DocumentCode :
1064916
Title :
Effect of Temperature on the Performance of Proportional APD-Based Modules for Gamma Ray Detection in Positron Emission Tomography
Author :
Spanoudaki, Virginia Ch. ; McElroy, David P. ; Torres-Espallardo, Irene ; Ziegler, Sibylle I.
Author_Institution :
Nuklearmedizinische Klinik und Poliklinik, Munich
Volume :
55
Issue :
1
fYear :
2008
Firstpage :
469
Lastpage :
480
Abstract :
MADPET-II is a small animal PET tomograph that features individual lutetium oxyorthosilicate (LSO) crystal readout from avalanche photodiodes (APDs). The detector signals are preamplified by 16-channel fully integrated ASICs which are placed as close as possible to the detector in order to avoid attenuation of the signal or unwanted stray capacitance. However, the power consumption of the preamplifier (30 mW per channel) can cause heat transfer and, consequently, gain drift to temperature sensitive detectors. Temperature measurements on the front-end electronics of MADPET-II have shown a maximum increase of approximately 30 C in the area around the preamplifier and in the area around the APD-LSO detector with respect to room temperature. In the presence of this temperature gradient, energy spectra have been acquired from which a significant drift of the photopeak (3.4% per C) and a small increase of the mean energy resolution (3% over the whole temperature range studied) with increasing temperature has been observed. The effect of temperature on the time resolution is small in comparison to the effect of walk and jitter introduced by the analog processing electronics. The behavior of two 48 LSO-APD front-end detector arrays in coincidence at temperatures below ambient and at various values of the APD bias voltage in terms of energy and time resolution has also been studied. The total current drawn by the APDs (leakage current and photocurrent) has been monitored at various temperatures and APD bias and was modelled and fitted by a theoretical function demonstrating a and dependence. No significant improvement on time resolution with decreasing temperature has been observed. For temperature stabilization and monitoring, thermoelectric cooling is considered appropriate for mounting in the limited free space of a PET scanner, especially when this is inside an MR scanner for simultaneous PET/MR imaging.
Keywords :
application specific integrated circuits; avalanche photodiodes; biomedical MRI; drift chambers; gamma-ray detection; heat transfer; high energy physics instrumentation computing; image scanners; leakage currents; position sensitive particle detectors; positron emission tomography; preamplifiers; proportional counters; readout electronics; scintillation counters; thermoelectricity; 16-channel fully integrated ASICs; 4x8 LSO-APD front-end detector arrays; MADPET-II; MR scanner; PET scanner; PET-MR imaging; analog processing electronics; avalanche photodiodes bias voltage; energy spectra; gain drift detector; gamma ray detection; heat transfer; leakage current; lutetium oxyorthosilicate crystal; mean energy resolution; photocurrent; positron emission tomography; preamplifier; proportional avalanche photodiodes based modules; readout electronics; stray capacitance; temperature 10 C; temperature 20 C to 25 C; temperature sensitive detector; thermoelectric cooling; time resolution; Animals; Avalanche photodiodes; Detectors; Energy resolution; Gamma ray detection; Positron emission tomography; Preamplifiers; Temperature distribution; Temperature measurement; Temperature sensors; APD gain; dark current; energy resolution; multiplication noise; positron emission tomography; proportional avalanche photodiodes; thermoelectric coolers;
fLanguage :
English
Journal_Title :
Nuclear Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9499
Type :
jour
DOI :
10.1109/TNS.2007.912877
Filename :
4448538
Link To Document :
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