Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1980-1984  (5)
Source
Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    A proposal for a highly efficient double-crystal monochromator for thermal neutrons (1984)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 17 (1984), S. 189-195 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The optimum parameters and properties of a new type of neutron monochromator based on elastically bent silicon single crystals are theoretically evaluated. The use of a fully asymmetrical geometry permits the achievement of rocking-curve widths exceeding 20' in the incident beam. The associated effect of the reflected-beam widening is compensated for by the second crystal in the parallel (1,−1) setting in opposite geometry. Reflectivity calculations indicate that this double-crystal system might be compared with the best single-crystal mosaic monochromators. Besides the easy control of the effective mosaicity and the corresponding integrated reflectivity by variation of the bending radius, a further advantage of this system is its simultaneous action as a neutron filter improving the ratio of the thermal neutron signal to the background.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889884011274
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Complete determination of subgrain misorientation by an X-ray topographic method (1981)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 14 (1981), S. 265-269 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A modification of the Berg-Barrett X-ray topographic method was developed which enables measurement of all three misorientation parameters of a general subgrain boundary. The described method is based on the evaluation of three topographs of a single, arbitrarily oriented crystal surface taken by symmetric zero-layer reflections. In practical tests performed on an as-grown Fe–3 Wt% Si single crystal, relative accuracy of 10% and angular sensitivity better than 1′ were achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889881009333
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A medium-resolution double-crystal diffractometer for the study of small-angle neutron scattering (1983)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 16 (1983), S. 498-504 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The angular resolution of the parallel (1, −1) double-crystal setting has been relaxed from the original value of 10 μrad for perfect silicon crystals into the region 0.1–1 mrad by their elastic deformation. The totally reflecting region of the dynamical diffraction curve is broadened proportionally to the deformation while the wings as well as the diffuse scattering intensity are not affected substantially. This experimentally verified fact causes gain both in intensity and the signal/noise ratio. First experiments were performed with bent Si single-crystal bars in symmetric 220 reflection geometry at θB = 16.7°. With bending radii of the order of 100 m, angular resolution 0.6 mrad and an effective neutron flux at the sample position of 400 mm−2 s−1 were achieved. These values do not depend on beam cross section.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889883010894
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A novel approach to dynamical neutron diffraction by a deformed crystal (1984)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 40 (1984), S. 120-126 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The propagation of neutron waves in a deformed crystal is considered from the point of view of quantum mechanics. Instead of solving the Takagi-Taupin equations the probability of transitions, induced by the variation of the interaction potential, between quantum states corresponding to the two sheets of the dispersion surface is calculated. In this way transmission and reflection coefficients for an incident plane wave are obtained after a simple analytical calculation for a wide class of crystal deformations. The predictions of this theory are found to be in agreement with direct solutions of the Takagi-Taupin equations as well as with the experimental results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108767384000271
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Multiple Bragg reflections of neutrons in an elastically deformed single crystal (1981)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 37 (1981), S. 459-465 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The large positive diffraction intensity changes on forbidden (222) planes, which are produced by simultaneous diffraction, were observed when a perfect Si single crystal was excited into vibration. The excited Umweganregung effect is of the same order as the diffraction intensity obtained on (111) planes under the same experimental conditions. The theoretical consideration is an extension of the lamellae model usually used in the two-wave approximation. Both the theory and the experimental results demonstrate that such an effect may cause very large errors especially in diffraction experiments with non-perfect single crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739481001125
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...