This module simulates a Fermi chopper with straight channels i.e. the very
fast neutrons are transmitted with only a time modulation and lower speed
neutrons are modulated both in time of flight and wavelength.
The geometry of the chopper consists of a rectangular shape object with
a wide channel system built in perpendicular direction to the beam (when
transmitting) - this is inserted into a cylinder frame in order not to transmit
neutrons which do not fly throught the channels (when the rectangular channel
system is rotated by 90°). The rotation axix coincides with Z.
Module parameters:
| Parameter Unit |
Description | Command option |
| position X, Y, Z [cm] |
center position of the Fermi chopper in the input frame | X, -Y, -V |
| height, width, depth [cm] |
dimensions of the Fermi chopper, depth means the length of the channels | -a -b -c |
| number of channels | number of straight channels | -l |
| wall thickness [cm] |
thickness of the wall between channels | -m |
| diameter [cm] |
diameter of the shadowing cylinder | -r |
| rotations per second | frequency of rotation | -n |
| phase [deg] |
dephasing angle at zero time | -q |
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Last modified:Thu Jan 29 15:10:25 MET 2004, G.Zs. Tuesday, 03-Jul-2007 16:14:09 CEST