A monochromator with variable horizontal and vertical curvatures for focussing in real and reciprocal space

Lechner, R.E.; Wallpach, R. v.; Graf, H.A.; Kasper, F.-J.; Mokrani, L.

doi:10.1016/0168-9002(94)90163-5

Cited by 19 publications

(11 citation statements)

References 2 publications

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“…2,3 Double-focusing composite crystal monochromators with variable horizontal and vertical curvature can provide significant increase in the intensity and have been employed in the numerous neutron instruments. [4][5][6][7] By the combination of this system with a horizontally focusing analyzer in a triple-axis spectrometer, considerable gain in a factor of about 100 can be obtained in measuring phonons in copper crystals within the acceptable wavelength resolution. 4 More complicated discussions of focusing monochromators can be found in Ref.…”

Section: Introductionmentioning

confidence: 99%

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Development of a thermal neutron focusing device using neutron supermirrors

Osakabe

Soyama

2005

Review of Scientific Instruments

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Exploration of ion temperature profile measurements at JET using the upgraded neutron profile monitora) Rev. Sci. Instrum. 83, 10D314 (2012); 10.1063/1.4734040 Polarizing neutron monochromator with reduced higher-order contributions Appl. Phys. Lett. 89, 253111 (2006); 10.1063/1.2410235 Polarized reflectometer for the investigation of surface magnetism, the new polarized neutron reflectometer with polarization analysis at the Laboratoire Léon Brillouin Rev.

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Section: Introductionmentioning

confidence: 99%

“…The right illustration shows the assembly of the focusing device 6,. the considerable gains in the peak intensity of about 2.0, 2.7 and 4.2 are obtained for the incident neutron energy of 30.5, 13.7, and 4.9 meV, respectively.…”

mentioning

confidence: 99%

Development of a thermal neutron focusing device using neutron supermirrors

Osakabe

Soyama

2005

Review of Scientific Instruments

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“…Doubly focusing monochromators successfully used elsewhere employ intricate mechanical devices to orient each individual crystal of the two-dimensional array at the proper focusing angle (Bu È hrer, 1994;Wagner et al, 1994;Lechner et al, 1994;Mikula et al, 1995;Cicognani et al, 2000). However, the mass of the focusing mechanisms for each crystal is much greater than that of the crystal and leads to a signi®cant level of background.…”

Section: Introductionmentioning

confidence: 99%

Cold pressing of copper single crystals for a large-area doubly focusing monochromator

2004

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The design for a large-area doubly focusing neutron monochromator consists of a large number of small square copper single crystals mounted onto thin aluminium blades that both buckle and rotate independently. This avoids the need for large individual alignment mechanisms for each crystal that introduce unacceptably high levels of background. However, it does require that the crystals be oriented such that the diffracting crystallographic planes are parallel to the crystal face. Cold pressing broadens the natural narrow mosaic of the virgin crystal discs to increase the diffracted intensity. This introduces anisotropy into the crystal that determines its orientation in the ®nal monochromator. The alignment procedure used for each crystal before cutting out the square tile in the correct orientation is described. A few crystals are characterized in detail by neutron diffraction at various stages of the operation, revealing the variation in the mosaic width and the angular position of the reciprocal-lattice vector as a function of the azimuthal angle by rotating the crystal about the normal to its face. The twofold symmetry of the mosaic width of the pressed crystal is modulated by the 2% periodicity introduced by the precession of the reciprocallattice vector around the crystal face normal. Satisfactorily aligned crystals have a variation in the angular position for diffraction within the allowed tolerance.research papers 456 Mildner, Brand and Clem Cold pressing of copper single crystals

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“…-using gradient crystals [2], -cold and hot pressing of the crystals [3,4] and other methods. In our laboratory, the cold hammering method [4] was used to increase the reflectivity of small single crystalline plates of Cu.…”

Section: Introductionmentioning

confidence: 99%

“…In our laboratory, the cold hammering method [4] was used to increase the reflectivity of small single crystalline plates of Cu. Presently, after some modifications of our equipment, this method is used to increase the reflectivity of big single crystalline plates of Cu and also CoFe (8 %at.)…”

Section: Introductionmentioning

confidence: 99%

Increase in Neutron Reflectivity from Big Cu and CoFe (8%at.) Alloy Single Crystal Plates Resulting from Cold Hammering of the Plates

et al. 1996

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In the paper changes of neutron reflectivity of big (120 x 70 x 10 mm 3 ) Cu single crystalline monochromators and CoFe (8 %gat.) single crystalline, polarising monochromators after cold hammering of the starting plates,'are described. An almost three times higher number of reflected neutrons (totaI reflectivity) and about 20 % higher intensity in peak maximum were observed, for Cu plates (measured in reflection from (220) plane)), while the mosaic's spread was about 2 times higher than the one measured for a non-treated plate. In the case of CoFe, 3 mm thick plates, a two times higher number of reflected neutrons and almost 60 % higher intensity in peak maximum were observed (measured in transmission -from (200) plane) after hammering, whiIe the mosaic's spread increase was rather smalI (about 15 %).

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A monochromator with variable horizontal and vertical curvatures for focussing in real and reciprocal space

Cited by 19 publications

References 2 publications

Development of a thermal neutron focusing device using neutron supermirrors

Development of a thermal neutron focusing device using neutron supermirrors

Cold pressing of copper single crystals for a large-area doubly focusing monochromator

Increase in Neutron Reflectivity from Big Cu and CoFe (8%at.) Alloy Single Crystal Plates Resulting from Cold Hammering of the Plates

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