Response of the D0 calorimeter to cosmic ray muons

Abstract

purpose detector facility designed for the study of proton-antiproton collision products at the center-of-mass energy of 2 TeV. It consists of an inner tracking volume, hermetic uranium/liquid argon sampling calorimetry, and an outer 4z-muon detector.In preparation for our first colllder run, the collaboration organized a Cosmic Ray Commissioning Run, which took place from February -May of 1991. This thesis is a detailed study of the response of the central calorimeter to cosmic ray. m_ons as extracted from data coilerted during this run. 11' '_ " _We have compared the shapes of the experimentally-obtained pulse height spec-tra to the Landau prediction for the ionization loss in a continuous thin absorber in the four electromagnetic and four hadronic layers of the calorimeter, and find good agreement after experimental effects are folded in.We have also determined an absolute energy calibration using two independent methods: one which measures the response of the electronics to a known amount of charge injected at the preamplifiers, and one which uses a carry-over of the calibration from a beam test of central calorimeter modules. Both absolute energy conversion factors agree with one another, within their errors. The calibration determined from the test beam carry-over, relevant for use with coillder physics data, has an error of 2.3%. We believe that, with further study, a final error of _ 1% will be achieved.The theory-to-experiment comparison of the peaks (or most probable values)of the muon spectra was used to determine the layer-to-layer consistency of the muon signal. We find that the mean response in the 3 fine hadronic layers is (12 ± 2)% higher than that in the 4 electromagnetic layers. These same comparisons have been used to verify the absolute enersy conversion factors. The conversion factors work well for the electromagnetic sections.