J.C. Santiard

High-accuracy, bidimensional read-out of proportional chambers with short resolution times

Abstract The pulses induced in a multiwire proportional chamber on orthogonal cathode strips are integrated after filtering through gates of variable widths, down to about 30 ns. The determination of the charge centroid gives two coordinates. With minimum ionizing particles the accuracy along the wires is better than 200 μ m (fwhm). The advantages of the method over other read-out methods or drift chambers are discussed. The pulse-height information may permit ambiguity removal for multiple tracks.

Proportional chambers for a 50,000-wire detector

Abstract A multiparticle spectrometer at the CERN Intersecting Storage Rings is equipped with proportional chambers. In this paper we describe the construction of 20 modular 100 × 200 cm 2 wire chambers, the electronics for a 50K wire system, and the performance of the chambers.

ICON, a current mode preamplifier in CMOS technology for use with high rate particle detectors

A current mode preamplifier named ICON is intended for use in experiments at high-rate hadron colliders. The transient response and noise performance have been analyzed. One chip has been made using an ICON circuit with resistive feedback to produce a preamplifier with a peaking time below 10 ns. This fast preamplifier has a gain of 870 mV/pC and a power dissipation of around 1 mW. Another chip was made which uses the ICON circuit as the front-end to a dual port analog memory. The noise measured is between 2500 e/sup -/ and 3000 e/sup -/. An important characteristic of ICON is that it can tolerate a detector leakage current of 10 mu A at the DC coupled input. Therefore, it is very suitable for silicon detector systems under several radiation conditions.<<ETX>>

Progress in Cherenkov ring imaging: Part 1. Detection and localization of photons with the multistep proportional chamber

Abstract The multistep proportional chamber, operated with a photosensitive gas filling, makes it possible to obtain stable multiplication factors in excess of 106 and can be used for the detection of single photoelectrons released in the gas. The efficiency and localization properties of the device in the detection of vacuum ultraviolet photons are discussed here, in view of its use for particle identification exploiting the Cherenkov ring-imaging method.

Final tests of the CsI-based Ring Imaging Detector for the ALICE experiment

We report on the final tests performed on a CsI-based RICH detector equipped with 2 C6F14 radiator trays and 4 photocathodes, each of 6438 cm 2 area. The overall performance of the detector is described, using different gas mixtures, in view of optimizing the photoelectron yield and the pad occupancy. Test results under magnetic field up to 0.9 T, photocathode homogeneity and stability are presented.

The CsI based Ring Imaging Detector for the ALICE experiment: Technical description of a large prototype

We report on the design and construction of a CsI-RICH detector composed of four CsI photocathodes of 64]40 cm2 each, and two C 6 F 14 radiator trays of 133]41 cm2. A detailed description of the novel elements is given and the performance of the detector is illustrated with some basic results obtained during the tests at the beam. ( 1999 Elsevier Science B.V. All rights reserved.

Development of innovative micro-pattern gaseous detectors with resistive electrodes and first results of their applications

The paper summarizes our latest progress in the development of newly introduced micro-pattern gaseous detectors with resistive electrodes. These resistive electrodes protect the detector and the front-end electronics in case of occasional discharges and thus make the detectors very robust and reliable in operation. As an example, we describe in greater detail a recently developed GEM-like detector, fully spark-protected with electrodes made of resistive kapton. We discovered that all resistive layers used in these studies (including kapton) that are coated with photosensitive layers, such as CsI, can be used as efficient photocathodes for detectors operating in a pulse counting mode. There is a description of the first applications of such detectors combined with CsI or SbCs photocathodes for the detection of UV photons at room and cryogenic temperatures.

Review of the hybrid photo diode tube (HPD): An Advanced light detector for physics

The HPD is a nonmultiplicative light detector with typical gain of 1000 to 5000. Its development project, mainly supported by the CERN LAA project and by the INFN group V, was originally intended to find a replacement for the photo multiplier (PM) tubes for scintillating fibre calorimeter readout. After five years of development the HPD has become a versatile light detector, commercially available for everyday use, that can outperform PM tubes in photon counting efficiency and resolution, multi tesla magnetic field operation, uniformity of response, fast pulse dynamic range, and gain stability. The HPD has also a wide edge on PMs on pixelization potential and it is getting more and more competitive on timing properties. A review of the HPD performances and its latest advances are reported.

Recent results of radiation damage studies in silicon

Abstract The RD2 Collaboration is making preliminary studies on a silicon tracking detector for use at the LHC. It is a priority that this detector should withstand the high level of radiation to be expected for LHC operation. Therefore systematic studies on the change of the detector performance due to radiation damage have been made, or are in progress. Well established results on neutron related damage at room temperature have been extended to lower temperatures, as foreseen for operation at LHC. For comparison proton damage studies have also been started. The detector properties under investigation include the reverse current, the depletion voltage and the charge collection efficiency. With a compressed 10 year LHC operational scenario we have successfully checked the ability of silicon detectors to survive the period influences of high fluence irradiation and subsequent annealing.

Identification of high p⊥ particles with the STAR-RICH detector

Abstract The STAR-RICH detector extends the particle identification capabilities of the STAR experiment for charged hadrons at mid-rapidity. This detector represents the first use of a proximity-focusing CsI-based RICH detector in a collider experiment. It provides identification of pions and kaons up to 3 GeV /c and protons up to 5 GeV /c . The characteristics and performance of the device in the inaugural RHIC run are described.