Imaging plates as position-sensitive detectors of positrons and γ-rays

Imaging plates have been used as position-sensitive detectors for positrons. Photo-stimulated luminescent material based on BaFX : Eu2+ (X=Cl, Br, I) is used. A linear relation between the positron fluence and output signal intensity readout by a “PIXsysTEM II” ( pixelized to 25 μm×25 μm is obtained, using 58Co and 22Na positron emitters. The linearity extends to six decades from 105 to 1011 positrons/cm2. Sensitivities of one γ-ray photon relative to a positron are 0.011 and 3.4×10−3 for 65Zn and 22Na, respectively.