Monte Carlo calculation of entire in situ gamma-ray spectra.

We present a method for the synthesis of entire in situ gamma-ray spectra based on Monte Carlo calculations and measured data that characterize the detector properties. The method can serve for the determination of the effective depth of 137Cs in soil based on the information contained in the low-energy part of an in situ spectrum. Effective depth is defined as the depth of a plane distribution of 137Cs beneath the surface that reproduces the fluence energy and angular distribution at 1 m above the ground of gamma rays belonging to the real 137Cs distributions. We managed to reproduce the measured in situ spectra with our method and to demonstrate that the method allows the determination of the effective depth of 137Cs with a precision of 10(-2) m. The method requires minimal experimental characterization of the detector and is not sensitive to the details of the detector model and the soil composition and density employed in the Monte Carlo calculations.

A theoretical description of diffusion and migration of 137Cs in soil.

Careful measurements of activity concentrations of 137Cs in soil samples taken layer by layer in autumn of 1999 in Slovenia are confronted with a prediction based on the diffusion-convection equation with a boundary condition which--unlike the boundary conditions applied in the literature so far--conserves the deposited activity over time, except for the natural decay. It is shown that it is essential to consider the deposits from atmospheric nuclear weapons tests and the Chernobyl accident to arrive at a good fit to the measured data. The corresponding Green's function as well as the diffusion constant and migration speed based on the analysis are given.

Superdeformation in the N = Z nucleus 36Ar: experimental, deformed mean field, and spherical shell model descriptions

A superdeformed rotational band has been identified in 36Ar, linked to known low-spin states, and observed to its high-spin termination at Ipi = 16(+). Cranked Nilsson-Strutinsky and spherical shell model calculations assign the band to a configuration in which four pf-shell orbitals are occupied, leading to a low-spin deformation beta(2) approximately 0.45. Two major shells are active for both protons and neutrons, yet the valence space remains small enough to be confronted with the shell model. This band thus provides an ideal case to study the microscopic structure of collective rotational motion.

Noise and vibration load of lumbermen.

At eight lumbering sites in Slovenia the noise load of lumbermen working with new and used motor saws was investigated by noise measurements at the ear level. A major contribution to the noise load (Leqv = 96-100 dB(A) came from motor saw operations such as limbing. Lumbermen are overloaded with interrupted noise for 25 per cent of their working time. The noise produced by a used motor saw exceeds the noise coming from a new one by 0.7 dB(A). Results of a pilot research into the lumbermen's vibration load generated by Husqvarna 266 and 254 motor saws are also presented. The measurements involved three cutting sites and four lumbermen for six days. The vibration load during the working hours ranged between 6.6 and 10.8 m/s-2. Owing to the fact that vibrations are interrupted and the exposure does not last throughout the working day, the vibration load does not reach a level which would be detrimental to lumbermen's health.