Small Angle Neutron Scattering Spectrometer Research Articles

Multi-tube area detector developed for reactor small-angle neutron scattering spectrometer SANS-J-II

A newly developed multi-tube area detector for a small-angle neutron scattering (SANS) spectrometer (SANS-J-II) at the research reactor JRR-3 in Tokai, Japan, has been implementedviathe use of one-dimensional position-sensitive3He detectors (tubes). Ninety-six active tubes of 8 mm in diameter and 650 and 580 mm in length were filled with 15 atm (1.52 MPa) of3He and aligned vertically parallel in order to cover a sufficiently large area for small-angle scattering measurement. These tubes are enclosed in an air chamber together with neutron encode and GATENET modules (VME boards), which compose a standard data acquisition system for the spallation neutron source of the Japan Proton Accelerator Research Complex. This system facilitates the acquisition of time-of-flight neutron event data. The multi-tube detector is mounted on a truck moving in a vacuum chamber of the SANS spectrometer. After discriminating noise originating from γ-rays, and calibrating the positions and sensitivities of individual tubes, the resolution was determined (i.e.channel widths along parallel and vertical directions along a tube). The counting rate of one tube was determined to be 1.4 × 103counts per second with a counting loss of 1%. This implies that the new detector, composed of 96 tubes, can detect more than 105neutrons per second with a counting loss of 1%. To demonstrate its use, small-angle scattering originating from a diblock copolymer film with a highly oriented lamellar microdomain was observed. The data acquisition in event mode has a great advantage in time-resolved measurements that are synchronized with external stimuli imposed on a sample.

A new small-angle neutron scattering spectrometer at China Mianyang research reactor

A new pinhole small-angle neutron scattering (SANS) spectrometer, installed at the cold neutron source of the 20MW China Mianyang Research Reactor (CMRR) in the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, has been put into use since 2014. The spectrometer is equipped with a multi-blade mechanical velocity selector, a multi-beam collimation system, and a two-dimensional He-3 position sensitive neutron detector. The q-range of the spectrometer covers from 0.01nm−1 to 5.0nm−1. In this paper, the design and characteristics of the SANS spectrometer are described. The q-resolution calculations, together with calibration measurements of silver behenate and a dispersion of nearly monodisperse poly-methyl-methacrylate nanoparticles indicate that our SANS spectrometer has a good performance and is now in routine service.

Small angle neutron scattering study of the gemini nonionic surfactant in heavy water solutions

The nonionic gemini surfactant α α'-[2,4,7,9-tetramethyl-5-decyne-4,7diyl]bis[ω hydroxyl-polyoxyethylene] (S-10) was investigated in heavy water solutions only for concentrations: 2.3%, 2.5%,3%, 3.4%, 4% and 5% at temperature 25°C with small angle neutron scattering (SANS) method. All of surfactants solutions were prepared using D2O (99.9% deuterated, Prikladnaia Chimia, St. Petersburg, Russia) as a solvent. The nonionic gemini surfactant S-10 was obtained from Air Products & Chemicals, Inc., and used without further purification. All SANS measurements were performed on V-4 SANS spectrometer at BENSC, Berlin (Germany). Neutrons were used in wavelength range of 0.02 – 4 nm−1. For the measurements quartz cells of were used during experiment. Up to 14 such cells were placed in a holder. Results from experiment was calculated and evaluated with PCG 2.0 program from Graz University (Austria). In the investigated solutions two axis ellipsoidal micelles was observed.

Design and Construction of the Control System for Batan Small Angle Neutron Scattering Spectrometer (SMARter)

A 36 m Small Angle Neutron Scattering (SANS) Spectrometer (SMARTer) has been installed in Serpong, Indonesia in 1992. As time goes by, the original main computer was out of order and the instrument had not been operated since 2003. In order to activate the SMARTer, in the year 2005, a work on designing and constructing a new control system for SMARTer was carried out. The main component of this control system is a programmable peripheral I/O (IC PPI 8255) and was assembled as a plug-in board at an ISA slot of a personal computer. An IC PPI 8255 was programmed to control the mechanical movements of the instrument’s components: four neutron guide tubes, six pinholes collimator, a detector and a beam stopper. The test either with or without neutron beam has shown that this control system can be implemented for the mechanical movements of SMARTer. Error of moving the detector in the distance range of 1.5 m – 18 m is only 1 mm and the other movements have no error at all (precise).

Experimental Evidence of Super Densification of Adsorbed Hydrogen by in-situ Small Angle Neutron Scattering (SANS)

ABSTRACTEntrapping hydrogen molecules within the nanopores of solid adsorbents serves as a unique alternative for on-board storing of hydrogen for transportation purposes. The key advantage of the physisorption process for hydrogen storage is the higher density values achieved with the adsorbed gas, compared to that of the compressed phase, translating into higher storage capacities at lower pressures. The necessary condition for effective adsorption is the presence of narrow micropores of < 2 nm in width which provide the most suitable environment of hydrogen adsorption. Despite numerous theoretical calculations or indirect experimental estimations, there has not been a direct experimental measurement of the density of adsorbed hydrogen as a function of pressure and/or pore size. In the present study, we report on the use of in-situ small angle neutron scattering (SANS) to study the phase behavior of hydrogen confined in narrow micropores. We provide for the first time direct experimental measurements of the effect of pore size and pressure on hydrogen adsorbed on a polyfurfuryl alcohol-derived activated carbon (PFAC), at room temperature and pressures up to 207 bar. SANS studies were carried out at the General-Purpose Small-Angle Neutron Scattering spectrometer of the High Flux Isotope Reactor at Oak Ridge National Laboratory. The measurements covered the Q-range from 0.01 to 0.8 Å-1, covering the pores in the range of 9 to 34 Å of the PFAC material. Initial results suggest that the density of adsorbed hydrogen is higher than the density of bulk hydrogen gas and increases with decreasing pore size.

NANOSIZE STRUCTURE OF SELF-ASSEMBLY SODIUM DODECYL SULFATE: A STUDY BY SMALL ANGLE NEUTRON SCATTERING (SANS)

Small Angle Neutron Scattering (SANS) investigation on the self-assembly sodium dodecyl sulfate (SDS) molecules as a function of concentration and additives has been carried out. SANS spectrometer which has been completely installed at the neutron scattering laboratory (NSL) BATAN in Serpong, Indonesia has played most important role to determine the growth (size) and also the shapes of a micelle structure. In this works we report that spherical micelle structure with a radius of 16.7 Å will transform to ellipsoidal or rod-like micelle structure with the long axis extends up to 50 Å by increasing the concentration of SDS. Similar to that the micelle structures change by addition of salt in SDS micellar solutions. Keywords: nanostructure, micelle, self-assembly

SMARTer for Materials Science and Biology Research

A 36-meter small-angle neutron scattering (SANS) spectrometer was constructed in the neutron-guide hall (NGH) of the 30 MW G.A. Siwabessy research reactor in 1992 [1]. It was the largest SANS spectrometer in the Asia-Oceania region at that time.

Improvement of performances of the small angle neutron scattering at NUR reactor

Small Angle Neutron Scattering (SANS) is a powerful technique for the investigation of inhomogeneities in matter. The technique provides valuable information over a wide variety of fields including chemical aggregation, defects in materials, surfactants, alloy segregation, polymers, biological membranes, viruses and macromolecules. In order to investigate the structures of micellar aggregations of asphaltene molecules as well as fluorinated surfactants which are of importance for the Algerian oil industry, a SANS spectrometer has been installed on beam port No. 4 of the NUR research reactor. Because SANS experiments are very time consuming and require low neutron background, an important effort was made to improve experimental conditions. This paper presents the general characteristics of SANS facility and addresses the various improvements that have been made.

Research and facility of neutron scattering in Indonesia

Neutron scattering activities in Indonesia during last fiscal year are reported in this paper. The neutron beam facilities in Serpong include one diffractometer (DN1-M) for residual stress measurements, one diffractometer (FCD/TD) for single-crystal structure determinations and texture measurements, one high resolution powder diffractometer (HRPD), one neutron radiography facility (NRF), one triple axis spectrometer (TAS), one small angle neutron scattering spectrometer (SANS) and one high-resolution small-angle neutron scattering spectrometer (HRSANS). Four instruments related to this symposium among them are discussed. The FCD/TD, HRSANS and TAS are not working now because of some electronic troubles. NRF is working but not at its best condition. The HRPD, DN1-M and SANS are running well, and HRPD is used heavily. The latest situation of the reactor and its operation mode are also described briefly in connection with activities of the neutron scattering instruments.

Optimization study for small angle neutron scattering spectrometer at the ET-RR-1 reactor

The design principle of a Small Angle Neutron Scattering (SANS) spectrometer is based on producing monochromatic neutron bursts using two phased rotors with curved slots. An optimization study of their number and shape to achieve the highly available intensity of monoenergetic neutrons at the required resolution is given. The study was applied to the improvement of the performance of the pulsed monochromatic double rotor system at ET-RR-1 to operate as SANS spectrometer. It is shown that for rotors having 19 slots each with radius of curvature 96.8 cm, the intensity gain factor is 13. The proposed SANS spectrometer could cover the neutron wavelength range from 2 Å up to 6 Å through small angles of scattering from 5 × 10 −3 rad to 0.1 rad, i.e., the scattering wavevector transfer between 0.6 Å −1 and 0.01 Å −1. The maximum neutron intensity on the specimen is 2 × 10 6 n s −1.

Focusing of neutron beams using curved mirrors for small angle scattering

Abstract Optical focusing using a long curved mirror at grazing incidence is a novelty in small angle neutron scattering (SANS) instrumentation. A good quality focused image is essential if such a device is to be used in a SANS spectrometer. On the one hand, a very smooth mirror surface is most important, since surface roughness produces a detrimental halo surrounding the focused image. This halo has been carefully investigated using X-ray and neutron measurements for different kinds of flat mirror samples. The best image quality is obtained with a highly polished ‘zerodur’ substrate coated with a 65Cu layer protected by a thin Al layer. On the other hand, the quality of the image strongly depends on parameters such as object size, mirror shape, wavelength distribution and gravity; the influence of these parameters has been investigated using ray-tracing Monte-Carlo simulations. These studies have encouraged us to build a 4 m long toroidal mirror to be installed late in 1995 at the new IN15 neutron spin-e...

Ultra-High Resolution Small-Angle Neutron Scattering Investigations of Liquid-Liquid Phase Separation in Linear Low-Density Polyethylene

ABSTRACTPrevious small-angle neutron scattering (SANS) studies [1] of heterogeneous ethylene-hexene linear low-density polyethylene (LLDPE) copolymers have confirmed the existence of a dispersed minority phase (volume fraction φ ∼ 10−2) consisting of highly branched, amorphous material. However, these experiments were conducted via a pinhole SANS spectrometer with an upper resolution limit ∼ 103 Å, whereas microscopy indicates that the dimensions of the disperse phase extend to the μm-range. We have therefore complemented these investigations via a Bonse-Hart ultra-small angle neutron scattering (USANS) instrument which increases the instrumental resolution in reciprocal space by a factor - 100, and thus particle size up to 30 μm can be resolved. The sensitivity of the USANS camera has recently been increased by two orders of magnitude by using the modified channel cut crystals [2], and the performance is therefore comparable to the best x-ray Bonse-Hart cameras. Xylene extraction removes the highly branched molecules and hence the volume fraction of the disperse phase is higher (φ ∼ 0.3) in the extracted material.

Small Angle Neutron Scattering at Mcmaster University

ABSTRACTWe describe the Small Angle Neutron Scattering spectrometer at McMaster University. We then discuss three examples of recent studies using this instrument: (1) the membrane-water interface in multilamellar vesicles; (2) magnetic ordering of Ni0.8Co0.2/Cu multilayers; and (3) precipitate sizes in titanium stabilized interstitial-free steels.

A small-angle neutron scattering study of cement porosities

Several techniques for measuring the porosity and pore-size distribution inhardened cement paste (HCP) have given conflicting results. This is partly because thesemethods require drying or pre-treatment of specimens. Small-angle neutron scattering(SANS) allows investigation of the fine-pore porosity without any such pre-treatment.Measurements using the Pluto SANS spectrometer indicate a bimodal distribution of near-spherical pores with diameters of 5 and 12 nm. The former have a well peaked size distributionand account for 1-1.5% porosity. The pores are relatively unaffected by the water-to-cementratios investigated although drying has the effect of collapsing the structure.