States)
T. Hontz, Area Detector Systems Corp. (United States)
D. Nguyen, Area Detector Systems Corp. (United States)
F. Augustine, Augustine Engineering (United States)
S. M. Gruner, Cornell Univ. (United States)
Cornell High Energy Synchrotron Source, Cornell Univ. (United States)
Ng. H. Xuong, Univ. of California, San Diego (United States)
D. R. Schuette, Cornell Univ. (United States)
M. W. Tate, Cornell Univ. (United States)
L. J. Koerner, Cornell Univ. (United States)

Published in SPIE Proceedings Vol. 6706:
Hard X-Ray and Gamma-Ray Detector Physics IX
Ralph B. James; Arnold Burger; Larry A. Franks, Editor(s)

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