Irradiation of MSGCs with low-energy neutrons

A large part of the inner tracker of CMS will be equipped with Micro Strip Gas Chambers (MSGCs). In addition to a high MIP rate these detectors also w ill be exposed to highly ionizing particles (HIP), as well as to a consider able flux of low-energy neutrons. We have performed experiments with neutro ns in the energy range of 0.3-2 MeV, which covers the main part of the neut ron spectrum prevailing within the CMS tracker volume. By means of time-of- flight a clear discrimination of the detector response to photons and neutr ons has been achieved. The most probable neutron energy deposit has been fo und to be equivalent to 30 MIPs with a conversion probability of epsilon = 10(-5). Two MSGCs, one based on bare glass and another on diamond-like coat ed glass, were irradiated with neutrons at high dose (4 x 10(7) n/cm(2)s). After an integral dose of 1 x 10(13) n/cm(2), equivalent to one LHC-year, n o indication of damage could be found. (C) 1998 Elsevier Science B.V. All r ights reserved.