Mars: the Durham magnetic automated

Abstract

A large solid iron spectrograph is described which will be used initially to measure the vertical spectrum and charge ratio of cosmic ray muons to momenta in excess of 5000 GeV/c. Scintillation counters and trays of digitised neon flash tubes are used as particle detectors and the spectrograph is connected to an I.B.M. 113O computer for on-line data recording and analysis of the events. The spectrograph has an acceptance of 818 cm(^2) ster. and an estimated maximum detectable momentum of approximately 6000 Gev/c. A momentum selector is incorporated in the spectrograph equipment which selects, for further analysis by the computer, particles with momenta above a few hundred GeV/c from the information contained in trays of digitised flash tubes situated at: three levels in the spectrograph. The computer calculates the momenta of particles selected in this way using the data contained in a further five trays of digitised flash tubes. A flash tube digitisation technique has been developed for use in the spectrograph and is described in detail. The technique utilises a simple probe on the front of the flash tube to detect an electrical pulse when the tube discharges. The pulse is fed into an electronic memory for the flash tube made from integrated circuit logic elements. The electronic circuits used for the flash tube data recording, the momentum selector, and the logic controlling the readout of data from the flash tube trays to the computer are described. The method of analysis of events by the computer is discussed.