Component Manual for the Neutron Ray-Tracing Package McStas, version 3.8.6

10.4  The L_monitor McStas Component

Wavelength-sensitive monitor.

Identification

Description

A square single monitor that measures the wavelength of the incoming neutrons.

Example: L_monitor(xmin=-0.1, xmax=0.1, ymin=-0.1, ymax=0.1, nL=20, filename="Output.L", Lmin=2, Lmax=10)

Input parameters

Parameters in boldface are required; the others are optional.

Name

Unit

Description

Default

nL

1

Number of wavelength channels

20

filename

string

Name of file in which to store the detector image

0

nowritefile

1

If set, monitor will skip writing to disk

0

xmin

m

Lower x bound of detector opening

-0.05

xmax

m

Upper x bound of detector opening

0.05

ymin

m

Lower y bound of detector opening

-0.05

ymax

m

Upper y bound of detector opening

0.05

xwidth

m

Width of detector. Overrides xmin, xmax.

0

yheight

m

Height of detector. Overrides ymin, ymax.

0

Lmin

Å

Minimum wavelength to detect

Lmax

Å

Maximum wavelength to detect

restore_neutron

1

If set, the monitor does not influence the neutron state

0

Links

The wavelength sensitive monitor

The component L_monitor is very similar to TOF_monitor and E_monitor. This component is just sensitive to the neutron wavelength. The wavelength spectrum is output in a one-dimensional histogram. between \(\lambda _\textrm {min}\) and \(\lambda _\textrm {max}\) (measured in Å).

As for the two other 1-dimensional monitors, this component outputs the total counts and a file with the histogram.