A high energy electron-photon detector employing flash tube arrays

Abstract

The development of a high energy electromagnetic shower detector for use in high energy electron or photon detection, particularly in machine experiments, is described. The detector is a modified version of a prototype chamber, which was successfully tested, and which is described briefly in this thesis. The detector gives fully digitised information from which incident particle energies and trajectories can be estimated. The detector consists of twelve flash tube arrays sandwiched between lead target. A total of 768 tubes are employed. They have an internal diameter of 0.8 cm a wall thickness of 0.03 cm. and are filled with a gas mixture of Ne (70%) –He (30%) 2% CH (_4) at 2.3 atmospheres pressure. The operation of these tubes under various working conditions has been extensively studied and the results are presented in the thesis. The detector has been tested in the positron beam at the Daresbury Laboratory, where digitised information was obtained using a computerised data acquisition system. The energies of the positrons used ranged from 0.1 to 3.5 GeV. Analysis of the data showed that the chamber operated satisfactorily in high backgrounds of radiation and was very capable in the detection of electromagnetic showers, giving energy and spatial resolutions comparable to those obtained by the conventional, more complex and more expensive detecting systems. However, the use of the detector was restricted to working at several events per minute, due to the build up of large induced clearing fields inside the flash tubes.