[en] The NEMO3 experiment is running since 2003 and aims at the research of the neutrinoless double beta decay signal (2β0ν) with an expected sensitivity of 0.1 eV on the effective mass. The discovery of this signal, forbidden by the Standard Model, would imply the non-conservation of the leptonic number and the existence of Majorana massive neutrinos. Experimental technique associates a tracking detector with a calorimeter and allows the identification of the two electrons and their energy measurement. With a period sensitivity over 10²³ years few events are expected. Background reduction and knowledge are fundamental. An accurate check of the gains of all the photomultipliers from the calorimeter is also necessary. The first part of this work consisted with the exploitation of the information obtained by the relative energy calibrations carried out daily with a laser light. This study led to an application method of the relative calibrations results for the NEMO3 data analysis. The second part of this work concerned the study of the different backgrounds of the 2β2ν and 2β0ν decays. The analysis of data taken with a neutron source in different shields configurations of the NEMO3 detector validated a program of photon generation produced by fast neutron interactions. Finally, this work has determined the 2β2ν ¹⁰⁰Mo decay period (∼ 7.2*10⁸ years) and a limit on the ¹⁰⁰Mo 2β0ν decay period (> ∼ 3.5*10²³ years). (author)

[en] Full text: The neutrino flavour oscillations hypothesis has been confirmed by several experiments, all are based on the observation of the disappearance of a given neutrino flavour. The long baseline neutrino experiment OPERA (Oscillation Project with Emulsion tRacking Apparatus) aims to give the first direct proof of the tau neutrino appearance in a pure muon neutrino beam (CERN neutrinos to Gran Sasso beam). The neutrino interactions in the detector are recorded by Emulsion Cloud Chambers (ECC), stacks of 57 nuclear emulsions interleaved with 1 mm thick lead plates. In 2008 the OPERA experiment has started full data taking in the CNGS beam and around 1700 interactions in the detector have been recorded. After a description of the experiment and the data taking procedure, a review of the current status and preliminary results from 2008 run will be presented. (author)

[en] Highlights: • A Monte Carlo code has been developed and validated using EGSnrc. • A radionuclide decay generator has been written and validated. • Detection efficiency can be calculated for High Purity Germanium detector. • A flexible and user friendly analysis software using MS Excel^® has been developed. • Functionalities and performances of the software are presented. - Abstract: At the JRC-Geel's RadioNuclide Metrology sector, a Monte Carlo code based on EGSnrc, and a general purpose calculation sheet implemented in Microsoft Excel^®, have been developed to make the quantitative gamma-ray spectrometry analysis of samples simpler and more robust. The further aim is that the software can be used by non-experts in gamma-ray spectrometry e.g. external researchers using JRC-Geel's facilities through the EUFRAT transnational access scheme. This paper presents the developed Monte Carlo software and the functionality included in the calculation sheet.

[en] In the present work, measurements of the cross-section functions for the "1"8"7Re(n,α)"1"8"4Ta, "1"8"7Re(n,2n)"1"8"6Re and "1"8"5Re(n,2n)"1"8"4Re reactions were performed in the energy range 13.08-19.5 MeV. We applied the neutron activation technique using several wide-energy neutron beams (NAXSUN), recently developed at the JRC-IRMM. This method involves measuring the activity of the radionuclides produced in a target by the in energy overlapping neutron beams and a subsequent unfolding procedure. The present results are the first experimental data on these cross-sections for incident neutron energies between 15 and 19.5 MeV and may contribute to improving evaluations and nuclear models. (orig.)

[en] A measurement station dedicated for quantitative radiological characterisation of naturally occurring radionuclides in a metallurgical company and based on gamma-ray spectrometry was developed. The station is intended for performing quality control of final non-ferrous metal products and for radiological checks of incoming materials. A low-background point-contact HPGe-detector was used and the signal was split in two branches to enable collecting simultaneously spectra with high amplification (for gamma-ray energies below 250 keV) and low amplification. - Highlights: • A gamma-ray spectrometer is installed in a secondary smelting facility. • The set-up and software is optimised for reliable and cost-effective monitoring. • Incoming materials and final products can be monitored. • It is focused on simultaneous measurement of ²¹⁰Pb and ²¹⁰Po. • Performances of the set-up are presented for ²¹⁰Pb and ²¹⁰Po.

[en] The dead-layer uniformity of the top surface of two high purity germanium detectors has been studied using a novel automated scanning set-up that allows a fine-grained topography of a detector's top and lateral surfaces. Comparisons between measurements and Monte Carlo simulations allowed implementation of a dead-layer variation into the detector model, which reproduces the measurements results. The effect of the non-uniform dead-layer on activity determinations based on low-energy γ-rays (i.e. below ∼100 keV) has been determined to be of the order of 10% or more. - Highlights: • We performed a top dead-layer topography of two HPGe detectors. • We identified a non-uniform dead-layer thickness along the surface of one of them. • We built a Monte Carlo model able to reproduce the measurements results. • We estimated an effect on the activity calculation for low energy γ-ray emitters of ∼50%

[en] Two electron spectrometers have been developed for the characterisation of scintillating counters with MeV range electrons. These spectrometers offer a monoenergetic electron beam ranging from 0.4 to 1.8 MeV with an energy resolution (FWHM) of 1.0 ± 0.2% at 1 MeV and a linearity better than 2%. The transverse profile of the beams consists of a typical 3.0 mm Gaussian width. These electron beams can automatically scan surfaces up to 60 × 200 cm"2 in 1 mm increments. They have been used in the calorimeter module development for the SuperNEMO experiment

[en] This work describes the development and optimization of the radiochemical separation of ¹⁴⁷Pm and ¹⁵¹Sm. The two main challenges addressed were: the radiochemical separation of the lanthanides by using LN Resin and DGA,N Resin, and the quantification of the chemical recovery of ¹⁴⁷Pm with a non-isotopic analogue (i.e. neodymium). The applicability of radiochemical separation procedures was investigated by using spiked samples. The optimized radiochemical separation procedure by using LN Resin was applied to a reactor cooling water primary coolant sample with an automated system. Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) was used to determine the chemical recoveries. (author)

[en] The first ever search for α decays to the first excited state in Yb was performed for six isotopes of hafnium (174, 176, 177, 178, 179, 180) using a high purity Hf sample of natural isotopic abundance with a mass of 179.8 g. For ${}^{179}$Hf, also α decay to the ground state of ${}^{175}$Yb was searched for thanks to the β-instability of the daughter nuclide ${}^{175}$Yb. The measurements were conducted using an ultra-low-background HPGe-detector system located 225 m underground. After 75 days of data taking no decays were detected but lower bounds for the half-lives of the decays were derived on the level of lim T${}_{1/2}$ ∼10${}^{15}$-10${}^{18}$ a. The decay with the shortest half-life based on theoretical calculation is the decay of ${}^{174}$Hf to the first 2${}^{+}$+ 84.3 keV excited level of ${}^{170}$Yb. The experimental lower bound was found to be T${}_{1/2}$ ≥ 3.3×10${}^{15}$ a.

[en] A search for double-beta decay of ${}^{190}$Pt and ${}^{198}$Pt with emission of γ-ray quanta was realized at the HADES underground laboratory with a 148 g platinum sample measured by two ultralow-background HPGe detectors over 8946 h. The isotopic composition of the platinum sample has been measured with high precision using inductively coupled plasma mass spectrometry. New lower limits for the half-lives of ${}^{190}$Pt relative to different channels and modes of the decays were set on the level of T${}_{1/2}$ ∼ 10${}^{14}$-10${}^{16}$ year. A possible exact resonant 0νKN transition to the 1,2 1326.9 keV level of ${}^{190}$Os is limited for the first time as T${}_{1/2}$ ≥ 2.5 × 10${}^{16}$ year. A new lower limit on the double-beta decay of ${}^{198}$Pt to the first excited level of ${}^{198}$Hg was set as T${}_{1/2}$ ≥ 3.2 × 10${}^{19}$ year, one order of magnitude higher than the limit obtained in the previous experiment.