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Research Paper | Radiological Sciences | Japan | Volume 7 Issue 5, May 2018

Zero-Dark-Counting Brief Measurement of X-ray Spectra Using a Lutetium-Oxyorthosilicate Multipixel-Photon Detector Driven in Pre-Geiger Mode

Toshiyuki Enomoto ^[2] | Eiichi Sato ^[3] | Hodaka Moriyama ^[2] | Osahiko Hagiwara ^[2] | Hiroshi Matsukiyo ^[2] | Manabu Watanabe ^[2] | Shinya Kusachi ^[2]

Abstract: Brief measurement of X-ray spectra using a detector, consisting of a lutetium oxyorthosilicate (LSO) crystal and a multipixel photon counter (MPPC) is described. X-ray photons are detected using the LSO crystal and a 0.5-mm-diam 3.0-mm-thick lead pinhole, and scintillation photons produced in the crystal are detected using the MPPC. The photocurrents flowing through the MPPC are converted into voltages and amplified using a stable high-speed current-voltage amplifier, and the output event pulses from the amplifier are sent to a multichannel analyzer to perform pulse-height analysis. Without the counts of photons from the LSO crystal, the dark count rate was reduced to 0 count per second by reducing the MPPC bias voltage to 65.11 V in the pre-Geiger mode. The photon energy was determined by two-point calibration using K-fluorescent energies of iodine and lead, and the energy resolutions was below 30 % at 74.2 keV. Using the LSO-MPPC detector, both the maximum-photon and the peak-count energies increased with increasing tube voltage, and the maximum count rate was 31 kilocounts per second at a tube voltage of 100 kV and a current of 0.16 mA. Dual-energy computed tomography was accomplished using gadolinium contrast media.

Keywords: X-ray spectra, LSO-MPPC detector, pre-Geiger mode, stable I-V amplifier, zero dark counting, fluorescent energy calibration, dual-energy CT

Edition: Volume 7 Issue 5, May 2018,

Pages: 1751 - 1756

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