The width and life-time of the quasibound state of the α cluster in intense monochromatic electromagnetic (laser) field are discussed in details. The laser modified three dimensional potential barrier felt by the α particle is investigated analytically in long wave approximation and zero-order approximations with some different nuclear models: Coulomb potential with rectangular well, and with Woods–Saxon type potential. We show that the circularly polarized electromagnetic field and the special parameters of the nuclear potentials determine an enhancement of the decay probability, so the life-time of the quasibound state decreases in few times compared to the case of free field.

The electron-nucleus interaction in a super-intense few-cycle x-ray pulse is investigated. The super-intense few-cycle x-ray pulse-induced internal conversion (IC) process is discussed in detail. The x-ray laser-pulse induced IC coefficient is calculated, and in particular, it is derived in the case of a pulse of Gaussian shape and for a bound-free electron transition. The IC coefficient of the IC process induced by a super-intense few-cycle soft-x-ray laser pulse in the case of the 99m Tc isomer is determined numerically. The results obtained for the IC coefficient show significant carrier angular frequency, carrier-envelope phase, and pulse-length dependencies. The infinite pulse-length limit and experimental aspects are also discussed.

Abstract. This paper presents the results of a round robin exercise carried out to compare specific activity measurements performed by eight European organisations on a set of ten neutron activation detectors containing the radio-nuclides 110m Ag, 60 Co, 54 Mn, 46 Sc and 94 Nb. The purpose of the exercise was to demonstrate the level of consistency between the participating organisations in blind tests of measurements relevant to reactor metrology. The samples used were selected from a stock of pre-existing irradiated material held at SCK•CEN. Taking turns over a period of approximately 9 months, the participating organisations received the samples, measured them and provided their results to an independent referee who collated and compared the data. The inter-comparison has demonstrated good agreement between the participants with standard deviations for each dosimeter varying between 1.6% and 3.1%. The paper provides results of the EWGRD Round Robin in an anonymised form together with discussion and conclusions which may be drawn from the exercise.

The change of the probability of proton emission in the nuclear photoeffect due to an intense coherent (laser) field is discussed near the threshold, where the hindering effect of the Coulomb field of the remainder nucleus is essential. The ratio of the laser-assisted and laser-free differential cross section is deduced and found to be independent of the polarization state of the γ field and the two types of initial nuclear state considered. The numerical values of this ratio are given at some characteristic parameters of the intense field. PACS numbers: 32.80.Wr,

A coupled thermal-hydraulics and reactor physics code system is being developed at the Institute of Nuclear Techniques of the Budapest University of Technology and Economics based on a higher-order transport approximation, the simplified spherical harmonics theory. The advantage of this method is that with a small increase in computational demand, it provides additional accuracy compared to diffusion theory. Besides - due to the fact that the multi-group SP3 and diffusion equations have a mathematically similar form - it requires minimal effort to implement an SP3 solution algorithm to an existing diffusion code. This paper focuses on an algorithm developed by the authors which applies Galerkin weighted residual method for spatial and theta method for time discretization. Results of two-group kinetic SP3 calculations performed with the SPNDYN code are also presented for various one-dimensional perturbations taking into account the delayed neutron precursor balance equations as well. The flexible nature of the SP3 equations makes the developed code a good starting point for more realistic dynamic calculations in the future.