In this paper we compare confocal apparatus tomography and computer tomography for medical use. Two aspects are illustrated: the process of image visualization and the dose deposition. The latter aspect is a damage factor of the object under investigation; it is why the data collection time is evaluated. Two principal tomography schemes are described and the expressions connecting the collected...

We report on the production of a continuous, slow, and cold beam of Rb atoms with an extremely high flux of 3.2 1012 atoms/s, a transverse temperature of 3 mK, and a longitudinal temperature of 90 mK. We describe the apparatus created to generate the atom beam. Hot atoms are emitted from a rubidium candlestick atomic beam source and transversely cooled and collimated by a 20 cm long atomic coll...

In this paper, a new multiresolution reconstruction approach for fan-beam tomography is established. The theoretical development assumes radial wavelets. An approximate reconstruction formula based on a near-radial quincunx multiresolution scheme is proposed. This multiresolution algorithm allows to compute both the quincunx approximation and detail coefficients of an image from its fan-beam pr...

The sum of all attenuation data acquired in one view of parallel-beam projections is a view angle independent constant. This fact is known as a data consistency condition on the two-dimensional Radon transforms. It plays an important role in tomographic image reconstruction and artifact correction. In this paper, a novel fan-beam data consistency condition (FDCC) is derived and presented. Using...

Wakefields excited in the small aperture collimators may damage the beam. As pointed out by K. Bane and P. Morton the wakefields can be reduced considerably by tapering the steps and using the “step+taper” collimator geometry. The optimisation of this kind of geometry for TTF 2 collimators with different apertures is carried out in the paper. For the optimal geometries the nonlinear near-wall w...

Activation products have been identified by in situ gamma spectroscopy at the isocenter of a medical linear accelerators shortly after termination of a high energy photon beam irradiation with 15 x 15 cm field size. Spectra have been recorded either with open or with closed collimator. Whilst some activation products disappear from the spectrum with closed collimator or exhibit reduced count ra...

An a irradiation device is described that utilises a commercially available disc-shaped americium-241 source of 8 cm diameter. The a particles traverse a moving collimator and the source is rotated to reduce the influence of source inhomogeneities. Source, collimator and a shutter disc are mounted in a container which is flushed with helium to reduce energy losses of the a particles before reac...