The `ESS_butterfly_test` Instrument

Site: ESS
Author: Peter Willendrup
Origin: ESS
Date: 2016-09-26

Test instrument for the updated BF1 butterfly moderator design

Identification

Test instrument for the updated BF1 butterfly moderator design.

The below example gives a 50-50 (statistics-wise) cold/thermal beam at beamline N10.

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
sector	str	Defines the 'sector' of your instrument position. Valid values are "N","S","E" and "W"	"N"
beamline	1	Defines the 'beamline number' of your instrument position. Valid values are 1..10 or 1..11 depending on sector	1
Lmin	AA	Minimum wavelength simulated	0.2
Lmax	AA	Maximum wavelength simulated	20
c_performance	1	Cold brilliance scalar performance multiplicator c_performance > 0	1
t_performance	1	Thermal brilliance scalar performance multiplicator t_performance > 0	1
index	1	Target index for source focusing. Defaults to illuminate the "cold collimated" brilliance monitor, thereby suppressing "dist"	25
dist	m	Distance from origin to focusing rectangle; at (0,0,dist) - alternatively use target_index	0
cold	1	Defines the statistical fraction of events emitted from the cold part of the moderator	1
Yheight	m	Defines the moderator height. Valid values are 0.03 m and 0.06 m	0.03
delta	m	Parameter that allows to scan "collimator" position	0
thres			0.003
repeat			1
E_smear			0.1
pos_smear			0.01
dir_smear			0.01