Investigating the suitability of GaAs:Cr material for high flux X-ray imaging

DOI: 10.1088/1748-0221/9/12/C12047

Authors: Matt Veale (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Steven Bell (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Diana Duarte (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Marcus French (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Matthew Hart (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Andreas Schneider (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Paul Seller (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Matthew Wilson (Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC)) , Slava Kachkanov (Diamond Light Source) , A D Lozinskaya (Functional Electronics Laboratory, Tomsk State University) , V A Novikov (Functional Electronics Laboratory, Tomsk State University) , O P Tolbanov (Functional Electronics Laboratory, Tomsk State University) , A. Tyazhev (Functional Electronics Laboratory, Tomsk State University) , A N Zarubin (Functional Electronics Laboratory, Tomsk State University)
Co-authored by industrial partner: No

Type: Conference Paper
Conference: 16th International Workshop on Radiation Imaging Detectors
Peer Reviewed: Yes

State: Published (Approved)
Published: December 2014
Diamond Proposal Number(s): 4984

Abstract: Semi-insulating wafers of GaAs material with a thickness of 500 micrometres have been compensated with chromium by Tomsk State University. Initial measurements have shown the material to have high resistivity (3 × 10[9] ohm cm) and tests with pixel detectors on a 250 micrometres pitch produced uniform spectroscopic performance across an 80 × 80 pixel array. At present, there is a lack of detectors that are capable of operating at high X-ray fluxes (> 10^8 photons s-1 mm-2) in the energy range 5–50 keV. Under these conditions, the poor stopping power of silicon, as well as issues with radiation hardness, severely degrade the performance of traditional detectors. While high-Z materials such as CdTe and CdZnTe may have much greater stopping power, the formation of space charge within these detectors degrades detector performance. Initial measurements made with GaAs:Cr detectors suggest that many of its material properties make it suitable for these challenging conditions. In this paper the radiation hardness of the GaAs:Cr material has been measured on the B16 beam line at the Diamond Light Source synchrotron. Small pixel detectors were bonded to the STFC Hexitec ASIC and were irradiated with 3 × 10^8 photons s-1 mm-2 monochromatic 12 keV X-rays up to a maximum dose of 0.6 MGy. Measurements of the spectroscopic performance before and after irradiation have been used to assess the extent of the radiation damage.

Journal Keywords: Cadmium Tellurides; Chromium; Diamonds; Gallium Arsenides; Irradiation; Kev Range; Monochromatic Radiation; Performance; Photons; Radiation Doses; Radiation Effects; Radiation Hardness; Stopping Power; Synchrotrons; Thickness; X Radiation

Subject Areas: Engineering, Materials


Instruments: B16-Test Beamline

Other Facilities: CF - 29/01/2015 - primary subject area needs checking before approving. Everything else is OK.

Added On: 29/01/2015 09:54

Documents:
1748-0221_9_12_C12047.pdf

Discipline Tags:

Detectors Materials Science Engineering & Technology

Technical Tags:

Diffraction