INTER IDF should position detectors at twoTheta

[gemmaguest]

Expected behavior

The INTER IDF should reposition detectors to twoTheta on Load.

Actual behavior

If using a linear detector, the detector is positioned at theta instead of twoTheta.

Steps to reproduce the behavior

Run the following script. Both the point and linear detectors should be re-positioned on load to twoTheta=2.6, but currently the linear detector is being placed at theta=1.3 instead. (Note that the output of this script is not exact because the pixel centre is not positioned precisely at twoTheta. This is expected.)

import math
 
def getTwoThetaForPixel(wkspace, detId):
    inst = wkspace.getInstrument()
    det = inst.getDetector(detId)
    return wkspace.detectorTwoTheta(det) * 180 / math.pi
 
print "Expected twoTheta=2.6 in both cases"
 
print "INTER43572 point-detector puts detectors at twoTheta (nearest pixel is 4):"
pixel=4
ws=Load(Filename='INTER43572')
detTwoTheta = getTwoThetaForPixel(ws,pixel)
print '  Detector ID',pixel,'twoTheta =', detTwoTheta
 
print "INTER43583 linear-detector puts detectors at theta instead of twoTheta (nearest pixel is 2047):"
pixel=2047
ws=Load(Filename='INTER43583')
detTwoTheta = getTwoThetaForPixel(ws,pixel)
print '  Detector ID',pixel,'twoTheta =', detTwoTheta

Platforms affected

All