Search results for "gea"
showing 10 items of 1040 documents
GEANT4 simulation of the neutron background of the C6D6 set-up for capture studies at n_TOF
2014
The neutron sensitivity of the C6D6 detector setup used at n_TOF facility for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire n_TOF experimental hall, including the neutron beam line, sample, detector supports and the walls of the experimental area has beeni mplemented in the simulations. The simulations have been analyzed in the same manner as experimental data, in particular by applying the Pulse Height Weighting Technique. The simulations have been validated against a measurement of the neutron background performed with anatC sample, showing an excellent agreement above 1 keV. At lower energies, an additional compo…
An evaluation of the antireflux properties of sodium alginate by means of combined multichannel intraluminal impedance and pH-metry.
2005
Summary Background : Alginate-based preparations act as mechanical antireflux barrier, which can reduce both acid and non-acid reflux events and limit the proximal migration of oesophageal refluxate. Aim : To evaluate all the above features with a novel technique, multichannel electrical impedance and pH-metry. Methods : Ten reflux patients underwent stationary impedancemetry and pH-metry after eating a refluxogenic meal. They were studied 1 h in basal conditions and 1 h after taking 10 mL of Gaviscon Advance. In both sessions, measurements were obtained in right lateral and supine decubitus. Results : Alginate preparation was able to decrease significantly (P < 0.05) the number of acid ref…
Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte …
2015
Abstract In this work a comparison between the response of alanine and Markus ionization chamber was carried out for measurements of the output factors (OF) of electron beams produced by a linear accelerator used for Intra-Operative Radiation Therapy (IORT). Output factors (OF) for conventional high-energy electron beams are normally measured using ionization chamber according to international dosimetry protocols. However, the electron beams used in IORT have characteristics of dose per pulse, energy spectrum and angular distribution quite different from beams usually used in external radiotherapy, so the direct application of international dosimetry protocols may introduce additional uncer…
The FIRST experiment at GSI
2012
The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at the SIS accelerator of GSI laboratory in Darmstadt has been designed for the measurement of ion fragmentation cross-sections at different angles and energies between 100 and 1000 MeV/nucleon. Nuclear fragmentation processes are relevant in several fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The start of the scientific program of the FIRST experiment was on summer 2011 and was focused on the measurement of 400 MeV/nucleon 12C beam fragmentation on thin (8 mm) graphite target. The detector is partly based on an alread…
Monte Carlo simulation of a single detector unit for the neutron detector array NEDA
2012
WOS: 000301813500009
Characterization of a neutron-beta counting system with beta-delayed neutron emitters
2016
Abstract A new detection system for the measurement of beta-delayed neutron emission probabilities has been characterized using fission products with well known β-delayed neutron emission properties. The setup consists of BELEN-20, a 4π neutron counter with twenty 3He proportional tubes arranged inside a large polyethylene neutron moderator, a thin Si detector for β counting and a self-triggering digital data acquisition system. The use of delayed-neutron precursors with different neutron emission windows allowed the study of the effect of energy dependency on neutron, β and β–neutron rates. The observed effect is well reproduced by Monte Carlo simulations. The impact of this dependency on …
The neutron background of the XENON100 dark matter search experiment
2013
TheXENON100 experiment, installed underground at the LaboratoriNazionali del Gran Sasso, aims to directly detect dark matter in the form of weakly interacting massive particles (WIMPs) via their elastic scattering off xenon nuclei. This paper presents a study on the nuclear recoil background of the experiment, taking into account neutron backgrounds from (alpha, n) reactions and spontaneous fission due to natural radioactivity in the detector and shield materials, as well as muon-induced neutrons. Based on MonteCarlo simulations and using measured radioactive contaminations of all detector components, we predict the nuclear recoil backgrounds for the WIMP search results published by theXENO…
Spectral modeling of scintillator for the NEMO-3 and SuperNEMO detectors
2010
We have constructed a GEANT4-based detailed software model of photon transport in plastic scintillator blocks and have used it to study the NEMO-3 and SuperNEMO calorimeters employed in experiments designed to search for neutrinoless double beta decay. We compare our simulations to measurements using conversion electrons from a calibration source of $\rm ^{207}Bi$ and show that the agreement is improved if wavelength-dependent properties of the calorimeter are taken into account. In this article, we briefly describe our modeling approach and results of our studies.
Radioactivity control strategy for the JUNO detector
2021
JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration…
Measurement of pion and proton response and longitudinal shower profiles up to 20 nuclear interaction lengths with the ATLAS Tile calorimeter
2010
The response of pions and protons in the energy range of 20–180 GeV, produced at CERN's SPS H8 test-beam line in the ATLAS iron–scintillator Tile hadron calorimeter, has been measured. The test-beam configuration allowed the measurement of the longitudinal shower development for pions and protons up to 20 nuclear interaction lengths. It was found that pions penetrate deeper in the calorimeter than protons. However, protons induce showers that are wider laterally to the direction of the impinging particle. Including the measured total energy response, the pion-to-proton energy ratio and the resolution, all observations are consistent with a higher electromagnetic energy fraction in pion-indu…