[en] The described irradiation assembly has been designed so that a) it can be adjusted to the dimensions of the material to be irradiated, b) individual parts can be reused, and c) it can be cooled effectively

[en] The described device allows a defined and homogeneous activation of solids in inhomogeneous neutron fields. This is achieved by moving the solids in the irradiation field so that the effects of field inhomogeneities are compensated

[en] The described device is to be used for loading, unloading or re-loading of nuclear reactors and can be applied to fuel assemblies or material to be irradiated. Its design has been aimed at developing a loading device of low mass, which can be easily maintained, inspected or repaired

[en] The described method is based on the homogeneous and defined distribution of radiation effects, particularly in activating and doping large amounts of solids by neutrons. Existing field inhomogeneities are compensated by moving the solids in the irradiation field

[en] The angular distribution of the transferred spin polarization of Kr M_4,5N₁N_2,3¹P₁ Auger electrons after primary ionization with circularly polarized light has been measured and the intrinsic parameters δ₁ and ξ₁ have been determined from experimental results. The explicit equation interconnecting the intrinsic parameters for Auger decay from a (d_5/2)^-1 core hole has been derived and is used for a detailed analysis of the transitions in terms of Auger amplitude ratios and phase shift differences. The results indicate that the final ionic state is well described by a ¹P symmetry. Additional constraints imposed on the intrinsic parameters for singlet states prevent unambiguous determination of Auger amplitudes from experiment even in the limiting case of pure LS coupling. (author)

[en] We have measured the spin polarization of Xe (4p)^-1 photoelectrons after ionization with circularly polarized light at photon energies close to the ionization threshold where a resonant enhancement of quadrupole transitions has recently been predicted. At a reaction angle of 90 deg. a nonvanishing longitudinal spin polarization component of about 4% clearly indicates a quadrupole contribution to the photoexcitation. This is the first experimental evidence for the influence of nondipole transitions on the photoionization process at excitation energies much below 1 keV in an observable other than the intensity angular distribution

No abstract available

[en] Dielectric spectroscopy as well as ²H and ³¹P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d₃) in the full concentration (c_TPP) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: T_g1(c_TPP) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower T_g2(c_TPP) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (α₂-process), the other (α₁-process) displays time constants identical with those of the slow PS matrix. Upon heating the α₁-fraction of TPP decreases until above some temperature T_c only a single α₂-population exists. Inversely, below T_c a fraction of the TPP molecules is trapped by the PS matrix. At low c_TPP the α₂-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the α₂-relaxation resembles a secondary process. Yet, ³¹P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high c_TPP the super-Arrhenius temperature dependence of τ₂(T), as well as FTS are recovered, known as typical of the glass transition in neat systems

[en] The DORA equipment allows defined grip of the irradiation assembly, its lifting, lowering and release. It secures shielding of the activated internals and of the window in the small reactor lid onto which the equipment is attached. The mechanical and electrical parts of the equipment are described in detail. Its control, drives and displays are electrically controlled. The equipment allows charging remote-controlled from the control room. (M.D.)

[en] A detailed investigation of the relation between five dynamical parameters (partial photoionization cross section σ, angular asymmetry parameter β and three spin polarization parameters A,α,ξ) and five corresponding theoretical values (three dipole matrix elements and two phase shift differences) describing photoionization from p_3/2,d_3/2 and d_5/2 subshells of rare-gas atoms reveals a systematic ambiguity preventing the extraction of a unique set of five theoretical values from the experimental data which constitute a 'complete experiment'. Xe(5p_3/2)^-1 photoionization serves as an example to illustrate the problem using a numerical procedure as well as a mathematical analysis. A new equation is presented which connects four dynamical parameters. From these facts it follows that a complete experiment on closed-shell atoms with the extraction of five theoretical values is, in principle, impossible, if the photoelectron properties are measured exclusively. (author)