[en] In this thesis it is shown that the method of the off-line γ spectroscopy is very well suited for the determination of nuclid cross sections for the construction of mass-yield and angular distributions. The experiments performed at beam energies of 6.7 and 7.6 MeV/u were tested with the extra-push model proposed by Swjatecki and fit together with the data of other experiments well to this systematics. The mass-yield distribution allowed the partition of the whole reaction cross section to the different reaction mechanisms. By the taken angular distributions this assignment could be confirmed. The shape of the angular distributions of the symmetric component could be described by a 1/sin θ distribution as indication for an isotropic product distribution in the center-of-mass system. It was interpreted as a kinetically completely damped fission process. (orig./HSI)

[en] Abstract only

[en] Radon levels were measured in all show caves, visitor mines and thermal spas of Northrhine-Westphalia. Long-term measurements were performed by a passive time-integrating method using diffusion type dosemeter with nuclear track detector. Radon-222 concentrations up to 12000 Bq m^-3 were found. Instantaneous measurements of Rn-222 were taken with Lucascells and a portable radon monitor. Decay products were determined via dust filter sampling followed by alpha spectrometry. Equilibrium factors ranged between 0.34 and 0.80. (author)

[en] By means of nuclear track detectors, quarterly determinations of Rn-222 concentrations in the black coal mines of North-Rhine-Westphalia have been possible since 1983. For the purpose of calibration, a calibration chamber with measuring systems for determining radon, radon daughter product, and aerosol concentrations was set up. Steady-state factors were determined along the mine air diffusion paths of two mines and are in the range of 5.8 to 34.7%. Possible Rn liberation paths were detected, which vary according to the mine, area of work and seam concerned. The Dorsten strata have increased values as there is a uranium-thorium anomaly. Assessment of the effective annual dose equivalent shows that miners working underground in North-Rhine-Westphalian black coal mines need not be categorized as class 'A', radiation-exposed personnel as specified in the ordinance on radiation protection, according to measurements carried out so far. (orig.)

No abstract available

No abstract available

No abstract available

[en] Measured fusion yields as a function of energy for the systems ¹³²Xe + sup(nat)Fe and ⁵⁶Fe + ²³⁸U are found to be in very good agreement with phenomenological capture model ('extra push') calculations, and not at all in agreement with classical-trajectory predictions. Furthermore, evidence is found in the system ¹³²Xe + sup(nat)Fe for the capture model implication that systems with similar effective fissilities are dynamically equivalent. The ⁵⁶Fe + ²³⁸U data are consistent with a large fusion barrier shift of ca. 35 MeV over and above the reaction barrier. (orig.)

[en] Published in summary form only

No abstract available