Enhancements to the spatial resolution and sensitivity of the MWPC-based PETRRA positron camera

PETRRA is a large-area, low-cost positron camera based on coupling BaF2 crystals to a multi-wire proportional chamber filled with a photo-sensitive gas tetrakis-dimethylamino ethylene (TMAE). The performance of this camera is comparable to the commercially available systems except for a lower sensitivity to 511 keV γ-rays obtained using the 1 cm thick crystals. In order to improve the cameraʹs γ-ray detection efficiency without losing spatial resolution, measurements with different crystal thickness were performed on a small prototype detector. The results show that by using segmented crystals it is possible to increase the detection efficiency using thicker crystals whilst retaining acceptable spatial resolution.