Design and material considerations for a sensitive scintillation detector as absorber for a resolution Compton-Camera

The primary energy of the photons and the angle under which they are detected by the absorption detector after the Compton scatter process in the scatter detector are the main parameters of a Compton-Camera determining the demands on the scatter- and the absorption detector. The design of a high resolution Compton-Camera results in using gamma energies higher than 400 keV and small scatter angles. Due to the forward scattering a very fast trigger signal is needed for coincidence measurements. In order to get a good efficiency in the absorption detector at such high energies a material with good stopping power is much-needed. For the design and the estimation of the performance of an absorption detector the detailed information of interaction branching ratios and radii in which the energy is deposited during an interaction is mandatory. Several simulations with ROSI have been done in order to optimize and estimate the expected performance of a fast 3D-position sensitive scintillation detector.