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[en] The Department of Nuclear Medicine, St. Marina University Hospital in Varna, is equipped with a self-shielded BG-75 cyclotron and synthesis unit for production of single doses of 18F-FDG. The cyclotron is capable to deliver 7.5 MeV proton beam with maximal current of 5 μA. During irradiation, a small target volume of 18O-enriched water is bombarded with protons and the resulting neutron and gamma fields induce nuclear reactions within the target bulk, machine components and shielding, the walls of the cyclotron vault. The aim of the present work is to define the radiological characteristics of the activation products generated during the operation of the cyclotron that need to be considered for daily maintenance and for decommissioning of the facility in future. For that purpose Monte-Carlo calculations with detailed models of the vault and the machinery are used. Key words: cyclotron, target, vault, activation, radioactive waste, Monte-Carlo simulations
[en] Absolute transition matrix elements are valuable observables in nuclear-structure physics since they are directly related to the nuclear wave functions. A key ingredient to determine transition matrix elements is the measurement of lifetimes of excited states. In a recent experiment, we extracted the lifetimes of 30 excited states of the low-abundant isotope "9"6Ru utilizing the Doppler-shift attenuation method (DSAM) in an inelastic proton-scattering experiment and taking advantage of the proton-γ coincidence technique. In contrast to the DSAM technique following inelastic neutron scattering, which was frequently performed to extract comprehensive lifetime information in the sub-picosecond regime, the (p,p"'γ) reaction requires a much less amount of target material and is thus especially suited to investigate low-abundant isotopes. In this contribution, the (p,p"'γ) method for lifetime measurements is presented and the results of recent experiments on "9"6Ru, "9"4Zr, and "1"1"2","1"1"4Sn are shown.