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

The ESS_moderator_short Component

A parametrised pulsed source for modelling ESS short pulses.

Identification

Description

Produces a time-of-flight spectrum, from the ESS parameters
Chooses evenly in lambda, exponentially decaying in time .
Adapted from Moderator by: KN, M.Hagen, August 1998

Units of flux: n/cm^2/s/AA/ster  
(McStas units are in general neutrons/second)

Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
size m Edge of cube shaped source  
l_low AA Lower edge of lambda distribution  
l_high AA Upper edge of energy distribution  
dist m Distance from source to focusing rectangle; at (0,0,dist)  
xw m Width of focusing rectangle  
yh m Height of focusing rectangle  
freq Hz Frequency of pulses  
T K Temperature of source  
tau s long time decay constant for pulse, 1a  
tau1 s long time decay constant for pulse, 1b (only for coupled water, else 0)  
tau2 s/AA long time decay constant for pulse, 2  
n 1 pulse shape parameter 1  
n2 1 pulse shape parameter 2  
chi2 1/AA lambda-distribution parameter in pulse 2  
I0 flux integrated flux 1 (in flux units, see above) (default 9e10)  
I2 flux*AA integrated flux 2 (default 4.6e10)  
branch1 1 limit for switching between distribution 1 and 2. (has effect only for coupled water, tau1>0)  
branch2 1 limit for switching between distribution 1 and 2. (default value 0.5)  
branchframe 1 limit for switching between 1st and 2nd pulse (if only one pulse wanted: 1)  

Output parameters

Name Unit Description Default
M  
F  
l_range  
w_mult  

Links


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

Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Feb 28 2006