Study of Micro Pixel Photon Counter for the Application to Positron Emission Tomography

TL;DR

This study evaluates the Micro Pixel Photon Counter's suitability for PET by characterizing its performance with different scintillator crystals, focusing on spatial, energy, and timing resolution, and its magnetic field insensitivity.

Contribution

It provides the first detailed characterization of MPPC coupled with scintillator crystals for PET, highlighting its potential advantages in resolution and magnetic field compatibility.

Findings

High photo-detection efficiency in blue spectral region

Good energy resolution at 511 keV

Coincidence time resolution measured

Abstract

The main challenges posed by the design of future Positron Emission Tomography machines are the improvement of the spatial and timing resolution and the combined operation with magnetic resonance. The Micro Pixel Photon Counter by Hamamatsu is a good candidate for this application. Its small size (down to 1 mm2) and the high photo-detection efficiency in the blue spectral region allow the direct readout of a highly segmented scintillator matrix improving the spatial resolution of the machine. Furthermore, this photo-detector is insensitive to static magnetic fields up to 5 T, which makes it a possible candidate for applications in a magnetic resonance environment, though tests in a fast changing gradient field need still to be performed. The aim of this study is the characterization of a system composed by a scintillator crystal readout via a MPPC. Crystals of 1x1x15 mm3 and 3x3x15 mm3 are directly coupled to a MPPC of the same size active area and the energy resolution at 511 keV is measured. The coincidence time resolution of two so assembled detector units is measured. A first comparison of the performances of LSO and LFS crystals is given.