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UpdateInstrumentFromFile v1¶

Summary ¶

Updates detector positions initially loaded in from the Instrument Definition File (IDF) with information from the provided file.

Properties ¶

Name	Direction	Type	Default	Description
Workspace	InOut	MatrixWorkspace	Mandatory	The name of the workspace in which to store the imported instrument
Filename	Input	string	Mandatory	The filename of the input file. Currently supports RAW, ISIS NeXus, DAT & multi-column (at least 2) ascii files. Allowed extensions: [‘.raw’, ‘.nxs’, ‘.dat’, ‘.s*’]
MoveMonitors	Input	boolean	False	If true the positions of any detectors marked as monitors in the IDF will be moved also
IgnorePhi	Input	boolean	False	If true the phi values form the file will be ignored
AsciiHeader	Input	string		If the file is a simple text file, then this property is used todefine the values in each column of the file. For example: spectrum,theta,t0,-,RKeywords=spectrum,ID,R,theta,phi. A dash means skip column. Keywords are recognisedas identifying components to move to new positions. Any other names in the listare added as instrument parameters.
SkipFirstNLines	Input	number	0	If the file is ASCII, then skip this number of lines at the start of the file

Some instrument definition file (IDF) positions are only approximately correct and the true positions are located within data files. This algorithm reads the detector positioning from the supplied file and updates the instrument accordingly. It currently supports ISIS Raw, ISIS NeXus files and ASCII files.

It is assumed that the positions specified in the file are all with respect to the a coordinate system defined with its origin at the sample position. Note that this algorithm moves the detectors without subsequent rotation, hence this means that detectors may not for example face the sample perfectly after this algorithm has been applied.

Additional Detector Parameters Using ASCII File ¶

The ASCII format allows a multi-column text file to provide new positions along with additional parameters for each detector. If a text file is used then the AsciiHeader parameter is required as it identifies each column in the file as header information in the file is always ignored. There is a minor restriction in that the first column is expected to specify either a detector ID or a spectrum number and will never be interpreted as anything else.

The keywords recognised by the algorithm to pick out detector position values & spectrum/ID values are: spectrum, ID, R,theta, phi. The spectrum/ID keywords can only be used in the first column. A dash (-) is used to ignore a column.

As an example the following header:

spectrum,theta,-,-,R

and the following text file:

 0.0000  -4.2508  11.0550  -2.4594
 0.0000   0.0000  11.0550   2.3800
130.4653  -0.4157  11.0050   0.6708
131.9319  -0.5338  11.0050   0.6545
133.0559  -0.3362  11.0050   0.6345

would tell the algorithm to interpret the columns as:

Spectrum number
Theta position value
Ignored: Detector’s electronics delay time – the difference of pulse synchronization signal time and the time DAE starts measuring frame time of given spectra.
Ignored: Sample to source distance for the particular detector
Sample-detector distance R.

Usage ¶

Example - Update Instrument:

import math
import os
# priting procedure
def print_10_detectors(instr_type,instr):
    ''' print first 10 detectors from given instrument '''
     # get first 10 detectors using detector ID

    print("{0} {1} instrument".format(instr_type, instr.getName()))
    for i in range(0,10):
      if i<3:
          detBase = 1
      else:
          detBase = 1101-3
      detID = detBase+i
      det1 = instr.getDetector(detID);
      pos = det1.getPos();
      print('det with ID: {0:5} is monitor? {1:5}, polar angle: {2:10.3f}, position: | {3:<10.3f} | {4:<10.3f} | {5:<10.3f}|'.format(\
             detID,det1.isMonitor(),(det1.getPhi()*(180/math.pi)),pos.X(),pos.Y(),pos.Z()))
    print('*********************************************************************************')

#--------------------------------------------------------------------------------------
# create sample workspace
ws=CreateSampleWorkspace();
#--------------------------------------------------------------------------------------
# load MARI
det=LoadInstrument(ws,InstrumentName='MARI', RewriteSpectraMap=True)
inst1=ws.getInstrument();
#
print_10_detectors('unCalibrated',inst1);
#--------------------------------------------------------------------------------------
# Prepare calibration file changing first 6 detectors & monitors
file_name = os.path.join(config["defaultsave.directory"], "TestCalibration.dat")
f = open(file_name,'w');
# prepare through each spectra in the test workspace and change its detector calibration parameters
f.write(' Test calibration file \n')
f.write(' detID  theta  delay source_dist detector_dist\n')
for i in range(0,6):
   f.write('{0}  {1}  {2}  {3}  {4}  {5}\n'.format(i+1,(i+1)*3.1415926/200,0.5,100,(i+1)*3.1415926/5,10))

f.close();
#--------------------------------------------------------------------------------------
# CALIBRATE:
UpdateInstrumentFromFile(ws,Filename=file_name,AsciiHeader='spectrum,theta,-,-,phi,R',MoveMonitors=True,SkipFirstNLines=2)
inst1=ws.getInstrument();
#--------------------------------------------------------------------------------------
# look at the result:
print_10_detectors('Calibrated',inst1);

Output:

unCalibrated MARI instrument
det with ID:     1 is monitor?     1, polar angle:      0.000, position: | 0.000      | 0.000      | -4.739    |
det with ID:     2 is monitor?     1, polar angle:      0.000, position: | 0.000      | 0.000      | -1.442    |
det with ID:     3 is monitor?     1, polar angle:      0.000, position: | 0.000      | 0.000      | 5.820     |
det with ID:  1101 is monitor?     0, polar angle:    -68.640, position: | 0.347      | -0.888     | 3.907     |
det with ID:  1102 is monitor?     0, polar angle:    -69.300, position: | 0.347      | -0.919     | 3.900     |
det with ID:  1103 is monitor?     0, polar angle:    -69.920, position: | 0.347      | -0.950     | 3.893     |
det with ID:  1104 is monitor?     0, polar angle:    -70.510, position: | 0.347      | -0.981     | 3.885     |
det with ID:  1105 is monitor?     0, polar angle:    -71.060, position: | 0.347      | -1.012     | 3.877     |
det with ID:  1106 is monitor?     0, polar angle:    -71.570, position: | 0.347      | -1.043     | 3.869     |
det with ID:  1107 is monitor?     0, polar angle:    -72.060, position: | 0.347      | -1.073     | 3.861     |
*********************************************************************************
Calibrated MARI instrument
det with ID:     1 is monitor?     1, polar angle:      0.628, position: | 0.003      | 0.000      | 10.000    |
det with ID:     2 is monitor?     1, polar angle:      1.257, position: | 0.005      | 0.000      | 10.000    |
det with ID:     3 is monitor?     1, polar angle:      1.885, position: | 0.008      | 0.000      | 10.000    |
det with ID:  1101 is monitor?     0, polar angle:      2.513, position: | 0.011      | 0.000      | 10.000    |
det with ID:  1102 is monitor?     0, polar angle:      3.142, position: | 0.014      | 0.001      | 10.000    |
det with ID:  1103 is monitor?     0, polar angle:      3.770, position: | 0.016      | 0.001      | 10.000    |
det with ID:  1104 is monitor?     0, polar angle:    -70.510, position: | 0.347      | -0.981     | 3.885     |
det with ID:  1105 is monitor?     0, polar angle:    -71.060, position: | 0.347      | -1.012     | 3.877     |
det with ID:  1106 is monitor?     0, polar angle:    -71.570, position: | 0.347      | -1.043     | 3.869     |
det with ID:  1107 is monitor?     0, polar angle:    -72.060, position: | 0.347      | -1.073     | 3.861     |
*********************************************************************************

Categories: AlgorithmIndex | DataHandling\Instrument | DataHandling\Raw

Source ¶

C++ header: UpdateInstrumentFromFile.h

C++ source: UpdateInstrumentFromFile.cpp