Focusing cold neutrons with multiple biconcave lenses for small-angle neutron scattering

Small angle neutron scattering (SANS) instruments typically cover a q (scattering vector) range from 0.001 to 0.6 Å−1. This range in q is achieved through a combination of cold neutrons (λ>4 Å) and a highly collimated beam. However, as a direct result of the unavailability of a cold source at the Canadian Neutron Beam Centre (CNBC), we have resorted to adapting a triple-axis spectrometer to perform SANS measurements. This is achieved through the use of multiple converging incident beams which enhance the neutron flux on the sample by a factor of 20, compared to a single beam of the same spot size. Furthermore, smearing effects due to vertical divergence from the slit geometry are reduced through the use of horizontal Soller collimators. As a result, this modified triple-axis spectrometer enables SANS measurements to a minimum q value (qmin) of ∼0.006 Å−1. Data obtained from the modified triple-axis spectrometer are in good agreement with those data from the 30 m NG3-SANS instrument located at the National Institute of Standards and Technology (Gaithersburg, MD, USA).

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“…1,2 To minimize peak asymmetry, as shown in Fig. 4, the dimension of q y 2 should approach that of q x 2 .…”

Section: B the Resolution Functionmentioning

confidence: 99%

Adapting a triple-axis spectrometer for small angle neutron scattering measurements

Nieh

Yamani

Kučerka

et al. 2008

Review of Scientific Instruments

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“…The USANS observed at q < 10 À3 Å À1 might be due to heterogeneous spatial distributions of the voids in the specimen. On the other hand, conventional pinhole SANS, which is available on SANS-J-II, covers the qregion from 3 Â 10 À3 Å À1 to 2 Â 10 À2 Å À1 by employing with sample-to-detector distance L s = 10.2 m. Focusing USANS experiments were performed on SANS-J-II, using a biconcave compound (MgF 2 ) lens (Koizumi et al, 2006;Eskildsen et al, 1998, Choi et al, 2000 with first and sample aperture sizes of 2.5 mm Â 2.5 mm and 20 mm diameter, respectively. To focused neutrons with = 6.65 Å at L s = 9.6 m, where the lens is allocated at nearly symmetric position L 1 = L 2 = 10 m, we needed 70 pieces of the biconcave lenses.…”

Section: Resultsmentioning

confidence: 99%

Wide-q observation from 10⁻⁴ to 2.0 Å⁻¹ using a focusing and polarized neutron small-angle scattering spectrometer, SANS-J-II

et al. 2007

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In order to extend an upper q-limit [q is the magnitude of the scattering vector q, defined by q = (4 / )sin , where and 2 are the wavelength and the scattering angle, respectively], high-angle 3 He sub-detectors were installed on a focusing and polarized neutron small-angle scattering spectrometer (SANS-J-II) at JRR-3, Tokai, Japan. Consequently, the upper q-limit was improved from 0.2 to 2.0 Å À1 . To quantitatively discriminate spin incoherent scattering from hydrogen or to perform nuclear spin polarization contrast variation, a remanent supermirror analyser is also available on the high-angle sub-detector. By combining a focusing ultra-small-angle scattering, realised by compound and/or magnetic lens and high-resolution area detector, SANS-J-II is able to cover from 3 Â 10 À4 to 2.0 Å À1 (four orders of magnitude of q), which benefits investigation of hierarchically ordered systems, found widely in hard, soft and bio-materials.

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“…The use of focusing collimators (biconcave MgF 2 lenses) enables us to measure a lower q region than that accessible by pinhole SANS. 27 Figure 4 shows a schematic picture of focusing SANS at SANS-J-II, JRR-3, Tokai, Japan. 28,29 A high-resolution area detector with 0.5 mm positional resolution was installed in addition to a MgF 2 lens resulting in a value of q min D3 Â 0 À3 nm À1 is attained; in contrast, the q min of pinhole SANS is 3 Â 10 À3 nm À1 .…”

Section: Scattering Studies Of Rubber-filler Systems M Takenakamentioning

confidence: 99%

Analysis of structures of rubber-filler systems with combined scattering methods

Takenaka

2012

Polym J

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This review presents an analysis of the hierarchical structures formed in rubber-filler systems by using combined scattering methods. The combined scattering methods utilize various scattering methods and are powerful tools for the quantitative characterization of hierarchical structures over a wide range of length scales, ranging from nanometers to micrometers. Scattering theories for the analysis of the experimental scattering functions and their applications are described. Polymer Journal (2013) 45, 10-19; doi:10.1038/pj.2012.187; published online 21 November 2012Keywords: combined scattering methods; hierarchical structure; rubber-filler systems INTRODUCTION Rubber-filler systems have been widely used in industrial applications, such as for tires and belts so on. 1-6 The use of fillers in rubber compounds reinforces the rubber material and improves the barrier properties. There are several important factors for controlling the efficiency of rubber reinforcement by fillers. The dispersion of filler particles in the rubber matrix is one of the most important factors in this process. Typically, following the use of conventional compounding processes, the fillers are not dispersed homogeneously and form hierarchical structures within the rubber matrices. For example, in rubber-carbon black (CB) systems, the CB primary particles are not distributed independently but coalesce into aggregates, which are indestructible units of CB, during conventional compounding processes. 2 The aggregates of CB, which are called aggregates or agglomerates, can also lead to the formation of hierarchical structures, which consist of higher levels of ordered structure. 2 It is believed that the hierarchical structures affect the efficiency of filler reinforcement. Other rubber-filler systems also form hierarchical structures; furthermore, the characteristic lengths and morphologies of each level of ordered structure, such as agglomerates, vary with the specific combination of rubber and filler used in the system in addition to the compounding processes. To analyze the hierarchical structure, scattering techniques are one of useful techniques. In scattering experiments, we investigated the angular dependence of the scattered intensities induced by the incident beam hitting samples. Although the interpretation of the scattering intensities is complicated, nonetheless, scattering techniques are suitable for obtaining the statistical features of rubber-filler systems. However, the length scales of the hierarchical structures can extend from nanometers to micrometers, which prevents the characterization

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Focusing cold neutrons with multiple biconcave lenses for small-angle neutron scattering

Cited by 151 publications

References 8 publications

Adapting a triple-axis spectrometer for small angle neutron scattering measurements

Adapting a triple-axis spectrometer for small angle neutron scattering measurements

Wide-q observation from 10⁻⁴ to 2.0 Å⁻¹ using a focusing and polarized neutron small-angle scattering spectrometer, SANS-J-II

Analysis of structures of rubber-filler systems with combined scattering methods

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Focusing cold neutrons with multiple biconcave lenses for small-angle neutron scattering

Cited by 151 publications

References 8 publications

Adapting a triple-axis spectrometer for small angle neutron scattering measurements

Adapting a triple-axis spectrometer for small angle neutron scattering measurements

Wide-q observation from 10−4 to 2.0 Å−1 using a focusing and polarized neutron small-angle scattering spectrometer, SANS-J-II

Analysis of structures of rubber-filler systems with combined scattering methods

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Wide-q observation from 10⁻⁴ to 2.0 Å⁻¹ using a focusing and polarized neutron small-angle scattering spectrometer, SANS-J-II