A Caltech Library Service

First test results from a high-resolution CdZnTe pixel detector with VLSI readout

Cook, Walter R. and Boggs, Steven E. and Bolotnikov, Aleksey E. and Burnham, Jill A. and Harrison, Fiona A. and Kecman, Branislav and Matthews, Brian W. and Schindler, Steven M. and Fitzsimmons, Michael (1999) First test results from a high-resolution CdZnTe pixel detector with VLSI readout. In: Penetrating Radiation Systems and Applications. Proceedings of the SPIE. No.3769. Society of Photo-Optical Instrumentation Engineers (SPIE) , Bellingham, WA, pp. 92-96. ISBN 0-8194-3255-5.

[img] PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We are developing a CdZnTe pixel detector with a custom low- noise analog VLSI readout for use in the High-Energy Focusing Telescope balloon experiment, as well as for future space astronomy applications. The goal of the program is to achieve good energy resolution (< 1 keV FWHM at 60 keV) and low threshold in a sensor with approximately 500 micrometers pixels. We have fabricated several prototype detector assemblies with 2 mm thick, 680 by 650 micrometers pitch CdZnTe pixel sensors indium bump bonded a VLSI readout chip developed at Caltech. Each readout circuit in the 8 X 8 prototype is matched to the detector pixel size, and contains a preamplifier, shaping amplifiers, and a peak stretcher/discriminator. In the first 8 X 8 prototype, we have demonstrated the low-noise preamplifier by routing the output signals off-chip for shaping and pulse-height analysis. Pulse height spectra obtained using a ^(241)Am source, collimated to illuminate a single pixel, show excellent energy resolution of 1.1 keV FWHM for the 60 keV line at room temperature. Line profiles are approximately Gaussian and dominated by electronic noise, however a small low energy tail is evident for the 60 keV line. We obtained slightly improved resolution of 0.9 keV FWHM at 60 keV by cooling the detector to 5 degree(s)C, near the expected balloon- flight operating temperature. Pulse height spectra obtained with the collimated source positioned between pixels show the effect of signal sharing for events occurring near the boundary. We are able to model the observed spectra using a Monte-Carlo simulation that includes the effects of photon interaction, charge transport and diffusion, pixel and collimator geometry, and electronic noise. By using the model to simulate the detector response to uncollimated radiation (including the effect of finite trigger threshold for reconstruction of the total energy of multi-pixel events), we find the energy resolution to be degraded by only 10% for full-face illumination, compared to the collimated case. The small value of the degradation is due directly to the low readout noise and amplifier threshold.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Boggs, Steven E.0000-0001-9567-4224
Harrison, Fiona A.0000-0003-2992-8024
Additional Information:© 1999 Society of Photo-Optical Instrumentation Engineers (SPIE). This work was supported by the NASA SR&T program under grant No. NAG5-5128.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:X-ray astrophysics - electronics - CdZnTe
Series Name:Proceedings of the SPIE
Issue or Number:3769
Record Number:CaltechAUTHORS:20180111-071950145
Persistent URL:
Official Citation:Walter R. Cook, Steven E. Boggs, Aleksey E. Bolotnikov, Jill A. Burnham, Fiona A. Harrison, Branislav Kecman, Brian Matthews, Steven M. Schindler, Michael Fitzsimmons, "First test results from a high-resolution CdZnTe pixel detector with VLSI readout", Proc. SPIE 3769, Penetrating Radiation Systems and Applications, (1 October 1999); doi: 10.1117/12.363688;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84246
Deposited By: Ruth Sustaita
Deposited On:11 Jan 2018 17:16
Last Modified:15 Nov 2021 20:18

Repository Staff Only: item control page