Title :
Design of a fast shaping amplifier for PET/CT APD detectors with depth-of-interaction
Author :
Pratte, J.-F. ; Pepin, C.M. ; Rouleau, D. ; Ménard, O. ; Mouine, J. ; Lecomte, R.
Author_Institution :
Dept. of Electr. & Comput. Eng., Sherbrooke Univ., Que., Canada
Abstract :
An integrated, 0.35 μm CMOS fast shaping amplifier has been designed for coincidence detection and zero-cross time pulse shape discrimination (PSD) in PET, and for high rate event counting in CT with APD-based detectors. Analytical simulations of CR-RCn filters of various order and shaping time constant were carried out to optimize the timing performance, keeping in mind the stringent channel density requirements of the detector front-end electronics. The filter was implemented with the biquadratic bandpass architecture using a folded cascode transconductance amplifier. The electronic timing resolution of the coincidence circuit was 92 ps in the ideal case without an APD (Cin=0pF), and 243 ps with an APD (Cin=30 pF). By comparison, the same system with the CMOS shaper replaced by an Ortec 579 Fast Filter Amplifier set to a shaping time of 10 ns yielded an electronic time resolution of 79 ps in the ideal case without capacitance, and 236 ps with the APD. The 511 keV coincidence time resolution for an LSO/APD detector was measured to be 1.49 ns.
Keywords :
CMOS integrated circuits; amplifiers; avalanche photodiodes; biomedical electronics; computerised tomography; diagnostic radiography; discriminators; positron emission tomography; pulse shaping circuits; readout electronics; semiconductor counters; timing circuits; 0.35 micron; 1.49 ns; 10 ns; 236 ps; 243 ps; 30 pF; 511 keV; 79 ps; 92 ps; APD detectors; CMOS fast shaping amplifier; CR-RCn filters; CT; Ortec 579 fast filter amplifier; PET; biquadratic bandpass architecture; channel density requirements; coincidence detection; computerised tomography; depth-of-interaction; electronic timing resolution; folded cascode transconductance amplifier; front-end electronics; high rate event counting; shaping time; shaping time constant; timing performance; zero-cross time pulse shape discrimination; Analytical models; Band pass filters; Detectors; Event detection; Performance analysis; Positron emission tomography; Pulse amplifiers; Pulse shaping methods; Shape; Timing;
Conference_Titel :
Nuclear Science Symposium Conference Record, 2001 IEEE
Print_ISBN :
0-7803-7324-3
DOI :
10.1109/NSSMIC.2001.1009680
