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[en] A world-wide radionuclide network consisting of 80 stations is under establishment in the framework of the comprehensive nuclear test-ban treaty (CTBT). These monitoring stations are essential for the verification regime of the treaty and they will be able to monitor the airborne particulate as well as xenon isotopes that are produced by nuclear tests. The equipment, the operation and the locations of these stations are chosen in such a way to provide a very high confidence of the compliance of the treaty.
[en] In this paper, we want to study a generalized form of γ-unstable Bohr Hamiltonian in which there is no degeneracy between the excited levels. For this study, we consider a Killingbeck potential for the system. The results show the elimination of the degeneracy between the levels. According to the results we reproduce experimental data of some Xenon isotopes and discuss about them. The results show a good agreement between the theoretical prediction and experimental data.
[en] Relative yields of Kr and Xe isotopes from the spontaneous fission of 248Cm and 250Cf have been determined mass spectrometrically. The yields are as follows: 83Kr/84Kr/85Kr/86Kr = 0.223/0.458/0.596/ identical 1.00 and 0.306/0.582/0.793/ identical 1.00; 131Xe/134Xe/136Xe = 0.486/0.819/1.075 identical 1.00 and 0.343/0.506/0.851/ identical 1.00 from 248Cm and 250Cf, respectively. The Xe yields from 248Cm agree with an earlier determination by Leich et al. Neither of these yield patterns matches that of fissiogenic Kr and Xe in carbonaceous chondrites and hence 248Cm and 250Cf are ruled out as progenitors of the meteoritic Kr and Xe. In general, none of the spontaneously fissioning nuclides of actinide elements can be identified as a possible progenitor. Even the mixtures of actinides, including a combination of 248Cm and 250Cm, are unsuitable. The origin of anomalous Kr and Xe in carbonaceous chondrites must then be traced either to the spontaneous fission of a superheavy element or to peculiarities in specific nucleosynthetic reactions. (orig.)
[en] Detection and measurement of atmospheric radioxenon is an important component of international monitoring systems for nuclear weapons testing. Monitoring stations separate xenon from air and perform isotopic analysis of the radioxenon. In one such radioxenon measurement scheme, the isotopes of interest are identified by coincident spectroscopy of electrons and photons in a β/γ coincidence spectrometer (BGCS). The β spectrometer is a plastic scintillator, manufactured as a cylindrical cell containing the separated xenon sample. This cell is surrounded by the NaI(Tl) γ spectrometer. We report here the development of a calibration process for the BGCS suitable for use in remote sampling systems. This procedure is based upon γ-ray Compton scattering, resulting in a true coincident signal in both detectors, generation of electrons over a wide energy range that matches the energy distribution of electrons from radioxenon decay, and a relative insensitivity to source location. In addition to gain calibration, this procedure determines the resolution of the β detector as a function of energy
[en] Full text: The neutron-rich Xe isotopes (Z=54) are located north-east of the doubly magic shell closures at Z=50 and N=82. In this region of the nuclear chart, the onset of octupole collectivity towards the 'magic' octupole numbers Z=56 and N=88 is expected too. The data presented here originate from two experimental campaigns performed at the Institut Laue-Langevin (ILL) in 2013 and the Argonne National Laboratory (ANL) at the turn of the year 2015/2016. The investigated nuclei were populated by neutron-induced fission of 235U and 241Pu (ILL) or spontaneous fission of 252Cf (ANL). Prompt gamma-ray spectroscopy of the fission fragments was performed with combined arrays of high-resolution HPGe detectors and fast LaBr3(Ce) detectors. The Xe isotopes of interest were tagged by gating in the HPGe detectors on one or more of its characteristic transitions. The lifetimes of excited states in the ps regime were determined from the LaBr3(Ce) detectors applying the 'Generalized Centroid Difference' (GCD) method . At ILL, the set-up consisted of 8 CLOVER detectors of EXILL combined with 16 LaBr3(Ce) detectors from the FATIMA collaboration . Several lifetimes in the yrast bands of 138,140,142Xe were determined, most of them for the first time . For the first time and more challenging, also two lifetimes in the odd isotopes 139,141Xe were measured. At ANL, the set-up consisted of half of GammaSphere (51 HPGe detectors) and 25 LaBr3(Ce) detectors from the NuSTAR-FATIMA collaboration . The status of the ongoing analyses and selected results will be presented. References:  J.-M- Regis et al., NIM A 726, 191 (2013);  J.-M- Regis et al., NIM A 763, 210 (2014);  S. Ilieva et al., Phys. Rev. C 94, 034302 (2016);  E. Gamba et al., contribution to this workshop. This work is supported by the German BMBF under grant no. 05P12RDNUP (NuPNET), ILL, the EXILL and FATIMA collaborations, the TU Darmstadt - GSI cooperation contract and HIC for FAIR; the work at ANL is funded by the U.S. DOE contract n. DE-AC02-06CH11357 and used resources of the DOE's ATLAS facility. (authors)
[en] The time-dependent and steady-state solutions for the transmission of a gaseous radioactive isotope through an adsorber bed are derived. Based on the mathematical results, criteria are given for the design of adsorber beds for decreasing the concentration of a radioactive contaminant. An example illustrates the possibility of reducing the radioactivity of short-lived xenon isotopes in a carrier gas flowing through adsorber beds. 12 refs
[en] An examination of proposed sampling sites near Chalk River Laboratories in Ontario, Canada is performed by considering the regional transport of radioxenon using atmospheric dispersion modeling. The local geography is considered, as are the local meteorological conditions during the summer months. In particular the impacts of predicted conditions on the imprinting of atmospheric radioxenon into the subsurface are considered and weighed against site proximity, geography, and geology. (author)