[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.

No abstract available

No abstract available

[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] 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] 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 [1]. At ILL, the set-up consisted of 8 CLOVER detectors of EXILL combined with 16 LaBr₃(Ce) detectors from the FATIMA collaboration [2]. Several lifetimes in the yrast bands of ^138,140,142Xe were determined, most of them for the first time [3]. 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 [4]. The status of the ongoing analyses and selected results will be presented. References: [1] J.-M- Regis et al., NIM A 726, 191 (2013); [2] J.-M- Regis et al., NIM A 763, 210 (2014); [3] S. Ilieva et al., Phys. Rev. C 94, 034302 (2016); [4] 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] Measurement of radioxenon isotopes is one of the key components of the verification regime of the comprehensive nuclear-test-ban treaty. The β-γ coincidence technique is the most sensitive method for radioxenon isotopes detection. The self-attenuation effect of β-particles is unavoidable during β-γ coincidence measurement due to the presence of gas matrixes, such as stable xenon and other carrier gases, in the sample. In this study, the detection efficiencies of β-particles for radioxenon isotopes in different volumes of different gas matrixes (xenon, nitrogen, and helium) were simulated using Geant4 and the self-attenuation effects were deduced accordingly. The method to correct for the self-attenuation effects was thereby provided. (author)

[en] In this paper, a new code, Multicomponent Isotope Separation Cascade Code (MISCC-HS), is developed to calculate the optimal parameters of a cascade for separating multicomponent mixtures. The Harmony Search, HS, algorithm for finding the optimum solution is implemented and developed in the MISCC-HS. Minimizing the total flow rate of a cascade with the prescribed external isotope concentration has been studied. To demonstrate the MISCC-HS capability in converging to the near optimal cascade, the optimization results for the separation of xenon isotopes are compared with the results for the R-cascade that optimized by virtual component variation. MISCC-HS results represent the cascade with fewer centrifuges than the R-cascade. Furthermore, the ability of MISCC-HS is evaluated with other optimization algorithms. Suitable alignment of the results indicates that the use of the HS for this problem guarantees the calculation of the optimal parameters.