High rate read-out of scintillators with CAEN V-1720 FADC
G. Viesti 1*, D. Cester 1, G. Nebbia 2, L. Stevanato 1, F. Neri 3, S. Petrucci 3, S. Selmi 3, C. Tintori 3
1 Dipartimento di Fisica, Università di Padova, Via Marzolo 8, Padova I-35131, Italy
2 INFN Sezione di Padova, Via Marzolo 8, Padova I-35131, Italy
3 CAEN S.p.A., Via Vetraia 11, I-55049, Viareggio (LU), Italy
In the SMANDRA (Stazione Mobile per Analisi Non-Distruttive e Radiometriche) mobile inspection station, the front end electronics consists of a battery operated VME minicrate hosting an HV power supply card (CAEN-V6533M) and a VME card with FADC units (CAEN-V1720 8 Channel 12bit 250 Ms/s Digitizer) used to perform digital pulse processing by FPGA. Laboratory tests have been performed to compare the capability of this compact and mobile front end system with respect to a traditional NIM based electronics.
Detailed laboratory results will be presented for two detectors: a LaBr (2” x2”) scintillator used for gamma ray spectroscopy and a liquid scintillator (NE213 type, 4” x 2”) used for neutron/gamma discrimination.
In case of the LaBr scintillator, it is found that a proper tuning of the digital pulse parameters used in the FPGA allows one to obtain energy resolutions comparable and even better than what is obtained by using standard NIM spectroscopy amplifiers and ADC. In the same way, the pulse processing in the FPGA allows obtaining on-line neutron/gamma discrimination with a Figure-OF-Merit (FOM) comparable with those obtained with the same detector by hardware processing the signals with NIM electronics or by software off-line analysis of FADC data.
However, the major advantage in working with FPGA is that such results are obtained on-line also at very high rate, tests being performed up to 145 kcps and 40 kcps in case of the LaBr and the NE213 detector, respectively. Further tests at higher rate are in progress.
Results obtained in using the V1720 card in coincidence mode will be also presented.
 see D. Cester et al. “An integrated mobile system for port security” this conference