Download Component Manual for the Neutron Ray

9.1
TOF monitor: The time-of-flight monitor
Name:
Author:
Input parameters
Optional parameters
Notes
TOF monitor
System
xmin , xmax , ymin , ymax , nchan , t0 , t1 , filename
∆t
The component TOF monitor has a rectangular opening in the (x, y) plane, given by
the x and y parameters, like for Slit. The neutron ray is propagated to the plane of the
monitor by the kernel call PROP Z0. A neutron ray is counted if it passes within the
rectangular opening given by the x and y limits.
Special about TOF monitor is that it is sensitive to the arrival time, t, of the neutron
ray. Like in a real time-of-flight detector, the time dimension is binned into small time
intervals. Hence this monitor maintains a one-dimensional histogram of counts. The nchan
time intervals begin at t0 and end at t1 (alternatively, the interval length is specified by
∆t). As usual in time-of-flight analysis, all times are given in units of µs.
The output parameters from TOF monitor are the three count numbers, N, I, and M2
for the total counts in the monitor. In addition, a file, filename, is produced with a list
of the same three data divided in different TOF bins. This file can be read and plotted
by the mcplot tool; see the System Manual.
9.2
TOF2E monitor: A time-of-flight monitor with simple
energy analysis
Name:
E monitor
Author:
System
Input parameters
xmin , xmax , ymin , ymax , nchan , Emin , Emax , t0 , Lflight , filename
Optional parameters
Notes
Not validated
The component TOF2E monitor resembles TOF monitor to a very large extent. Only
this monitor converts the neutron flight time to energy - as would be done in an experiment. The apparent neutron energy, Eapp is calculated from the apparent velocity, given
by
vapp =
Lflight
,
t − t0
(9.1)
where the time offset, t0 defaults to zero. Eapp is binned in nchan bins between Emin and
Emax (in meV).
The output parameters from TOF2E monitor are the total counts, and a file with 1dimensional data vs. Eapp , similar to TOF monitor.
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Risø–R–1538(rev.ed.)(EN)