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McStas: SNS_source_analytic Component

[ Identification | Description | Input parameters | Output parameters | Links ]

The SNS_source_analytic Component

A source that produces a time and energy distribution from parameterized SNS moderator files


  • Author: F. X. Gallmeier
  • Origin: SNS Oak Ridge National Laboratory
  • Date: October 18, 2010
  • Version:(Unknown)


Produces a time-of-flight spectrum from SNS moderator files
moderator files can be obtained from the author
IMPORTANT: The output units of this component are N/pulse
IMPORTANT: The component needs a FULL PATH to the source input file
(1) the raw moderator files are per Sr.  The parameters focus_xw focus_yh and dist
provide the solid angle with which the beam line is served.
The best practice is to set focus_xw and focus_yh to the width and height of the
closest beam component, and dist as the distance from the moderator
location to this component.
(2) Be sure that Emin and Emax are within the limits of 1e-5 to 100 eV
(3) the proton pulse length T determines short- and long-pulse mode

Beamport definitions:
BL11: a1Gw2-11-f5_fit_fit.dat
BL14: a1Gw2-14-f5_fit_fit.dat
BL17: a1Gw2-17-f5_fit_fit.dat
BL02: a1Gw2-2-f5_fit_fit.dat
BL05: a1Gw2-5-f5_fit_fit.dat
BL08: a1Gw2-8-f5_fit_fit.dat

WARNING: This is a contributed Component.

Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
xwidth default 0.1 m [m] width of moderator 0.10
yheight default 0.12 m [m] height of moderator 0.12
dist no default [m] Distance from source to the focusing rectangle  
focus_xw no default [m] Width of focusing rectangle  
focus_yh no default [m] Height of focusing rectangle  
Emin default 0.01 meV [meV] minimum energy of neutrons 0.01
Emax default 1e5 meV [meV] maximum energy of neutrons 1.0e5
tinmin default 0 us [us] minimum time of neutrons 0.0
tinmax default 2000 us [us] maximum time of neutrons 2000.0
sample_E 0
sample_t 0
proton_T 0 us [us] proton pulse length 0.0
p_power default 2 MW [MW] proton power 2.0
n_pulses default 1 [] number of pulses 1.0


[ Identification | Description | Input parameters | Output parameters | Links ]

Generated automatically by McDoc, Peter Willendrup <> / Wed Jan 12 15:13:20 2022

Last Modified: Wednesday, 12-Jan-2022 16:13:20 CET
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