GetEiT0atSNS v1#

Summary#

Get Ei and T0 on ARCS and SEQUOIA instruments.

See Also#

GetEi

Properties#

Name

Direction

Type

Default

Description

MonitorWorkspace

InOut

Workspace

Mandatory

Monitor workspace

IncidentEnergyGuess

Input

number

-1

Incident energy guess

Ei

Output

number

T0

Output

number

Description#

Get Ei and T0 on ARCS and SEQUOIA instruments. It accounts for the following:

  • in the ADARA framework, the monitors are in the first frame.

  • SEQUOIA has event based monitors.

  • some data acquisition errors will create unphysical monitor IDs. This will be ignored

  • when vChTrans is 2, on ARCS and SEQUOIA there is no chopper in the beam (white beam). Will return not a number for both Ei and T0

The algorithm is doing the following:

  • Check which spectra corresponds to a physical monitor (as per instrument definition file)

  • Change the time of flight in the monitor spectra to the correct frame

  • Rebins the monitor workspace with a step of 1 microsecond

  • Uses GetEi to calculate incident energy and T0

Usage#

Note

To run these usage examples please first download the usage data, and add these to your path. In Mantid this is done using Manage User Directories.

w=Load('ADARAMonitors.nxs')
run=w.getRun()
from mantid.kernel import DateAndTime
run.setStartAndEndTime(
    DateAndTime("2015-01-27T11:00:00"),
    DateAndTime("2015-01-27T11:57:51")
)
LoadInstrument(Workspace=w,InstrumentName='SEQUOIA',RewriteSpectraMap=False)
AddSampleLog(Workspace=w,LogName='vChTrans',LogText='1',LogType='Number Series')
AddSampleLog(Workspace=w,LogName='EnergyRequest',LogText='20',LogType='Number Series')
res=GetEiT0atSNS(w)

print("Incident energy: {:2.2f} meV".format(res[0]))
print("T0: {:2.2f} microseconds".format(res[1]))

Output:

Incident energy: 20.09 meV
T0: 30.42 microseconds

Categories: AlgorithmIndex | Inelastic\Ei

Source#

Python: GetEiT0atSNS.py