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A mapping measurement using pulsed neutron diffraction with time-of-flight method is performed on a full-shape Japanese sword made in Keicho era (1596–1615) to elucidate the manufacturing process. The obtained diffraction patterns are analyzed by the Rietveld refinement and a line profile analysis. The constituent phases in the area closer to the back of the blade (ridge) are found to be ferrite and cementite, composing pearlite, while the area close to the edge is composed by martensite and austenite. The distributions of constituent phases are well explained with the distributions of dislocation density and crystallite size. The carbon contents in the area closer to the ridge side estimated from the phase fraction of cementite and in the area closer to the edge side considered from the phase fraction of austenite are similar, 0.9–1.0 mass%, expecting that the Japanese sword used in this study was created by the technique of maru, i.e., the use of a single type of high-carbon steel for the whole volume. The residual macroscopic stresses are estimated from the obtained lattice parameters of constituent phases. The distributions of residual macroscopic stresses in the width and thickness directions are small. The stress in the longitudinal direction is compressive at the ridge side, turns to quite large tensile at the middle part of width, then drastically decreases to be quite large compressive at the edge side of about −650 MPa.

3 He neutron spin filters require a homogeneous magnetic field, otherwise the nuclear polarization of the 3 He gas will easily be lost by small magnetic field gradients. Magnetic cavities with field gradients of 10−4/cm or better are often in demand, and many such cavities - Helmholtz coils, solenoids, permanent magnet circuits, etc - have been developed [1] . These magnetic cavities are designed mostly by using simulations, but the actual magnetic fields may differ from the calculations because of the presence of the environmental magnetic field as well as nearby magnetic materials. To evaluate the real magnetic fields, a precision magnetometry system with a precision of 10-5 was developed.

The RITS code was developed for quantitative evaluation and visualization of crystalline structural information (e.g. crystallographic texture, preferred crystal orientation, crystallite block size and crystal lattice strain, etc.) of a material, analyzing position-dependent Bragg edge transmission spectra measured in an imaging experiment with pulsed neutrons. Originally, this code was neither able to deal with all the crystal structures that were classified into 230 types of space groups, nor applicable to materials composed of multi elements and multi crystalline phases. Therefore, we improved the RITS code for expansion of its capability, and then performed some demonstrations of simulation calculations and profile fitting analyses of experimental data. In this article, we present the new algorithm and the new functions of the improved RITS code, and the results of the simulation calculations and the experimental data analyses.

We have developed a prototype time-resolved neutron imaging detector employing the micro-pixel chamber (muPIC), a micro-pattern gaseous detector, coupled with a field programmable gate array-based data acquisition system for applications in neutron radiography at high-intensity neutron sources. The prototype system, with an active area of 10cm x 10cm and operated at a gas pressure of 2 atm, measures both the energy deposition (via time-over-threshold) and 3-dimensional track of each neutron-induced event, allowing the reconstruction of the neutron interaction point with improved accuracy. Using a simple position reconstruction algorithm, a spatial resolution of 349 +/- 36 microns was achieved, with further improvement expected. The detailed tracking allows strong rejection of background gamma-rays, resulting in an effective gamma sensitivity of 10^-12 or less, coupled with stable, robust neutron identification. The detector also features a time resolution of 0.6 microseconds., 10 pages, 13 figures; accepted for publication in NIMA

Pulsed neutron imaging methods provide information on crystallographic structure, magnetic field, elemental composition, hydrogen bound state and other material features. Such methods have been expected to be a powerful complement to the traditional imaging method. Data analysis codes, detectors and new applications are being developed in Japan, and a new imaging beam line is being constructed at J-PARC. Here, recent progress in Japanese research on pulsed neutron imaging is presented, and a design for construction of the new imaging beam line is reported.

We have developed a prototype time-resolved neutron imaging detector employing a micro-pattern gaseous detector known as the micro-pixel chamber ({\mu}PIC) coupled with a field-programmable-gate-array-based data acquisition system. Our detector system combines 100{\mu}m-level spatial and sub-{\mu}s time resolutions with a low gamma sensitivity of less than 10^-12 and high data rates, making it well suited for applications in neutron radiography at high-intensity, pulsed neutron sources. In the present paper, we introduce the detector system and present several test measurements performed at NOBORU (BL10), J-PARC to demonstrate the capabilities of our prototype. We also discuss future improvements to the spatial resolution and rate performance.

The Energy-Resolved Neutron Imaging System RADEN, located at the J-PARC Materials and Life Science Experimental Facility in Japan, is the world's first dedicated high-intensity, short-pulsed neutron imaging beam line. To carry out energy-resolved neutron imging at RADEN, we use cutting-edge detector systems employing micropattern detectors and data acquisition systems based on Field Programmable Gate Arrays to provide the necessary sub-μs time resolution, high counting rates, and event-by-event background rejection. One such detector, the Micro Pixel Chamber-based Neutron Imaging Detector (μNID), provides a spatial resolution of 120 μm (s), time resolution of 0.6 μs, 18% detection efficiency for thermal neutrons, and effective gamma sensitivity of less than 10−12. We have recently increased the rate capacity of the μNID from 600 kcps to more than 8 Mcps via an upgrade of the readout electronics and the introduction of a new gas mixture optimized for higher count rate, better spatial resolution, and higher detection efficiency. We are also developing new detection elements with strip pitches of 280 μm and 215 μm, down from 400 μm, with a corresponding improvement in the spatial resolution expected. Here, we present the progress of the ongoing development of the μNID, including the results of recent on-beam tests performed at RADEN.

Energy-resolved neutron imaging enables non-destructive analyses of bulk structure and elemental composition, which can be resolved with high spatial resolution at bright pulsed spallation neutron sources due to recent developments and improvements of neutron counting detectors. This technique, suitable for many applications, is demonstrated here with a specific study of ~5–10 mm thick natural gold samples. Through the analysis of neutron absorption resonances the spatial distribution of palladium (with average elemental concentration of ~0.4 atom% and ~5 atom%) is mapped within the gold samples. At the same time, the analysis of coherent neutron scattering in the thermal and cold energy regimes reveals which samples have a single-crystalline bulk structure through the entire sample volume. A spatially resolved analysis is possible because neutron transmission spectra are measured simultaneously on each detector pixel in the epithermal, thermal and cold energy ranges. With a pixel size of 55 μm and a detector-area of 512 by 512 pixels, a total of 262,144 neutron transmission spectra are measured concurrently. The results of our experiments indicate that high resolution energy-resolved neutron imaging is a very attractive analytical technique in cases where other conventional non-destructive methods are ineffective due to sample opacity.

One of the most interesting applications of neutron imaging is that it enables the observation of magnetic field. Because the interaction between the neutron spin and the magnetic field depends on the neutron energy, it is important to study the neutron energy dependence of magnetic field imaging to quantitatively treat the characteristics of the magnetic field. In this study, we have performed a polarized pulsed neutron imaging experiment using a time-of-flight method at J-PARC and have analyzed the energy dependence of the obtained polarization image. We have also quantitatively analyzed the strength and the direction of the magnetic field relative to the quantized axis inside a solenoid coil.

We have a plan to build an imaging beam line, Energy-Resolved Neutron Imaging System (ERNIS), at Materials and Life Science Experimental Facility (MLF) at Japan Proton Accelerator Research Complex (J-PARC). In pulsed neutron imaging, we use characteristic features of the neutron total cross section, depending on the neutron wavelength, to get sample information such as crystallographic structure and nuclide composition. One of the most important items to be determined for a beam line at J-PARC is the choice of moderator among coupled, decoupled, and poisoned moderators. From the wavelength resolution point of view, we decided to use the decoupled moderator, which could cover major experiments performed at a pulsed neutron source. Here, we discuss the structure of the imaging beam line at beam line 22 of the J-PARC neutron source as well as the arrangement of insertion devices and the experimental area.

The neutron resonance absorption imaging technique with a high-speed video camera was successfully demonstrated at the beam line NOBORU, J-PARC. Pulsed neutrons were observed through several kinds of metal foils as a function of neutron time-of-flight by utilizing a high-speed neutron radiography system. A set of time-dependent images was obtained for each neutron pulse, and more than a thousand sets of images were recorded in total. The images with the same time frame were summed after the measurement. Then the authors obtained a set of images having enhanced contrast of sample foils around the resonance absorption energies of cobalt (132 eV), cadmium (28 eV), tantalum (4.3 and 10 eV), gold (4.9 eV) and indium (1.5 eV).

Polarized neutron spin filters are being developed based on spin-exchange optical pumping. In the present study a high-power diode laser (85 W) was used to excite Rb atoms and the laser linewidth was narrowed using an external cavity. The optics in the external cavity were designed by ray tracing. The ray-trace calculations demonstrated that a doublet lens in front of the laser eliminates aberrations. The maximum spectral peak height in the doublet optics was found to be 25% higher than for a singlet lens.

Glass cells play an important role in polarized 3 He neutron spin filters. To evaluate the scattering and absorption contribution from glass cells during neutron scattering experiments, we measured small-angle scattering and neutron transmission in GE180 and other glasses. The small-angle neutron scattering measurements revealed that the glasses used for 3 He spin filters have acceptably lower scattering: dΣ ( Q )/ dΩ =4–7×10 −4 cm −1 at Q =0.03–0.12 A −1 . The transmission measurement was performed at J-PARC. Neutron transmission of about 92% through empty GE180 cells was observed over a wide wavelength range 0.014–7.0 A. To pursue the possibility of being a structural influence on 3 He spin relaxation in GE180 glass cells, we performed precise X-ray diffraction measurement using synchrotron radiation at SPring-8. From these measurements, a structural difference was observed among GE180 glasses with different thermal treatments.

For the future fundamental physics experiments by using cold neutrons, we are developing a device which can measure the neutron polarization degree by accuracy significantly below 10 −3 . A quadrupole magnet is one of the promising candidate to measure the neutron polarization degree by such extremely high precision. We have performed a polarization experiment by using the quadrupole magnets at the Very Cold Neutron (VCN) port of the PF-2 in the Institute Laue-Langevin (ILL). As a result, we obtained the polarization degree P with very high accuracy P =0.9994±0.0001( stat. )±0.0003( syst. ), which meet our requirement significantly.

Polarized 3He neutron spin filters are suitable devices for polarizing neutrons at spallation neutron facilities because of the wide coverage in energy range and the large solid-angles. The glass cell plays an important role in the 3He spin filters. In order to get good quality of glass cells, the investigation on the microscopic structure would be helpful. In this paper, we report on the results of X-ray diffraction for several glasses. We observed a correlation between the position of the first peak and the helium permeation velocity. We also observed a small difference in the diffraction curve among GE180 glasses with different thermal treatment. Desirable structure for 3He spin filters is discussed.

A new experimental technique to measure spatial distribution of small-angle neutron scattering (SANS) is proposed. Since SANS reflects the nanostructures of samples, high-efficiency mapping of the ...

For efficient differential-phase-contrast imaging, we have demonstrated the wavelength-resolved neutron Talbot-Lau interferometry with the wavelength resolution of 0.11 A over a wide wavelength range of 2.5–7.5 A at RADEN in the J-PARC Materials and Life Science Experimental Facility. The time-of-flight measurement has clearly showed that the visibility of moire fringes and intensity oscillations of the interferometer varied continuously with the wavelength, and the wavelength dependence of the differential phase of metal samples was measured. Based on the analysis utilizing this wavelength dependence, we achieved both high statistical precision and high accuracy in the differential-phase-contrast imaging, and succeeded in the quantitative evaluation of the optical potentials of metals.

Pulsed-neutron imaging is attractive technique in the research fields of energy-resolved neutron radiography and RANS (RIKEN) and RADEN (J-PARC/JAEA) are small and large accelerator-driven pulsed-neutron facilities for its imaging, respectively. To overcome the insuficient spatial resolution of the conunting type imaging detectors like μ NID, nGEM and pixelated detectors, camera detectors combined with a neutron color image intensifier were investigated. At RANS center-of-gravity technique was applied to spots image obtained by a CCD camera and the technique was confirmed to be effective for improving spatial resolution. At RADEN a high-frame-rate CMOS camera was used and super resolution technique was applied and it was recognized that the spatial resolution was futhermore improved.

Modulating permanent magnet sextupole lens (PMSx) for focusing pulsed cold neutrons is under development. The synchronized modulation of its field gradient suppresses the chromatic aberration which arises from the Time Of Flight method. The strength of the magnetic field, the torque, and the rise of temperature during its operation are studied on a fabricated prototype. Experiments on focusing pulsed very cold neutrons (VCN) at ILL (Institute of Laue Langevin, France) were carried out and VCN with around λ =40 A were focused by the PMSx at a focal length of about 0.5 m. The experimental results are presented in conjunction with the principle of the neutron focusing and the modulating method of the focal strength of permanent magnet lens with the double ring structure.

A new beamline for a fundamental physics experiment is under construction at BL05 port in the Materials and Life Science Facility (MLF) at Japan Proton Accelerator Research Complex (J-PARC); this beamline is designed using novel techniques of neutron optics and it is termed “Neutron Optics and Physics.” The beam from the moderator is deflected by multi-channel supermirrors and split into three branches for individual experiments. In this study, we have optimized the design of the beam optics and shields using the Monte Carlo simulation package PHITS. The neutron fluxes of beams are expected to be 9.2×105 /cm2/μstr/s/MW, 1.2×109 /cm2/s/MW, and 4.0×108 /cm2/s/MW, with polarization of 99.8%.

We have constructed a new system which could analyze a position distribution of several elements in a sample with 2 dimensional prompt γ-ray analysis (2D PGA) system using focused neutron beam at JAEA. We aimed that the system could analyze local information in a sample with a good signal γ-ray from interested elements to noise of background γ-ray ratio. As a result, this system could determine the position resolution and spatial resolution within 1 mm.

We performed a cold neutron polarization experiment using a polarization device based on a quadrupole magnet. By passing through the aperture of the quadrupole magnet, positive and negative polarity neutrons are accelerated in opposite directions and spatially separated due to the magnetic field gradient. Then, we extracted the one-spin component and analyzed the polarization degree by using a sextupole magnet and position-sensitive detector. As a result, very high neutron polarization degree P=0.9993±0.0025 was obtained. Advantages of the quadrupole magnet as the neutron polarization device and its application to neutron scattering experiments are discussed.

We performed small-angle neutron and X-ray scattering (SANS and SAXS) measurements on an elongated blend of low molecular weight deuterated polyethylene (PE) and high molecular weight hydrogenated one (97.2/2.8) in a very wide range of scattering vector of 1 × 10-4−3 A-1 to elucidate hierarchic structure of the so-called shish-kebab. Comparing the SANS and SAXS data, we found that the hydrogenated high molecular weight PE formed a large and long object aligned along the elongation direction. The SANS data were analyzed in terms of the multicore−shell cylinder model, and we found that the long oriented structure had radius of ∼1 μm and length of ∼12 μm and included about three extended chain crystals with radius of ∼45 A. We believe that this oriented long object with a relatively low aspect ratio of about 12:1, which is called the row structure in this paper, is a precursor formed from deformation of network of high molecular weight components due to entanglements.

We have constructed a focusing-geometry small-angle neutron scattering (FSANS) instrument, SANS-J-II, with two kinds of neutron focusing device: a series of compound refractive lenses made of MgF2 and a magnetic neutron lens based on an extended Halbach-type sextupole magnet. In this study, we investigated the performance of the FSANS instrument with the magnetic neutron lens. The intensity distribution of a direct neutron beam focused on the detector plane by the magnetic neutron lens had a ratio of the peak height to the background level of \sim\!6\times 10^4 for a polarized neutron beam with a polarization degree of \sim \!0.99. It is found that a minimum value of the measurable q range [where q is the modulus of the scattering vector and is defined as q = (4\pi/\lambda)\sin(\theta/2), where \theta is the scattering angle and \lambda is the neutron wavelength], q_{\rm min}, of 6.5 \times 10^{-4} A−1 can be achieved by the FSANS instrument with the magnetic neutron lens using neutrons with \lambda = 6.6 A and \Delta \lambda/\lambda = 0.13 for the full width at half maximum.

The recently commissioned Energy-Resolved Neutron Imaging System, RADEN, located at the J-PARC Materials and Life Science Experimental Facility (MLF), is the world's first dedicated high-intensity, pulsed neutron imaging instrument. In addition to conventional radiography and tomography, the wide bandwidth and accurate measurement of neutron energy by time-of-flight is utilized to perform energy-resolved neutron imaging. Such techniques allow direct imaging of the macroscopic distribution of microscopic properties of materials in situ, including crystallographic structure and internal strain, nuclide-specific density and temperature distributions, and internal/external magnetic fields. To carry out such measurements in the high-rate, high-background environment at RADEN, we use cutting-edge detector systems, recently developed in Japan, employing micro-pattern detectors or fast Li-glass scintillators with high-speed, Field Programmable Gate Array-based data acquisition. These counting-type detectors offer sub-μs time resolution, high neutron count rates, and event-by-event gamma rejection. The available detectors offer a range of spatial resolutions from 0.3 to 3 mm and counting rates from 0.6 to 8 Mcps. In the present paper, we show the performance of these detectors as measured at RADEN. We also consider planned improvements to the detector systems that will allow us to achieve finer spatial resolutions by several factors and order-of-magnitude higher count rates.

The neutron energy resolved three-dimensional imaging system using a high-speed video camera has been newly developed at Japan Proton Accelerator Research Complex (J-PARC). The aim for this research is to investigate more rapidly a spatial distribution of several elements and crystals in various kinds of materials or substances. A high-speed video camera (CMOS, 1300 k frame/sec) of the present system allows us to obtain TOF images consecutively resolved into narrow energy ranges in the pulsed neutron energy region from 0.01 eV to a few keV. We confirmed that the neutron transmission ratio obtained by the present system was consistent with that of theoretical expectation when a step-wedge sample made of Fe, from 5 mm to 10 mm in thickness, was used as a sample. And three-dimensional images reconstructed by the Filtered Back Projection method could be successfully enhanced the image contrast of specific materials by selecting neutron energy. The results show that there is the possibility to apply the present system for practical use in near future.

We found that Cadmium (Cd) was not only a suitable thermal neutron absorber as a poison material in a pulsed spallation neutron source, but also had a long life time with a small sacrifice in neutron intensities at an intense source. Therefore, we decided to use Cd as the poison material in the first moderator in the Japan Spallation Neutron Source (JSNS). In the development stage of JSNS, canning of a Cd plate by an aluminum alloy (Al-alloy) with the Cold Isostatic Pressing method (CIP) failed and the Al-alloy cover of the Cd plate was broken. In order to correct the manufacturing process, we have to observe the inside of the sample to find the reason for failure. Figure 1 shows an ultra-sonic image of the failure sample by the transmission method. Some untransmittable regions can be found in the figure. To investigation the inside of the canning Cd plate non-destructively, we applied the energy selective neutron imaging method. We measured the transmission of the canning Cd plate used by the micro-pixel chamber (PIC) [2, 3] neutron detector at NOBORU (BL10) in JSNS. As a result, several vacancies could be found and the distribution of the amount of Cd could be also obtained. The detailed result will be shown in the presentation.

J-PARC Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan Research Center for Neutron Science and Technology, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan J-PARC Center, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan Research Reactor Institute, Kyoto University (KURRI), Kumatori, Osaka 590-0494, Japan

The neutron imaging and diffraction instruments at Materials and Life Science Experimental Facility (MLF) at J-PARC are expected to play an important role in the microstructure characteristic evaluation of steel materials further for industry application. Neutron transmission spectrum measured at a neutron imaging detector coupled with time-of-flight (TOF) method at a pulsed source, can quantitatively and non-destructively visualize the spatial distributions of the wider area by 2D mapping of textures and the microstructures information inside a relatively thicker material than the traditional electron, X-ray and neutron experiments. In this study, neutron imaging experiment was performed using NOBORU, BL10 of MLF at J-PARC. Four kinds of cast duplex stainless steel with ferrite and austenite microstructure were studied here, which were produced by different casting method at different temperature. Firstly, a two-dimensional scintillation detector using wavelength-shifting (WLS) fibers [1] with pixel size of 0.52mm × 0.52mm and illuminated area 55mm × 55mm was used for data collection. Then, measurement by Micro Pixel Chamber (μPIC)-based neutron imaging detector [2] having higher spatial resolution about 0.2mm was conducted. Data analysis code RITS (Rietveld Imaging of Transmission Spectra) [3] will be used for microstructure including crystalline phase, lattice strain, crystallite size, texture evaluation. This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.

A novel energy-resolved neutron imaging system “RADEN” has been constructed at BL22 at the Materials and Life Science Experimental Facility (MLF) at J-PARC. RADEN was designed for conventional radiography and tomography as well as for Bragg-edge transmission, resonance absorption analysis, and visualization of the magnetic field. Good energy and wavelength resolution of pulsed neutron source at the MLF is fully utilized in this instrument. To maximize flexibility of neutron brightness, beam divergence, and field of view at the sample position, a custom-made shutter block with triple inserts was designed and replaced with the original block, which had a single insert.

Super-resolution and center-of-gravity processing improve the resolution of neutron-transmitted images. These processing methods calculate the center-of-gravity pixel or sub-pixel of the neutron point converted into light by a scintillator. The conventional neutron-transmitted image is acquired using a high-speed camera by integrating many frames when a transmitted image with one frame is not provided. It succeeds in acquiring the transmitted image and calculating a spectrum by integrating frames of the same energy [3]. However, because a high frame rate is required for neutron resonance absorption imaging, the number of pixels of the transmitted image decreases, and the resolution decreases to the limit of the camera performance. Therefore, we attempt to improve the resolution by integrating the frames after applying super-resolution or center-of-gravity processing. The processed results indicate that center-of-gravity processing can be effective in pulsed-neutron imaging with a high-speed camera. In addition, the results show that super-resolution processing is effective indirectly. A project to develop a real-time image data processing system has begun, and this system will be used at J-PARC in JAEA.

We have developed a multichannel parabolic guide for thermal neutron beam focusing. The guide was designed with multichannel structure, seven channels in the present case, to focus a neutron beam with wide cross section effectively. The multichannel structure is made with parabolically bent NiC/Ti supermirrors with critical reflection angles m = 3.0 and 3.6 times as much as that of nickel and thickness of 0.55 mm. The guide consists of two focusing devices with each length of 900 mm, which are separated by a gap of 150 mm for neutron beta decay experiments. The focal length of the guide is 995 mm away from the exit of the guide. The cross section of the guide is 90 × 20 mm 2 at the entrance and 52.3 × 12.1 mm 2 at the exit. The guide was installed at a thermal neutron beam line for neutron-induced prompt gamma-ray analysis (PGA) of JRR-3M in JAEA with straight supermirror guides with m = 3.0 . Focusing properties of the parabolic guide were measured at the focal point with a CCD imaging system and we obtained a gain of 9.6 and 4.1 in peak flux compared with those in cases of using the vacuum tube and the straight guide, respectively. The parabolic guide has been successfully used to enhance the efficacy of PGA and have also applied to neutron beta decay experiments.

We have developed a magnetic neutron lens (MNL) based on an extended Halbach-type permanent sextupole magnet. The effective aperture size is 30 mm in diameter and the length is 2400 mm. The sextupole magnetic field distribution | B |=( G /2) r 2 with the gradient coefficient G =10,660±530 T/m 2 are generated inside the magnet, where r is the distance from the magnet center axis. The neutron-focusing property is investigated by using pulsed polarized neutrons. The obtained results are discussed in comparison with numerical simulation results. The application to the focusing-geometry small-angle neutron scattering experiments is discussed.

Neutron refractive optics is a powerful tool for beam focusing due to its large effective aperture compared to reflective optics. Because neutron refraction angle decreases with shorter wavelengths, the application of refractive optics has been restricted to the cold neutron range. To expand the applicable wavelength range, we have developed a new refractive optics using an amorphous perfluoropolymer. This refractive optics is composed of several hundred thin sheets, each of which has a large number of grooves on the top surface. The refraction experiment was performed at the H-8 beam port of KENS, and it was confirmed that the thermal neutron beam can be refracted using this material prism.

The appearance of ferromagnetism in the surface regime of Pd nanoparticles was recently reported [Phys. Rev. Lett. 91, 197201 (2003)]. To experimentally confirm the surface magnetism, the effects of O2 gas adsorption on the Pd nanoparticles are studied based on the measurements of the coverage and magnetization. The surface ferromagnetism was weakened in the samples fully covered with O2 gas. However, the ferromagnetic moment remained after the exposure to O2 gas. This result shows the ferromagnetism existing in the internal regime in addition to the surface magnetism. [DOI: 10.1380/ejssnt.2006.439]

X-ray magnetic circular dichroism (XMCD) of Pd 97.1 Fe 2.9 fine particle samples is studied at the Pd L 2,3 edges. The magnetic moment of a Pd atom, which is estimated using the magneto-optical sum rule, is ∼0.06µ B /atom independent of particle size, while the total magnetization of the particle samples decreases monotonically with decreasing particle size. We attribute the size dependent magnetization to a reduction in the Fe magnetic moment at the surface region with decreasing particle size. Analysis of the XMCD data is reported in detail.

A demonstration study of focusing geometry small-angle neutron scattering (FSANS) experiment was successfully performed using a superconducting sextupole magnet as a neutron focusing device and a polarized cold neutron beam. The obtained small-angle neutron scattering intensities from monodispersed SiO2 spherical particles were discussed in terms of the scattering function taking into account the q -resolution.

We proposed a method to improve signal–noise ratio of the Fresnel-type neutron lens. The Gd mask of concentric circle thin layer reduced 80% noise, at the best, due to the Fresnel-type lens shape. As the transmission for 1.1 nm neutrons decreased from 0.83 to 0.79 by using the Gd mask, the loss was 0.04.

A scintillating detector and its data acquisition system are being developed for neutron scattering experiments. An Anger camera with a 64-channel flat panel PMT is used. The fast DAQ system discriminated and eliminated noise events from neutron events. WLS materials are being developed to use high quantum efficiency PMT.