Search results for "Beta particle"

In-situ observation of beta-ray induced UV optical absorption in a-SiO2: radiation darkening and room temperature recovery

2006

International audience; We studied the optical absorption in the 3.0-6.2 eV range induced in bulk amorphous SiO2 by beta-ray irradiation up to similar to 1 MGy at room temperature. The induced absorption was measured in situ both during irradiation and in the post irradiation time. Our data evidence E', center as the main defect induced by irradiation and the partial decay of their absorption band at about 5.8 eV after irradiation. A quantitative analysis of the time evolution of the induced absorption shows that the transmission recovery observed after irradiation is compatible with the reaction of radiation-induced defects with H-related (H-2, H2O) species diffusing in the amorphous matrix

Radiolanthanides in Nuclear Medicine

2004

Short and medium effects on the environment of Valencia, Spain, of the Chernobyl nuclear plant accident.

1991

As a consequence of the 26 April 1986 accident at the Chernobyl nuclear plant, a large amount of radioactivity was released into the atmosphere. The radioactive plume formed could be detected in practically the whole of the Northern Hemisphere a few days later. The zone most affected by the radioactive cloud over Spain was that of the Mediterranean coast and the Balearic Islands. In this paper, the authors examine the level of the radioactive contamination reached in various receptive media in Valencia, such as air, dry-fallout, water, soil, grass and milk samples collected in Valencia immediately after the accident. The activity levels are compared with those found during 1964 and 1965 due…

Laser spectroscopy and β-decay asymmetry from on-line implanted nuclei

1985

The method of collinear laser spectroscopy is combined with s-radiation detected optical pumping by implanting the optically oriented atoms into a cubic crystal.

Beta-decay half-lives of very neutron-rich nuclei and their consequences for the astrophysical r-process

2005

Half-lives for Gamow-Teller β-decay of very neutron-rich nuclei have been calculated using the RPA shell-model code of Krumlinde and Muller. For the examples of the isotope sequences of 27Co and 37Rb, and of nuclei around 132Sn it is demonstrated that close agreement between experiment and theory can be obtained, provided an appropriate choice of model parameters is made for each mass region. On the basis of this agreement, T1/2 predictions for isotopes up to the r-process path are made and compared to earlier model calculations. Possible implications of the results on the site and the cycle time of the r-process are discussed.

Note on the decay of200Au

1972

Gamma and beta rays from the decay of200Au (48.4 min) were studied employing Ge(Li) and plastic detectors in various singles and coincidence arrangements. The intensity of the β-branch to the ground state of200Hg was determined as 79%, and the disintegration energy of200Au to be asQβ=2.26 ± 0.06 MeV. A tentative spin and parity assignment of (1,2)+ is proposed for levels at 1515.2 and 1972.5 keV in 200Hg

High-precision mass measurement ofS31with the double Penning trap JYFLTRAP improves the mass value forCl32

2010

Generation of oxygen deficient point defects in silica by γ and β irradiation

2007

We report an experimental study of the effects of y and β irradiation on the generation of a point defect known as ODC(II) in various types of commercial silica (a-SiO 2 ). The ODC(II) has been detected by means of photoluminescence (PL) spectroscopy measuring the PL band centered at 4.4 eV and excited at 5.0 eV associated to this defect. Our experiments show that ODC(II) are induced in all the investigated materials after irradiation at doses higher than 5 x 10 2 kGy. A good agreement is observed between the efficiencies of generation of ODC(II) under y and β irradiation, enabling a comprehensive study up to the dose of 5 x 10 6 kGy. Two different growth rates, one in the low and one in th…

Total absorption spectroscopy study of the β decay of Br86 and Rb91

2017

The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the IGISOL facility in Jyvaskyla and further purified using the JYFLTRAP. 86Br and 91Rb are considered high priority contributors to the decay heat in reactors. In addition 91Rb was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decay was well known from high-resolution measurements. Our results shows that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renormalized.

Circular Polarization of External Bremsstrahlung Produced by Beta Rays

1958

For energies smaller than 600 kev, the polarization was previously measured using forward scattering from magnetized iron, but a quantitative comparison was not performed. Computations were done for monoenergetic electrons falling on a thin absorber, whereas in all experiments the whole beta spectruan and thick absorbers were used. It is shown thnt even in this case a comparison with theory is possible as the diffusion of the electrons in the absorber has practically no influence on the polarization. Strong dependence of the circular polarization on the atomic number of the absorber is investigated. (W.D.M.)