[en] The work we present consists of the development of a computerised 3-D scanning system running under LABVIEW[reg]. 3-D magnetic field measurements, form an important application allowing a fast on-line determination of charged particle trajectories in real magnetic fields. The set-up consists of a Hall-probe, movable in three dimensions, mimicking a charged particle entering a magnetic field with well-defined transport characteristics (energy, position, momentum). The measured local field components are used as input to a LABVIEW[reg] program, which calculates the local direction of the flight-path of the particle. Then the probe is moved along this direction with a predetermined step-length. In this way, the real path of the charged particle is determined step by step automatically accounting for all magnetic field imperfections. Trajectories can be determined without the measurement of the whole 3-D field configuration

[en] Complete text of publication follows. The Laboratory of Subatomic and Radiation Physics of the University of Gent is equipped with a 15 MeV 20 kW linear electron accelerator (linac) facility. This accelerator was initially designed for fundamental nuclear physics research but was modified to generate beams for new experimental interdisciplinary projects. In its present configuration the accelerator is used as a multipurpose apparatus for research in the fields of polymer chemistry (crosslinking), biomaterials (hydrogels, drug delivery systems, implants), medicine (extracorporeal bone irradiation, human grafts), biomedical materials, food technology (package materials, food preservation), dosimetry (EPR of alanine systems, geldosimetry), solid-state physics, agriculture and nuclear and radiation physics. In this paper an overview will be presented of both the various research projects around our linac facility involving radiation chemistry and the specialised technologies facilitating this research

[en] This study aimed to investigate the feasibility of brain single-photon emission tomography (SPET) in the letter and category fluency paradigm of the Controlled Oral Word Association (COWA) test in healthy volunteers. Two groups each comprising ten right-handed healthy volunteers were injected twice with 370 MBq technetium-99m ethyl cysteinate dimer following a split-dose paradigm (resting and activation condition). Statistical parametric mapping (SPM96) was used to determine voxelwise significant changes. The letter fluency and the category fluency activation paradigm had a differential brain activation pattern. The posterior part of the left inferior prefrontal cortex (LIPC) was activated in both paradigms, with the category fluency task having an extra activation in the anterior LIPC. In the category fluency task, but not the letter fluency task, an activation in the right inferior prefrontal cortex was found. These findings confirm to a large extent the results of previous functional magnetic resonance imaging and positron emission tomography studies in semantic and phonological activation paradigms. The choice and validity of various methodological characteristics of the experimental design leading to these results are critically discussed. It is concluded that brain SPET activation with the letter fluency and category fluency paradigm under standard neuropsychological conditions in healthy volunteers is both technically and practically feasible. (orig.)