Chernobyl still affects the environment of Greece: Recent measurements of 137^{137}Cs in soil cores of Grevena-Trikala area

<p>A poster presented at HNPS2013 (http://nuclpart.phys.uoa.gr/HNPS/HNPS2013) held in Athens 31.05-01.06.2013</p

137Cs Retainment in Central Greece Soils: A Study Undertaken a Radiocesium Halflife After Chernobyl

<p>A poster presented at ENVIRA2015, Thessaloniki, Greece 21-24.09.2015</p

New experimental validation of the pulse height weighting technique for capture cross-section measurements

The accuracy of the pulse height weighting technique for the determination of neutron capture cross-sections is investigated. The technique is applied to measurements performed with C6D6 liquid scintillation detectors of two different types using capture samples of various dimensions. The data for well-known (n,γ) resonances are analyzed using weighting functions obtained from Monte Carlo simulations of the experimental set-up. Several causes of systematic deviation are identified and their effect is quantified. In all the cases measured the reaction yield agrees with the standard value within 2%. © 2003 Elsevier B.V. All rights reserved

Time-energy relation of the n_TOF neutron beam: Energy standards revisited

The accurate determination of neutron cross-sections as a function of the neutron energy at a time-of-flight facility requires a precise knowledge of the time-energy relation for the neutron beam. For the n_TOF neutron beam at CERN, produced by spallation of high-energy protons on a Pb target, the time-energy relation is connected to the production mechanism and to the subsequent moderation process. A calibration of the neutron energy scale is proposed based on detailed Monte Carlo simulations of the facility. This time-energy relation has been experimentally validated by means of dedicated measurements of standard energy resonances, from 1eV to approximately 1MeV. On the basis of the present measurements, it is proposed to correct the energy of the 1.3eV resonance of 193Ir, which is commonly considered as an energy standard. © 2004 Elsevier B.V. All rights reserved

A low-mass neutron flux monitor for the n_TOF facility at CERN

A small-mass system has been developed for monitoring the flux of neutrons with energy up to 1 MeV at the new time-of-flight facility at CERN, n_TOF. The monitor is based on a thin Mylar foil with a 6Li deposit, placed in the neutron beam, and an array of Silicon detectors, placed outside the beam, for detecting the products of the 6Li(n, α)3H reaction. The small amount of material on the beam ensures a minimal perturbation of the flux and minimizes the background related to scattered neutrons. Moreover, a further reduction of the γ-ray background has been obtained by constructing the scattering chamber hosting the device in carbon fibre. A detailed description of the flux monitor is here presented, together with the characteristics of the device, in terms of efficiency, resolution and induced background. The use of the monitor in the measurement of neutron capture cross-sections at n-TOF is discussed