[ Identification | Description | Input parameters | Output parameters | Links ]
ILL_D1A
InstrumentD1A is a reliable diffractometer for standard crystallographic problems. It gives excellent results with the Rietveld method owing to its near perfect Gaussian peak-shape in the 2θ-range 30° to 150°. Special features include a high fixed take-off angle of 122 deg, giving high resolution at large scattering angles (up to 160 deg); a bank of 25 high efficiency collimators and counters; an anisotropically squashed germanium monochromator focussing a 250 mm high beam onto only 30 mm; a wide choice of wavelengths, from 1.39 Angs to 2.99 Angs, quickly available by simple rotation of the focussing monochromator; The large monochromator take-off angle means that the diffraction pattern is focussed for the parallel geometry shown (2θ = 122°). The counter can be swept through 0 deg to 2θ = 160° deg for the highest angle counter, usually in steps of 0.05 deg. Monochromator Neutron wavelength Ge 117 DM=0.7946 AA 1.390 Ge 335 DM=0.8655 AA 1.514 Ge 115 DM=1.0925 AA 1.911 (optimal) Ge 113 DM=1.712 AA 2.994 The sample is a powder or a liquid, in a container can, all positioned in an Al environment (e.g. cryostat/furnace shield). This instrument model does not include the guide. For the 'SiO2' sample, one may change the Temperature to simulate a phase transition (for teaching purposes): T[C] 573 1650 quartz alpha < quartz beta < melt silica Example: mcrun D1A.instr lambda=1.911 mcrun D1A.instr -N 10 lambda=1.911 Powder="SiO2" Temperature=300,2000
Name | Unit | Description | Default |
---|---|---|---|
lambda | Angs | Wavelength at monochromator | 1.911 |
DM | Angs | d-spacing of monochromator. Use DM=0 to compute the values from the requested wavelength. | 0 |
powder | extension .qSq | [str] File name for powder description, or S(q) file | "SiO2" |
Temperature | K | Sample temperature, to study phase changes. Only applies when Powder is set to SiO2. | 300 |
ILL_D1A.instr
.
[ Identification | Description | Input parameters | Output parameters | Links ]
Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Mon Feb 7 13:18:37 2011