Coherent emission of transition radiation in periodic radiators

Measurements have been made of X-ray transition radiation spectra, which were produced by relativistic electrons traversing periodic stacks of mylar and lithium foils. The dependence of the spectral yield on the stack parameters and on the momentum of the electrons establishes the influence of long-range coherence in the emission of transition radiation. (5 refs)

Iron liquid-argon and uranium liquid-argon calorimeters for hadron energy measurement

The authors studied, with a specially designed hadron calorimeter, the contributions of different mechanisms affecting the energy resolution of such instruments. It is shown that in ordinary materials the resolution is dominated by 'nuclear fluctuations'. Measurements with a uranium calorimeter show that these fluctuations can be effectively compensated by the amplifying effect of nuclear fission in uranium. The resolution at low energies is good ( sigma =9.6% for 10 GeV/c pions) and improving with energy. (12 refs)

Hadron cascades in iron and uranium

Cascade developments of hadrons and electrons are studied in iron and uranium-238 through the measurement of the total ionization produced in a fine grained multiplate ion chamber array. In iron the distribution of total ionization is dominated by nuclear binding energy fluctuations. In uranium-238, however, this fluctuation is compensated by correlated fission energy deposit resulting in a considerable reduction in the measured ionization fluctuation. (7 refs)

aus Kassel Breichter:

Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar. Zusammenfassung Mikrostreifengasdetektoren (MSGCs) sind ein vielversprechender Kandidat für großflächige Anwendungen. Sie vereinen eine gute Ortsauflösung mit hoher Granularität und einem geringen Preis. Als mögliche Erweiterung der einfachen MSGC kann eine Gas–Elektronenvervielfachungsfolie hinzugefügt werden, um die Betriebssicherheit zu erhöhen. Der äußere Teil der Spurkammer des Compact Muon Solenoid (CMS) Experimentes des zukünftigen Large Hadron Colliders (LHC) am Centre de Recherche Nucléaire (CERN) sollte mit MSGCs ausgestattet werden. In der zentralen Spurkammer sollten einfache MSGCs verwendet werden. Für den Vorwärts und Rückwärtsteil war MSGC+GEM Technologie vorgesehen. Diese Arbeit beschreibt den Bau und Test einer Vorserie von 18 voll funktionsfähige

A Test Setup for Quality Assurance of Front End Hybrids

The APV Readout Control (ARC) Test Setup is a compact, cost efficient test and diagnostic tool which is suited for full operation and characterisation of FE hybrids and Si-Detector modules. This note gives an overview of the construction and the features of the test facility. Based on the ARC setup and the experience gained with one prototype FE hybrid, possible quality assurance scenarios for short and long term tests of FE hybrids are also presented

Micro Strip Gas Chambers with Gas Electron Multipliers and their Application in the CMS Experiment

Micro Strip Gas Chambers (MSGCs) have become a very popular type of gaseous detector throughout the last decade. However, its good spatial resolution and high rate capability was overshadowed by instabilities when operated in environments with a high particle flux. Since a major part of the tracking system of the upcoming Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) was planned to be built based on this technology, considerable efforts have been taken to solve those difficulties. This thesis looks at one possible approach to get rid of high rate instabilities: the application of a Gaseous Electron Multiplier (GEM) as a second amplification stage for an MSGC. The design goal was to build a robust detector with the capability of operating safely in the harsh LHC environment with expected particle fluxes up to 10 4 Hz/mm 2 while maintaining the full MSGC performance in terms of spatial resolution and detection efficiency. Such detectors have been successfully built. Stable operation with particle fluxes up to 3x10 4 Hz/mm 2 could be shown. Full detection efficiency of 99 % has been reached at a signal to noise ratio of 18. A spatial resolution of better than 40µm has been achieved. A full scale detector in the CMS baseline design for the forward tracker has been realised and successfully tested in LHC-like conditions