79 research outputs found
Response to electrons and pions of the calorimeter for the CHORUS experiment
No full textWe built and tested on charged particle beams the high energy-resolution calorimeter for the CHORUS experiment, which searches for nu(mu)-nu(tau) oscillations in the CERN Wide Band Neutrino Beam. This calorimeter is longitudinally divided into three sectors: one electromagnetic and two hadronic. The first two upstream sectors are made of lead and plastic scintillating fibers in the volume ratio of 4/1, and they represent the first large scale application of this technique for combined electromagnetic and hadronic calorimetry. The third sector is made of a sandwich of lead plates and scintillator strips and complements the measurement of the hadronic energy flow. In this paper, we briefly describe the calorimeter design and we show results on its response to electrons and pions, obtained from tests performed at the CERN SPS and PS. An energy resolution of sigma(E)/E=(32.3+/-2.4)%/root E(GeV)+(1.4+/-0.7)% was achieved for pions, and sigma(E)/E=(13.8+/-0.9)%/root V(GeV)+(-0.2+/-0.4)% for electrons
THE HIGH-RESOLUTION CALORIMETER OF THE CHORUS EXPERIMENT
No full textThe CHORUS Collaboration is presently building a new detector for the search of vμ−vτ oscillations on the CERN neutrino beam, this experiment being sensitive to a mixing angle an order of magnitude smaller than previous experiments. The basic components of the CHORUS “hybrid” detector are an active target made of nuclear emulsions (for the direct observation of the decay of τ-leptons), an air-core spectrometer with scintillating fiber tracking, a lead-scintillator (fibers and strips) calorimeter (with μ-tracking provided by planes of limited streamer tubes) and a muon spectrometer, consisting of iron toroids and drift chambers. We report here on the design of the calorimeter and on the tests performed on prototype modules
CONSTRUCTION AND TEST OF MODULES OF THE CHORUS CALORIMETER
No full textThe CHORUS Collaboration is presently building a new detector for the search of nu(mu)-nu(tau) oscillations in the CERN neutrino beam, the experiment being sensitive to a mixing angle an order of magnitude smaller than the present limit. The basic components of the CHORUS ''hybrid'' detector are an active target made of nuclear emulsions, an air core spectrometer with scintillating fiber tracking, a high resolution calorimeter and a muon spectrometer. An account is given here of the design of the 110-tons compensating calorimeter, made of 1 mm diameter scintillating fibers embedded in a lead matrix, and of the test results from the first modules produced
SPACE RESOLUTION OBTAINED WITH A HIGHLY SEGMENTED SCIFI EM CALORIMETER
No full textDuring the setting up of the LEP-5 experiment, we tested a longitudinal SCIFI e.m. calorimeter, having a module cross area 25 x 25 mm2 and 12.5 x 12.5 mm2 for large and small modules respectively. The results were obtained with 10 and 50 GeV electrons, and concern the impact point resolution and the transverse distribution of the e.m. shower energy inside the calorimeter
CONSTRUCTION AND TEST OF CALORIMETER MODULES FOR THE CHORUS EXPERIMENT
No full textThe construction of modules and the assembly of the calorimeter for CHORUS, an experiment that searches for nu(mu) nu(tau) oscillation, have been completed. Within the experiment, the calorimeter is required to measure the energy of hadronic showers produced in neutrino interactions with a resolution of similar to 30%/root E(GeV). To achieve this performance, the technique, developed in recent years, of embedding scintillating fibers of 1 mm diameter into a lead matrix has been adopted for the most upstream part of the calorimeter. A more conventional system, of alternating layers of lead and scintillator strips, was used for the rest. Details of module construction as well as results obtained when modules were exposed to electron and muon beams are presented
Antihydrogen production and precision experiments - The ATHENA collaboration
No full textThe study of CPT invariance with the highest achievable precision in all particle sectors is of fundamental importance for physics. Equally important is the question of the gravitational acceleration of antimatter. In recent years, impressive progress has been achieved at the Low Energy Antiproton Ring (LEAR) at CERN in capturing antiprotons in specially designed Penning traps, in cooling them to energies of a few milli-electron volts, and in storing them for hours in a small volume of space. Positrons have been accumulated in large numbers in similar traps, and low energy positron or positronium beams have been generated. Finally, steady progress has been made in trapping and cooling neutral atoms. Thus the ingredients to form antihydrogen at rest are at hand. We propose to investigate the different methods to form antihydrogen at low energy, and to utilize the best of these methods to capture a number of antihydrogen atoms sufficient for spectroscopic studies in a magnetostatic trap. Once antihydrogen atoms have been captured at low energy, spectroscopic methods fan be applied to interrogate their atomic structure with extremely high precision and compare it to its normal matter counterpart, the hydrogen atom. Especially the 1S-2S transition, with a lifetime of the excited state of 122 ms and thereby a natural linewidth of 5 parts in 10(16) offers in principle the possibility to directly compare matter and antimatter properties at a level of 1 part in 10(18). Additionally, comparison of the gravitational masses of hydrogen and antihydrogen, using either ballistic or spectroscopic methods, can provide direct experimental tests of the Weak Equivalence Principle for antimatter at a high precision
NEUTRAL CURRENT COUPLING-CONSTANTS FROM NEUTRINO-ELECTRON AND ANTINEUTRINO-ELECTRON SCATTERING
No full textWe are reporting on a determination of neutral current coupling constants from a study of differential cross sections of muon- (anti)neutrino-electron scattering. The results were obtained with the CHARM-II detector which was exposed to the CERN wide band neutrino beam in the years 1987-1990. A total of about 2100 ve and 2200 v ̄e scattering events were observed. From a comparison between the data and predicted event distributions, the effective vector and axial-vector neutral current coupling constants of the electron were determined to be ge_v=-0.025+/-0.019 and ge_A=-0.503+/-0.018
A high-resolution tracking detector based on capillaries filled with liquid scintillator
No full textResults are presented on tests in a 5 GeV/c hadron beam of a high-resolution tracking detector constructed from 20 μm diameter glass capillaries filled with liquid scintillator. Details are given of the techniques used to eliminate noise in the readout system and to reduce cross-talk between capillaries. A spatial resolution of 15 μm is obtained.0info:eu-repo/semantics/publishe
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