3.5

UpdateInstrumentFromFile v1

../_images/UpdateInstrumentFromFile-v1_dlg.png

UpdateInstrumentFromFile dialog.

Summary

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

Alias

This algorithm is also known as: UpdateInstrumentFromRaw

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’, ‘.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

Description

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:

1   0.0000  -4.2508  11.0550  -2.4594
2   0.0000   0.0000  11.0550   2.3800
3 130.4653  -0.4157  11.0050   0.6708
4 131.9319  -0.5338  11.0050   0.6545
5 133.0559  -0.3362  11.0050   0.6345

would tell the algorithm to interpret the columns as:

  1. Spectrum number
  2. Theta position value
  3. Ignored: Detector’s electronics delay time – the difference of pulse synchronization signal time and the time DAE starts measuring frame time of given spectra.
  4. Ignored: Sample to source distance for the particular detector
  5. 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 xrange(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}|\n'.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')
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 xrange(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: Algorithms | DataHandling | Instrument | DataHandling | Raw