14.70  The Spot_sample McStas Component

Spot sample.

Identification

• Author: Garrett Granroth

• Origin: Oak Ridge National Laboratory

• Date: 14.11.14

Description

A sample that is a series of delta functions in omega and Q. The Q is determined by a two theta value and an equal number of spots around the beam center. This component is a variation of the V sample written by Kim Lefmann and Kristian Nielsen. The following text comes from their original component. A Double-cylinder shaped incoherent scatterer (a V-sample) No multiple scattering. Absorbtion included. The shape of the sample may be a box with dimensions xwidth, yheight, zthick. The area to scatter to is a disk of radius ’focus_r’ situated at the target. This target area may also be rectangular if specified focus_xw and focus_yh or focus_aw and focus_ah, respectively in meters and degrees. The target itself is either situated according to given coordinates (x,y,z), or setting the relative target_index of the component to focus at (next is +1). This target position will be set to its AT position. When targeting to centered components, such as spheres or cylinders, define an Arm component where to focus at.

Example: spot_sample(radius_o=0.01, h=0.05, pack = 1, xwidth=0, yheight=0, zthick=0, Eideal=100.0,w=50.0,two_theta=25.0,n_spots=4)

Input parameters

Parameters in boldface are required; the others are optional.

Links

• Component source code found in file Spot_sample.comp.