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Fusion product diagnostics based on four commercially available single-crystal chemical vapor deposition (s-CVD) diamond detectors are installed in the Large Helical Device (LHD) in order to understand energetic ion confinement. Characteristics of s-CVD diamonds were surveyed using alpha and D-T neutron sources. It is found that the energy resolutions of s-CVD diamonds for ∼ 5 MeV alpha particles and 14 MeV neutrons are 1%–3% and ∼ 1.7%, respectively. Moreover, the response of four s-CVD diamond detectors to alpha particles and D-T neutrons is almost identical. The installation positions of the diamond detectors in the vacuum vessel are searched for, based on the loss points of charged fusion products reckoned by Lorentz orbit calculations. Energy- and time-resolved measurement of fusion product flux will progress in further understanding of energetic ion confinement in LHD.

The use of a single neutron/gamma detector is an interesting solution to detect and identify gamma emitters and also special nuclear materials (SNM), being able to discriminate between the two kinds of particles and also to perform good-resolution gamma spectroscopy. In this framework, we present a comprehensive characterization of a medium sized (2" × 2") CLLB (Cs2LiLaBr6:Ce) scintillation detector, in order to give the necessary information to assess its deployment in applications regarding homeland security and radiation monitoring. In particular, the parameters studied are: energy resolution, full-energy peak gamma efficiency, time resolution, thermal neutron/gamma discrimination capability, decay time of the signals, high counting rate performance and minimum detectable activities (of 137Cs and 252Cf sources). We employed digital nuclear electronics combined with a pulse shape discrimination algorithm to acquire and analyze the data. We compared our results with reported data for smaller CLLB scintillators, finding good agreement. Experiments were combined with Monte Carlo simulations (using GEANT4 v10.6.0 and MCNP5 v1.60) in order to complement the characterization. The obtained results suggest that the 2” × 2” CLLB detector offers better performance with respect to other scintillators of the same size such as NaI(Tl), CsI, CeBr, etc. which are commonly used in a radiation monitoring systems.

Neutron spallation sources always require new instrument upgrades and innovations in order to improve the quality of their experiments. In this framework, the capability to accurately measure total neutron cross sections at the VESUVIO instrument at the ISIS Facility can be boosted by a tailored transmission detector. For this reason, the first double ceramic thick GEM detector has been realised. Detectors based on GEM technology are broadly developed thanks to their characteristics, such as good spatial resolution (< 0.5 mm), good detection efficiency, high rate capability (MHz/mm2) and a possible coverage area of some meters at low costs. This article shows the realisation of a GEM detector made of a 10B4C cathode, two ceramic thick GEM foils and a padded anode, as well as the device characterisation on the VESUVIO beam line, where stability, γ-sensitivity, imaging capability and sample analysis have been studied. The successful results confirm that the ceramic thick GEM detector performs well in thermal and epithermal neutron detection and it will allow the scientific user community of the instrument to perform better quality transmission measurements so as to determine more accurate total neutron cross section of condensed-matter systems.

We present the current status of our project of developing a photon counting detector for medical imaging. An example motivation lays in producing a monitoring and dosimetry device for boron neutron capture therapy, currently not commercially available. Our approach combines in-house developed detectors based on cadmium telluride or thick silicon with readout chip technology developed for particle physics experiments at CERN. Here we describe the manufacturing process of our sensors as well as the processing steps for the assembly of first prototypes. The prototypes use currently the PSI46digV2.1-r readout chip. The accompanying readout electronics chain that was used for first measurements will also be discussed. Finally we present an advanced algorithm developed by us for image reconstruction using such photon counting detectors with focus on boron neutron capture therapy. This work is conducted within a consortium of Finnish research groups from Helsinki Institute of Physics, Aalto University, Lappeenranta-Lahti University of Technology LUT and Radiation and Nuclear Safety Authority (STUK) under the RADDESS program of Academy of Finland. Keywords: Solid state detectors, X-ray detectors, Gamma detectors, Neutron detectors, Instrumentation for hadron therapy, Medical-image reconstruction methods and algorithms.

The e_LiBANS project aims at creating accelerator based compact neutron facilities for diverse interdisciplinary applications. After the successful setting up and characterization of a thermal neutron source based on a medical electron LINAC, a similar assembly for epithermal neutrons has been developed. The project is based on an Elekta 18 MV LINAC coupled with a photoconverter-moderator system which deploys the ({\gamma},n) photonuclear reaction to convert a bremsstrahlung photon beam into a neutron field. This communication describes the development of novel diagnostics to qualify the thermal and epithermal neutron fields that have been produced. In particular, a proof of concept for the use of silicon carbide photodiodes as a thermal neutron rate detector is presented., Comment: 10 pages, 10 figures, accepted for publication to JINST on the 17th April 2020

The SoLid experiment has been designed to search for an oscillation pattern induced by a light sterile neutrino state, utilising the BR2 reactor of SCK$\bullet$CEN, in Belgium. The detector leverages a new hybrid technology, utilising two distinct scintillators in a cubic array, creating a highly segmented detector volume. A combination of 5 cm cubic polyvinyltoluene cells, with $^6$LiF:ZnS(Ag) sheets on two faces of each cube, facilitate reconstruction of the neutrino signals. % The polyvinyltoluene scintillator is used as an $\overline{\nu}_e$ target for the inverse beta decay of ($\overline{\nu}_e + p \rightarrow e^{+}+n$), with the $^6$LiF:ZnS(Ag) sheets used for associated neutron detection. Scintillation signals are read out by a network of wavelength shifting fibres connected to multipixel photon counters. Whilst the high granularity provides a powerful toolset to discriminate backgrounds; by itself the segmentation also represents a challenge in terms of homogeneity and calibration, for a consistent detector response. The search for this light sterile neutrino implies a sensitivity to distortions of around $\mathcal{O}$(10)\% in the energy spectrum of reactor $\overline{\nu}_e$. Hence, a very good neutron detection efficiency, light yield and homogeneous detector response are critical for data validation. The minimal requirements for the SoLid physics program are a light yield and a neutron detection efficiency larger than 40 PA/MeV/cube and 50 \% respectively. In order to guarantee these minimal requirements, the collaboration developed a rigorous quality assurance process for all 12800 cubic cells of the detector. To carry out the quality assurance process, an automated calibration system called CALIPSO was designed and constructed., Comment: Submitted to JINST

Born in the late 90's, Micro-Pattern Gaseous Detectors (MPGD) have opened the way for the construction of detectors whose performance surpasses that of the previous generations in terms of spatial resolution, high-rate capability and increased radiation hardness. Micro-Mesh Gaseous Structure (Micromegas) and the Gas Electron Multiplier (GEM), the mostly used MPGD-type, are mature technologies exploited in a variety of experiments at high energy physics. Thanks to their excellent performance and their modularity several application beyond HEP profited from their introduction such as medical imaging, dosimetry and beam diagnostics for high energy beams and for nuclear reactors. Among all the new developments, performance of MPGD-based detectors fast/thermal neutron detection linked to magnetic and inertial fusion experiments as well as spallation neutron sources will be reviewed underlining the new capabilities of these devices over state of the art.

For many years artificial diamond detectors have been studied for application in high temperature environments. An open question is whether the performance of such detectors is influenced by the electrical contacts. In the attempt to better understand this point, a systematic study of electrical contacts deposited with different techniques and materials on top of commercial artificial single crystal diamond (SCD) films was performed. In this paper we report on the results obtained using three types of electric contacts produced both using metal and not metal layers: a) double Schottky, b) double ohmic; c) Schottky-ohmic contacts. The detectors were studied under 14 MeV neutron irradiation, and were operated in pulse mode. The pulse height spectra (PHS) produced by the 14 MeV neutrons were recorded as a function of temperature and the detector behaviour was studied by analysing the variation of the peak produced in the PHS by the 12C(n,α)9Be reaction induced by 14 MeV neutrons in carbon. The maximum operational temperature limit of the tested detectors was found to be around 230ˆC and it resulted to be slightly dependent, within ±10ˆC, upon the type of the electrical contact. It turned out that, together with the type of the electrical contact, other parameters such as the intrinsic diamond properties and the film thickness have to be considered to understand the response of the detector at high temperature.

In recent years, silicon photomultiplier (SiPM) technology has been getting attention from various applications due to its low cost, immunity to magnetic field, compactness and ruggedness. However, its applicability in experiments with harsh radiation environments is still limited due to lack of corresponding radiation damage studies. A 10-year lifetime operation in a typical Small Angle Neutron Scattering (SANS) experiment with an acceptable degradation in photon detection efficiency has already been reported. In this article, we discuss the feasibility study of SiPM technology in neutron time of flight experiments. For this purpose, two analog SiPMs, developed by SensL and Hamamatsu, have been irradiated with cold neutrons (5 Å ) up to a dose of 6⋅1012 n/cm2 at the KWS-1 instrument of the Heinz Maier-Leibnitz Zentrum (MLZ) in Germany. After irradiation, the timing resolutions of the SiPMs have been measured under pulsed laser beam with a few hundred photons (405 nm) per pulse, and a degradation of up to 6 ps has been observed. The degradation might be a result of noise increase, introduced by surface defects caused by neutron exposure damage. Additionally, variation of the excess voltage helped to reveal the difference in the timing resolutions between irradiated and non-irradiated SiPMs, which remained almost constant.

© 2018 IOP Publishing Ltd and Sissa Medialab. This paper describes the design and performance of a 50 liter, two-segment 6Li-loaded liquid scintillator detector that was designed and operated as prototype for the PROSPECT (Precision Reactor Oscillation and Spectrum) Experiment. The two-segment detector was constructed according to the design specifications of the experiment. It features low-mass optical separators, an integrated source and optical calibration system, and materials that are compatible with the 6Li-doped scintillator developed by PROSPECT. We demonstrate a high light collection of 850±20 PE/MeV, an energy resolution of σ = 4.0±0.2% at 1 MeV, and efficient pulse-shape discrimination of low dE/dx (electronic recoil) and high dE/dx (nuclear recoil) energy depositions. An effective scintillation attenuation length of 85±3 cm is measured in each segment. The 0.1% by mass concentration of 6Li in the scintillator results in a measured neutron capture time of τ = 42.8±0.2 μs. The long-term stability of the scintillator is also discussed. The detector response meets the criteria necessary for achieving the PROSPECT physics goals and demonstrates features that may find application in fast neutron detection.

European Spallation Source (ESS) will deliver neutrons at high flux for use in diverse neutron scattering techniques. The neutron source facility and the scientific instruments will be located in Lund, and the Data Management and Software Centre (DMSC), in Copenhagen. A number of detector prototypes are being developed at ESS together with its European in-kind partners, for example: SoNDe, Multi-Grid, Multi-Blade and Gd-GEM. These are all position sensitive detectors but use different techniques for the detection of neutrons. Except for digitization of electronics readout, all neutron data is anticipated to be processed in software. This provides maximum flexibility and adaptability and allows deep inspection of the raw data for commissioning which will reduce the risk of starting up new detector technologies. But it also requires development of high performance software processing pipelines and optimized and scalable processing algorithms. This report provides a description of the ESS system architecture for the neutron data path. Special focus is on the interface between the detectors and DMSC which is based on UDP over Ethernet links. The report also describes the software architecture for detector data processing and the tools we have developed, which have proven very useful for efficient early experimentation, and can be run on a single laptop. Processing requirements for the SoNDe, Multi-Grid, Multi-Blade and Ge-GEM detectors are presented and compared to event processing rates archived so far., Comment: 26 pages

Building the European Spallation Source (ESS), the most powerful neutron source in the world, requires significant technological advances at most fronts of instrument component design. Detectors are not an exception. The existing implementations at current neutron scattering facilities are at their performance limits and sometimes barely cover the scientific needs. At full operation the ESS will yield unprecedented neutron brilliance. This means that one of the most challenging aspects for the new detector designs is the increased rate capability and in particular the peak instantaneous rate capability, i.e.\,the number of neutrons hitting the detector per channel, pixel or cm$^2$ at the peak of the neutron pulse. This paper focuses on estimating the incident and detection rates that are anticipated for the Small Angle Neutron Scattering (SANS) instruments planned for ESS. Various approaches are applied and the results thereof are presented.

We have measured the ionization efficiency of silicon nuclear recoils with kinetic energy between 1.8 and 20 keV. We bombarded a silicon-drift diode with a neutron beam to perform an elastic-scattering experiment. A broad-energy neutron spectrum was used and the nuclear recoil energy was reconstructed using a measurement of the time of flight and scattering angle of the scattered neutron. The overall trend of the results of this work is well described by the theory of Lindhard et al. above 4 keV of recoil energy. Below this energy, the presented data shows a deviation from the model. The data indicates a faster drop than the theory prediction at low energies. Fil: Izraelevitch, Federico Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Fermi National Accelerator Laboratory; Estados Unidos Fil: Amidei, D.. University of Michigan; Estados Unidos Fil: Aprahamian, A.. University of Notre Dame; Estados Unidos Fil: Arcos Olalla, R.. Universidad de Guanajuato; México Fil: Cancelo, Gustavo Indalecio Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fermi National Accelerator Laboratory; Estados Unidos Fil: Casarella, C.. University of Notre Dame; Estados Unidos Fil: Chavarria, A. E.. University of Chicago; Estados Unidos Fil: Collon, P.. University of Notre Dame; Estados Unidos Fil: Estrada, Juan. Fermi National Accelerator Laboratory; Estados Unidos Fil: Fernández Moroni, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fermi National Accelerator Laboratory; Estados Unidos Fil: Guardincerri, Yann. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fermi National Accelerator Laboratory; Estados Unidos Fil: Gutiérrez, G.. Fermi National Accelerator Laboratory; Estados Unidos Fil: Gyurjinyan, A.. University of Notre Dame; Estados Unidos Fil: Kavner, A.. University of Michigan; Estados Unidos Fil: Kilminster, B.. Universitat Zurich; Suiza Fil: Liao, J.. Universitat Zurich; Suiza Fil: Liu, Q.. University of Notre Dame; Estados Unidos Fil: López, M.. Universidad Nacional de Asunción; Paraguay Fil: Molina, J.. Universidad Nacional de Asunción; Paraguay Fil: Privitera, P.. University of Chicago; Estados Unidos Fil: Reyes, M. A.. Universidad de Guanajuato; México Fil: Scarpine, V.. Fermi National Accelerator Laboratory; Estados Unidos Fil: Siegl, K.. University of Notre Dame; Estados Unidos Fil: Smith, M.. University of Notre Dame; Estados Unidos Fil: Strauss, S.. University of Notre Dame; Estados Unidos Fil: Tan, W.. University of Notre Dame; Estados Unidos Fil: Tiffenberg, Javier Sebastian. Fermi National Accelerator Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Villanueva, L.. Universidad de Guanajuato; México

A Bonner sphere spectrometer (BSS) plays an important role in characterizing neutron spectra and determining their neutron dose in a neutron-gamma mixed field. A BSS consisting of a set of nine polyethylene spheres with a (3)He proportional counter was developed at Peking University to perform neutron spectrum and dosimetry measurements. Response functions (RFs) of the BSS were calculated with the general Monte Carlo code MCNP5 for the neutron energy range from thermal up to 20 MeV, and were experimentally calibrated with monoenergetic neutron beams from 144 keV to 14 MeV on a 4.5 MV Van de Graaff accelerator. The calculated RFs were corrected with the experimental values, and the whole response matrix was completely established. The spectrum of a (241)Am-Be source was obtained after unfolding the measurement data of the BSS to the source and in fair agreement with the expected one. The integral ambient dose equivalent corresponding to the spectrum was 0.95 of the expected value. Results of the unfolded spectrum and the integral dose equivalent measured by the BSS verified that the RFs of the BSS were well established.

The next generation of very-short-baseline reactor experiments will require compact detectors operating at surface level and close to a nuclear reactor. This paper presents a new detector concept based on a composite solid scintillator technology. The detector target uses cubes of polyvinyltoluene interleaved with $^6$LiF:ZnS(Ag) phosphor screens to detect the products of the inverse beta decay reaction. A multi-tonne detector system built from these individual cells can provide precise localisation of scintillation signals, making efficient use of the detector volume. Monte Carlo simulations indicate that a neutron capture efficiency of over 70% is achievable with a sufficient number of $^6$LiF:ZnS(Ag) screens per cube and that an appropriate segmentation enables a measurement of the positron energy which is not limited by gamma-ray leakage. First measurements of a single cell indicate that a very good neutron-gamma discrimination and high neutron detection efficiency can be obtained with adequate triggering techniques. The light yield from positron signals has been measured, showing that an energy resolution of 14%/$\sqrt{E({\mathrm{MeV}})}$ is achievable with high uniformity. A preliminary neutrino signal analysis has been developed, using selection criteria for pulse shape, energy, time structure and energy spatial distribution and showing that an antineutrino efficiency of 40% can be achieved. It also shows that the fine segmentation of the detector can be used to significantly decrease both correlated and accidental backgrounds., 17 pages, 15 figures, submitted to JINST

A scintillating-fiber (Sci-Fi) detector has been employed to measure 14 MeV neutrons for the triton burnup study in the first deuterium plasma campaign of the Large Helical Device (LHD). The pulse-height spectra of the Sci-Fi detector are used to choose a suitable threshold for the discrimination of 14 MeV neutrons from a mix-radiation field of low-energy neutrons and gamma-rays. The measured pulse-height spectra of the Sci-Fi detector have two components with different decay slopes from the LHD experiment. To study the pulse-height property of the Sci-Fi detector, the pulse-height spectra on different energy neutrons have been measured by using the accelerator-based neutron source with d-D, p-Li, and d-Li reactions. Meanwhile, the simulations of the detector response have been performed by using the Particle and Heavy Ion Transport code System (PHITS). In the LHD experiment, the first decay component of the pulse-height spectra in low-pulse-height region has been found to correspond to the signals induced by 2.45 MeV neutrons and gamma-rays. In addition, the high-pulse-height region has been confirmed by both the accelerator experiment and the PHITS calculation to correspond to the recoil-proton edge induced by triton burnup 14 MeV neutrons. The detection efficiency of 14 MeV neutrons for the Sci-Fi detector calculated by the PHITS code agrees well with the detection efficiency of 14 MeV neutrons for the Sci-Fi detector evaluated in the LHD experiment. The Sci-Fi detector can work as a standard detector for the 14 MeV neutron measurement with a suitable threshold.

The paper describes a new compact neutron spectrometer optimized for the detection of 2.5 MeV neutrons for fusion plasma applications. The first neutron spectroscopy measurements on a nuclear fusion plasma experiment (EAST) with this detector are also reported together with the data interpretation. The detector allowed separating the different neutron emission components from the plasma and to validate the effectiveness of the Neutral Beam Injection (NBI) heating. A possible improvement of the diagnostic has been also identified in order to increase the detector sensitivity to weak components of the neutron spectrum, such as those due to the Ion Cyclotron Resonace Heating (ICRH). The relatively simple response function of the (CLYC)-L-7 detector to 2.5 MeV neutrons together with its good capability in the n/gamma discrimination, makes this detector an interesting spectrometer for deuterium (D) plasma diagnostics. In particular, its compactness allows for integration in a multi-line of sight camera where space constraints are present.

© 2016 IOP Publishing Ltd and Sissa Medialab srl. Nuclear recoil events produced by neutron scatters form one of the most important classes of background in WIMP direct detection experiments, as they may produce nuclear recoils that look exactly like WIMP interactions. In DarkSide-50, we both actively suppress and measure the rate of neutron-induced background events using our neutron veto, composed of a boron-loaded liquid scintillator detector within a water Cherenkov detector. This paper is devoted to the description of the neutron veto system of DarkSide-50, including the detector structure, the fundamentals of event reconstruction and data analysis, and basic performance parameters.

International audience; Nuclear recoil events produced by neutron scatters form one of the most important classes of background in WIMP direct detection experiments, as they may produce nuclear recoils that look exactly like WIMP interactions. In DarkSide-50, we both actively suppress and measure the rate of neutron-induced background events using our neutron veto, composed of a boron-loaded liquid scintillator detector within a water Cherenkov detector. This paper is devoted to the description of the neutron veto system of DarkSide-50, including the detector structure, the fundamentals of event reconstruction and data analysis, and basic performance parameters.

A new neutron imaging and diffraction facility, called IMAT, is currently being commissioned at the ISIS pulsed neutron spallation source. IMAT will take advantage of neutron time-of-flight measurement techniques for flexible neutron energy selection and effective energy discrimination. The instrument will be completed and commissioned within the next few months, after neutrons have been recently delivered to the sample area. From 2016 IMAT will enable white-beam neutron radiography and tomography as well as energy-dependent neutron imaging. The facility will offer a spatial resolution down to 50 microns for a field of view of up to 400 cm(2). IMAT will be operated as a user facility for material science applications and will be open for developments of time-of-flight imaging methods.

Agradecimentos: The DarkSide-50 Collaboration would like to thank LNGS laboratory and its staff for invaluable technical and logistical support. This report is based upon work supported by the US NSF (Grants PHY-0919363, PHY-1004072, PHY-1004054, PHY-1242585, PHY-1314483, PHY-1314507 and associated collaborative grants, grants PHY-1211308 and PHY-1455351), the Italian Istituto Nazionale di Fisica Nucleare (INFN), the US DOE (Contract Nos. DE-FG02-91ER40671 and DE-AC02-07CH11359), and the Polish NCN (Grant UMO-2012/05/E/ST2/02333). We thank the staff of the Fermilab Particle Physics, Scientific and Core Computing Divisions for their support. We acknowledge the financial support from the UnivEarthS Labex program of Sorbonne Paris Cite (ANR-10-LABX-0023 and ANR-11-IDEX-0005-02) and from the São Paulo Research Foundation (FAPESP) Abstract: Nuclear recoil events produced by neutron scatters form one of the most important classes of background in WIMP direct detection experiments, as they may produce nuclear recoils that look exactly like WIMP interactions. In DarkSide-50, we both actively suppress and measure the rate of neutron-induced background events using our neutron veto, composed of a boron-loaded liquid scintillator detector within a water Cherenkov detector. This paper is devoted to the description of the neutron veto system of DarkSide-50, including the detector structure, the fundamentals of event reconstruction and data analysis, and basic performance parameters FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

IMAT is a new cold-neutron imaging facility at the neutron spallation source ISIS at the Rutherford Appleton Laboratory, U.K.. The ISIS pulsed source enables energy-selective and energy-resolved neutron imaging via time-of-flight (TOF) techniques, which are available in addition to the white-beam neutron radiography and tomography options. A spatial resolution of about 50 μm for white-beam neutron radiography was achieved early in the IMAT commissioning phase. In this work we have made the first steps towards achieving higher spatial resolution. A white-beam radiography with 18 μm spatial resolution was achieved in this experiment. This result was possible by using the event counting neutron pixel detector based on micro-channel plates (MCP) coupled with a Timepix readout chip with 55 μm sized pixels, and by employing an event centroiding technique. The prospects for energy-selective neutron radiography for this centroiding mode are discussed.

A neutron imaging detector based on neutron-sensitive microchannel plates (MCPs) was constructed and tested at beamlines of thermal and cold neutrons. The MCPs are made of a glass mixture containing B-10 and natural Gd, which makes the bulk of the MCP an efficient neutron converter. Contrary to the neutron sensitive scintillator screens normally used in neutron imaging, spatial resolution is not traded off with detection efficiency. While the best neutron imaging scintillators have a detection efficiency around a percent, a detection efficiency of around 50% for thermal neutrons and 70% for cold neutrons has been demonstrated with these MCPs earlier. Our tests show a performance similar to conventional neutron imaging detectors, apart from the orders of magnitude better sensitivity. We demonstrate a spatial resolution better than 150 um. The sensitivity of this detector allows fast tomography and neutron video recording, and will make smaller reactor sites and even portable sources suitable for neutron imaging., Comment: Submitted to the proceedings of the 19th International Workshop on Radiation Imaging Detectors (iWoRiD) 2-6 July 2017, Krakow, Poland

The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS) searches for the neutrinoless double beta decay of 76-Ge. In view of the GERDA Phase II data collection, four new 228-Th radioactive sources for the calibration of the germanium detectors enriched in 76-Ge have been produced with a new technique, leading to a reduced neutron flux from ( alpha; n ) reactions. The gamma activities of the sources were determined with a total uncertainty of 4 percent using an ultra-low background HPGe detector operated underground at LNGS. The emitted neutron flux was determined using a low background LiI(Eu) detector and a 3-He counter at LNGS. In both cases, a reduction of about one order of magnitude with respect to commercially available 228-Th sources was obtained. Additionally, a specific leak test with a sensitivity to leaks down to 10 mBq was developed to investigate the tightness of the stainless steel capsules housing the sources after their use in cryogenic environment., 14 pages, 5 figures, 3 tables

A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic neutrons produced from a deuteron beam of varying energy (300 to 1500 AMeV) in experiment S406 at GSI, Darmstad, Germany. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Measurements of the time of flight jitter of neutrons, in the mentioned energy range, point to a contribution of the resistive plate chamber in the order of 150 ps, independent of the neutron energy.

A neutron detector based on EJ301 liquid scintillator has been employed at EAST to measure the neutron energy spectrum for D-D fusion plasma. The detector was carefully characterized in different quasi-monoenergetic neutron fields generated by a 4.5 MV Van de Graaff accelerator. In recent experimental campaigns, due to the low neutron yield at EAST, a new shielding device was designed and located as close as possible to the tokamak to enhance the count rate of the spectrometer. The fluence of neutrons and gamma-rays was measured with the liquid neutron spectrometer and was consistent with 3He proportional counter and NaI (Tl) gamma-ray spectrometer measurements. Plasma ion temperature values were deduced from the neutron spectrum in discharges with lower hybrid wave injection and ion cyclotron resonance heating. Scattered neutron spectra were simulated by the Monte Carlo transport Code, and they were well verified by the pulse height measurements at low energies., Comment: 19 pages,10 figures, 1 table

Measurements of the fast neutron energy spectrum at the ISIS spallation source are reported. The measurements were performed with a Proton Recoil Telescope consisting of a thin plastic foil placed in the neutron beam and two scintillator detectors. Results in the neutron energy range 30 MeV < E-n < 80 MeV are in good agreement with Monte Carlo simulations of the neutron spectrum.

The resonance structure in neutron induced reaction cross sections can be used to determine the elemental compositions of materials or objects. The occurrence of resonances is the basis of neutron resonance capture analysis (NRCA) and neutron resonance transmission analysis (NRTA). NRCA and NRTA are fully non-destructive methods to determine the bulk elemental composition without the need of any sample preparation and resulting in a negligible residual activity. They have been applied to determine the elemental composition of archaeological objects and to characterize reference materials used for cross section measurements. For imaging applications a position sensitive neutron detector has been developed within the ANCIENT CHARM project. The detector is based on a 10 × 10 array of 6Li-glass scintillators mounted on a pitch of 2.5 mm, resulting in a 25 × 25 mm2 active area. The detector has been tested at the time-of-flight facility GELINA and used at the ISIS spallation source to study cultural heritage objects.

The performance of a single crystal diamond (4.7x4.7x0.5mm(3) active volume) detector was tested in the ISIS pulsed neutron beam using biparametric (time of flight and pulse height) data acquisition. Three characteristic regions in the biparametric spectra are observed: i) low pulse height events with very short time of flight induced by gamma-rays; ii) low pulse height events at longer flight times (i.e. neutron energies E-n > 3.5-6 MeV), possibly due to neutron elastic scattering off C-12; iii) events with large pulse height and flight times corresponding to E-n > 6 MeV mainly due to inelastic reactions such as C-12(n,alpha)Be-9 and C-12(n,n')3 alpha. The potential use of this detector is discussed in relation to the ChipIr neutron beam line for fast neutron irradiation of electronic components at the ISIS spallation source.