From 239cd15b8bf35d8f1edef67022d7d0dbf62b0920 Mon Sep 17 00:00:00 2001
From: hallc-online <jlabhallconline@gmail.com>
Date: Fri, 25 Aug 2017 17:24:34 -0400
Subject: [PATCH] Add method THcHallCSpectrometer::CalculateTargetQuantities
This method calculates the target quantities using the focal
plane quantities and the optics matrix. Previously
this was done in THcHallCSpectrometer::FindVertices.
Now in THcHallCSpectrometer::FindVertices there is
a call to CalculateTargetQuantities
This method will be called by THcExtTarCor
to do the xtar correction.
---
src/THcHallCSpectrometer.cxx | 112 +++++++++++++++++++++++++----------
src/THcHallCSpectrometer.h | 1 +
2 files changed, 82 insertions(+), 31 deletions(-)
diff --git a/src/THcHallCSpectrometer.cxx b/src/THcHallCSpectrometer.cxx
index 158dad9..6917fc8 100644
--- a/src/THcHallCSpectrometer.cxx
+++ b/src/THcHallCSpectrometer.cxx
@@ -10,6 +10,42 @@
The usual name of this object is either "H", "S", "P"
for HMS, SOS, or suPerHMS respectively
+ In method ReadDatabase calls the THaSpectrometer::SetCentralAngles(th_geo,ph_geo,bend_down)
+ bend_down is flag that should equal kFALSE for Hall C spectrometers
+ th_geo and ph_geo in degrees.
+ Define the LAB coordinate system so the +Z points to beam dump, +Y is up, +X is beam left
+ th_geo is rotation about the Y axis in XZ plane to coordinates X',Y=Y',Z'
+ After th_geo rotation, ph_geo rotation is about the X' axis in the Y'Z' plane.
+ Calls THaAnalysisObject::GeoToSph to calculate the spherical angles. th_sph and ph_sph
+ th_sph is rotation about the Y axis in XZ plane to coordinates X',Y=Y',Z
+ After th_sph rotation, ph_sph rotation is about the original Z axis
+ In Lab coordinate system:
+ X = r*sin(th_geo)*cos(ph_geo) X = r*sin(th_sph)*cos(ph_sph)
+ Y = r*sin(ph_geo) Y = r*sin(th_sph)*sin(ph_sph)
+ Z = r*cos(th_geo)*cos(ph_geo) Z = r*cos(th_sph)
+
+ cos(th_sph) = cos(th_geo)*cos(ph_geo)
+ cos(ph_sph) = sin(th_geo)*cos(ph_geo)/sqrt(1-cos^2(th_geo)*cos^2(ph_geo))
+
+ GeoToSph is coded so that
+ 1) negative th_geo and ph_geo = 0 returns th_sph=abs(th_geo) and ph_sph =180
+ 2) positive th_geo and ph_geo = 0 returns th_sph=th_geo and ph_sph =0
+
+ Using the spherical angles, the TRotation fToLabRot and inverse fToTraRot are calculated
+ fToLabRot is rotation matrix from the spectrometer TRANSPORT system to Lab system
+ TRANSPORT coordinates are +X_tra points vertically down, +Z_tra is along the central ray and +Y_tra = ZxX
+ For ph_sph = 0 X_lab = Y_tra*cos(th_sph) + Z_tra*sin(th_sph)
+ Y_lab = -X_tra
+ Z_lab = -Y_tra*sin(th_sph) + Z_tra*cos(th_sph)
+ For ph_sph = 180 X_lab = Y_tra*cos(th_sph) - Z_tra*sin(th_sph)
+ Y_lab = -X_tra
+ Z_lab = Y_tra*sin(th_sph) + Z_tra*cos(th_sph)
+
+
+
+
+
+
\author S. A. Wood
*/
@@ -224,7 +260,13 @@ Int_t THcHallCSpectrometer::ReadDatabase( const TDatime& date )
fTheta_lab=fTheta_lab + fThetaCentralOffset*TMath::RadToDeg();
Double_t ph = fPhi_lab+fPhiOffset*TMath::RadToDeg();
cout << "Central angles = " << fTheta_lab << endl;
- SetCentralAngles(fTheta_lab, ph, false);
+ // SetCentralAngles method in podd THaSpectrometer
+ // fTheta_lab and ph are geographical angles, converts to spherical coordinates
+ // Need to set fTheta_lab to negative for spectrometer like HMS on beam right
+ // This gives phi_sph = 180 th_sph=abs(th_geo)
+ // Computes TRotation fToLabRot and fToTraRot
+ Bool_t bend_down = kFALSE;
+ SetCentralAngles(fTheta_lab, ph, bend_down);
Double_t off_x = 0.0, off_y = 0.0, off_z = 0.0;
fPointingOffset.SetXYZ( off_x, off_y, off_z );
@@ -313,7 +355,40 @@ Int_t THcHallCSpectrometer::FindVertices( TClonesArray& tracks )
for (Int_t it=0;it<tracks.GetLast()+1;it++) {
THaTrack* track = static_cast<THaTrack*>( tracks[it] );
+ Double_t xptar=kBig,yptar=kBig,ytar=kBig,delta=kBig;
+ Double_t xtar=0;
+ CalculateTargetQuantities(track,xtar,xptar,ytar,yptar,delta);
+ // Transfer results to track
+ // No beam raster yet
+ //; In transport coordinates phi = hyptar = dy/dz and theta = hxptar = dx/dz
+ //; but for unknown reasons the yp offset is named htheta_offset
+ //; and the xp offset is named hphi_offset
+
+ track->SetTarget(0.0, ytar*100.0, xptar+fPhiOffset, yptar+fThetaOffset);
+ track->SetDp(delta*100.0+fDeltaOffset); // Percent. (Don't think podd cares if it is % or fraction)
+ // There is an hpcentral_offset that needs to be applied somewhere.
+ // (happly_offs)
+ Double_t ptemp = fPcentral*(1+track->GetDp()/100.0);
+ track->SetMomentum(ptemp);
+ TVector3 pvect_temp;
+ TransportToLab(track->GetP(),track->GetTTheta(),track->GetTPhi(),pvect_temp);
+ track->SetPvect(pvect_temp);
+ }
+
+ if (fHodo==0 || (( fSelUsingScin == 0 ) && ( fSelUsingPrune == 0 )) ) {
+ BestTrackSimple();
+ } else if (fHodo!=0 && fSelUsingPrune !=0) {
+ BestTrackUsingPrune();
+ } else if (fHodo!=0){
+ BestTrackUsingScin();
+ }
+
+ return 0;
+}
+//
+void THcHallCSpectrometer::CalculateTargetQuantities(THaTrack* track,Double_t gbeam_y,Double_t xptar,Double_t ytar,Double_t yptar,Double_t delta)
+{
Double_t hut[5];
Double_t hut_rot[5];
@@ -322,8 +397,6 @@ Int_t THcHallCSpectrometer::FindVertices( TClonesArray& tracks )
hut[2] = track->GetY()/100.0 + fZTrueFocus*track->GetPhi() + fDetOffset_y;//m
hut[3] = track->GetPhi() + fAngOffset_y;//radians
- Double_t gbeam_y = 0.0;// This will be the y position from the fast raster
-
hut[4] = -gbeam_y/100.0;
// Retrieve the focal plane coordnates
@@ -351,35 +424,12 @@ Int_t THcHallCSpectrometer::FindVertices( TClonesArray& tracks )
sum[k] += term*fReconTerms[iterm].Coeff[k];
}
}
- // Transfer results to track
- // No beam raster yet
- //; In transport coordinates phi = hyptar = dy/dz and theta = hxptar = dx/dz
- //; but for unknown reasons the yp offset is named htheta_offset
- //; and the xp offset is named hphi_offset
-
- track->SetTarget(0.0, sum[1]*100.0, sum[0]+fPhiOffset, sum[2]+fThetaOffset);
- track->SetDp(sum[3]*100.0+fDeltaOffset); // Percent. (Don't think podd cares if it is % or fraction)
- // There is an hpcentral_offset that needs to be applied somewhere.
- // (happly_offs)
- Double_t ptemp = fPcentral*(1+track->GetDp()/100.0);
- track->SetMomentum(ptemp);
- TVector3 pvect_temp;
- TransportToLab(track->GetP(),track->GetTTheta(),track->GetTPhi(),pvect_temp);
- track->SetPvect(pvect_temp);
- }
-
- if (fHodo==0 || (( fSelUsingScin == 0 ) && ( fSelUsingPrune == 0 )) ) {
- BestTrackSimple();
- } else if (fHodo!=0 && fSelUsingPrune !=0) {
- BestTrackUsingPrune();
- } else if (fHodo!=0){
- BestTrackUsingScin();
- }
-
-
- return 0;
+ xptar=sum[0];
+ ytar=sum[1];
+ yptar=sum[2];
+ delta=sum[3];
}
-
+//
//_____________________________________________________________________________
Int_t THcHallCSpectrometer::TrackCalc()
{
diff --git a/src/THcHallCSpectrometer.h b/src/THcHallCSpectrometer.h
index d0302a6..cd968dc 100644
--- a/src/THcHallCSpectrometer.h
+++ b/src/THcHallCSpectrometer.h
@@ -41,6 +41,7 @@ public:
virtual Int_t ReadDatabase( const TDatime& date );
virtual void EnforcePruneLimits();
+ virtual void CalculateTargetQuantities(THaTrack* track,Double_t gbeam_y,Double_t xptar,Double_t ytar,Double_t yptar,Double_t delta);
virtual Int_t FindVertices( TClonesArray& tracks );
virtual Int_t TrackCalc();
virtual Int_t BestTrackSimple();
--
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