BaF2 scintillators with wire chamber readout for positron emission tomography

This work is part of the design study for a medical positron emission tomography (PET) system based on the use of BaF2 scintillator and photosensitive wire chambers with TMAE. The number of photoelectrons per MEV (phe/MeV) is measured in the wire chamber and on a photomultiplier for crystals from five different suppliers. For the best crystals 26.7±2.0 phe/MeV in TMAE are observed, corresponding to an average quantum efficiency of TMAE for the fast component of BaF2 of (7.6±0.7)%. The performance of a PET scanner based on this principle was evaluated with a detailed Monte Carlo simulation. It is shown that the reduced energy resolution with wire chambers has only a marginal effect on the scatter rejection in the scanner. Finally LaF3:Nd3+ as an alternative to BaF2 was tested and found to give a disappointing photoelectron yield.