[en] The ²³⁰U decay chain has been investigated using Ge(Li) spectrometers in singles and coincidence measurements. The internal-conversion spectra have been studied in a β-spectrometer with a Si(Li) detector placed in a homogeneous magnetic field. A total of 31 γ-ray transitions, 14 of which have not been reported before, have been observed in the decay of ²³⁰U and its descendants. All transitions could be unambiguously placed in the individual level schemes. The new band-heads at 805 and 914 keV in ²²⁶Th and ²²²Ra, respectively, are proposed as 0⁺ quadrupole-pairing vibrations. No evidence has been found for the existence of 0⁺ two-phonon harmonic octupole states in these nuclei. A possible anharmonicity of the octupole vibrations is discussed. (Auth.)

[en] We studied the ground state band properties of ²¹²Po, ²¹⁸Rn and ²³²U using the binary cluster model. The nuclei are treated as a ²⁰⁸Pb-core plus a cluster interacting via a local potential of Saxon–Woods type functional form whose parameters are derived from Michigan-3-Yukawa (M3Y) microscopic potential model. Further correction in the internal structure of the hybrid potential model is attributed to the nucleon distribution in the overlap region of the core-cluster system. Overall our calculated results are found to compare favourably well with available experimental data.

[en] It is demonstrated that the search performed by Wieland et al. for the elusive 1^- state in ²¹⁸Ra was not optimized and an alternative experiment is discussed. We demonstrate that existing data on Ra-Th nuclei and Sm-Gd nuclei raise further doubts on suggestions and implication of Wieland et al

[en] This evaluation was completed in 2007. Literature available by January 2007 was included. Decay Scheme: ²¹⁸Rn disintegrates by alpha emissions to the 609-keV level (0.127 (7)%) and to the ground state (99.873 (7)%) of ²¹⁴Po. Spins and parities are from the mass-chain evaluation of Y. A. Akovali (1987El12, 1995El08, 1998Ak04 and 2006Ja03 for A = 218 and 1995El07 for A = 214). A good agreement was found between the recommended Q value from Audi and the effective Q value (7262.5 (20) keV) calculated from decay scheme data

[en] Areas of high natural radiation expose the local population to doses greater than the world average. One of the routes of exposure is food intake. The activity concentration (AC) of 5 natural radionuclides in 7 types of foods was analyzed. The highest CA measured was 2.40 Bq.kg^-1 for the U_nat in the potato. The multivariate statistic identified two groups: (U_nate ²³²Th) and [(²¹⁰Pb and ²²⁸Ra) and ²²⁶Ra]

No abstract available

No abstract available

[en] Recent studies of three-count total alpha sequential sampling and counting methods using a law of propagation of erros (LPE) model has shown that small variations in pump flow rate and airborne radon progeny concentrations present from measurement to measurement can result in much larger variations in the overall precision of measurement than can be predicted on the basis of counting statistics alone. In contrast, results predicted by a Monte Carlo simulation (MCS) model developed in this work show that these variations have only a small effect on the overall precision of measurement for radon progeny concentrations typically found in uranium mines (1000-3700 Bq m^-3) and in buildings with potential alpha energy concentrations equal to or exceeding 4x10^-7 J m^-3(0.02 WL). The discrepancy observed between results predicted by the MCS model and the LPE model is attributed mainly to the LPE model assumption of independence of variations in alpha count totals and independence of variations in estimated airborne radon progeny concentrations. For the case where radioactive decay is the only source of random error, the LPE model assumption of independence in estimated airborne radon progeny concentrations results in an overestimation of the relative standard deviation of the potential alpha energy concentration by from 80 to 105%. Monte Carlo precision estimates evaluated for sequential three-count total-alpha measurement techniques show that precision estimates based on counting statistics alone are reliable when measurement to measurement pump flow rate variations are less than 3% and litre to litre concentration variations are less than 10%. (orig.)

[en] In this paper the α-decay of even-even nuclei from ground state to ground state and ground state to excited states of daughter nuclei within the Coulomb and Proximity Potential model which has been modified by incorporating the ground-state deformations β₂ and β₄ of the parent and daughter but treating the cluster as a sphere have been studied

[en] The half-lives of ²¹⁴Po and ²¹⁸Rn have been measured. The radionuclides were produced in the decay of a ²³⁰U source and the emitted alpha-particles were measured in nearly-2π geometry with an ion-implanted planar silicon detector. The data acquisition was performed with a digitiser operated in list mode, saving the energy and time of detection (10 ns precision timestamp) of each event. The half-lives were deduced from the time differences between the alpha-decays populating the nuclide of interest and those corresponding to its decay. Different methods were applied, based on delayed coincidence counting and time-interval distribution analysis. The resulting half-lives are 33.75 (15) ms for ²¹⁸Rn and 164.2 (6) μs for ²¹⁴Po, both in agreement with some of the literature values, and obtained with higher precision in this work. - Highlights: ► Measured half-lives of ²¹⁴Po 33.75 (15) ms, and ²¹⁸Rn 164.2 (6) μs. ► Results consistent with literature, but uncertainty now reduced. ► Used digital data acquisition to analyse delayed coincidences.