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The High Resolution Chopper Spectrometer (HRC) is installed at the Japan Proton Accelerator Research Complex (J-PARC) and is utilized for a wide range of dynamical studies of materials over a wide energy-momentum space with high resolution. Neutron Brillouin scattering (NBS), i.e., inelastic neutron scattering close to the forward direction, can be performed with the HRC, because this instrument utilizes low angle detectors and high-energy neutrons which facilitates a high resolution. Since the solid angle of the detection area for NBS experiments is limited to very low scattering angles, improvements of the HRC are required to increase the neutron flux with reducing the background. Given the success of the HRC for NBS studies, the neutron intensities for NBS experiments have been improved by changing the detector layout, reducing deformation of the slit package during rotation of the Fermi chopper, and fabricating a longer collimator. At present, we have made further improvements. At around the incident neutron energy Ei = 100 meV, the neutron flux was significantly increased for an energy resolution of ΔE∕Ei = 2%, and the best energy resolution achieved was nearly 1% resolution with an acceptable neutron flux.

Seven time-of-flight quasielastic/inelastic neutron scattering instruments are installed on six beamlines in the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC). Four of these instruments are chopper-type direct-geometry spectrometers, one is a near-backscattering indirect-geometry spectrometer, and the other two are spin-echo-type spectrometers. This paper reviews the characteristic features, recent scientific outcomes, and progress in development of MLF spectrometers.

We report magnetic studies on the charge and spin ordering in La2− xSrxCoO4 for x = 1 / 3 , 0.60, and 0.75. The magnetic susceptibility displays a clear cusp which we attribute to a spin glass freezing transition in all three compositions stduied. The behaviors of the evaluated effective magnetic moment and Curie-Weiss temperature indicate that the antiferromagnetic (AFM) interaction among Co 2 + ions surrounded by the non-magnetic Co 3 + weakens with increasing the doping concentration x. In addition, we have found that the incommensurate AFM short range order is frozen at T g which is further below the onset temperature T IC of the neutron intensity of the incommensurate AFM correlation.

Magnetic excitations in the metallic antiferromagnet F e 0.5 M n 0.5 were investigated using the inelastic neutron scattering technique at low temperatures well below the antiferromagnetic transition temperatures ( T N ). The observed peak positions in low energies well sit on the antiferromagnetic dispersion relation reported in the early study. However, the peak positions in higher energies shift to higher energies than that of the antiferromagnetic spin wave dispersion relation. This behavior is the same as one of the behaviors suggesting that the spin waves merge with the continuum of the individual particle-hole excitations at higher energies in F e 0.7 M n 0.3 .

The crystalline electric field (CEF) excitations in CePtSi3 with the non-centrosymmetric structure were investigated by inelastic neutron scattering (INS) experiment. CEF excitations were observed at 5.3 and 17.5 meV. We discuss the CEF parameters and wave function of CePtSi3 by comparing those of other CeTX3(T: transition metal, X: Si, Ge) systems.

Inelastic X-ray scattering (IXS) experiments were performed on polycrystalline Mg97Zn1Y2 and Mg85Zn6Y9 alloys with synchronized long-period stacking ordered (LPSO) phase of about 24% and 100%, respectively, together with the reference pure Mg at room temperature for investigating the impurity effects in the microscopic elastic properties of the LPSO alloys. Inelastic neutron scattering (INS) measurements were also carried out on a polycrystalline Mg97Zn1Y2 alloy. The IXS measurements were carried out for the momentum transfers Q between 1.6 and 15.9 nm−1 including the whole first- and partially second Brillouin zones, and for the energy transfers ω below 40 meV. Peaks arising from longitudinal acoustic (LA) modes were clearly observed in the IXS spectra of both the LPSO alloys and pure Mg, while transverse acoustic (TA) modes can mainly be detected in the second Brillouin zone. The dispersion relations in pure polycrystalline Mg are in good agreement with those of previous INS data on single crystal Mg. Broader inelastic signals and larger quasielastic peaks are characteristic for the LPSO alloys due to the phonon scattering by the Zn/Y impurities. Only the TA excitation energies increase by adding the impurities, which indicate a harder stiffness of the bond angles relating to the existence of the L12-type clusters in the LPSO alloys. Besides, new impurity-derived dispersion-less excitation modes are observed at about 10 meV by adding the Zn/Y impurities. By comparing with the INS data on the polycrystalline LPSO alloy, the contributions of the impurities to these excitation modes are discussed using the differences in the scattering cross-sections between neutrons and X-rays.

J-PARC, Japan Proton Accelerator Research Complex provides short pulse proton beam at a repetition rate 25Hz and the maximum power is expected to be 1MW. Materials and Life Science Experimental Facility (MLF) has 23 neutron beam ports and 21 instruments have already been operated or under construction/commissioning. There are 6 inelastic/quasi-elastic neutron scattering spectrometers and the complementary use of these spectrometers will open new insight for life science.This article is part of a Special Issue entitled “Science for Life” Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.

We report on a wide angle neutron spin analyzer for neutron energies up to 40 meV ( λ = 1.4 A) that was recently realized in collaboration with Tohoku University and KEK, Japan (Ohoyama et al., 2014; Yokoo et al., 2014). Curved polarizing Fe/Si supermirrors with m = 5.5/1.5 (Schanzer et al., 2016) are arranged radially around the sample covering an angular range of 40° if all channels are equipped with supermirrors. The mirrors are saturated by a vertical permanent magnetic field B ≃ 40 mT generated by NdFeB magnets. It was optimized using finite element analysis. The polarization and transmission of the spin filter have been determined at the beamline BOA at the Swiss spallation neutron source (SINQ) to be P = ( 0 . 975 ± 0 . 01 ) and T u p = T = ( 0 . 55 ± 0 . 017 ) for spin-up neutrons at λ = 3 A ( E = 9 meV), respectively. The transmission is excellent considering that approximately one third of the neutrons hit the front faces of the polarizing blades. The experimental results are in good agreement with Monte Carlo simulations using the software package McStas.

Collective dynamics of liquid deuterated methanol was studied at room temperature using neutron scattering. The inelastic excitation energy of coherent scattering from liquid deuterated methanol was proportional to the momentum transfer Q in the range of 0.2 to 0.9 A − 1 ; the high-frequency sound velocity of liquid deuterated methanol obtained from the dispersion relation was 1770 ± 30 m s − 1 . The positive dispersion for liquid deuterated methanol was ~ 60%, about half that of liquid heavy water (~ 100%) previously reported. This could be reflective of the different number of hydrogen bonds. At Q positions below the first peak in S ( Q ), the dispersion relation of liquid deuterated methanol derived from neutron scattering was almost identical to that obtained from X-ray scattering. However, the excitation energy obtained from neutron scattering at Q positions above the first peak in S ( Q ) is larger than that from X-ray scattering, which could be ascribed to intramolecular methanol vibrations.

We studied the effect of magnetic Nd-ion substitution on the metal-nonmetal transition at a transition temperature of 63 K of PrRu4P12, which is characterized by antiferro-type electric multipole ordering of Pr-ion 4f electrons. The transition temperature of Pr1-xNdxRu4P12 depends weakly on the Nd concentration x as compared to Laand Ce-substituted compounds. Inelastic neutron-scattering measurements revealed that the energies and widths of crystalline field excitation peaks of Pr 4f 2 in Pr0.85Nd0.15Ru4P12 are very similar to those of PrRu4P12. These experimental results indicate that the ordered state is robust against the substitution of magnetic Nd ions as compared to the La and Ce substitutions. Magnetic interactions between the Pr ions and the Nd ions in Pr1-xNdxRu4P12 help stabilize the magnetic triplet ground state of the Pr ions that appears in the antiferro-type multipole ordered phase. Therefore, the nonmagnetic multipole ordered phase of PrRu4P12 is compatible with the magnetic perturbation., Conference : 20th International Conference on Magnetism, ICM 2015, Location : Barcelona, SPAIN, Date : JUL 05-10, 2015

Inelastic neutron scattering experiments were performed on an intermetallic compound, MnP. We used a newly developed High Resolution Chopper Spectrometer, HRC, for energy transfers E ≤ 75 meV , besides various triple axis spectrometers; LTAS for energy transfers E ≤ 2 meV , TOPAN for E ≤ 7.5 meV and TAS-1 for E ≤ 35 meV . Spin wave excitations were observed in the ferromagnetic phase of MnP in the entire Brillouin zone along the a⁎- and b⁎-axes. The zone boundary energies of spin waves were determined to be around 60 meV along the a⁎-axis and around 75 meV along the b⁎-axis, and the dispersion relations showed two branches for both axes. The observed dispersion relations of spin waves were well described by an isotropic Heisenberg interaction adding a single ion anisotropy with two sub-lattices.

The feasibility of a large area window using a thin aluminum plate on the surface of the vacuum chamber for neutron scattering instruments at a pulsed neutron source was investigated. In the prototype investigation for a window with an area of 1 m × 1.4 m and a thickness of 1 mm, the measured pressure dependence of the displacement agreed well with a calculation using a nonlinear strain–stress curve up to the plastic deformation region. In addition, we confirmed the repetition test up to 2000 pressurization-and-release cycles, which is sufficient for the lifetime of the vacuum chamber for neutron scattering instruments. Based on these investigations, an actual model of the window to be mounted on the vacuum chamber of the High Resolution Chopper Spectrometer (HRC) at J-PARC was designed. By using a calculated stress distribution on the window, the clamping structure capable of balancing the tension in the window was determined. In a model with a structure identical to the actual window, we confirmed the repetition test over more than 7000 pressurization-and-release cycles, which shows a lifetime long enough for the actual usage of the vacuum chamber on the HRC.

We developed a T0 chopper rotating at 100 Hz at the High Energy Accelerator Research Organization (KEK) for the reduction of background noise in neutron scattering experiments at the Japan Proton Accelerator Research Complex (J-PARC). The T0 chopper consists of a rotor of 120 kg made from Inconel X750, supported by mechanical bearings in vacuum. The motor is located outside the vacuum and the rotation is transmitted into vacuum through magnetic seals. The motor should rotate in synchronization with the production timing of pulsed neutrons. The rotational fluctuations and running time were in good agreement with the specifications, i.e., phase control accuracy of less than 5 μ s and running time of more than 4000 h without changing any component. A semi-auto installation mechanism was developed for installing under the shielding and for maintenance purposes. Based on the result of the development, actual machines were made for the neutron beamlines at J-PARC. We successfully reduced the background noise to 1/30 at neutron energies near 500 meV.

We developed a Fermi chopper by modification of a turbo molecular pump with a magnetic bearing system, and the actual device, rotating at f =100–600 Hz using a rotation system similar to the turbo molecular pump, was successfully produced for inelastic neutron scattering experiments at the Japan Proton Accelerator Research Complex (J-PARC). We assumed a phase control accuracy of Δ τ ≤ 0.3 μ s , i.e., a frequency resolution of Δ f ≤ 0.01 Hz at a rotational frequency of f =600 Hz, as the specification for the development. The phase control system was developed using a direct digital synthesizer (DDS) system with a frequency control unit of 0.00058 Hz at f =600 Hz. The phase control accuracy in the produced Fermi chopper was observed to be Δ τ = 0.08 μ s at f =600 Hz, well within the specification parameters. After mounting the produced Fermi chopper on the High Resolution Chopper Spectrometer (HRC) at J-PARC, the energy resolution for an incident neutron energy E i =206 meV was observed to be identical to the designed standard resolution of Δ E / E i = 2.5 % . We were able to produce a state-of-the-art Fermi chopper.

We installed the data acquisition (DAQ) system on the High Resolution Chopper Spectrometer (HRC) at beamline BL12 at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). In inelastic neutron scattering experiments with the HRC, the event data of the detected neutrons are processed in the DAQ system and visualized in the form of the dynamic structure factor. We confirmed that the data analysis process works well by visualizing excitations in single-crystal magnetic systems probed by inelastic neutron scattering.

We investigated the irradiation properties of the components of a T0 chopper. The organic materials in the rotor bearing grease, the magnetic fluids in seals, and the rubber in the timing belt, as well as the semiconductor materials in the rotation sensor and motor encoder, were all irradiated with high-energy γ - rays up to 100 kGy. No significant damage that shortens the lifetime of a T0 chopper was observed for the mechanical components. However, the semiconductor components were damaged by the irradiation. For the rotation sensor system detecting the rotor phase, the signal from a marker on the rotor shaft was transmitted outside the shielding by an optical fiber with radiation-proofing and the electrical circuits were removed from the beamline shielding. The lifetime of the motor encoder possibly meets the requirement for the maintenance period of the T0 chopper.

To study condensed-matter dynamics over a wide energy–momentum space with high resolution, we constructed the High Resolution Chopper Spectrometer (HRC) at beamline BL12 at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). With the construction nearly completed, we proceeded to characterize the HRC. We confirmed that, under limited conditions, the neutron intensity and energy resolution of the HRC agree well with the design values.

Extracellular superoxide dismutase (SOD3), a secretory copper-containing antioxidant enzyme, plays an important role in various oxidative stress-dependent cardiovascular diseases. Although cofactor copper is required for SOD3 activity, it remains unknown whether it can regulate SOD3 transcription. We previously demonstrated that SOD3 activity requires the copper chaperone antioxidant-1 (Atox1), involved in copper delivery to SOD3 at the trans-Golgi network (TGN). Here we show that copper treatment in mouse fibroblasts significantly increases mRNA and protein levels of SOD3, but not SOD1, which is abolished in Atox1-deficient cells. Copper promotes Atox1 translocation to the nucleus. Promoter deletion analysis identifies copper- and Atox1-response elements (REs) at the SOD3 promoter. Gel-shift and ChIP assays reveal that Atox1 directly binds to the Atox1 RE in a copper-dependent manner in vitro and in vivo. Adenovirus-mediated reexpression in Atox1(-/-) cells of nucleus-targeted Atox1 (Atox1-NLS), but not TGN-targeted Atox1 (Atox1-TGN), increases SOD3 transcription without affecting SOD3 activity. Importantly, reexpression of both Atox1-NLS and Atox1-TGN together, but not either alone, in Atox1(-/-) cells increases SOD3 activity. SOD3 transcription is positively regulated by copper through the transcription factor function of Atox1, whereas the full activity of SOD3 requires both the copper chaperone and the transcription factor functions of Atox1. Thus, Atox1 is a potential therapeutic target for oxidant stress-dependent cardiovascular disease.

Copper plays a fundamental role in regulating cell growth. Many types of human cancer tissues have higher copper levels than normal tissues. Copper can also induce gene expression. However, transcription factors that mediate copper-induced cell proliferation have not been identified in mammals. Here we show that antioxidant-1 (Atox1), previously appreciated as a copper chaperone, represents a novel copper-dependent transcription factor that mediates copper-induced cell proliferation. Stimulation of mouse embryonic fibroblasts (MEFs) with copper markedly increased cell proliferation, cyclin D1 expression, and entry into S phase, which were completely abolished in Atox1-/- MEFs. Promoter analysis and EMSA revealed that copper stimulates the Atox1 binding to a previously undescribed cis element in the cyclin D1 promoter. The ChIP assay confirms that copper stimulates Atox1 binding to the DNA in vivo. Transfection of Atox1 fused to the DNA-binding domain of Gal4 demonstrated a copper-dependent transactivation in various cell types, including endothelial and cancer cells. Furthermore, Atox1 translocated to the nucleus in response to copper through its highly conserved C-terminal KKTGK motif and N-terminal copper-binding sites. Finally, the functional role of nuclear Atox1 is demonstrated by the observation that re-expression of nuclear-targeted Atox1 in Atox1-/- MEFs rescued the defective copper-induced cell proliferation. Thus, Atox1 functions as a novel transcription factor that, when activated by copper, undergoes nuclear translocation, DNA binding, and transactivation, thereby contributing to cell proliferation.

We derived analytical expressions of energy (E) and momentum (Q) resolutions on a chopper spectrometer, including timing and geometrical parameters, such as a pulse width at a moderator, an opening time of a chopper, spectrometer lengths, sizes of a moderator, of a sample and of a position-sensitive detector (PSD) and pixel sizes in a PSD. For a long linear PSD, resolutions change for pixels dependently on their positions inside the PSD, because of the change in the flight path lengths. Controlling the pixel sizes can reduce such nonuniformity in resolutions. However, in order to diminish the nonuniformity in both of the E and Q resolutions simultaneously, the PSD length was found to be limited.

Sirius , recently installed at KENS, is the world first time-of-flight neutron powder diffractometer with 28.5 m supermirror guide tube. It has realized both the highest resolution and intensity in Japan. Adoption of supermirror guide enables us to incorporate short-wavelength neutrons into structure analyses. This, together with the high resolution, does not only improve the accuracy of refined atomic coordinates in Rietveld refinements, but also extend a possibility of powder diffraction beyond average structure analyses.

A new small/wide-angle neutron diffractometer (SWAN) was installed at a spallation pulsed-neutron source at KEK (KENS). SWAN utilizes incident neutrons having a wide wavelength band from a solid methane moderator at 26 K, and was designed to cover a wide momentum-transfer (Q) range of 0.005≤Q≤12 A−1 with high intensity. It has been confirmed that the available Q range of SWAN is 0.008≤Q≤2 A−1, up to now. An additional refinement of the instrument and installation of detectors should lead to a realization of the designed Q-range.

We have investigated the dilute effect on a typical orbital ordering system KCuF 3 by partially substituting Zn for Cu. The crystal structure has been examined as a function of Cu concentration at room temperature by X-ray diffraction. It is found that the phase transition from a tetragonal structure to a cubic one occurs with decreasing Cu concentration. This structural phase transition is confirmed to be an orbital order–disorder transition by the resonant X-ray scattering (RXS) technique.

We investigated static and dynamical properties in the three-dimensional percolating Heisenberg antiferromagnets, RbMn c Mg 1 - c F 3 , with the magnetic concentration close to the percolation threshold, c P = 0.312 , around the superlattice point well below T N . In neutron diffraction experiment, the wave number dependence of the elastic scattering component was well fitted to q - x . Magnetic fractons were also studied using inelastic neutron scattering, and the observed fractons showed the dispersion relation of q z . The determined exponents, x = 2.43 ± 0.05 and z = 2.5 ± 0.1 , were in good agreement with the fractal dimension ( D f = 2.48 ) .

We have performed neutron scattering experiments to investigate the static magnetic structure and the magnetic critical scattering in the three-dimensional percolating Heisenberg antiferromagnet, RbMn 0.31 Mg 0.69 F 3 , whose magnetic concentration is just at the percolation concentration for a cubic lattice, c P = 0.312 . Magnetic scattering was observed around the superlattice point, ( 1 2 , 1 2 , 1 2 ) . We determined the Neel temperature of this system to be T N = 4.0 ± 0.5 K , and found that the critical scattering above T N is similar to that observed in the homogeneous system. At T = 1.6 K well below T N , the scattering function is described by a sum of the critical scattering and elastic scattering components, and we demonstrated that the q -variation of the intensity of the elastic scattering component can be described using the fractal dimension.

The neutron depolarization method is applied to the study of mesoscopic magnetism such as the ferromagnetic domain structure, the spin glass and even the magnetic flux distribution in superconductors. The wavelength dependent neutron depolarization senses the magnetic field in the mesoscopic scale inside the bulk material. In this review, we summarize our recent results and discuss the physics of these subjects.

From polarized neutron experiments on colloidal suspensions of cobalt particles (ferrofluids) the intraparticle structure was determined consistently with the results from magnetization measurements and electron micrographs. The interparticle correlations under both a weak and a large external field were investigated. The correlation was isotropic under the weak field but it became strongly anisotropic under the large field. Additionally, the agglomeration process of particles in the external field has been investigated by using a new technique of neutron depolarization.

The temperature dependence of the inverse magnetic correlation length of the S =3/2, one-dimensional Heisenberg antiferromagnet, CsVCl 3 , was determined using neutron scattering, above the three-dimensional ordering temperature in order to discuss the one-dimensional properties of this system. The measurements were performed on a crystal-analyzer spectrometer at a pulsed neutron source and also on a triple-axis spectrometer (in the double-axis mode) at a steady-state neutron source. From these results it is concluded that the inverse correlation length κ is proportional to the temperature, as predicted by classical theory and that the correction of the kinematical factor ( k f / k i ) is essential to deduce the magnetic correlation.

The temperature dependence of spin dynamics in the S = 3 2 Heisenberg antiferromagnetic chain, CsVCl3, was studied by inelastic neutron-scattering experiment. The dynamical scattering function can be described by a Lorentzian with a q-independent line width, as predicted by the classical spin model. Although the line width is expected to vanish at T = 0 K in the classical spin model, the observed line width is extrapolated to be finite at T = 0 K. This result suggests that quantum fluctuations play an important role at low temperatures in fS = 3 2 spin-chain systems.

A neutron guide tube was mounted on Sirius, the high-resolution powder diffractometer newly installed at Neutron Science Laboratory (KENS) at High Energy Accelerator Researh Organization (KEK), and its performance was investigated. A NiC/Ti supermirror with the critical wave number triple of that of natural nickel was employed for the guide tube coating in order to utilize shorter wavelengths (∼1 A) required on the powder diffractometry. The wavelength-dependent intensity gain is observed, which enhances the performance of Sirius over the powder diffractometer already existing at KENS without a guide tube.

High-resolution neutron inelastic experiments gave the first direct experimental evidence for anomalous spin diffusion in systems with fractal geometry. The diffusive motions of spins at high temperatures in the near-percolating 2D antiferromagnet, Rb2Co0.6Mg0.4F4, were observed. The scattering function integrated over momentum space in the paramagnetic phase reveals a long-tailed spectrum having the form of E−x superimposed on the Lorentzian line shape. This observation of a power-law decay function is compared with similar measurements on a pure compound Rb2CoF4.

Inelastic pulsed-neutron scattering experiments from CsVCl3, a S = 3 2 Heisenberg antiferromagnetic chain compound, were performed above TN. The excitation positions were well fitted to a classical spin-wave dispersion relation and a quantum renormalization factor was confirmed. We found that the line width of the spectrum was broad and independent of q.

Polarized-neutron transmission experiments on a triangular-lattice antiferromagnet, LiNiO 2 , have been performed. The transmitted beam through the sample was depolarized below the lower transition temperature T N2 . The transmitted beam also includes small-angle neutron-scattering, and magnetic small-angle neutron-scattering separated from the transmission was observed below the upper transition temperature T N1 .

The contrast variation method in polarized neutron scattering is used to determine the magnetic structure of fine particles in the ferrofluid. The “contrast” in the scattering power was varied by mixing D 2 O with the water solvent of the ferrofluid. Then the diffracted intensity of polarized neutrons is sensitive to the “contrast”, which enables to determine the microscopic structure of dispersed particles in the ferrofluid.

Complex susceptibility measurements have been carried out on a diluted square lattice antiferromagnet of Ising spins, Rb 2 Co c Mg 1− c F 4 ( c p =0.593) to elucidate the magnetic anomaly probed by μSR. The temperature dependence of the median correlation time deduced by the Cole–Cole plot indicates that the anomaly of μSR is caused by the slowing-down of Ising-cluster excitations associated with development of two-dimensional short range order.

We performed inelastic neutron scattering experiments on [Ni(chxn) 2 Br]Br 2 . Magnetic excitations peaked at 6 meV were observed at the magnetic zone center at 5 K , also, integrated intensity including quasielastic scattering showed a maximum at 35 K . These properties are consistent with the spin-Peierls state.

Muon spin relaxation was measured on Rb 2 Co c Mg 1− c F 4 to study magnetic ordering and spin fluctuations in diluted Ising spin nets with concentration near the percolation threshold, c p =0.593. In a c =0.6 compound, the μSR spectrum shows a distinct anomaly due to the long-range ordering of the fractal lattice at 31 K much higher than T N =20 K . Comparing with the results for a c =0.5 compound, the observed spectra for the c =0.6 compound are analysed in terms of the spin fluctuations of the fractal lattice and the isolated spin clusters which are frozen gradually below 15 K.

We report on recent neutron inelastic scattering results on NaV2O5 in wide ω– Q space supporting the realization of zigzag-type charge ordering in the low-temperature singlet state of NaV2O5, as has been already indicated by our earlier neutron scattering studies.

We have performed neutron inelastic scattering experiments in order to investigate the high-energy magnetic excitations in chromium. The commensurate diffuse mode has been measured up to an enerfy of 550 meV, the mode remains highly localised in Q and persists past an expected energy gap at 440 meV.

Neutron depolarization studies were performed on single crystals of the superconducting materials in order to elucidate the mixed state below the critical temperature by changing the cooling magnetic field. The quantitative analysis of the wavelenght dependence of the depolarization shows that the magnetic flux forms the vortex line in the bulk crystal. The lower critical field is readily determined and also the penetration depth of the magnetic flux was determined under the simple assumption.

We demonstrate that neutron depolarization technique using pulsed polarized neutron beams is useful for studies on magnetization processes for ferrofluids by using both Co- and magnetite-ferrofluid. Remarkable difference in magnetization was observed with different cooling processes. The results are discussed on the basis of the model where each ferromagnetic particle is of single domain.

When sodium linear dodecylbenzenesulfonate (LAS), sodium dodecylsulfate (AS) and glucose were incubated with sewage bacteria, a high level of chloroform was produced on chlorination in the course of biodegradation. In addition to LAS, AS and glucose, the primary biodegradation intermediates of LAS and AS were not able to produce high level of chloroform. Acetoacetic acid was found to produce a large quantity of chloroform on chlorination amounting to 55.5% on a molar basis. The formation of acetoacetic acid in the course of biodegradation was determined and it was found that from 51 to 87% of the total chloroform produced could be explained to be derived from acetoacetic acid. These results indicate that acetoacetic acid functions as a potential chloroform precursor in the biodegradation of organic materials by sewage bacteria.

Polarized neutrons scattering from Fe 65 62 Ni 35 was measured to demonstrate the correlation of the magnetic inhomogeneous structure with the fluctuation of chemical composition. The results imply that the contribution of the dynamic spin fluctuation to small-angle scattering becomes more than that of the static magnetic inhomogeneous structure near and above T c .

Anomalous damping of acoustic phonons has been observed from the measurements of the linewidths of Brillouin components near the transition temperature in Gd2(MoO4)3 and the temperature dependence of damping constants has been fitted by a power law. Just below T0, the phonons propagating along the x-axis can only travel one wavelength in their relaxation time.

Brillouin spectra of longitudinal phonons which represent elastic constants c11, c22 and 11 have been measured as a function of temperature using a double Fabry-Perot interferometer. The observed phonons show softening and an anomalous increase in damping near the phase transition point.