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[en] The photon diagnostics available at the SwissFEL Aramis beamline are described. The working principles of various devices, their function and their expected or measured performance are discussed. The SwissFEL Aramis beamline, covering the photon energies between 1.77 keV and 12.7 keV, features a suite of online photon diagnostics tools to help both users and FEL operators in analysing data and optimizing experimental and beamline performance. Scientists will be able to obtain information about the flux, spectrum, position, pulse length, and arrival time jitter versus the experimental laser for every photon pulse, with further information about beam shape and size available through the use of destructive screens. This manuscript is an overview of the diagnostics tools available at SwissFEL and presents their design, working principles and capabilities. It also features new developments like the first implementation of a THz-streaking based temporal diagnostics for a hard X-ray FEL, capable of measuring pulse lengths to 5 fs r.m.s. or better.
[en] The quality factors for heavy particle dose in tissue from first interactions of monoenergetic neutrons calculated directly from the new quality factor determination given in ICRU Report 40 are presented as a function of neutron energy. The results of the calculation are compared with previously published calculations based on old concepts. For neutron energies from 100 keV up to 1 MeV these differences are about a factor of two. (author)
[en] The main objective of this research project was to investigate the suitability of the silicon photodiode as a light sensor for scintillation detection of ionising radiation. The type of instrument originally envisaged would be particularly applicable to measurement of gamma-ray dose rates. During the course of the research, it was found that some modern silicon photodiodes are very effective as direct semiconductor detectors for both charged particles, and also for photons in the energy range 8 - 140 keV. The development of the photodiode as a scintillation light detector also proved highly successful. Using a CsI(T1) scintillator and commercially available photodiodes, pulse height energy spectra rivalling those obtainable from conventional photomultiplier-NaI(T1) assemblies were achieved. By comparing scintillation pulses with direct gamma absorption events in the photodiode, the light output of CsI(T1) was determined to be significantly higher than that of NaI(T1), which is usually accepted as the most efficient scintillator at room temperature. The detector assembly developed was successfully employed in the acquisition of data for a gamma ray transmission computer tomography system. (author)
[en] The I.B. spectrum of a complex source consisting of 35S, 33P and 32P was measured in the energy range 80-1700 keV. A NaI(Tl) crystal spectrometer was used. A new approach was tried to decompose the I.B. spectrum into its three components. The resulting I.B. spectra were analyzed adopting the variable width peeling off method. The experimental I.B. probability is compared with the 'KUB', 'Nilsson' and 'Lewis and Ford' theories. A quite good agreement has been obtained. (orig.)