A gas proportional scintillation counter for use in large area detector systems without photomultipliers

The properties of a prototype gas proportional scintillation (GPS) detector module are described. The module (25 × 25 × 14 cm3) is intended to form the basic unit of large area (up to ≈ 100 m2) calorimetric cosmic ray burst detector. Ionisation from particle tracks in the module is collected onto a point electrode where the GPS signal is generated. A concave mirror focusses this point source onto the end of a fibre optic light guide. In the proposed large area detector these fibres are brought together onto a low light level TV camera which performs the readout. The prototype module has demonstrated an adequate light output for the detection of single muons by such a readout system and also permitted the the investigation of the main operating parameters (gas mixture, EHT, pressure, etc) and operational requirements such as proportionally and long term stability.