Thin large area scintillating tile detectors with sensitivity to minimum ionizing particles

Thin large area scintillating tiles with fibre readout and sensitivity to minimum ionizing particles (MIPs) have been fabricated. Such detectors require no in-situ high voltage or gas supplies and are especially useful when there are high magnetic fields in the detection region and limited space for installation. In this paper one particular application is discussed in detail, that is the use of scintillating tiles with fibre readout installed in the OPAL endcap regions in order to improve trigger performance, time resolution and hermiticity for LEP II operation. The tiles were required to have uniform response, high efficiency for MIPs and good time resolution. The chosen design satisfies these requirements, with a light yield of 14 photoelectrons per minimum ionizing particle and a time resolution of 3 ns. (21 refs).