The crystal neutron diffractometer resolution function, spatial effects included

Abstract

A procedure for computing the resolution function for a crystal neutron diffractometer, taking into account the spatial con®guration of the experimental setup and the monochromator curvature, is presented. A brief general description of the matrix computation technique is given. The program DAX, which employs this technique, is presented.

OS04W0288 New monochromator performances based on Bragg diffraction optics for high-resolution neutron strain/stress diffractometers

“…Recently, an analytical approximation of instrumental line shapes [20] and matrix computation technique (program DAX [21]) have been published which basically permits an evaluation of the resolution function and intensity properties of neutron diffractometer taking into account a spatial configuration of the experimental set-up and the monochromator curvature and including also a double crystal monochromator For finding the optimum parameters (crystal cut, thickness and bending radius) Monte Carlo simulations should be used [22,23]. However, according to our knowledge, simulation computation techniques have not yet been used for estimation of multiple reflection effects in elastically deformed crystals.…”

New Trends in Thermal Neutron Spectrometry Getting High-Resolution Performances in Thermal Neutrons Spectrometry by Using Inverse Space Focusing

“…The sample position given by ( 5) correspond to a certain value of the scattering angle 2 s . The question is: if we keep the same sample position corresponding to a certain scattering angle value, how much is decreased the resolution if we measure the pattern for a certain To find an answer to this important problem, computations were made, using the DAX program [4], for the configuration existing at INR Pitesti and a sample of 2.5 cm width, 3 cm height and .5 cm thickness, for 5 values of the scattering angle, 30 0 , 50 0 , 70 0 , 90 0 and 110 0 , for which the optimum sample orientation angles are 29 0 , 37 0 , 90 0 , 121 0 , 144 0 respectively; were computed the line widths for a range of 20 0 around the above mentioned scattering angle values. The results are given in Figure 2.…”

The resolution function for a pulsed-source TOF neutron spectrometer with crystal monochromator

“…The matrix method [2], has been successfully used for different configurations, for example the TOF diffractometers with pulsed source [3], or with steady state source [4], the three-axis spectrometers [5], or the crystal diffractometers [6]. The matrix procedure is a convenient one and should be preferred if the normal approximation is still valid and a detailed line profile description is not required, otherwise a Monte Carlo procedure should be used.…”