TY - JOUR
T1 - Simple charge division readouts for imaging scintillator arrays using a multi-channel PMT
AU - Siegel, Stefan
AU - Silverman, Robert W.
AU - Shao, Yiping
AU - Cherry, Simon R.
N1 - Funding Information:
The authors wish to thank Wayne Seemungal and Esso Flyckt (Philips Photonics) for advice and for the loan of the XP1722 MC-PMT, and Ken Meadors for technical support. This work was supported by a grant from The Whitaker Foundation and NIH Training Grant T32-CA09092 (S.S .).
PY - 1996
Y1 - 1996
N2 - Three simple charge division circuits were assembled and tested as 2-D position encoding readouts for multi-channel photomultiplier tubes (MC-PMT). They were evaluated with an 8×8 array of individual scintillators (2×2×10 mm BGO) coupled to a 64 channel MC-PMT (Philips XP1722) via 25 cm long, 2 mm diameter, double clad, optical fibers (Kuraray). This type of gamma-ray imaging detector has many potential applications in medical and industrial imaging. Though independent channel readout would allow for the discrimination of scatter within the array, and higher count rates, it would also require an excessive amount of supporting electronics. This is especially true for systems comprised of many MC-PMTs. In this study, the number of channels being read out was reduced from 64 to 4 using three different simple resistor networks. These circuits take advantage of the discretized nature of the scintillator array, the low interchannel crosstalk of the MC-PMT and low input impedance current-sensitive preamplifiers. For each circuit, the scintillator identification accuracy was compared. The identification accuracy as a function of deposited energy was also determined by exposure to various gamma-ray emitters. It was found that the preamplifier circuit noise contributed the most to the degradation of the detector's spatial response so several low noise op amps were evaluated. It was also determined that keeping the preamplifier input impedance small was necessary for accurate positioning. The coincidence timing resolution of the detector (15 ns) is only slightly degraded by the readout circuit.
AB - Three simple charge division circuits were assembled and tested as 2-D position encoding readouts for multi-channel photomultiplier tubes (MC-PMT). They were evaluated with an 8×8 array of individual scintillators (2×2×10 mm BGO) coupled to a 64 channel MC-PMT (Philips XP1722) via 25 cm long, 2 mm diameter, double clad, optical fibers (Kuraray). This type of gamma-ray imaging detector has many potential applications in medical and industrial imaging. Though independent channel readout would allow for the discrimination of scatter within the array, and higher count rates, it would also require an excessive amount of supporting electronics. This is especially true for systems comprised of many MC-PMTs. In this study, the number of channels being read out was reduced from 64 to 4 using three different simple resistor networks. These circuits take advantage of the discretized nature of the scintillator array, the low interchannel crosstalk of the MC-PMT and low input impedance current-sensitive preamplifiers. For each circuit, the scintillator identification accuracy was compared. The identification accuracy as a function of deposited energy was also determined by exposure to various gamma-ray emitters. It was found that the preamplifier circuit noise contributed the most to the degradation of the detector's spatial response so several low noise op amps were evaluated. It was also determined that keeping the preamplifier input impedance small was necessary for accurate positioning. The coincidence timing resolution of the detector (15 ns) is only slightly degraded by the readout circuit.
UR - http://www.scopus.com/inward/record.url?scp=0030164341&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030164341&partnerID=8YFLogxK
U2 - 10.1109/23.507162
DO - 10.1109/23.507162
M3 - Article
AN - SCOPUS:0030164341
SN - 0018-9499
VL - 43
SP - 1634
EP - 1641
JO - IEEE Transactions on Nuclear Science
JF - IEEE Transactions on Nuclear Science
IS - 3 PART 2
ER -