E. Nappi

The macro detector at the Gran Sasso Laboratory

Abstract The MACRO detector is presently under construction, its installation at Gran Sasso being planned to start in September 1987. It is a large area detector, the acceptance for isotropic particle fluxes being around 10 000 m 2 sr, designed to search for rare phenomena in the cosmic radiation. It makes use of three detection techniques: liquid scintillator counters, plastic streamer tubes, and track-etch. It will perform a search for GUT monopoles (or any supermassive charged penetrating particle), a survey of cosmic point sources of HE gammas and neutrinos, a systematic study of the penetrating cosmic ray muons, and will be sensitive to neutrino bursts from gravitational stellar collapses in the Galaxy.

A proximity focusing RICH detector for kaon physics at Jefferson lab hall A

Important information on the LN interaction can be obtained from High Resolution Hypenuclear Spectroscopy experiments with electromagnetic probes. A challenging experiment on electroproduction of hypernuclei is scheduled for 2003 in Hall A at Jefferson Lab. One of the challenges is the high performance particle identification system needed. The signal is expected to be rare compared to the very high pion and proton backgrounds due to the small electron and kaon detection angles. The ‘‘standard’’ Hall A PID apparatus (TOF and two aerogel threshold Cherenkov detectors) does not provide sufficient suppression of the background. Simulations and calculations have shown that a RICH detector would solve the problem. A proximity focusing fluorocarbon/CsI detector similar to the ALICE RICH detector has been designed, built, tested and commissioned. The results show that the detector performs as expected. r 2003 Published by Elsevier Science B.V. PACS: 29.40.Ka; 85.60.Gz

A transition radiation detector for electron identification in a high energy experiment

Abstract We have built a transition radiation detector consisting of four sets of multilayered polyethylene radiators each followed by a xenon-filled proportional chamber. This detector has been used in a hadron-proton scattering experiment at CERN SPS to discriminate electrons from hadrons in the final state. Using the technique of recording chamber signals of amplitude exceeding a fixed threshold we normally achieved 0.5% pion contamination at 80% electron efficiency.

Transition radiation detectors for underground and space laboratories

Abstract The performances of transition radiation detectors are reviewed. We discuss the applications of these devices to measure the energy of cosmic rays muons in underground laboratories and present the first results from prototypes operating in the TeV energy region. Another interesting application of transition radiation detectors is the discrimination of positron from protons in the outer space to search for primordial antimatter. Prototypes developed for WIZARD experiment are described.

A Progress report on the development of the CsI - RICH detector for the ALICE experiment at LHC

The particle identification in ALICE (A Large Ion Collider Experiment) at LHC will be achieved by two complementary systems based on time-of-flight measurement, at low p t , and on the Ring Imaging Cherenkov (RICH) technique, at p t ranging from 2 to 5 GeV/c, respectively. The High Momentum PID (HMPID) system will cover &5% of the phase space, the single-arm detector array being composed by seven 1.3]1.3 m2 CsI-RICH modules placed at 4.7 m from the interaction point where a density of about 50 particles/m2 is expected. A1 m 2prototype, 2 of HMPID module size, has been successfully tested at the CERN/PS beam where 18 photoelectrons per event have been obtained with 3 GeV/c pions and 10 mm liquid C 6 F 14 radiator. Mechanical problems related to the liquid radiator vessel construction have been solved and the prototype, fully equipped, will be tested at the CERN/SPS to investigate the PID capability in high particle density events. In this report, after an introductory discussion on the requirements for PID in ALICE, the HMPID prototype is described and the main results of beam tests on large area CsI photocathodes, operated in RICH detectors, are given. ( 1998 Elsevier Science B.V. All rights reserved.

Evaluation of the deflections in the radiator vessel of the ALICE RICH array using numerical methods

Abstract The RICH array in ALICE (A Large Ion Collider Experiment) at CERN-LHC is being designed following the basic criterion to optimize the detector performances in terms of Cherenkov angle resolution and the minimisation of the total material traversed by the incoming particles. Due to the physics requirements, low deformation of the liquid freon container is mandatory, therefore a careful engineering design to predict the deflection of the radiator structure when filled with freon is needed. The aim of this study is the design of the liquid freon container under different static load conditions since the RICH array is placed in a barrel frame structure of about 4 m radius and 8 m length. Because of its high stiffness and low weight, a honeycomb sandwich with NOMEX ® core and carbon fiber skins is used for the vessel structure. Different solutions are analyzed using numerical techniques, based on Navier double series expansion and finite element method. They show good agreement and highlight the possibility of obtaining negligible stresses and strains.