The H1 experiment at HERA 1988-

Quite early I was engaged in the discussions and preparation for the ep collider HERA. In 1988 we obtained the formal support from the Research Council to paticipate in the H1 experiment.

H1 is a magnetic detector with a central tracking devise surrounded by a liquid Argon calorimeter and an instrumented return yoke for back-up calorimetry and muon detection. Since the centre-of mass is moving in the direction of the proton, special care has to be taken in this direction, the so-called forward direction. Therefore a separate muon spectrometer is being installed in this region. The Lund group was, together with a group from the University of Manchester, the responsible for the construction of this detector. It consists of a toroid magnet providing a field of 1.5 Tesla over a distance of 1.2 metres. In front of and behind the magnet there are three double layers of large drift chamber planes to determine the polar and azimuthal angles of the tracks. Good space resolution is necessary to achieve good momentum resolution and linking between the track segments in the muon spectrometer and the central tracking system.

A Monte-Carlo study was performed inorder to find out how of the background contributions from decaying pions and kaons as well as punch-throughs and sneak-throughs of hadrons could be separated from prompt muons. This study gave the basic information on how a special muon trigger for the forward system could be constructed. The trigger system was developed together with new collaborators from the University of Birmingham. The analogue logic for this trigger has been developed in Lund. It is implemented and working in the detector since several years.

In Lund we have also built a radiation monitor system for the silicon-strip vertex detector in H1 which includes a read out system based on a 10 MHz FADC and a special CPU for pulse analysis. Also the software for the data aquisition and the monitoring has been developed by us. A prototype was in operation during 1994 and worked without problems. The full number of 12 radiation monitors was installed early 1995 together with an updated version of the read out system and has since then been operating.