Showing papers by "C.W.E. van Eijk published in 1992"
25 Oct 1992
TL;DR: In this article, the quantum efficiency of five Philips XP2020Q photomultiplier tubes (PMTs), one Hamamatsu R2059 PMT, and a Na-salicylate coated glass window were determined using a calibrated EMI 9426 PMT as a reference.
Abstract: The quantum efficiency curves of five Philips XP2020Q photomultiplier tubes (PMTs), one Hamamatsu R2059 PMT, and a Na-salicylate coated glass window are determined using a calibrated Thorn EMI 9426 PMT as a reference. The QE of XP2020Q PMTs at wavelengths smaller than 230 nm appears much better than the values specified by the manufacturer. Consequently, the often reported photon yield of 2000 photons/MeV for the fast component of the scintillation pulses from pure BaF/sub 2/ crystals determined with this tube is overestimated. The authors' results, obtained by means of calibrated equipment and using 662-keV gamma -rays, yield a value of 1400 photons/MeV. >
78 citations
25 Oct 1992
TL;DR: In this paper, the scintillation properties of Ce/sup 3+/ and Pr/sup3+/ doped complex fluoride crystals were studied by means of X-ray and gamma ray excitation.
Abstract: The scintillation properties of Ce/sup 3+/ and Pr/sup 3+/ doped complex fluoride crystals of composition CsGd/sub 2/F/sub 7/:Ce/sup 3+/, Pr/sup 3+/ and K/sub 2/YF/sub 5/:Ce/sup 3+/, Pr/sup 3+/ and of Pr/sup 3+/ doped Y/sub 3/Al/sub 5/O/sub 12/:Pr/sup 3+/ single crystals are studied by means of X-ray and gamma ray excitation. The Ce/sup 3+/ and Pr/sup 3+/ doped fluoride crystals show 5d-4f luminescences at wavelengths near 340 nm and 240 nm, respectively. 5d-4f luminescence of Pr/sup 3+/ doped Y/sub 3/Al/sub 5/O/sub 12/ is observed between 300 and 400 nm. The absolute light yield in photons/MeV is presented together with results from scintillation decay time experiments. >
42 citations
TL;DR: In this paper, the luminescence decay of BaF2 doped with lanthanum was studied, and the decay shows contributions from cross-luminescence (CL) and self-trapped exciton (STE) luminecence.
Abstract: The luminescence decay of BaF2 doped with lanthanum was studied. The decay shows contributions from cross-luminescence (CL) and self-trapped exciton (STE) luminescence. The STE luminescence is quenched in the doped crystals, and shows two non-exponential decay components. Models yielding good fits to the decay data are discussed, as well as the physical relevance of the fitting parameters found.
17 citations
TL;DR: In this article, the self-trapped exciton (STE) luminescence at 300 nm with a decay time of 620 ns in pure BaF2 can be suppressed by La3+ or Nd3+ doping.
Abstract: The self-trapped exciton (STE) luminescence at 300 nm with a decay time of 620 ns in pure BaF2 can be suppressed by La3+ or Nd3+ doping. Crystals were studied with La concentrations ranging from 0.2 mol.% to 22 mol.% and Nd3+ concentrations between 0.15 and 11 mol.% X-ray induced emission spectra at temperatures from 90 K to 430 K and decay-time spectra are presented. Information about trapping of electrons by La3+ ions and the activation energy for thermal quenching of STE luminescence is obtained from a fit of the experimental data to a model calculation. The conclusions obtained for La3+ -doped crystals can also be employed for explaining similar aspects of the STE luminescence observed for the Nd3+ -doped BaF2 crystals.
14 citations
Journal Article•
6 citations
01 Dec 1992-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the authors describe an experiment with a new approach to the problem by the introduction of a gas scintillation proportional detector, which is the first evidence for physics beyond the standard model of interactions of elementary particles.
Abstract: Evidence for the existence of a 17 keV neutrino was first reported in 1985. Since then many experiments have been performed, however, with contradicting results. Confirming the existence of a 17 keV neutrino would represent the first evidence for physics beyond the standard model of interactions of elementary particles. Consequently it is of extreme importance to settle the question of the 17 keV neutrino mass. In this paper we describe an experiment with a new approach to the problem by the introduction of a gas scintillation proportional detector.
3 citations
25 Oct 1992
TL;DR: In this paper, a gas scintillation proportional detector was used to search for 17-keV neutrinos in the semiconductor lattice with a count rate of 1000 events per second, of which 300 are considered good events.
Abstract: An experiment in which a gas scintillation proportional detector is used to search for 17-keV neutrinos is described. With this detector, possible disturbing solid-state phenomena from tritium in the semiconductor lattice are excluded. With a count rate of 1000 events per second (including position information), of which 300 are considered good events, it takes 40 days to produce the required statistics. It is shown that the detector considered possesses the required energy resolution with drift properties. >
2 citations
07 Jun 1992
TL;DR: In this article, the CPLEAR experiment is aimed at precise CP violation tests using initially pure K 0 and K 0 beams from the intense source provided by the annihilation of the LEAR p - beam in hydrogen.
Abstract: The CPLEAR experiment is aiming at precise CP violation tests using initially pure K 0 - and K 0 beams from the intense source provided by the annihilation of the LEAR p - beam in hydrogen. The strangeness tagging efficiency and the systematic errors have been studied and found to be in agreement with the design specifications. The measurement of the differential time asymmetry of the π+π− decays allowed the direct observation of differences in the decay rates of particles and antiparticles. The CP violating parameters were determined as |ν±| = (2.32 ± 0.14) · 10−3 and ψ± = 42.3° ± 4.4°. First results in the reconstruction and analysis of the neutral kaon decays into two neutral pions and the Ke3 decay are presented.