/// Calculate the distances traversed by the neutrons within the sample
/// @param detector :: The detector we are working on
/// @param L2s :: A vector of the sample-detector distance for each segment of
/// the sample
void AbsorptionCorrection::calculateDistances(const IDetector &detector,
std::vector<double> &L2s) const {
V3D detectorPos(detector.getPos());
if (detector.nDets() > 1) {
// We need to make sure this is right for grouped detectors - should use
// average theta & phi
detectorPos.spherical(detectorPos.norm(),
detector.getTwoTheta(V3D(), V3D(0, 0, 1)) * 180.0 /
M_PI,
detector.getPhi() * 180.0 / M_PI);
}
for (size_t i = 0; i < m_numVolumeElements; ++i) {
// Create track for distance in cylinder between scattering point and
// detector
V3D direction = detectorPos - m_elementPositions[i];
direction.normalize();
Track outgoing(m_elementPositions[i], direction);
int temp = m_sampleObject->interceptSurface(outgoing);
/* Most of the time, the number of hits is 1. Sometime, we have more than
* one intersection due to
* arithmetic imprecision. If it is the case, then selecting the first
* intersection is valid.
* In principle, one could check the consistency of all distances if hits is
* larger than one by doing:
* Mantid::Geometry::Track::LType::const_iterator it=outgoing.begin();
* and looping until outgoing.end() checking the distances with it->Dist
*/
// Not hitting the cylinder from inside, usually means detector is badly
// defined,
// i.e, position is (0,0,0).
if (temp < 1) {
// FOR NOW AT LEAST, JUST IGNORE THIS ERROR AND USE A ZERO PATH LENGTH,
// WHICH I RECKON WILL MAKE A
// NEGLIGIBLE DIFFERENCE ANYWAY (ALWAYS SEEMS TO HAPPEN WITH ELEMENT RIGHT
// AT EDGE OF SAMPLE)
L2s[i] = 0.0;
// std::ostringstream message;
// message << "Problem with detector at " << detectorPos << " ID:" <<
// detector->getID() << '\n';
// message << "This usually means that this detector is defined inside the
// sample cylinder";
// g_log.error(message.str());
// throw std::runtime_error("Problem in
// AbsorptionCorrection::calculateDistances");
} else // The normal situation
{
L2s[i] = outgoing.cbegin()->distFromStart;
}
}
}
AMControlInfoList REIXSXESCalibration::computeSpectrometerPosition(int gratingIndex, double eV, double focusOffsetMm, double tiltOffsetDeg) const
{
qDebug() << "Spectrometer Geometry calculations for: " << gratingNames().at(gratingIndex) << eV << "eV," << focusOffsetMm << "mm defocus," << tiltOffsetDeg << "deg tilt offset:";
AMControlInfoList rv;
double hexU = hexapodU(gratingIndex);
QVector3D hexXYZ = hexapodXYZ(gratingIndex);
QVector3D hexRST = hexapodRST(gratingIndex);
QVector3D detPos = detectorPos(eV, gratingIndex);
double theta = spectrometerTheta(detPos);
double translation = detectorTranslation(detPos, theta, focusOffsetMm);
double spectrometerRotation = spectrometerRotationDrive(theta);
double tilt = tiltStageDrive(eV, gratingIndex, theta, tiltOffsetDeg);
rv.append(AMControlInfo("spectrometerRotationDrive", spectrometerRotation, 0,0, "mm", 0.1, "Linear drive motor for spectrometer angle"));
rv.append(AMControlInfo("detectorTranslation", translation, 0,0, "mm", 0.1, "Detector translation"));
rv.append(AMControlInfo("detectorTiltDrive", tilt, 0.0, 0.0, "mm", 0.1, "Linear drive motor for detector tilt"));
rv.append(AMControlInfo("hexapodX", hexXYZ.x(), 0, 0, "mm", 0.1, "Hexapod X position"));
rv.append(AMControlInfo("hexapodY", hexXYZ.y(), 0, 0, "mm", 0.1, "Hexapod Y position"));
rv.append(AMControlInfo("hexapodZ", hexXYZ.z(), 0, 0, "mm", 0.1, "Hexapod Z position"));
rv.append(AMControlInfo("hexapodU", hexU, 0,0, "deg", 0.1, "Hexapod Tilt around X axis"));
rv.append(AMControlInfo("hexapodR", hexRST.x(), 0,0, "mm", 0.1, "Hexapod rotation point R"));
rv.append(AMControlInfo("hexapodS", hexRST.y(), 0,0, "mm", 0.1, "Hexapod rotation point S"));
rv.append(AMControlInfo("hexapodT", hexRST.z(), 0,0, "mm", 0.1, "Hexapod rotation point T"));
qDebug() << " Alpha required for rowland condition (deg):" << r2d(alpha(gratingIndex));
qDebug() << " Beta using that alpha, at " << eV << "eV:" << r2d(beta(eV, gratingIndex));
qDebug() << " Angle of slit-origin ray above y axis (deg)" << r2d(sTheta(gratingIndex));
qDebug() << " Grating tilt to achieve required alpha (deg):" << hexU;
qDebug() << " r (mm):" << r(gratingIndex);
qDebug() << " r-prime (mm):" << rPrime(eV, gratingIndex);
qDebug() << " Spectrometer dTheta: angle up from y axis to center of detector (deg):" << r2d(dTheta(eV, gratingIndex));
qDebug() << " Detector position:" << detPos;
qDebug() << " Spectrometer theta: (deg)" << r2d(theta);
qDebug() << " Translation: (mm)" << translation;
qDebug() << " Spectrometer rotation stage translation: (mm)" << spectrometerRotation;
qDebug() << " Detector tilt phi (detector angle down to positive y axis) (deg):" << r2d(detectorPhi(eV, gratingIndex));
qDebug() << " Extra tilt on top of spectrometer angle" << r2d(detectorPhi(eV, gratingIndex) - theta);
qDebug() << " Tilt stage translation: (mm)" << tilt;
return rv;
}
