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Simulation of 5 MeV-proton irradiation of different construction steels for nuclear installations was performed using the MCNPX code to support proton irradiation experiments aimed at studying accelerated radiation aging. The main goal of the simulations was to predict an induced activity of the studied samples during implantation experiments. The materials investigated were different types of Fe-Cr-based construction steels comprising ferritic/martensitic steels and its oxide dispersion strengthened variant. The paper presents calculation details specific for a couple of MeV-protons simulations comprising the information on the proton nuclear data and the physics models' usage in the MCNPX code. The reaction rates and the energy deposition were calculated to quantify the main interaction mechanisms, whereby the capability of the MCNPX code to track the secondary particles was used. Physics models were employed to determine the nuclides inventory produced during irradiation. The induced mass activity was calculated from the number of radioactive residuals and reached values between 15 and 67 kBq/g immediately after irradiation. The results from simulations will be compared with the activity of the samples determined by gamma spectroscopy measurements in our next paper. [ABSTRACT FROM AUTHOR]

The study of neutrinoless double beta decay (DBD) has attracted much attention because it can provide valuable information about the mass and the nature of the neutrino. DBD itself is also of interest in nuclear physics. While DBD has been observed in about a dozen nuclei, the positron DBD (β+β+/EC-β +) continues to be elusive. An important signature for β +β + decay is the simultaneous emission of four 511 keV gamma rays, and the coincident detection of these gamma rays can improve the measurement sensitivity. This paper presents an estimation of sensitivity for EC-β+and β +β+, employing coincidence measurement with two high-purity Ge (HPGe) detectors. Simulations for coincident detection efficiency (εc) of 511 keV gamma rays with two HPGe detectors were carried out using GEANT4 for different source geometries to optimize the mass efficiency product (Mεc). A source of size 55 mm × 55 mm × 5 mm (thickness) sandwiched between the front faces of the detectors was found to be optimal for two pairs of 511 keV gamma rays in the present detector setup. The coincident background was estimated at sea level with moderate lead shielding. With this setup, the sensitivity for T1/2 measurement of EC-β+in 112Sn and β +β+ in 106Cd was estimated to be ∼1019–1020 years for one year of measurement time. [ABSTRACT FROM AUTHOR]

The design of programming interfaces like ROOT written by CERN group in Switzerland leads the way of analyzing spectroscopy mainly in nuclear physics applications. One of the topics is a signal processing in terms of currency, voltage or frequency of a radiation hitting the detector systems. Mathematical approaches finding the fit parameters in maximum Likelihood for the normal distribution and the effect of choosing the distinct methods in fitting settings will be presented in this paper. [ABSTRACT FROM AUTHOR]