[en] Published in summary form only

[en] Letter-to-the-editor

[en] Letter-to-the-editor

[en] A pulse-shape discrimination circuit designed for use with multidetector arrays has been tested. Each module, containing two channels, occupies a single slot in a standard nuclear instrumentation module (NIM) crate and can be used without alteration, tests have shown, with either NE213 liquid scintillator detectors for neutron-gamma ray discrimination or with NaI(Tl) detectors for charged particle identification. Variations of the circuit which minimize either the power consumption or the complexity are presented. Outputs are provided for either a charge-to-digital converter or a time-to-digital converter. (orig.)

[en] T-d neutron yields have been determined with a high accuracy of about 1% by measuring the associated α-particles from the ³H(d,n)⁴He reaction using a ³H-Ti-Cu solid target at selected incident deuteron energies in the range 140-300 keV. Our results on the determination of the neutron yield as well as the neutron fluence rate at a certain position far from the neutron source point are presented. The T-d neutrons were produced by the 300 kV Cockcroft-Walton accelerator of Rikkyo University. We used a silicon p-i-n photodiode as an α-particle detector for the yield determination and a NE213 liquid scintillator (2 in. x 2 in.) or a counter telescope with a (CD₂)_n radiator as a neutron detector for the fluence rate determination. A collimator with a hole of different size (2, 3 or 4 mm in diameter) was placed in front of the α-particle detector to define precisely the solid angle. The n-γ discrimination of the NE213 neutron detector was completely performed. The results on the neutron yields obtained by both methods are compared and discussed. The time characteristics of the neutron detector have also been studied using both the associated α-particle detectors of the silicon photodiode and the NE102A thin (10 μm) scintillator, which were placed at 90⁰ with respect to the deuteron beam direction. (orig.)

[en] We discuss the architecture of a device based on the concept of associative memory designed to solve the track finding problem, typical of high energy physics experiments, in a time span of a few microseconds even for very high multiplicity events. This ''machine'' is implemented as a large array of custom VLSI chips. All the chips are equal and each of them stores a number of ''patterns''. All the patterns in all the chips are compared in parallel to the data coming from the detector while the detector is being read out. (orig.)

[en] Retractable targets of carbon fibres with nominal diameters of 30, 7 and 4.5 μm have been in use at the collision point of the SLC (the SLAC Linear Collider). The target mechanism is compatible with the Mark II detector now in place at the collision point. Beam profiles are measured in horizontal and vertical axes by using magnetic dipoles to scan the beams across the fibres. Two signal detection mechanisms are available. Electron emission from the fibres is measured with the help of charge-sensitive amplifiers. Bremsstrahlung from the fibres is detected by downstream counters. Examples of measurements are given, and limits on the use of the techniques are discussed. (orig.)

[en] The CHARM II Collaboration has built a massive, fine-grained and low-density detector for the study of muon-neutrino and muon-antineutrino scattering on electrons. The detector consists of a target calorimeter of 692 t of glass followed by a magnetic spectrometer. The calorimeter is used to detect the different types of neutrino interactions, and to measure the energy and direction of the produced particle showers; the spectrometer permits the determination of the momentum of muons produced in charged-current reactions on nuclei. The calorimeter is composed of 441 detector planes having a total of 154560 plastic streamer tubes with digital readout of the wires and of 73920 cathode pickup strips grouped in 9240 channels with analog readout. It is further instrumented with 1540 scintillators. A complete description of the detector and some results of its performance with cosmic-ray muons are presented. (orig.)

[en] A polarimeter for the polarized proton beam has been constructed at KEK. The measurement of the beam polarization at 3.5 GeV was performed by the newly constructed polarimeter. Monitoring of the beam polarization during the experiment was successfully done by a polyethylene target. The present paper describes the structure, the characteristics and the results of practical use for the experiment. (orig.)

[en] The choice of quench gas can have a significant effect on the gas gain and energy resolution of gas-filed proportional counters. Details are given on the performance obtained with a variety of quench additives of varying ionization potentials for use in xenon-filled systems. It is confirmed that optimum performance is obtained when the ionization potential is closely matched to the first metastable level of xenon (8.3 eV) as is the case with xenon + trimethylamine and xenon + dimethylamine. For these mixtures the Penning effect is at its strongest. (orig.)