.. algorithm::
.. summary::
.. alias::
.. properties::
Description
-----------
Some instrument definition file (:ref:`IDF <InstrumentDefinitionFile>`)
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.
Related or similar algorithms
##############################
See :ref:`algm-LoadDetectorInfo` which can do similar job modifying the detector parameters and positions and working with special format ASCII files or ISIS raw or special nexus files.
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:
#. 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:**
.. testcode:: exUpdateInstrumentFromFile
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}|'.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 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);
.. testcleanup:: exUpdateInstrumentFromFile
os.remove(file_name)
**Output:**
.. testoutput:: exUpdateInstrumentFromFile
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::
.. sourcelink::