Author/Authors :
Studen، نويسنده , , A. and Burdette، نويسنده , , D. and Chesi، نويسنده , , E. and Cindro، نويسنده , , V. and Clinthorne، نويسنده , , N.H. and Dulinski، نويسنده , , W. and Fuster، نويسنده , , J. and Han، نويسنده , , L. M. Kagan-Rosenzweig، نويسنده , , H. and Lacasta، نويسنده , , C. and Llosa، نويسنده , , G. and Marques، نويسنده , , A.C. and Malakhov، نويسنده , , N. R. Meier-Melikyan، نويسنده , , D. and Mikuz، نويسنده , , M. and Park، نويسنده , , S.J and Roe، نويسنده , , S. and Rogers، نويسنده , , W.L. and Steinberg، نويسنده , , J. and Weilhammer، نويسنده , , P. and Wilderman، نويسنده , , S.J. and Zhang، نويسنده , , L. and ?ontar، نويسنده , , D.، نويسنده ,
Abstract :
Compton collimated imaging may improve the detection of gamma rays emitted by radioisotopes used in single photon emission computed tomography (SPECT). We present a crude prototype consisting of a single 500 μm thick, 256 pad silicon detector with pad size of 1.4×1.4 mm2, combined with a 15×15×1 cm3 NaI scintillator crystal coupled to a set of 20 photo multipliers. Emphasis is placed on the performance of the silicon detector and the associated read-out electronics, which has so far proved to be the most challenging part of the set-up. Results were obtained using the VATAGP3, 128 channel low-noise self-triggering ASIC as the silicon detectorʹs front-end. The noise distribution (σ) of the spectroscopic outputs gave an equivalent noise charge (ENC) with a mean value of 〈σ〉=137 e with a spread of 10 e, corresponding to an energy resolution of 1.15 keV FWHM for the scattered electron energy. Threshold settings above 8.2 keV were required for stable operation of the trigger. Coincident Compton scatter events in both modules were observed for photons emitted by 57Co source with principal gamma ray energies of 122 and 136 keV.
Keywords :
Silicon pad detectors , MEDICAL IMAGING , Compton camera , single photon emission computed tomography (SPECT) , Tracking and position-sensitive detectors
