Evaluation of K x-ray escape and crosstalk in CdTe detectors and multi-channel detectors
- Matsushita Electric Industrial Co., Ltd., Moriguchi, Osaka (Japan). Device Process Technology Research Lab.
The simple structure of CdTe semiconductor detectors facilitates their downsizing, and their possible application to radiographic sensors has been studied. The escape of K X-rays from these detectors increases with reduction of their dimensions and affects the measurements of X- and gamma-ray spectra. K X-rays also produce crosstalk in multi-channel detectors with adjacent channels. Therefore, K X-rays which escape from the detector elements degrade both the precision of energy spectra and spatial resolution. The ratios of escape peak integrated counts to total photon counts for various sizes of CdTe single detectors were calculated for gamma rays using the Monte Carlo method. Also, escape and crosstalk ratios were simulated for the CdTe multi-channel detectors. The theoretical results were tested experimentally for 59.54-keV gamma rays from a {sup 241}Am radioactive source. Results showed that escape ratios for single detectors were strongly dependent on element size and thickness. The escape and crosstalk ratios increased with closer channel pitch. The calculated results showed a good agreement with the experimental data. The calculations made it clear that K X-rays which escaped to neighboring channels induced crosstalk more frequently at smaller channel pitch in multichannel detectors. A radiation shielding grid which blocked incident photons between the boundary channels was also tested by experiment and by calculation. It was effective in reducing the probability of escape and crosstalk.
- OSTI ID:
- 72651
- Journal Information:
- IEEE Transactions on Nuclear Science, Journal Name: IEEE Transactions on Nuclear Science Journal Issue: 3 Vol. 42; ISSN 0018-9499; ISSN IETNAE
- Country of Publication:
- United States
- Language:
- English
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