T. Ino

High Intensity Chopper Spectrometer 4Seasons At J-parc

Design and performance of a new chopper spectrometer 4SEASONS, which is under construction for the spallation neutron source at Japan Proton Accelerator Research Complex (J-PARC), are described. This spectrometer has middle energy resolution and two orders higher performance than current state-of-the-art chopper spectrometers by utilizing a unique beam transport design and the repetition rate multiplication (RRM) method. 4SEASONS has a specification optimized for the study of the high critical temperature (T c) superconductivity, and should be suitable for collecting weak inelastic signals from a single crystal over a wide four-dimensional (4D) Q-ω space.

Development of a Fresnel lens for cold neutrons based on neutron refractive optics

Abstract We have developed compound refractive lenses (CRLs) for cold neutrons, which are made of vitreous silica and have an effective potential of (90.1– 2.7×10 −4 i ) neV . In the case of compound refractive optics, neutron absorption by the material deteriorates lens performance. Thus, to prevent an increase in neutron absorption with increasing beam size, we have developed Fresnel lenses using the electrolytic in-process dressing grinding technique. The lens characteristics were carefully investigated with experimental and numerical simulation studies. The lenses functioned as a neutron focusing lens, and the focal length of 14 m was obtained with a 44-element series of the Fresnel lenses for 10 A neutrons. Moreover, good neutron transmission of 0.65 for 15 A neutrons was obtained due to the shape effect. According to comprehensive analysis of the obtained results, it is possible to realize a CRL for practical use by choosing a suitable lens shape and material.

Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams

Abstract A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with 6 Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

Developments of In-Situ SEOP Polarized 3He Neutron Spin Filter in Japan

We launched the polarized 3He neutron spin filters (NSF) project in order to provide neutron polarization for the pulsed neutron beams in Japan. We adopted the in-situ spin exchange optical pumping (SEOP) technique to polarize the nuclear spin of 3He atoms because it has some advantages for our applications. The overall system size is compact and it avoids the problem of the time decay of nuclear spin of 3He thus suppressing the costs of maintenance and providing other advantages [1, 2] with respect to data analysis and quality. In this paper, we performed pulsed neutron beam tests of our compact in-situ SEOP NSF system at the BL10 beamline in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex (J-PARC). The polarization of the 3He gas reached was 73 % and a pump-up time constant of 9.5 h was observed. This paper is a status report about the development of in-situ SEOP NSF system for the pulsed beam at J-PARC.

Pulsed ultra-cold neutron production using a Doppler shifter at J-PARC

We have constructed a Doppler-shifter-type pulsed ultra-cold neutron (UCN) source at the Materials and Life Science Experiment Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). Very-cold neutrons (VCNs) with 136-

Measurement Of Neutron Scattering With Noble Gas To Search For A Short-range Unknown Force

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Polarisation Analysis Neutron Spectrometer, POLANO, at J-PARC - Concept and Magnetic Field Optimisation

velocity in a neutron beam supplied by a pulsed neutron source are decelerated by reflection on a m=10 wide-band multilayer mirror, yielding pulsed UCN. The mirror is fixed to the tip of a 2,000-rpm rotating arm moving with 68-

Development of a magnetic lens and prism for cold neutrons and their application to neutron scattering experiments

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Measurement of angular correlation of (n,gamma) reaction with polarized neutrons

velocity in the same direction as the VCN. The repetition frequency of the pulsed UCN is

Development of neuron compound lens and prism based on neutron refractive optics

8.33~\mathrm{Hz}