Absorption of scintillation light in a 100 l liquid xenon gamma-ray detector and expected detector performance

An 800 l liquid xenon scintillation gamma-ray detector is being developed for the MEG experiment which will search for mu(+) -> e(+)gamma decay at the Paul Scherrer Institut. Absorption of scintillation light of xenon by impurities might possibly limit the performance of such a detector. We used a 1001 prototype with an active volume of 372 x 372 x 496 mm(3) to study the scintillation light absorption. We have developed a method to evaluate the light absorption, separately from elastic scattering of light, by measuring cosmic rays and a sources. By using a suitable purification technique, an absorption length longer than 100 cm has been achieved. The effects of the light absorption on the energy resolution are estimated by Monte Carlo simulation. (c) 2005 Elsevier B.V. All rights reserved.