scholarly journals Multiple Bragg reflections of neutrons accompanying a strong allowed reflection at a constant neutron wavelength

2016 ◽  
Vol 72 (a1) ◽  
pp. s413-s413
Author(s):  
Pavol Mikula ◽  
Miroslav Vrána ◽  
Jan Šaroun ◽  
Jan Čapek
Keyword(s):  
Neutron Wavelength

scholarly journals First measurements with the new 3He-filled Monoblock Aluminium Multitube neutron detector developed at the ILL for ANSTO PLATYPUS reflectometer

2020 ◽  
pp. 1-15
Author(s):  
Luis Abuel ◽  
Friedl Bartsch ◽  
Andrew Berry ◽  
Jean-Claude Buffet ◽  
Sylvain Cuccaro ◽  
...  
Keyword(s):  
Research Collaboration ◽  
Detection Efficiency ◽  
Mechanical Design ◽  
Performance Parameters ◽  
Detector Performance ◽  
High Detection ◽  
Neutron Wavelength ◽  
High Detection Efficiency ◽  
Main Detector ◽  
Characterisation Methods

A detector upgrade was carried out on the PLATYPUS instrument dedicated to neutron reflectometry at the Australian Nuclear Science and Technology Organisation (ANSTO). The new detector, developed in the framework of a research collaboration between the ILL and ANSTO, is based on the Monoblock Aluminium Multi-tube (MAM) detector design already in use on several reflectometers and SANS instruments at the ILL. This article provides a technical description of the mechanical design and read-out electronics of the PLATYPUS detector and its commissioning on the PLATYPUS instrument. The main detector performance parameters have been measured and are presented here as well as the characterisation methods and the results of several reflectometry measurements. These measurements show an improvement in experimental data quality resulting from high positional resolution, high detection efficiency and reduced neutron scattering background in the 2.5–19 Å neutron wavelength range used in PLATYPUS instrument.

The diffraction detector for the EMD of the CSNS

2021 ◽  
Vol 16 (12) ◽  
pp. P12018
Author(s):  
Q. Yu ◽  
B. Tang ◽  
C. Huang ◽  
Y. Wei ◽  
S. Chen ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Detection Efficiency ◽  
Grazing Angle ◽  
Incident Neutron ◽  
Silicon Photomultiplier ◽  
Detector Module ◽  
Neutron Wavelength ◽  
Thermal Neutron Detector ◽  
Application Specific Integrated Circuit ◽  
Design And Manufacture

Abstract On 23rd August 2018, the China Spallation Neutron Source (CSNS) located in Dongguan operated 4 neutron instruments. In the future, twenty neutron spectrometers will be built to provide multidisciplinary platforms for scientific research by national institutions, universities, and industries. Engineering Material Diffractometer (EMD), which will be used for strain measurements in engineering materials and components, will be constructed at the Beamline 8 in 2022. A novel thermal neutron detector, which will comply with the requirements of EMD application, is being developed. This detector will consist of 6LiF/ZnS(Ag) scintillation screens, wavelength shifting fiber (WLSF) arrays, a silicon photomultiplier (SiPM) and Application Specific Integrated Circuit (ASIC) read-out electronics. Each scintillation screen will be inclined with respect to the incident neutron beam at a grazing angle θ = 17°. Such geometry will not only improve the spatial resolution of detectors but also the neutron detection efficiency. The prototype of detector module has been tested at the neutron Beamline 20 at the CSNS. The experimental results obtained for this prototype illustrate that the pixel size of detector module is 3 mm and the detection efficiency exceeds 40% at the neutron wavelength of 1 Å. Based on these results, we design and manufacture the final version of the detector for the EMD application, which is characterized by low power consumption, highly integrated and easy to install. 70 such detectors will be installed till the end of 2021.

Insight into neutron focusing: the out-of-focus condition

2013 ◽  
Vol 46 (5) ◽  
pp. 1361-1371 ◽  
Author(s):  
B. Hammouda ◽  
D. F. R. Mildner ◽  
A. Brûlet ◽  
S. Desert
Keyword(s):  
Standard Deviation ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Neutron Wavelength ◽  
Focus Condition ◽  
The Mean ◽  
The Individual ◽  
Multiple Holes ◽  
Good Agreement

Neutron focusing leads to significant gains in flux-on-sample in small-angle neutron scattering and very small angle neutron scattering instruments. Understanding the out-of-focus condition is necessary for less than optimal conditions such as for short instruments and low neutron wavelengths. Neutron focusing is investigated using a three-pronged approach. The three methods are analytical calculations, resolution measurements and computer simulations. A source aperture containing a single small-size hole and a sample aperture containing multiple holes are used to produce multiple spots on the high-resolution neutron detector. Lens focusing elongates off-axis spots in the radial direction. The standard deviation for the size of each spot is estimated using these three approaches. Varying parameters include the neutron wavelength, the number of focusing lenses and the location of holes on the sample aperture. Enough agreement for the standard deviation of the individual neutron beams was found between the calculations and the measurements to give confidence in this approach. Good agreement was found between the standard deviations obtained from calculations and simulations as well. Excellent agreement was found for the mean location of these individual spots.

Convergent-beam neutron crystallography

2004 ◽  
Vol 37 (5) ◽  
pp. 778-785 ◽  
Author(s):  
W. M. Gibson ◽  
A. J. Schultz ◽  
J. W. Richardson ◽  
J. M. Carpenter ◽  
D. F. R. Mildner ◽  
...  
Keyword(s):  
Focal Length ◽  
Single Crystal Sample ◽  
Polycapillary Optics ◽  
Crystal Sample ◽  
Integrated Intensity ◽  
Neutron Wavelength ◽  
Powder Samples ◽  
Focal Spot Diameter ◽  
Convergent Beam ◽  
Pulsed Neutron

Two monolithic polycapillary optics of different focal length and beam convergence are employed to investigate the use of focusing lenses for the neutron convergent-beam method for time-of-flight crystallography with a broad neutron wavelength bandwidth. The optic of short output focal length (15.5 mm) with a beam convergence of 16.8 (10)° has a focal spot diameter of ∼100 µm for 3.2 Å neutrons. For an MnF2single-crystal sample of this diameter on a pulsed neutron source, this lens gives an expected integrated intensity gain of ∼100 for a 020 Bragg peak. Further measurements on a powder diffractometer show that the expected diffracted beam intensities for Ni have gains in excess of 500 for powder samples of this diameter. The degradation of resolution is minimized in the backscattering geometry.

scholarly journals Feasibility Study Of Neutron Wavelength Compressor For EDM Measurement

2017 ◽  
Author(s):  
Masaaki Kitaguchi ◽  
Yoshihisa Iwashita ◽  
Hirohiko M. Shimizu
Keyword(s):  
Feasibility Study ◽  
Neutron Wavelength

scholarly journals First Experiment of Spin Contrast Variation Small-Angle Neutron Scattering on the iMATERIA Instrument at J-PARC

2020 ◽  
Vol 4 (4) ◽  
pp. 33 ◽  
Author(s):  
Yohei Noda ◽  
Tomoki Maeda ◽  
Takayuki Oku ◽  
Satoshi Koizumi ◽  
Tomomi Masui ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Coherent Scattering ◽  
Proton Spin ◽  
Neutron Polarization ◽  
Stray Magnetic Field ◽  
Beam Experiment ◽  
Neutron Wavelength

Recently, we have developed a novel dynamic nuclear polarization (DNP) apparatus with a magnetic field of 7 T and a sample temperature of 1 K. High proton spin polarizations from −84% to 76%, for TEMPO doped polystyrene samples, have been demonstrated. This DNP apparatus satisfies the simultaneous requirement for quick and easy sample exchange and high DNP performance. On the iMATERIA (BL20) instrument at J-PARC, the first beam experiment using this DNP apparatus has been performed. For this experiment, the beamline was equipped with a supermirror polarizer. The stray magnetic field due to the superconducting magnet for DNP was also evaluated. The stray magnetic field plays an important role for in maintaining the neutron polarization during the transportation from the polarizer to the sample. The small-angle neutron scattering (SANS) profiles of silica-filled rubber under dynamically polarized conditions are presented. By applying our new analytical approach for SANS coherent scattering intensity, neutron polarization (PN) as a function of neutron wavelength was determined. Consequently, for the neutron wavelength, range from 4 Å to 10 Å, |PN| was sufficient for DNP-SANS studies.

Moving crystal slow-neutron wavelength analyser

1973 ◽  
Vol 106 (3) ◽  
pp. 461-464 ◽  
Author(s):  
B. Buras ◽  
J.K. Kjems
Keyword(s):  
Slow Neutron ◽  
Neutron Wavelength

The New Materials Science Diffractometer RSD at CIAE

2014 ◽  
Vol 777 ◽  
pp. 161-164
Author(s):  
Jun Hong Li ◽  
Yun Tao Liu ◽  
Jian Bo Gao ◽  
Rui Hu ◽  
Rong Deng Liu ◽  
...  
Keyword(s):  
Research Reactor ◽  
Materials Science ◽  
Research Work ◽  
Analytical Techniques ◽  
Industrial Applications ◽  
New Materials ◽  
Neutron Wavelength ◽  
Position Sensitive ◽  
Double Focusing ◽  
Non Destructive

China Advanced Research Reactor (CARR) is a 60 MW tank-in-pool inverse neutron trap type reactor at CIAE. In order to use the non-destructive analytical techniques for phase specific residual stresses research, the new materials science diffractometer RSD was designed at CARR, which is one of the first commissioned instruments to meet the demand of industrial applications. The system comprises two types of monochromator, mosaic flat copper (220) and perfect double focusing silicon (311). The take-off angle of monochromator could change continuously from 41 to 109 degree. Therefore the neutron wavelength varies from 0.895 and 2.666 angstrom. The detector is a one dimension position sensitive detector. Various affiliated equipments enable it to do texture and tensional experiments. The best resolution could reach 0.2% using double focusing Si (311) monochromator. When RSD is available for routine operation, some research work in the field of nuclear industrial and aviatic engineering materials will be carried out using the beam of CARR.

Three Dimensional Numerical Simulation of Thermal-Hydraulic Behaviors of CSNS Decoupled Poisoned Hydrogen Moderator With Non-Uniform Heat Source

2016 ◽  
Author(s):  
Jian-Fei Tong ◽  
Jiao-Long Wang ◽  
Hao-Chun Zhang ◽  
Yu Ji ◽  
He-Ping Tan
Keyword(s):  
Heat Source ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Cooling Capacity ◽  
Thermal Design ◽  
Source Distribution ◽  
Ansys Fluent ◽  
Uniform Heat ◽  
Neutron Wavelength ◽  
Heat Source Distribution

The Chinese Spallation Neutron Source (CSNS) is the national major scientific equipment, which will be completed around 2018. The moderator is the core of the CSNS parts, and CSNS uses three types of moderator to meet the requirements of different neutron wavelength and pulse shapes, and the structure and flow field of Decoupled Poisoned Hydrogen Moderator (DPHM) is the most complicated. Currently, Computational Fluid Dynamics (CFD) is the primary tool for thermal design of DPHM to ensure the reliability of calculation result and precision of the engineering requirements. In the current work, three-dimensional simulation of fluid-solid conjugate heat transfer and flow for container pipe, poisoned plate and moderator material were carried out, by compiling corresponding UDF program for ANSYS FLUENT to describe the non-uniform heat source distribution accurately. Thermal-Hydraulic behaviors such as pressure disturbance, pressure rise and temperature distribution cooling capacity are investigated.

Resolution functions of time-of-flight small-angle neutron scattering instruments with rectangular apertures

2007 ◽  
Vol 40 (1) ◽  
pp. 40-50 ◽  
Author(s):  
B. Grabcev
Keyword(s):  
Gravitational Field ◽  
Elastic Scattering ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Time Of Flight ◽  
Careful Analysis ◽  
Mathematical Relationship ◽  
Angle Scattering ◽  
Neutron Wavelength

Analytic forms are found for resolution functions of small-angle neutron scattering instruments. The expressions are developed as a function of momentum transfer (Q) rather than separately in terms of neutron wavelength (λ) and scattering angle (θ). Effects caused by the gravitational field as well as by quasi-elastic scattering are included. Explicit analytic forms for the transmission functions are proposed for both the incident and scattered beams, enabling careful analysis of any problem regarding small-angle scattering experiments. Due to the reciprocal mathematical relationship between λ, θ andQ, [λ, θ] space is employed to approach different aspects of the topic. Applications to time-of-flight instruments with rectangular apertures, including the choice of the most convenient instrumental parameters, the analysis of smearing effects and the data reduction toQspace, are presented.

Sign in / Sign up

Export Citation Format

Share Document