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We have fabricated m= 2.9 NiC/Ti supermirror on a silicon wafer in which surface roughness is about 0.4 nm by ion beam sputtering technique. The reflectivity of supermirror at m =2.8 and 2.9 were 0.94 and 0.90, respectively. The reflectivity of 0.94 at m =2.8 is in the vicinity of theoretical limit including the effects of absorption and incoherent scattering. We show the experimental results and theoretical expectation based on a simple Debye-Waller roughness model, and discuss realistic reflectivity limit of supermirror deposited on the ordinary silicon substrate.

We obtained highly polarized very cold neutrons through a quadrupole magnet with a large aperture. When neutrons go through a quadrupole magnet, parallel-spin neutrons are attracted to the magnet axis and anti-parallel-spin neutrons are repelled off the axis. Therefore, the neutrons through a sufficiently long quadrupole magnet have completely parallel-spin. At the downstream of the quadrupole magnet, we placed another quadrupole magnet to divide neutrons into two regions depending on their spin directions. We obtained the neutron polarization from the integrated count of the two regions and found it was 99.88±0.09 (stat.)±0.05 (syst.)%.

It is planned that three neutron resonance spin echo spectrometers will be installed in the No. 17 beam port of JSNS. In order to install these three spectrometers in one beam port, the neutron incident beam system to be installed in No. 17 port cannot only supply three polarized neutron beams to these spectrometers, but should also create very low background levels of neutron and gamma rays in the experimental area. We report based on shield evaluations how to realize the low background level by using two highly curved neutron guide tubes with high quality supermirrors.

We have installed a MIEZE-type spin echo spectrometer at the C3-1-2-2 (MINE1) port at the JRR-3 M in the Japan Atomic Energy Agency. By combining neutron reflectometry and the MIEZE, it is possible to detect inelastic and quasi-elastic scattering on the surface and at the interface. We have succeeded in measuring a MIEZE signal for which the Fourier time is up to 0.8 ns. Though the Fourier time is small, we tested several samples by the MIEZE reflectometer.

Moire fringes were observed as a bright and high-contrast image using a neutron spin interferometer with a relatively divergent cold neutron beam at the MINE2 beam line of JRR-3M. The two spin states were selectively deflected with the relative angle in the range of 92–184 nrad on transmission through the magnetic field gradient in the range of 3.2–6.4 G/cm produced by a 5 cm long quadrupole electromagnet. We analyzed the result with a first-order calculation taking into account the finite beam divergence and found that the beam divergence is required to be less than the angular separation of individual Moire loci, for the observation of Moire fringes, and is not required to be less than the angular separation of the two beam paths.