Empirical performance of polycrystalline silicon pixel circuit components for monolithic, large-area photon counting arrays
- 14 October 2021
- journal article
- research article
- Published by IOP Publishing in Engineering Research Express
- Vol. 3 (4), 045014
- https://doi.org/10.1088/2631-8695/ac2fae
Abstract
Photon counting detectors (PCDs) offer several advantages for medical x-ray imaging compared to conventional imagers. However, current PCDs, whose circuits are fabricated using crystalline silicon semiconductor material, are not well-suited for large-area imaging applications such as breast CT and kilovoltage cone-beam CT (kV CBCT) in radiotherapy. To address this challenge, prototype PCDs based on polycrystalline silicon (a semiconductor better suited for manufacture of large-area devices) were created and, in this paper, an empirical determination of the maximum count rate of individual pixel circuit components (amplifier, comparator, clock generator and counter) corresponding to those prototypes is reported. For each circuit component, test input pulses (which were generated so as to approximate those in a complete pixel circuit) were used to obtain output response waveforms from which count rate was determined. The maximum count rate (in units of counts per second, cps) for the amplifier was determined to be 20.8 kcps while that of the comparator, clock generator and counter components were determined to be 1.2 Mcps, 98 kcps and 4.9 Mcps, respectively. The comparator and counter components provide count rates beyond that required for breast CT (~108 kcps at a pixel pitch of 330 µm) while those components as well as the clock generator exceed the rate required for kV CBCT in radiotherapy (~72 kcps at a pitch of 400 µm). It is anticipated that new polycrystalline silicon circuit designs for the amplifier and clock generator could provide count rates sufficient for both applications.Keywords
This publication has 33 references indexed in Scilit:
- Vision 20/20: Single photon counting x‐ray detectors in medical imagingMedical Physics, 2013
- LAMBDA — Large Area Medipix3-Based Detector ArrayJournal of Instrumentation, 2012
- Photon counting spectral CT versus conventional CT: comparative evaluation for breast imaging applicationPhysics in Medicine & Biology, 2011
- Performance of single-photon-counting PILATUS detector modulesJournal of Synchrotron Radiation, 2009
- Experimental feasibility of multi-energy photon-counting K-edge imaging in pre-clinical computed tomographyPhysics in Medicine & Biology, 2008
- K-edge imaging in x-ray computed tomography using multi-bin photon counting detectorsPhysics in Medicine & Biology, 2007
- Average glandular dose in routine mammography screening using a Sectra MicroDose Mammography unitRadiation Protection Dosimetry, 2005
- Medipix2: A 64-k pixel readout chip with 55-/spl mu/m square elements working in single photon counting modeIEEE Transactions on Nuclear Science, 2002
- A photon counting pixel chip with energy windowingIEEE Transactions on Nuclear Science, 2000
- A readout chip for a 64/spl times/64 pixel matrix with 15-bit single photon countingIEEE Transactions on Nuclear Science, 1998