[en] The constancy check and its organisation is a peculiar problem to be solved by equipment operators. The organisational concept strongly is determined by factors such as hospital structure, practice organisation, and equipment. For the university hospital under investigation, the best suited solution found, taking into account various factors such as e.g. costs or personnel management, is the centralized concept. (orig./HP)

[en] In toroidal magnet systems for fusion devices, the superconductors are exposed to high axial tension and transversal pressure, which modifies the characteristics of the superconductors, especially of Nb₃Sn. The paper explains the effects of the stresses on the critical currents, taking a NET superconductor reduced-scale model made of Nb₃Sn as an example. (orig.)

[en] Channeling is a powerful method for the investigation of the properties of crystalline materials (e.g. lattice site location, defect structures, etc.). More than a decade ago the program code CASSIS has been developed to extend the possible simulation of channeling phenomena to non-cubic crystal lattices, high foreign atom concentrations and PIXE-channeling. Due to the rapid progress in computer technology it is necessary to review and refurbish the existing code by substituting calculation procedures by more sophisticated and more precise ones. Another topic addressed during this refurbishment was the lack of user-friendliness of the old code. The introduction of a simplified input scheme and automatic procedures for the calculation of necessary secondary inputs resolved this situation. As an example and demonstration of possible applications a detailed large-dimension 2-D scan of silicon is presented and discussed.

[en] The basic concepts of the Monte Carlo computer simulation program CASSIS (Channeling Adapted Simulation of Swift Ions in Solids) for channeling phenomena are presented and discussed. In contrast to common computer codes CASSIS is able to perform calculations for high foreign atom concentrations, complex noncubic crystal lattices and PIXE-channeling. The feasibility of the program is demonstrated for different materials. (orig.)

[en] A fundamental task within the framework of a project searching for new radiopharmaceuticals for systemic therapy was the evaluation of the capabilities of the Portuguese Research Reactor (RPI) for the production of several important radionuclides. The feasibility of producing ⁶⁴Cu, ⁷⁷As, ¹⁵³Sm, ¹⁶⁵Dy, ¹⁶⁶Ho, ¹⁷⁰Tm, ¹⁷⁷Lu, ¹⁸⁶Re, ¹⁹⁹Au and ¹¹¹Ag in useful quantities was evaluated for the present RPI operation schedule (12 h cycles) and for continuous operation. The main evaluation criteria are expressed in terms of specific activity for continuous irradiation and/or 12 h cycle and the use of natural or enriched targets if necessary. Selected samples were irradiated and a comparison between measured activities and values calculated according to the irradiation schedule and using the same software was performed

[en] SrTiO₃ (STO) has been deposited on (1 0 0)InP substrates by laser ablation to propitiate the integration of La-modified PbTiO₃ (PLT). The optimum conditions found for STO deposition using a KrF excimer laser were laser fluence J=4 J/cm², oxygen pressure PO₂=10^-3 mbar and a substrate temperature T_s=580-630 deg. C. The STO films so obtained show [1 0 0]-texture and low roughness, σ∼0.8% of the layer thickness. [0 0 1+1 0 0]-textured Pb_0.775La_0.15TiO₃ films with a uniform composition close to the target one and σ∼2% of layer thickness were obtained on these STO buffers. The analysis of the STO surface properties under the scaling theory framework suggests an efficient surface diffusion of the arriving species as the origin of the low roughness

[en] In order to study the possibility of Cr doping of lithium niobate (LiNbO₃) by ion implantation Y-cut congruent lithium niobate samples were implanted with 100 keV Cr⁺ ions at room temperature to fluences of 1x10¹⁶ and 5x10¹⁶ cm^-2. Annealings were performed in a conventional furnace at 600 deg. C, 800 deg. C and 1000 deg. C for 15 min to 240 min under a flowing wet oxygen atmosphere. The optical absorption of the samples was studied in the spectral range from the ultraviolet (300 nm) to the infrared (3.5 μm). Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) studies were performed in order to investigate the lattice recovery and the incorporation of the Cr dopant. Annealings at 600 deg. C and 1000 deg. C yielded a virtually complete lattice recovery and the Cr dopant was incorporated substitutionally in the same way as in melt-doped crystals. On the other hand at 800 deg. C the annealing was hampered by the formation of clusters

[en] PETRA-III is a 3rd generation synchrotron light source dedicated to users at 14 beam lines with 30 instruments. This operates with several filling modes such as 60, 240 and 320 bunches with 100 mA or 40 bunches with 80 mA at a positron beam energy of 6 GeV. The horizontal beam emittance is 1 nmrad while a coupling of 1% amounts to a vertical emittance of 10 pmrad. During a user run unscheduled beam dumps triggered by Machine Protection System may occur. In many cases the reason can be identified but in some it remains undetected. Though the beam is lost some signature is left in the ring buffers of the 226 BPM electronics where last 16384 turns just before the dump are available for post-mortem analysis. Scrutinizing turn by turn orbits and the frequency spectrum measured at a BPM can improve understanding of such a beam loss and may help to increase the efficiency of operation by eliminating the sources. Here we discuss in detail the functionality of a Java GUI used to investigate the reasons for unwanted dumps. In particular, the most effective corrector method is applied to identify correctors that might have perturbed the golden orbit leading to violations of the interlock limits. (author)

[en] The redistribution and incorporation of Ir dopants introduced by implantation of 130 keV Ir⁺ ions with a fluence of 5x10¹⁶ cm^-2 into LiNbO₃ was investigated by Rutherford backscattering spectrometry at random and aligned incidence using 1.6 MeV He⁺ ions. The samples were subjected to annealing in a conventional furnace at temperatures ranging from 500 deg. C to 1000 deg. C under a flowing wet oxygen atmosphere. For all temperatures a measurable diffusion effect was found. Channeling angular scans performed for the sample annealed at 1000 deg. C reveal that a partial incorporation of the Ir dopant into the LiNbO₃ host lattice took place

[en] The Portuguese research reactor (RPI) was converted to LEU fuel in 2007 and will continue to operate until at least 2016. A project to replace its nuclear instrumentation and control (I and C) system is currently underway. As in other nuclear installations, discussions were held on keeping an analogue system or migrating to a digital one. A final decision was made to acquire an analogue system that was functionally compatible with the current system and to develop a computer interface in-house for non-safety-related functions. The selection of a supplier was made and, as required by budget restrictions, a partial procurement of the main modules started in 2005. Several actions have been taken in recent years regarding the modernization of the radiological protection system of the RPI. In this paper, we will discuss the lessons learned with the major refurbishment done from 1987-1989 and plans for the modernization of the nuclear I and C system and the radiological protection system of the RPI. (author)