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McStas: ILL_H22_D1B_noenv

[ Identification | Description | Input parameters | Links ]

The ILL_H22_D1B_noenv Instrument

The D1B diffractometer on the H22 curved thermal guide at the ILL

Identification

  • Site: ILL
  • Author: FARHI Emmanuel (farhi@ill.fr) and SANCHEZ Javier (sanchez-montero@ill.fr)
  • Origin: ILL
  • Date: June, 2008

Description

The D1B diffractometer on the H22 curved thermal guide at the ILL.

D1B is a two-axis spectrometer dedicated to diffraction experiments requesting a
high neutron flux. A great number of experiments performed on D1B concern the
determination of magnetic structures. At small angles where the magnetic peaks
are expected, a high spatial resolution can be achieved, the FWHM reaches 0.2°
(for a sample with = 8 mm). Three pyrolitic graphite monochromators focusing
onto the sample position provide a flux of 6.5·106 n cm-2s-1. A second
wavelength with = 1.28 Å is available by using a germanium monochromator. D1B is
equipped with 3He/Xe position-sensitive detector composed of a system of
multi-electrodes with 400 cells, which span a 2 range of 80°. The detector can
be moved so that an angular range of 2°<2<130° can be covered. The specially
designed cryostat is known for its low background crucial for some experiments
with small intensity changes. Because of its high flux at = 2.52 Å together with
the large multi-detector, surface studies such as adsorbed phases as well as
real-time diffraction experiments are possible. Collecting a diffraction pattern
with sufficient statistics in minutes (1-5 min) even seconds allows in situ
studies of reaction kinetics. A fast detection of phase transitions can also be
obtained by scanning the temperature. A complete thermal variation of the
diffraction patterns (1.5 - 300 K) can be achieved in few hours (3-5h).

Input parameters

Parameters in boldface are required; the others are optional.
NameUnitDescriptionDefault
lambdaAAmean incident wavelength.2.52
dlambdaAAwavelength full width.0.03
DMAAMono lattice spacing0
PowderstrFile name for powder description, LAZ/LAU/Fullprof"Na2Ca3Al2F14.laz"
RVmMonochromator vertical curvature, 0 for flat, -1 for automatic setting2.2
L1mSource-Monochromator distance0.25
L2mMonochromator-Sample distance3.0
L3mSample-Detector distance1.500
TRAS_XmAdditional monochromator translation along X, left/righ w.r.t beam-0
TRAS_ZmAdditional monochromator translation along Z, along guide0
TILTdegMonochromator additional tilt, for rocking curves0
THETA_MdegMono takeoff angle22.11
R_pitchdegAngular pitch between the absorbing blades.42
R_rimInner radius of the collimator0.324
R_romOuter radius of the collimator0.419
R_hmHeight of the collimator0.090
R_ttmindegLower scattering angle limit-130
R_ttmaxdegHigher scattering angle limit-2
R_present1Presence flag for the radial collimator. 0: unactivate component.1
verbose1Print DIF configuration. 0 to be quiet1
Inc_Cryo1Cryostat incoherent fraction0.02
Trans_Cryo1Cryostat event transmission0.85
Trans_Spl1Sample event transmission0.2
Inc_Spl1Sample incoherent fraction0.05

Links


[ Identification | Description | Input parameters | Links ]

Generated on 2023-09-19 20:01:36


Last Modified: Wednesday, 03-Jan-2024 19:59:10 CET
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