YAP scintillators for resonant detection of epithermal neutrons at pulsed neutron sources

Recent studies indicate the resonance detector (RD) technique as an interesting approach for neutron spectroscopy in the electron volt energy region. This work summarizes the results of a series of experiments where RD consisting of YAlO3 (YAP) scintillators were used to detect scattered neutrons with energy in the range 1-200 eV. The response of YAP scintillators to radiative capture gamma emission from a U-238 analyzer foil was characterized in a series of experiments performed on the VESUVIO spectrometer at the ISIS pulsed neutron source. In these experiments a biparametric data acquisition allowed the simultaneous measurements of both neutron time-of-flight and gamma pulse height (energy) spectra. The analysis of the gamma pulse height and neutron time of flight spectra permitted to identify and distinguish the signal and background components. These measurements showed that a significant improvement in the signal-to-background ratio can be achieved by setting a lower level discrimination on the pulse height at about 600 keV equivalent photon energy. Present results strongly indicate YAP scintillators as the ideal candidate for neutron scattering studies with epithermal neutrons at both very low (<5degrees) and intermediate scattering angles. (C) 2004 American Institute of Physics

Facility for fast neutron irradiation tests of electronics at the ISIS spallation neutron source

The VESUVIO beam line at the ISIS spallation neutron source was set up for neutron irradiation tests in the neutron energy range above 10 MeV. The neutron flux and energy spectrum were shown, in benchmark activation measurements, to provide a neutron spectrum similar to the ambient one at sea level, but with an enhancement in intensity of a factor of 107. Such conditions are suitable for accelerated testing of electronic components, as was demonstrated here by measurements of soft error rates in recent technology field programable gate arrays

Prompt gamma activation studies on archaeological objects at a pulsed neutron source

The potential of Prompt Gamma Activation Analysis (PGAA) for non-destructive quantitative investigation of archaeological objects at a pulsed neutron spallation source was studied. Experiments were performed on the ROTAX time-of-flight diffractometer of the ISIS neutron source on a chalcolithic copper axe, a limestone sample from the ancient Quarry of Masarah (Egypt), a Roman bronze fibula and two fragments of glass from the Roman Villa Adriana. For reference and comparison, measurements were also performed at the PGAA station of the Budapest research reactor. It is found that the performance of a PGAA analysis at a pulsed source, with a make-shift set-up on an instrument designed for diffraction studies, cannot match the achievable results at a dedicated PGAA facility at a reactor source. However, the possibility of performing different investigations, e.g., neutron diffraction for structure analysis and PGAA for elemental analysis, at a single facility on one and the same object remains attractive and offers useful applications in the field of cultural heritage

Fast ion energy distribution from third harmonic radio frequency heating measured with a single crystal diamond detector at the Joint European Torus

Neutron spectroscopy measurements with a single crystal diamond detector have been carried out at JET, for the first time in an experiment aimed at accelerating deuterons to MeV energies with radio frequency heating at the third harmonic. Data are interpreted by means of the expected response function of the detector and are used to extract parameters of the highly non-Maxwellian distribution function generated in this scenario. A comparison with observations using a time of flight and liquid scintillator neutron spectrometers is also presented. The results demonstrate the capability of diamond detectors to contribute to fast ion physics studies at JET and are of more general relevance in view of the application of such detectors for spectroscopy measurements in the neutron camera of next step tokamak devices.EURATOM 63305

a telescope proton recoil spectrometer for fast neutron beam lines

A telescope proton recoil spectrometer for fast neutron beam-lines C. Cazzaniga1,3,∗, M. Rebai2,3, M. Tardocchi3, G. Croci2,3, M. Nocente2,3, S. Ansell1, C. D. Frost1, and G. Gorini2,3 1ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK 2Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica, Piazza della Scienza 3, Milano, Italy 3Istituto di Fisica del Plasma "P. Caldirola", Associazione EURATOM-ENEA/CNR, Via Cozzi 53, Milano, Italy ∗E-mail: [email protected]

Study of archaeological samples via neutron techniques

The discovery of ancient artefacts and artworks usually raises a variety of questions such as the correct determination of their historical and cultural timeframe, the place and method of production, the choice of treatments and conditions for restoration and preservation. In the field of archaeometry, new perspectives are opened up by the use of neutron techniques. Results on a selection of archaeological samples, Etruscan bronzes coming from the Museo Nazionale di Villa Giulia and Roman marbles from Villa Adriana (Tivoli, Rome), are presented. ANCIENT CHARM project aims to develop a quantitative 3D imaging technique. This work presents some of results on a series of experimental investigation performed on test samples called “Black Boxes”. Elements’ and compounds’ identification on the internal features of the boxes are obtained by the combined use of different neutron analysis methods. The presented studies successfully showed the high potential of neutron techniques in the study of ancient archaeological artefacts

Single-crystal Diamond Detector for DT and DD plasmas diagnostic

Single-crystal Diamond Detectors (SDD) are good candidates as high-energy neutron detectors in the extreme conditions of the next generation thermonuclear fusion facilities like the ITER experiment, due to their high radiation hardness, fast response time and small size. Neutron detection in SDDs is based on the collection of electron-hole pairs produced by charged particles generated by neutron interaction on 12C. In this work the SDD response to neutrons with energies between 2.8 and 3.8MeV was determined at the Legnaro CN accelerator at the INFN Laboratories in Legnaro (PD, Italy). This work is relevant for the characterization of SDDs response functions, which are key points for Deuterium-Deuterium and Deuterium-Tritium plasma diagnostic

Time-stability of a Single-crystal Diamond Detector for fast neutron beam diagnostic under alpha and neutron irradiation

Single-crystal Diamond Detectors (SDDs), due to their good charge carrier transport properties, low leakage and therefore good energy resolution, are good candidates for fast neutron measurement on pulsed spallation sources and fusion plasma experiments. Moreover, diamonds are known to be resistant to neutron irradiation. Nevertheless, measurements show transient effects during irradiation with ionizing particles, as the alpha particle calibration sources. The decrease of the detector counting rate of a counting chain and the pulse height are interpreted as due to a charge trapping inside the detector, which modifies the drift electric field. These instabilities are strongly dependent on the specific type of the interaction. Measurements have been carried out with both alpha particles in the laboratory and neutrons at the ISIS neutron spallation source. We show that these polarization effects are not permanent: the detector performances can be restored by simply inverting the detector bias high voltage. Prime Novelty Statement The measurements described in the paper were performed in order to study the polarization effect in Single-crystal Diamond Detector. This effect was observed under alpha particle and neutron irradiation. With the Transient Current Technique an interpretation of the effect is given