Design and performance of two new double crystal monochromators

1997 ◽  
Author(s):  
D. J. Holly ◽  
W. P. Mason ◽  
F. H. Middleton ◽  
T. Sailor ◽  
R. E. Smith
Keyword(s):  
Double Crystal ◽  
And Performance

Design and performance of the variable-wavelength Bonse–Hart ultra-small-angle neutron scattering diffractometer KOOKABURRA at ANSTO

2018 ◽  
Vol 51 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Christine Rehm ◽  
Liliana de Campo ◽  
Alain Brûlé ◽  
Frank Darmann ◽  
Friedl Bartsch ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Pyrolytic Graphite ◽  
Bragg Angle ◽  
Double Crystal ◽  
And Performance ◽  
Doubly Curved

The double-crystal ultra-small-angle neutron scattering (USANS) diffractometer KOOKABURRA at ANSTO was made available for user experiments in 2014. KOOKABURRA allows the characterization of microstructures covering length scales in the range of 0.1–10 µm. Use of the first- and second-order reflections coming off a doubly curved highly oriented mosaic pyrolytic graphite premonochromator at a fixed Bragg angle, in conjunction with two interchangeable pairs of Si(111) and Si(311) quintuple-reflection channel-cut crystals, permits operation of the instrument at two individual wavelengths, 4.74 and 2.37 Å. This unique feature among reactor-based USANS instruments allows optimal accommodation of a broad range of samples, both weakly and strongly scattering, in one sample setup. The versatility and capabilities of KOOKABURRA have already resulted in a number of research papers, clearly demonstrating that this instrument has a major impact in the field of large-scale structure determination.

Design and performance of a thermal-neutron double-crystal diffractometer for USANS at NIST

2005 ◽  
Vol 38 (6) ◽  
pp. 1004-1011 ◽  
Author(s):  
J. G. Barker ◽  
C. J. Glinka ◽  
J. J. Moyer ◽  
M. H. Kim ◽  
A. R. Drews ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Small Angle ◽  
Measurement Range ◽  
Beam Intensity ◽  
Material Structure ◽  
Multiple Reflections ◽  
Double Crystal ◽  
Before And After ◽  
And Performance ◽  
Double Crystal Diffractometer

An ultra-high-resolution small-angle neutron scattering (USANS) double-crystal diffractometer (DCD) is now in operation at the NIST Center for Neutron Research (NCNR). The instrument uses multiple reflections from large silicon (220) perfect single crystals, before and after the sample, to produce both high beam intensity and a low instrument background suitable for small-angle scattering measurements. The minimum detector background to beam intensity ratio (noise-to-signal, N/S) forq≥ 5 × 10−4 Å−1is 4 × 10−7. The instrument uses 2.38 Å wavelength neutrons on a dedicated thermal neutron beam port, producing a peak flux on the sample of 17300 cm−2 s−1. The typical measurement range of the instrument extends from 3 × 10−5 Å−1to 5 × 10−3 Å−1in scattering wavevector (q), providing information on material structure over the size range from 0.1 µm to 20 µm. This paper describes the design and characteristics of the instrument, the mode of operation, and presents data that demonstrate the instrument's performance.

Design and performance of a multilayered mirror monochromator in the low-energy region of the VUV

1998 ◽  
Vol 5 (3) ◽  
pp. 714-715 ◽  
Author(s):  
Harutaka Mekaru ◽  
Tsuneo Urisu ◽  
Yoshiyuki Tsusaka ◽  
Shin Masui ◽  
Eijiro Toyota ◽  
...  
Keyword(s):  
Thin Film ◽  
Background Noise ◽  
Energy Region ◽  
Photon Flux ◽  
Double Crystal ◽  
Crystal Type ◽  
Thin Film Filter ◽  
And Performance ◽  
Reflection Component ◽  
High Output

For the energy region from tens to hundreds of electron volts, the multilayered mirror (MLM) monochromator has never been realized due to the difficulty of reducing the background noise of the total reflection component, in spite of its usefulness in synchrotron radiation experiments. In this work, a double-crystal-type MLM monochromator equipped with a thin-film filter has been designed on the basis of trial fabrication of the mirror-driving system and of Mo/Si and Mo/C MLMs; its performance has been evaluated by calculating its output photon flux. It is shown that by using the MLMs at low incident angles, combined with an appropriate thin-film filter, it is possible to make a practical monochromator with high output photon flux and low background noise.

scholarly journals Design and performance of the Advanced Light Source double‐crystal monochromator

1995 ◽  
Vol 66 (2) ◽  
pp. 1748-1750 ◽  
Author(s):  
G. Jones ◽  
S. Ryce ◽  
D. W. Lindle ◽  
B. A. Karlin ◽  
J. C. Woicik ◽  
...  
Keyword(s):  
Light Source ◽  
Double Crystal ◽  
Double Crystal Monochromator ◽  
Advanced Light Source ◽  
And Performance

Analytical and Experimental Investigation of Flow and Fracture Mechanisms Induced by Indentation in Single Crystal MgO

1982 ◽  
Vol 26 ◽  
pp. 299-306
Author(s):  
T. Larchuk ◽  
T. Kato ◽  
R. N. Pangborn ◽  
J. C. Conway
Keyword(s):  
Fracture Behavior ◽  
Large Degree ◽  
Surface Damage ◽  
Fracture Mechanisms ◽  
Flow Zone ◽  
Double Crystal ◽  
Contact Loading ◽  
X Ray ◽  
Static Contact ◽  
And Performance

The flow and fracture behavior of ceramic and other brittle materials under the influence of contact loading is important to both component fabrication and performance. The ease of machining, severity of residual surface damage and rate of wear during subsequent service are controlled to a large degree by the character and extent of the flow zone and its influence on the fracture mode. This Investigation was undertaken to provide experimental verification of the results obtained through elastic/plastic finite element modeling cf the stress distribution and deformations introduced by static contact loading. Experimentally, X-ray double-crystal diffractometry (DCD) was applied to obtain a mapping of the distortions produced beneath a Vickers indenter, and hence to evaluate the effect of material and geometric parameters on the flow and fracture mechanisms.

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