Speaker
Dr
Katrin Straub
(University of Pisa / INFN)
Description
The pixel identification capability is a common problem of gamma-ray detectors using matrices of scintillating materials coupled to position sensitive photodetectors. In Positron Emission Tomography (PET) systems an improvement of pixel identification leads to a reduction of the coding factor thus improving the spatial resolution of the system.
In order to promote light spread and avoid overlap of responses, ultra-transmitting (UT) glasses can be inserted between the crystal and PMT array to gain pixel identification efficiency especially at the peripheral active area exploiting the enhanced light spread.
The development of improved PET detector response regarding energy resolution and pixel identification quality is not only due to the selection of the material/geometry of the crystal, a suitable PMT and dedicated readout electronics, but depends also on the assembly of these hardware components.
Our detector module dedicated for PET measurements consists of a scintillating LYSO crystal matrix (pitch 1.7 mm) coupled to a multi-anode PMT (Hamamatsu H8500C, active area 49 x 49 mm$^2$) and is read out by modular frontend electronics processing timing and anger-like position signals.
In this work we have studied, in comparison to direct coupling, the effect of using UT glasses of three thicknesses, d = 0.7, 1.0, and 1.35 mm, on pixel identification performance (peak-to-valley ratio and linearity) and energy resolution for different regions of the active area of the PMT.
Primary author
Dr
Katrin Straub
(University of Pisa / INFN)
Co-authors
Prof.
Alberto Del Guerra
(Department of Physics, University of Pisa and INFN, Sezione di Pisa, Pisa, Italy)
Mrs
Giancarlo Sportelli
(Department of Physics, University of Pisa and INFN, Sezione di Pisa, Pisa, Italy)
Dr
Nahema Marino
(Department of Physics, University of Pisa and INFN, Sezione di Pisa, Pisa, Italy)
Dr
Niccolo' Camarlinghi
(Department of Physics, University of Pisa and INFN, Sezione di Pisa, Pisa, Italy)
Dr
Nicola Belcari
(Department of Physics, University of Pisa and INFN, Sezione di Pisa, Pisa, Italy)
Dr
Stefano Ferretti
(Department of Physics, University of Pisa and INFN, Sezione di Pisa, Pisa, Italy)
Prof.
Valeria Rosso
(Department of Physics, University of Pisa and INFN, Sezione di Pisa, Pisa, Italy)
