6533b7d1fe1ef96bd125cbad

RESEARCH PRODUCT

<title>Studies of the activation background in CsI(Tl) detectors</title>

subject

description

CsI scintillation crystals are widely used as detection in (gamma) -ray astronomy observations. In the MeV energy region, one of the most important background sources in CsI is the (beta) decays induced in the crystal by cosmic ray protons and their secondaries. One recent idea for reducing this background is to use discrete detector arrays to reject the large amount of localized (beta) decay events. Two experiments were carried out with 1 cm3 CsI crystals bombarded with energetic proton beams and fast/thermal neutrons, with the aim of evaluating the effectiveness of this method in pixelated (1 cm3) CsI detectors. The ratio of the number of decays resulting in single site and multiple site events was found to be less than 1 in the energy band above 400 keV for the proton induced spallation background, while it is above 8 for the neutron induced background. The combined result indicates that more than 80% of the induced radioactive decays in the energy band between 200 keV and 2 MeV are single site events, and thus their rejection by the use of discrete CsI arrays will significantly improve the sensitivity of the detector.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.