John Garvey

The UA1 calorimeter trigger

Abstract We describe the design, construction and performance of the fast calorimeter trigger used in the UA1 experiment on the CERN p p collider. Calorimeter energy signals are digitized rapidly and used to trigger on possible electrons, hadronic jets, total transverse energy and missing transverse energy, with many possible options. We also describe the minimum-bias pretrigger, based on scintillator hodoscopes.

Performance of a UA1 Hadron Calorimeter Prototype

The hadron calorimeter for the UA1 experiment at the CERN SPS proton-antiproton collider consists of a lead-scintillator sandwich plus an iron-scintillator sandwich with wavelength shifter readout. We have tested prototype modules in muon and hadron beams in the momentum range from 0.7 to 90 GeV/c. For several angles of incidence, we have studied the uniformity of the response to hadrons as a function of position. This has included regions where there is reduced sensitivity due to mechanical constraints and the presence of the wavelength shifter readout. The response, resolution and degree of shower containment were measured as a function of incident momentum.

Central Hadron Calorimeter of UA1

Abstract An iron—scintillator sampling calorimeter is described, which measures hadronic energy in proton-antiproton interactions at the CERN 540 GeV SPS collider. Construction details are given of the instrumentation of the magnet pieces of the UA1 experiment and of the methods used to measure the calorimeter response and resolution. The system of lasers and quartz fibres, which allows long term monitoring of the calorimeter response, is also described.

The H1 SPACAL time-to-digital converter system

This paper describes a pipelined 1400-channel Time-to-Digital Converter (TDC) system for the H1 Scintillating Fibre Calorimeter, which will soon be installed in the H1 experiment at DESY. The main task of the TDC system is to determine the time of arrival of energy depositions, and send this information from bunch crossings that satisfy the event trigger into the H1 data acquisition system. In addition, the TDC system must monitor the timing trigger, which vetoes bunch crossings that contain too much background energy. Products of the interaction are separated from background on the basis of their different times of arrival with respect to the bunch crossing clock. For this monitoring the TDC system uses automatic on-board histogramming hardware that produces a family of histograms for each of 1400 channels. The TDC function is performed by the TMC1004 ASIC. The system digitises over a range of 32 ns per bunch crossing with Ins bins and a precision of Ins. Because of the way the TMC1004 is designed, it is possible to vary the size of the bins between 0.6 ns and 3 ns by trading off measurement range for bin size. The system occupies two 9U VME crates. >