E. Perrin

The evaporative cooling system for the ATLAS inner detector

This paper describes the evaporative system used to cool the silicon detector structures of the inner detector sub-detectors of the ATLAS experiment at the CERN Large Hadron Collider. The motivation for an evaporative system, its design and construction are discussed. In detail the particular requirements of the ATLAS inner detector, technical choices and the qualification and manufacture of final components are addressed. Finally results of initial operational tests are reported. Although the entire system described, the paper focuses on the on-detector aspects. Details of the evaporative cooling plant will be discussed elsewhere.

Construction and performance of the ATLAS silicon microstrip barrel modules

Abstract The ATLAS Semiconductor Tracker (SCT) consists of four barrel cylinders and 18 end-cap disks. This paper describes the SCT modules of the barrel region, of which more than 2000 are about to be constructed. The module design is fixed. Its design concept is given together with the electrical, thermal and mechanical specifications. The pre-series production of the barrel modules is underway using mass-production procedures and jigs. The pre-series modules have given satisfactory performances on noise, noise occupancy, electrical as well as mechanical and thermal properties. In addition, irradiated modules were demonstrated to work successfully. Also first results from a 10-module system test are given.

Performance of a prototype BGO calorimeter in an electron beam from 2 to 50 GeV

Abstract A prototype of the L3 electromagnetic calorimeter to be used at LEP and consisting of 100 tapered BGO crystals has been tested in an electron beam in the energy range of 2 to 50 GeV. The energy resolution and linearity of response have been measured, and are compared to predictions made with the GEANT Monte Carlo program.

The L3 Silicon Microvertex Detector: installation and results on 1993 performance

Abstract The status of the Silicon Microvertex Detector (SMD) and its installation into the LEP-L3 experiment are presented, highlighting novel features and sophisticated techniques. Preliminary results based on 1993 data are given and compared with Monte Carlo predictions, to understand the detector performances and its tracking capabilities.

A study of the dimensional stability of the AMS silicon tracker

The Alpha Magnetic Spectrometer (AMS) is designed as an independent module for installation on the International Space Station (ISS) for an operational period of 3 years. The AMS is the first cosmic ray spectrometer equipped with a large area silicon tracker . A preliminary version of the detector was flown on the NASA space shuttle Discovery during June 2–12, 1998. Results for the dimensional stability of the silicon tracker planes based on the flight data, and the metrology data recorded before and after the flight, are presented.

Performance of a light emitting multistep avalanche chamber tracking system in Pb+Pb collisions

Abstract The construction and operation of light emitting multistep avalanche chambers will be described. Based on a preliminary analysis of data taken during the first Pb ion run at CERN the performance and operation of the tracking system will be discussed.

A silicon microstrip tracker in space: Experience with the AMS silicon tracker on STS-91

SummaryThe Alpha Magnetic Spectrometer (AMS) is designed as an independent module for installation on the International Space Station (ISS) in the year 2003 for an operational period of three years. The principal scientific objectives include the searches for antimatter and dark matter in cosmic rays. The AMS tracker uses silicon microstrip sensors to reconstruct charged-particle trajectories. A first version of the AMS, equipped with 2.1 m2 of silicon sensors and a permanent magnet, was flown on the NASA space shuttle Discovery duringJune 2–12, 1998. In this contribution, we describe the detector and present results of the tracker performance duringthe flight.

BEAM TEST of the ATLAS SILICON DETECTOR MODULES with BINARY READOUT in the CERN H8 BEAM in 19961

detector with small angle stereo readout. Readout will be AC-coupled from n-type implant strips in n-bulk crystals. increased depletion voltage [3], the junctions will be at the nstrips allowing the possibility of operation under partial depletion of the silicon. The readout electronics [4] employs a 1 bit binary scheme whereby only hits above a single threshold are recorded. In such a scheme the required resolution is achieved with 75pm pitch detectors. Noise OccuPancY must be well below not to exceed the bandwidth of the data transmission system. A key Derformance reauirement of such a system is to maintain are reprted from a beam test Of Prototype After radiation induced type inversion of the bulk and micro strip detectors and front-end electronics designed for use at the LHC. The detector assemblies were 12 cm long and were read out with binary electronics. Both irradiated and unirradiated assemblies were measured in a 1.56T magnetic field for efficiency, noise occupancy, and resolution as a function of bias voltage, binary hit threshold, and detector rotation angle with respect to the beam direction. Measurements were also performed at a particle flux comparable to the one expected at the LHC.

A large-acceptance spectrometer for tracking in a high-multiplicity environment, based on space point measurements and high-resolution time-of-flight

A large acceptance tracking system, specially developed for tracking at very high particle densities encountered in ultra-relativistic heavy-ion collisions is described. The system is a combination of multi-step avalanche chambers equipped with electronic pad readout with high position resolution in two dimensions and streamer-tube detectors with pad readout, with coarser position resolution, that is sufficient for safe pattern recognition. A high-resolution time-of-flight system (time resolution better than 90 ps) provides particle identification up to 8 GeV/c for pions and protons and pion/kaon separation up to 4 GeV/c. All detectors in the tracking system are read out with new, high-performance integrated circuits. The system can operate at high event rates due to efficient zero suppression. The performance of the system for tracking under real running conditions with Pb-beam at 158 A GeV in the WA98 experiment at CERN is presented

Performance of the ATLAS silicon strip detector modules

Abstract The performance of the silicon strip detector prototypes developed for use in ATLAS at the LHC is reported. Baseline detector assemblies (“modules”) of 12 cm length were read out with binary electronics at 40 MHz clock speed. For both irradiated and unirradiated modules, the tracking efficiency, noise occupancy, and position resolution were measured as a function of bias voltage, binary hit threshold, and detector rotation angle in a 1.56 T magnetic field. Measurements were also performed at a particle flux comparable to the one expected at the LHC.