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[en] This paper investigates, through theory and experiment, the influence of the plain-parallel electrode surface dimensions change on the type A measurement uncertainty of a GM counter. The possibilities of applying these results to practical structures are examined by using the methods of mathematical statistics. Special attention is devoted to the influence of electrode surface enlargement on the statistical behavior of the pulse number random variable, expressed in the form of the enlargement law. In the theoretical part of the paper, the general surface enlargement law is derived. Comparison of experimental results with those predicted by the surface enlargement law proved its validity for expressing the type A measurement uncertainty of GM counters constructed with a plain-parallel electrode configuration with a homogenous electric field. (author)
[en] A Monte Carlo method-based model of a hot cavity surface ion source with a spherically shaped ionizer is presented. A numerical code enables studies of ion source efficiency as a function of an extraction voltage, geometry of the ionizer and its temperature, the size of extraction aperture and many other factors. The calculation results for a variety of mentioned parameters are presented. A novel configuration of surface ion source is proposed and discussed - the efficiency of the source with an almost spherically shaped ionizer could be much higher than that of currently used constructions of ion sources. (author)
[en] The maximum energy release in the beta-decay of 3H to 3He is a crucial parameter in the determination of the electron antineutrino's mass by the Karlsruhe Tritium Neutrino Experiment (KATRIN). An independent measurement of this Q-value with an uncertainty of less than 100 meV would serve as an important systematic check, but an improvement of the presently accepted Q-value by an order of magnitude is necessary. Even for Penning trap mass spectrometry, which derives the mass difference of the two nuclei from the measurement of their mass ratio, this represents an ambitious goal only to be accomplished by a dedicated experiment, such as THe-Trap. The double Penning trap mass spectrometer, originally developed and built at the University of Washington, has been commissioned in a customized laboratory at the MPIK in Heidelberg. The mass of the ion is related to its three eigenfrequencies in the trap. A frequency-locked loop in the axial mode provides for continuous indirect monitoring of the radial modes. Details of the detection system are given.
[en] Usually, proportional counter tubes are used in 57Fe Moessbauer spectroscopy for the detection of the 14.4 keV transition line. % and further signal processing. The recent developement of Si-based solid state detectors led to commercially available drift detectors (SDD) and high purity PiN diodes without the necessity of cooling with liquid nitrogen. First applications of SDD detectors in the analysis of minerals are already highly promising. In this talk, we present a detailed comparison between the three detector types and their use in Moessbauer spectroscopy using a standard absorber-source-combination (metallic iron with a 2.0 GBq 57Co/Rh source) in absorbtion geometry. Starting with the definition of a global efficiency function, which optimises the goodness of a Moessbauer spectrum and thus the required measurement time, we examined the influence of the intrinsic detector parameters on the global efficiency.
[en] A study is being carried out using a surrogate vibro-packed fuel pin with micro-spheres of two different sizes to get the density distribution by gamma transmission technique. A shielded (with 2 mm slit of ∼ 2''SS collimator) LaBr scintillation detector is used as the detector system. A strong 137Cs source is used as the source. The source strength as it is transmitted through the fuel pin is measured by the scintillation detector. The entire length of the fuel pin is gradually moved up from one end to other end and the detector is allowed to continuously examine the transmission profile of the fuel pin. The instrumentation for the fuel pin scanner has been developed and is integrated with the system. The instrumentation includes microcontroller based motor control system and customized detector pulse counting systems. The systems are interfaced to a computer through serial communication. (author)
[en] First results from a new simple simulation of X-ray spectroscopy with an Al0.8Ga0.2As p+-p--n+ spectroscopic X-ray photon counting avalanche photodiode are presented and compared with experimentally obtained data. Particular attention is paid to the experimentally observed phenomenon of an additional peak being present in the spectrum from a radioisotope source that, whilst previously reported, had not been fully explained. The additional peak is shown to result from the unequal distributions of multiplications undergone by the charge carriers created by photons absorbed in the p+ and p- layers. The consequences of this effect for future AlGaAs X-ray photon counting avalanche photodiode designs are discussed.
[en] In-beam SPECT during therapeutic proton beam irradiation is a novel method for three dimensional in-vivo dose verification. For this purpose a Compton camera design is evaluated with respect to the special requirements and conditions that arise from this application. Different concepts are studied by means of simulation concerning the angular resolution and efficiency. It was found that a cadmium zinc telluride system can perform sufficiently well. For further evaluation the construction of a semiconductor scintillator hybrid system is under way.