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A detailed characterization of doped paraterphenyl (p-Terphenyl) neutron detectors was obtained by means of γ-sources and a 252 Cf fission chamber. The intrinsic timing resolution, the energy resolution up to 2 MeV ee , and the electron-equivalent energy calibration were determined using γ-sources. The neutron time-of-flight spectrum from the spontaneous fission of 252 Cf provided information on the proton energy calibration, the light output function, and the intrinsic neutron detection efficiency between 0 and 8 MeV for a threshold of 250 keV. Measurements of the latter were also performed using monoenergetic neutron beams. The applied experimental methods were cross-checked using two BC501A scintillation detectors, which were previously calibrated at the Physikalisch-Technische Bundesanstalt in Braunschweig, Germany. Results were compared to Monte-Carlo simulations performed using NRESP7 and NEFF7 codes. [ABSTRACT FROM AUTHOR]

Abstract: A new neutron beam line facility with low background has been installed on the TANDEM accelerator facility of CEA/DIF at Bruyères-le-Châtel (France) to allow (n, xn) reactions studies with a new neutron-multiplicity detector. Beam neutrons are produced by nuclear reaction between a proton or deuteron beam and a deuterium or tritium target. The neutron beam is defined by a channel going through a shielding system built around the neutron production source. The design of the shielding system has been carried out using the MCNP (version 4C) code. The beam characteristics (size, energy spectra and flux) were measured. The neutron-beam energy range covers 3–25MeV, the beam being purely monoenergetic below 8MeV. [Copyright &y& Elsevier]

Ion stopping experiments in plasma for beam energies of few hundred keV per nucleon are of great interest to benchmark the stopping-power models in the context of inertial confinement fusion and high-energy-density physics research. For this purpose, a specific ion detector on chemical-vapor-deposition diamond basis has been developed for precise time-of-flight measurements of the ion energy loss. The electrode structure is interdigitated for maximizing its sensitivity to low-energy ions, and it has a finger width of 100 μm and a spacing of 500 μm. A short single α-particle response is obtained, with signals as narrow as 700 ps at full width at half maximum. The detector has been tested with α-particle bunches at a 500 keV per nucleon energy, showing an excellent time-of-flight resolution down to 20 ps. In this way, beam energy resolutions from 0.4 keV to a few keV have been obtained in an experimental configuration using a 100 μg/cm2 thick carbon foil as an energy-loss target and a 2 m time-of-flight distance. This allows a highly precise beam energy measurement of δE/E ≈ 0.04%–0.2% and a resolution on the energy loss of 0.6%–2.5% for a fine testing of stopping-power models. [ABSTRACT FROM AUTHOR]

CARMEN is a 4π neutron detector filled with a gadolinium-loaded liquid scintillator built to measure neutron multiplicity distributions. It is used to study fission and (n,xn) reactions. In addition to neutron multiplicity measurements, CARMEN can be used to measure neutron energy spectra with the time-of-flight technique, thanks to the time properties of the prompt signal. The detector, detection technique and efficiency determination are presented in detail. Two examples are also presented: the measurement of 252 Cf spontaneous fission neutron multiplicity probability distribution and the measurement of the neutron energy spectrum emitted by an Am-Be radioactive source. [ABSTRACT FROM AUTHOR]

New fission chambers dedicated to Prompt Fission Neutron Spectra measurements with the time-of-flight technique have been developed. The actinide mass embedded in the chamber was maximized, while the alpha-fission discrimination and the time resolution were optimized. Moreover, to reduce the neutron background and spectra distortions, neutron scattering with the materials were minimized by the choice of material and structure. These chambers were then tested and validated during tests and in-beam experiments. [ABSTRACT FROM AUTHOR]

The major advances achieved over the last decades in the understanding of fundamental neutrino physics allow us to apply the detection of reactor antineutrino signals to automatic and nonintrusive nuclear power plant surveys. Here, we present the NUCIFER experiment, a 1-ton Gd-doped liquid scintillator detector to be installed a few 10 m from a reactor core for measurements of its thermal power and plutonium (Pu) content. The design of such a small volume detector has been focused on high detection efficiency (\sim50% and good background rejection. Detailed simulations of reactor-emitted antineutrino spectrum and detector response have been developed and used to calculate the NUCIFER sensitivity to illicit retrieval of Pu from the core. These results have been presented in October 2008 to the International Atomic Energy Agency (IAEA), which has expressed its interest in the potentialities of this detector as a new safeguard tool. [ABSTRACT FROM PUBLISHER]

The creation of isomeric nuclei by neutron capture in the resonances energy range was studied with the lead slowing-down assembly CIRENE. The isomeric-ratio measurement of 8 nuclei allows to determine the spin of the compound nucleus at the binding energy. An experiment on 177Lu underlines the role of the spin of a resonance on the isomeric-state feeding probability. [ABSTRACT FROM AUTHOR]

A large volume (4 l) liquid NE213 scintillator detector for neutrons in the energy range up to 800 MeV has been calibrated using a high accuracy tagging technique at En=21,34,50,60 and 100 MeV. The experiment is described together with a discussion of the accuracy in the absolute efficiency calibration. Results are presented on total and differential detection efficiencies along with information on the underlying nuclear reactions causing the detector response, including both charged particles and γ-rays. The present results complement previous measurements for the same detector, so that an efficiency calibration now exists over an energy range of En=2–800 MeV. The empirical results are compared with a calculated energy dependence of the detector response to neutrons. [Copyright &y& Elsevier]

The Neutrons For Science (NFS) facility will provide intense neutron beams in the energy range between 1 MeV and 40 MeV. The neutron monitoring will be ensured by a detector consisting of a glass cell containing EJ309 liquid scintillator coupled to a photomultiplier. The goal of this study was the characterization of this monitor. Two experiments were performed to measure the light response of the scintillator from 3.6 MeV to 45 MeV as well as the detection efficiency between 3.6 MeV and 15.9 MeV. The obtained light response was used to adapt the simulation program SCINFUL to EJ309 scintillator. SCINFUL was then used to reproduce within 5 percent uncertainty the detector efficiency determined experimentally. [ABSTRACT FROM AUTHOR]