P. H. Fisher

An antimatter spectrometer in space

Abstract We discuss a simple magnetic spectrometer to be installed on a satellite or space station. The purpose of this spectrometer is to search for primordial antimatter to the level of antimatter/matter ≈10 −9 , improving the existing limits obtained with balloon flights by a factor of 10 4 to 10 5 . The design of the spectrometer is based on an iron-free, NdFeB permanent magnet, scintillation counters, drift tubes, and silicon or time projection chambers. Different design options are discussed. Typically, the spectrometer has a weight of about 2 tons and an acceptance of about 1.0 m 2 sr. The availability of the new NdFeB material makes it possible for the first time to put a magnet into space economically and reliably.

The L3 vertex detector: design and performance

Abstract The L3 vertex detector is comprised of the time expansion chamber (TEC), the Z -chamber and a layer of plastic scintillating fibers. The TEC has shown a high spatial resolution and an excellent multi-track reconstruction capability at LEP luminosity. The Z -chamber provides information about the z -coordinates of the tracks and the fibers are used for calibrating the drift velocity with a high precision. A description of the L3 vertex detector, its readout and data acquisition and its performance during the 1990 LEP running period is presented in this paper.

A study of spatial resolution for a preshower detector with aluminum absorber and silicon strip sampler

Abstract We have studied the spatial resolution of a preshower system with aluminum as absorber and silicon strips as the active sampling detector. The test beam was performed at X3 of the CERN SPS using an electron beam with energies between 4 and 50 GeV. The shower profiles of different beam momenta and absorber thicknesses are compared to full GEANT simulations.

Performance of the L3 plastic scintillating fibre calibration system

Abstract The L3 plastic scintillating fibre system is used to calibrate the central tracker by providing an external measurement of the track position in the bending plane. We describe the performance of the system during the LEP runs of 1989–1995 on the Z and the results of the calibration using the PSF system.

Spatial resolution of wedge shaped silicon microstrip detectors

Abstract Several wedge-shaped silicon microstrip detectors with pitches from 30 to 100 μm have been designed by our group and beam tested at the CERN SPS. We find the spatial resolution σ becomes larger at the rate of 0.21 μm per 1 μm increase in pitch, but the number of strips per cluster remains about the same as the pitch varies from 30 to 100 μm.