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V. Hannen,
E. Aprile,
F. Arneodo,
L. Baudis,
M. Beck,
K. Bokeloh,
A. D. Ferella,
K. Giboni,
R. F. Lang,
O. Lebeda,
H. -W. Ortjohann,
M. Schumann, A. Spalek,
D. Venos,
C. Weinheimer
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ABSTRACT: The isomer 83mKr with its half-life of 1.83 h is an ideal calibration source
for a liquid noble gas dark matter experiment like the XENON project. However,
the risk of contamination of the detector with traces of the much longer lived
mother isotop 83Rb (86.2 d half-life) has to be ruled out. In this work the
release of 83Rb atoms from a 1.8 MBq 83Rb source embedded in zeolite beads has
been investigated. To do so, a cryogenic trap has been connected to the source
for about 10 days, after which it was removed and probed for the strongest 83Rb
gamma-rays with an ultra-sensitive Germanium detector. No signal has been
found. The corresponding upper limit on the released 83Rb activity means that
the investigated type of source can be used in the XENON project and similar
low-background experiments as 83mKr generator without a significant risk of
contaminating the detector. The measurements also allow to set upper limits on
the possible release of the isotopes 84Rb and 86Rb, traces of which were
created alongside the production of 83Rb at the Rez cyclotron.
09/2011;
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ABSTRACT: Photo-absorption of γ-rays in thin Al, Co, Ti, and Mo convertors was examined with the aim to produce quasi monoenergetic photoelectrons having an energy spread of 0.5-4.7eV about mean kinetic energies at discrete values between 18632 and 80321eV. The photoelectron rates were estimated for commercial photon sources of (241)Am, (119m)Sn, (125m)Te and (109)Cd with activities of 0.55-3.7GBq. Photoelectrons ejected by (241)Am γ- and X-rays from Co convertors were measured with two different electron spectrometers and obtained energy spectra were compared with Monte Carlo predictions.
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 04/2011; 69(4):672-7. · 1.09 Impact Factor
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ABSTRACT: Photoabsorption of nuclear gamma-rays in thin metallic convertors was examined with the aim to produce monoenergetic photoelectrons of kinetic energy around 18.6 keV and natural width of about 1 eV. Calculations were carried out for commercial photon sources of 241Am (1.1 GBq) and 119mSn (0.5 GBq) irradiating Co and Ti convertors. Photoelectrons ejected by 241Am gamma- and X-rays from Co convertors of various thickness were measured with two electrostatic spectrometers. Comment: 22 pages, 3 tables, 11 figures, 58 references
03/2010;
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D. Venos,
J. Kaspar,
M. Zboril,
O. Dragoun,
J. Bonn,
A. Kovalik,
O. Lebeda,
M. Rysavy,
K. Schlosser, A. Spalek,
Ch. Weinheimer
[show abstract]
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ABSTRACT: The mono-energetic conversion electrons from the decay of 83mKr represent a unique tool for the energy calibration, energy scale monitoring and systematic studies of the tritium beta spectrum measurement in the neutrino mass experiment KATRIN. For this reason, the long term stability of energy of the 7.5 keV and 17.8 keV conversion electrons populated in the decay of solid 83Rb/83mKr vacuum evaporated sources was examined by means of two electron spectrometers.
03/2009;
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ABSTRACT: The mono-energetic conversion electrons from the decay of (83m)Kr represent a unique tool for energy calibration and systematic studies of the tritium beta spectrum measured in neutrino mass determination experiments. For this reason, the corresponding parent isotope was produced in reactions (nat)Kr(p,xn)(83)Rb. The behaviour of (83)Rb (T(1/2)=86.2d) and its daughter product (83m)Kr (T(1/2)=1.83h) was examined, when the (83)Rb was trapped in a cation-exchanger chromatographic paper or in zeolite. Using gamma spectroscopy measurements, recommendations for the production of a (83)Rb/(83m)Kr radionuclide generator based on these cation-exchangers and suitable for the neutrino mass determination experiment KATRIN were deduced.
Applied Radiation and Isotopes 10/2005; 63(3):323-7. · 1.17 Impact Factor
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ABSTRACT: The -spectrum of 241Pu with the endpoint energy of 20.8 keV was measured in the energy range from 0.2 to 9.2 keV. The spectra were recorded during 5700 h with an electrostatic spectrometer set to a resolution of E/E = 0.011. Electron energy losses within the radioactive source were treated by means of extensive Monte Carlo simulations of individual elastic and inelastic electron collisions. The upper limit for the admixture of hypothetical neutrinos with the rest masses between 14 and 17 keV/c2 was derived to be less than 0.40% (the lowest limit being 0.10% for the 16 keV/c2 mass) at the 95% C.L., independently of any free phenomenological parameter.
Journal of Physics G Nuclear and Particle Physics 09/1999; 25(9):1839. · 4.18 Impact Factor
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ABSTRACT: Backscattering in various backings of the 63Ni beta -sources was simulated by means of the Monte Carlo method under conditions similar to recent experiments. The relative intensity and energy distribution of backscattered electrons were found to depend strongly on the beta -particle energy. These findings should be taken into account in an accurate analysis of low-energy beta -spectra in particular when searching for the 17 keV neutrino.
Journal of Physics G Nuclear and Particle Physics 12/1998; 19(12):2071. · 4.18 Impact Factor
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ABSTRACT: The influence of the residual T atoms appearing after the decay of T_2 molecule on the beta-spectrum shape is considered. Recent experiments performed in Mainz, Troitsk, and Livermore are briefly reviewed from this viewpoint. Aspects connected with the possible time dependent change of the tritium source composition are discussed.
02/1998;
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ABSTRACT: By depositing PVD coatings on already conventionally galvanized steel sheets novel zinc alloy coatings have been developed. One of the biggest advantages of PVD coatings lies in the broad choice of coating materials as there are no constraints due to chemical reactions between the substrate and the coating. This leads to a variety in the coating compositions. Accordingly, PVD processes enable customized solutions for various purposes. Magnesium on galvanized sheet steel has been identified as a very promising coating system. Corrosion performance is improved considerably while other properties like forming, joining and painting are comparable to or better than the untreated galvanized material.
http://dx.doi.org/10.1051/metal:2004117.
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ABSTRACT: The effect of undetected imperfections of the energy scale on the results of electron spectroscopy experiment is studied for the conditions close to the tritium β-decay experiment KATRIN [1]. A numerical model of the experiment is developed, verified, and used to deduce general trends of fitted parameters. The effects of energy bias and of wrong slope of the calibration line are studied in more detail.
Sci. Czech Rep.
