[en] In the present thesis on measurements of the quasi-elastic and elastic differential cross section for photon scattering is reported which were performed in the region of giant dipole resonances on nuclei in the mass range 181 ≤ A ≤ 238. (orig./HSI)

[en] A short survey on nuclear risks and the nuclear safety conception is followed by the attempted clear definition of the semantic import of section 7, sub-section (2), No. 3 of the Atomic Energy Act. There are first beginnings of a concretization of the state-of-the-art in science and technology, i.e. all kinds of sub-legislative regulations such as the regulations of the Radiation Protection Ordinance which show scientific substance, guidelines issued by the Ministers, as well as codes for practice set up by various technical bodies and standardization associations, all of which are designed to compensate for this loop hole in the legislation. This study goes to examine to what extent administration and jurisdiction may take into account such codes of practice for the concretization of the legal requirements, and whether they are even binding on those executing the law. Only the respective regulations of the Radiation Protection Ordinance have a binding effect. All other guidelines and codes of practice are not legally binding per se, nor are they capable of being legally permitted by being referred to in terms of legal norms or by the self-commitment of those executing the law. Any attempt of using them, as the basis of a prime facie evidence or as an anticipating expertise, at least evidentarily for the concretization will have to fail owing to their evaluating character and to the fact that they may interfere in sociological conflict. An exception may be a case where a clear distinction can be made as to what extent the contents of such codes of practice is related to scientific and technological findings or to decisions based on evaluations. In such a case, a prima facil evicdence for the conformity of the regulation in question with the state-of-the-art in science and technology may be considered, which would easy the concretization of Art. 7 II Section 3 of the Atomic Law. (orig./HSCH)

[en] Parameters for generating fluorescence radiation are given, for example, in ISO 4037-1. These parameters are the high voltage of the X ray tube, the mass per area of the aluminium primary filter behind the X ray tube, the material and mass per area of the fluorescence target and the secondary filter. A computer program was developed to calculate the generated fluorescence spectra. The results of these calculations have shown that the parameters for the generation of fluorescence radiation given in ISO 4037-1 can be optimised. The program was checked by comparison of the calculations with experiments for two different radiation qualities. Optimised parameters were determined for different fluorescence radiation qualities (as contained in ISO 4037-1 and others). (author)

[en] Full text: The nuclear data work at PTB concentrates on the measurement of differential elastic and inelastic neutron scattering cross section, double differential neutron emission spectra and activation cross section for nuclides of relevance in fusion technology. For these investigations, a multi-detector time-of-flight spectrometer is installed at the PTB CV28 isochronous cyclotron. The D(d,n) reaction is employed for neutron production using a D₂ gas target. The measurements are carried out in the energy range between 6 MeV and 15 MeV where no monoenergetic neutron sources are available. So far, cross sections for the following materials were measured with high precision: - elastic and inelastic scattering section (DX): ¹⁴N, ¹⁶O, ^natSi, ^natTi, ⁴¹V, ^natCr, ^natFe, ^natCu, ^natPb - neutron emission cross sections (DDX): ^natTi, ⁴¹V, ^natCr, ^natCu, ^natPb - activation cross sections: ¹⁹F, ²4Mg, ²⁷Al, ²⁸Si, ²⁹Si, ³⁰Si, ⁴⁶Ti, ⁴⁸Ti, ⁵¹V, ⁵²Cr, ⁵⁴Fe, ⁵⁶Fe, ⁵⁹Co, ⁵⁸Ni, ⁶³Cu, ⁶⁵Cu, ⁶⁴Zn, ⁹³Nb, ¹⁰³Rh All finally analyzed cross section data were submitted to the NEA data bank with full documentation of uncertainties for inclusion in the EXFOR data bank. In addition to the work carried out at the PTB accelerator facility, experience in neutron metrology and nuclear data measurements at neutron energies above 20 MeV were acquired in experiments at the neutron beam facilities in Louvain-la-Neuve and Cape Town where cross sections for the production of residual nuclei, fission cross sections and (n, xn γ) cross sections were measured in collaboration with other groups. This expertise can also be used for work related to the special nuclear data needs of the IFMIF project, e.g. Li+d neutron and photon emission cross sections at lower deuteron energies, scattering and activation cross sections for structural materials as well as dosimetry cross sections at energies below and above 20 MeV. (author)

[en] The consistency of spectral neutron fluence determination with hydrocarbon scintillation detectors using time-of-flight techniques and fluence measurements with a proton recoil telescope, has been investigated for neutron energies of 44 MeV and 65 MeV. If the full response of the scintillation detector, including contributions from n-C reactions, is used for the fluence determination, the results differ up to 15% from the measurements with a proton recoil telescope. The deviations depend on the detection threshold and the neutron energy. They are mainly due to an inadequate description of the n-C reaction channels and the cross section data sets available in the Monte Carlo codes SCINFUL and KENT01 used to calculate the response and the efficiency of the scintillator. Better agreement, however, has been found if only events due to n-p scattering are used for the analysis. The accuracy achievable with the scintillation detector is limited by the uncertainty of the angular differential n-p scattering cross section data and by imperfections of the Monte Carlo simulation. (orig.)

[en] Angular distributions and integrated cross sections for the ⁹Be(α,n₀)¹²C reaction have been measured at E_α=10.43 MeV and 12.62 MeV using the neutron time-of-flight facility at the PTB Braunschweig. Absolute neutron detection efficiencies were calculated by Monte Carlo simulations, whereby the detector thresholds were determined using a californium source. Monitoring and absolute cross section normalization were obtained by alpha beam current integration. The Be target mass was determined by weighing with an uncertainty of 1.2%. A comprehensive investigation of corrections and uncertainty sources was carried out and is discussed in detail. The differential and integrated cross sections are transformed to those of the ¹²C(n, α₀)⁹Be reaction, corresponding to incoming neutron energies of E_n=14.02 MeV and 15.66 MeV, respectively. (orig.)

[en] Neutrons were scattered on a sample of natural iron at 12 incident energies in the range between 9.4 MeV and 15.2 MeV. Differential cross sections of the elastic scattering (natural iron) and of the inelastic scattering to the first excited level of ⁵⁶Fe (Q=-0.847 MeV) were determined for angles between 12.5 deg and 160 deg with total uncertainties between of 3% and 10%. Legendre polynomial least-squares fits resulted in integrated cross sections with uncertainties of 2% (elastic data) and 7% (inelastic data). The cross sections obtained in this work were compared with data from the literature. Inelastic scattering cross sections were determined within the scope of a pseudolevel analysis up to excitation energies of nearly 5.5 MeV. At higher excitation energies the scattering spectrum is contaminated by scattered breakup neutrons from the D+d source used hampering an analysis of the data. (orig.)

[en] Differential cross sections of the ⁹Be(α,n)¹²C reaction have been measured at 19 alpha energies between 7 MeV and 16 MeV. Besides the differential cross sections from the ⁹Be(α,n)¹²C(g.s.) reaction, also those of the ⁹Be(α,n)¹²C(E_ex) reactions were derived for excitation energies E_ex = 4.439, 7.654, 9.641, 10.84, 11.83 and 12.71 MeV. Possible sources of uncertainties have been extensively investigated and the corresponding results have been published in part 1. All partial and integrated cross sections from the ⁹Be(α,n)¹²C(g.s.) reaction were determined with uncertainties of less than 5%. The angular distributions were fitted to Legendre polynomial expansions by the least-squares method. A comparison of the measured cross sections with data from other authors and with an evaluation shows considerable deviations in some cases. Tests were also carried out to ascertain how well an interpolation of the Legendre coefficients reproduces the magnitude and shape of the experimentally determined angular distributions. All angular distributions are presented in figures, together with their Legendre polynomial expansions and data from the literature if available. The a_l coefficients of the Legendre polynomial expansions are given in the Appendix. (orig.)

[en] Full text: The Physikalisch-Technische Bundesanstalt (PTB) is the national metrology institute of Germany and was founded in 1887 by Werner von Siemens and Hermann Helmholtz. It was the first metrology institute world-wide. By law PTB has to ensure the uniformity of metrology in Germany. One of the main tasks of PTB is to ensure the traceability of measurement results to the international system of units, i.e. the SI system, through national standards. PTB is organized in 8 divisions; one of them is division 6 responsible for the metrology of ''Ionizing Radiation''. (author)

[en] A dosemeter badge with two TL detectors has been designed for the simultaneous measurement of H_p,(0.07) and H_p(10). The performance of the dosimetry system has been investigated for various X and β ray fields with radiation incidence between 0^o and 75^o. For arbitrary mixtures of the test radiation fields the response to H_p(0.07) varies between 0.57 and 1.62. The response of the dosemeter to H_p(10) ranges between 0.39 and 1.60 for X rays. The thin TL detector has some stability problems which can probably be reduced by optimising the annealing procedure. (Author)