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

10.2  The TOF2E_monitor McStas Component

TOF-sensitive monitor, converting to energy

Identification

Description

A square single monitor that measures the energy of the incoming neutrons from their time-of-flight

Example: TOF2E_monitor(xmin=-0.1, xmax=0.1, ymin=-0.1, ymax=0.1, Emin=1, Emax=50, nE=20, filename="Output.nrj", L_flight=20, T_zero=0)

Input parameters

Parameters in boldface are required; the others are optional.

Name

Unit

Description

Default

nE

1

Number of energy 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

Emin

meV

Minimum energy to detect

Emax

meV

Maximum energy to detect

T_zero

s

Zero point in time

L_flight

m

flight length user in conversion

restore_neutron

1

If set, the monitor does not influence the neutron state

0

Links

A time-of-flight monitor with simple energy analysis

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, \(E_\textrm {app}\) is calculated from the apparent velocity, given by \begin {equation} v_\textrm {app} = \frac {L_\textrm {flight}}{t-t_0} , \end {equation} where the time offset, \(t_0\) defaults to zero. \(E_\textrm {app}\) is binned in nchan bins between \(E_\textrm {min}\) and \(E_\textrm {max}\) (in meV).

The output parameters from TOF2E_monitor are the total counts, and a file with 1-dimensional data vs. \(E_\textrm {app}\), similar to TOF_monitor.