Building a pixellated detector for gamma-ray imaging: the PICsIT example

An imaging detector in the gamma range has its applications in various and different fields spanning from the medical diagnostic to the gamma astronomy. One of the techniques used in building such kind of 'gamma cameras' is based on the replication of individual pixel, each one being a stand alone detector. This kind of philosophy has been used in the construction of the PICsIT detector. PICsIT is the high-energy detector layer of the Imager IBIS that is one of the major instruments on board the INTEGRAL satellite observatory that the European Space Agency (ESA) will launch next October from Baikonour. PICsIT is made of 4096 CsI(Tl) scintillating detector 8.4 x 8.4 x 30 mm in size coupled to a PIN PD. Its operative range is 180-20400 keV and its operative modes allows to collect the information from both photoelectric events, which involves just one pixel and Compton or Pair events that involves more than one pixel at the same time. PICsIT is operating with a coded mask placed 3 in far from the detector. PICsIT has been integrated in the INTEGRAL satellite since the end of the year 2001 and is now undergoing the test foreseen for this kind of experiments. (C) 2003 Elsevier B.V. All rights reserved.