The final 20 layer prototype for the AMS transition radiation detector : beamtests, data analysis, MC-studies
type: CreativeWork
description: The AMS TRD prototype, as described in this thesis, was subjected to 2 high energy beamtests at CERN test facilities (X7,H6) in summer 2000, where more than 3 million events of p+,e-,pi- and mu- data with beam energies up to 250 GeV have been recorded. The data analysis is based solely on single track events. These are selected from several selection criteria, applied to all events with a successfully reconstructed single track from linear regression. The rejection analysis was mainly focused on the prototype's capability of rejecting protons against electrons. These rejection factors as functions of beam energy were determined in two different ways, namely using the Cluster Counting and a Likelihood method. The Cluster Counting (CC) method is based on the binary counting of hits on the track above a certain energy threshold, *Ecut*, and the requirement of a minimum number, *Hcut*, of such hits for an event to be selected "electron-like". This *Hcut*, referring to a defined *Ecut*, is chosen such that 90% of the electrons are accepted. The application of this same *Hcut* to all proton events is used to calculate the rejection factor, as the ratio of total number of proton events in the sample, divided by those events that are selected "electron-like". This analysis derived rejection factors ranging from (625 +/- 117) at 20 GeV down to (80 +/- 5) at 250 GeV beam energy. The indicated errors are calculated from the statistical uncertainty of the selected number of proton events. The likelihood (LH) method uses the full proton and electron energy spectra as single hit probability distributions, after normalisation to an integral of one. For each event, the single hit probabilities for the hits on the track are multiplied and the geometric mean is calculated separately for the electron (Pe) and proton (Pp) hypotheses. The electron likelihood is finally calculated as the ratio Le = -ln(Pe/(Pe+Pp)). In the *Le* distribution of electron events the *LHcut* is now chosen suc…
abstract: The AMS TRD prototype, as described in this thesis, was subjected to 2 high energy beamtests at CERN test facilities (X7,H6) in summer 2000, where more than 3 million events of p+,e-,pi- and mu- data with beam energies up to 250 GeV have been recorded. The data analysis is based solely on single track events. These are selected from several selection criteria, applied to all events with a successfully reconstructed single track from linear regression. The rejection analysis was mainly focused on the prototype's capability of rejecting protons against electrons. These rejection factors as functions of beam energy were determined in two different ways, namely using the Cluster Counting and a Likelihood method. The Cluster Counting (CC) method is based on the binary counting of hits on the track above a certain energy threshold, *Ecut*, and the requirement of a minimum number, *Hcut*, of such hits for an event to be selected "electron-like". This *Hcut*, referring to a defined *Ecut*, is chosen such that 90% of the electrons are accepted. The application of this same *Hcut* to all proton events is used to calculate the rejection factor, as the ratio of total number of proton events in the sample, divided by those events that are selected "electron-like". This analysis derived rejection factors ranging from (625 +/- 117) at 20 GeV down to (80 +/- 5) at 250 GeV beam energy. The indicated errors are calculated from the statistical uncertainty of the selected number of proton events. The likelihood (LH) method uses the full proton and electron energy spectra as single hit probability distributions, after normalisation to an integral of one. For each event, the single hit probabilities for the hits on the track are multiplied and the geometric mean is calculated separately for the electron (Pe) and proton (Pp) hypotheses. The electron likelihood is finally calculated as the ratio Le = -ln(Pe/(Pe+Pp)). In the *Le* distribution of electron events the *LHcut* is now chosen suc…
author: Orboeck, Jörg
language: eng
keywords: info:eu-repo/classification/ddc/530, Physik, AMS, TRD, transition radiation, rejection, TR GEANT Simulation
date published: 2003
date modified: 2026-07-30T19:42:31Z
provider: RWTH Aachen University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Publikationsserver der RWTH Aachen University