The Time-of-flight method is usually used for energy analysis of the neutrons at a pulsed neutron source, which causes some different features from the reactor. Flight path length is essential for determining energy resolution and so on. Here, we present a brief introduction on the present status of materials from the source to the detector. Importance of devices including the detectors is stressed for the future neutron science.

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The design status of the 1MW spallation neutron source (JSNS) in the J-PARC project is to be described with an emphasis of the particular features in terms of structural components which form the central part of target station. Also, this article is expected to give a guide of which following sections are treating in specific technical issues such as spallation reactions, moderator neutronics and its technology, and radiation shielding.

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Most parts of the 1 MW pulsed spallation neutron source JSNS are regarded as radiation shield in complicated 3-D geometry. We have developed a shielding calculation method with a particle simulation code that is based on the Monte Carlo method. The method enabled us shielding designs for the 3-D shielding structure of JSNS with high accuracy. Basic structure of JSNS was optimized by the design calculations.

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The multi-purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS is introduced. Three application topics of PHITS for the spallation neutron source of J-PARC, the optimization study of the spallation neutron source, the heat and DPA calculation, and the neutron beam transport, are shown.

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We report the status of development of Ag-In-Cd decoupler. We adopted Ag-In-Cd alloy as a deoupler material to obtain excellent pulsed neutron beam with a short decay. However, it is necessary to establish the bonding technic between Ag-In-Cd alloy and Al alloy which is structural moderator material. We found that the optimal bonding condition between Al alloy (A5083) Ag-In-Cd ally using HIPing method even if real size scale bonding test. We are going to next stage to fabricate the moderator-reflector system.

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We are developing TO choppers for neutron scattering experiments at the J-PARC. First, we designed and assembled a TO chopper running at 100 Hz, and investigated its mechanical properties. The phasing accuracy of ±5μs, whish is necessary for utilizing 2 eV neutrons, was realized, and vibrations of the system were reasonably low. We are now continuously operating the system to examine the life time.

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The reflectivity of multilayer neutron mirrors depends on the interface roughness. In order to smoothen the interfaces, we have investigated multilayer deposition techniques using ion beam sputtering (IBS) method. NiC/Ti multilayers were deposited as a function of carbon mixing ratio, and were characterized. It was confirmed that the nickel grain size was decreased by deposition of Ni₃C compound and the reflectivity of supermirror with 2.4Qc was improved. Furthermore, ion polishing technique was developed in combination with IBS. The dependencies of ion polishing time, ionacceleration energy and incident angle were studied. It was observed that the reflectivities and the interface roughness are obviously improved using ion-polishing. We have constructed an IBS coating system with large deposition area for the mussproduction of high performance supermirrors and curved mirrors.

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Multilayer mirror is one of the most useful devices for slow neutron experiments. A multilayer with small d-spacing and supermirror with large-m is desirable to enlarge utilization efficiency for neutron scattering experiments. Recently we have installed an ion beam sputtering instrument to Research Reactor Institute, Kyoto University (KURRI). We have succeeded in fabricating m=6 NiC/Ti supermirrors using ion beam sputtering technique, and fabricated very small d-spacing multilayer which has maximum number of layers so far. In this report, we show the performance of these multilayers as neutron mirror and discuss its application.

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Two kinds of curved supermirror deveices were proposed for focusing of thermal and cold neutrons. One is a focusing mirror with multiple-parabolic surface (mPRB) for thermal neutorns of wavelength of 1.8Å, and the other is with paraboloidal surface (PRB) for cold neutrons of 8.8Å. The mPRB was constructed by thirty-two pieces of 3Qc Ni/Ti supermirrors deposited on Borate float glass of 150mm×100mm×0.4mm. The supermirrors were lined with parabolic wedge-shaped acrylic-resin spacers so that they were formed into four pieces of 1200mm long mirror and constituted 3 channels with parabolic shapes. It converged 3.3 times as many neutrons of 1.8Å on the area of lmm width one-dimensionally as would arrive without it at T1-3 beam port (HERMES) in JRR-3M, JAERI. The amount of detected neutrons had good agreement with that expected by the Monte Carlo simulation. The PRB consisted of four pieces of quartz glass substrates with a quarter of a paraboloidal surface. The surfaces of these pieces were coated by 3Qc Ni/Ti supermirror, 1.5Qc Ni/Ti supermirror, Ni layer, and no material. It converged 6.9 times as many neutrons of 9.5Å on the area of lmm² two-dimensionally as would arrived without it at NOP beam port in JRR-3M, JAERI. The amount of detected neutrons was about 14% in comparison with what is expected by the Monte Carlo simulation.

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Development of neutron optical devices based on the refraction at the material interface is reported. For the focusing of the cold neutrons, biconcave lens and Fresnel type lens have realized and now they are used in the neutron scattering experiment, e. g. the main focusing device of Focusing geometry SANS. A neutron optical device composed of several hundreds of small material prisms with the size of 90 μm, called Microprism, is constructed using amorphous perfluoropolymer films to refract thermal neutrons.

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As a neutron has a magnetic dipole moment, we can control a neutron beam by using magnetic field gradient. A sextupole magnet functions as an ideal focusing lens for the neutron beam. By using the sextupole magnet, we can obtain precisely focused neutron beam free from neutron scattering and attenuation by substances. Thus, the sextupole magnet has been considered to be appropriate neutron focusing device for a focusing-geometry SANS (F-SANS) experiment. We have developed magnetic neutron lenses based on the sextupole magnet which has sufficiently large aperture and strong focusing power for the F-SANS experiment, and constructed a F-SANS instrument using the magnetic lens. Here, some results of the F-SANS experiments are also shown and discussed.

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Neutron spin handling could be used for beam control and spectroscopy. Energy analysis could be performed with Drabkin energy filters, by which inelastic component with a Δλ, a Δλ/λ or a ΔE could be extracted for all incident wavelength. Pulsed spin-flipper and polarization analyzer could be used as a neutron chopper (spin-flip chopper) whose opening time, number of windows and phase are controlled independently. It was demonstrated that S/N ratio can be enhanced up to 1.5×10⁵ by installing three spin-flip choppers in sequence.

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Neutron detector systems are key to the success of high power pulsed spallation neutron sources like JSNS and SNS. We organized many small meetings to discuss about neutron detector systems for the instruments at JSNS, especially about requirements and candidates. Detector developers summarized specifications of detector systems that are available now or under development, and discussed about the requirements and candidates with neutron instrument designers. At the first stage, we will employ improved versions of conventional-detector systems such as He-3 gas linear position sensitive detector and improved version of the ZnS scintillation detector systems developed at ISIS. We will continue R&D's to develop high performance detector systems, such as MSGC/MPGC, MSGC in a gas tube and various scintillation based detector systems. Our plan is to add such high performance detector systems at a later time to the instruments.

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Nowadays, neutron detectors draw many attentions since new intense spallation neutron sources and new neutron optics are being realized. Conventional neutron detectors suffer from their poor count rate characteristics, position resolutions, and energy resolutions, etc. Since those properties are related one another in a complicated way, better design of the neutron detector engineering is required. Also, people anticipate new innovative technologies to overcome the current limitation of the detector performance. Future trends for neutron detectors are introduced in this paper.

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Development of scintillating and gaseous neutron detectors in Japan Atomic Energy Research Institute is briefly described. In this paper, the performances of the developed 2-d neutron detectors, concerning ZnS/⁶LiF scintillating detectors with wavelength shifting fiber read-out and micro-strip gas chambers with individual read-out, are presented.

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A neutron scintillation detector based on a position-sensitive photomultiplier has been developed for beam profile, neutron spin echo and small angle neutron scattering measurements. This photomultiplier has good spatial resolution, less than 1mm². The detection efficiency of gamma ray background is very low using a thin ZnS/⁶LiF scintillator. The effective area of this detector is around 60cm².

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In recent years, the requirement for a two-dimensional detector system with a relatively good positional resolution has become more crucial for neutron-scattering instruments. Several versatile readout systems have been developed at KENS. Some systems are for He-3 gas detectors, and others are for neutron-scintillators with photo-multiplier tubes (PMT). This report mentions several readout systems for the neutron-scintillators.

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Current status of neutron imaging plate (NIP) is reviewed. The characteristics of NIP is given by comparing with the one of the gas-fnled proportional position sensitive detector (PSD). The gamma-ray sensitivity and optimum condition of the NIP are reviewed. The future prospect of the NIP is presented.

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A new Multiple Prompt Gamma-ray Analysis (MPGA) method is proposed and its beam line has been constructed at JRR-3 neutron guide hall. The expected performance for MPGA as well as for neutron activation analysis is presented.

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