Dynode-Timing Method for PET Block Detectors

Abstract

The focus of this paper is the investigation of a new dynode-timing technique optimized for PET block detectors. This method allows utilization of dynode signals from single but especially multiple photo-multiplier tubes (PMTs), operated with negative high-voltage. The technique will provide an event-timing trigger without deteriorating the anode signal. A printed circuit board has been developed and built for this investigation.Benchmark measurements have been performed, comparing timing of the anode signal with timing of the inverted last-dynode signal and timing of the dynode signal extracted via a newly developed LVPECL-logic based board. Timing measurements were performed with plastic as well as LSO scintillators. From single PMT measurements we find a 30 ps improvement with the dynode-timing method compared to the standard anode timing with two Photonis XP2020Q PMTs with LSO (10 mm 10 mm 10 mm). For a quad-PMT block detector, assembled of four Hamamatsu R9800 with a Hi-Rez block, the timing-resolution improves 10%, by 43 ps compared to the standard anode timing.

Timing resolution improvement using DOI information in a four-layer scintillation detector for TOF-PET

“…It is known that even a non-layered crystal array shows crystalby-crystal timing properties, depending on the positional relationship between the crystal and the PMT or other factors such as reflectors and other crystals [44,45]. Therefore, in the next step, we need to check the TOF shift as a function of thee-dimensional position, not only vertical but also horizontal, of the crystal by using the real four-layer LYSO detector without dummy crystals.…”