/*
$Log$
+Revision 1.10 2001/04/25 14:50:42 gosset
+Corrections to violations of coding conventions
+
Revision 1.9 2000/10/16 15:30:40 gosset
TotalMomentumEnergyLoss:
correction for change in the absorber composition (JP Cussonneau)
BransonCorrection();
}
+
+// Keep this version for future developments
//__________________________________________________________________________
+// void AliMUONTrackParam::BransonCorrection()
+// {
+// // Branson correction of track parameters
+// // the entry parameters have to be calculated at the end of the absorber
+// Double_t zEndAbsorber, zBP, xBP, yBP;
+// Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta;
+// Int_t sign;
+// // Would it be possible to calculate all that from Geant configuration ????
+// // and to get the Branson parameters from a function in ABSO module ????
+// // with an eventual contribution from other detectors like START ????
+// // Radiation lengths outer part theta > 3 degres
+// static Double_t x01[9] = { 18.8, // C (cm)
+// 10.397, // Concrete (cm)
+// 0.56, // Plomb (cm)
+// 47.26, // Polyethylene (cm)
+// 0.56, // Plomb (cm)
+// 47.26, // Polyethylene (cm)
+// 0.56, // Plomb (cm)
+// 47.26, // Polyethylene (cm)
+// 0.56 }; // Plomb (cm)
+// // inner part theta < 3 degres
+// static Double_t x02[3] = { 18.8, // C (cm)
+// 10.397, // Concrete (cm)
+// 0.35 }; // W (cm)
+// // z positions of the materials inside the absober outer part theta > 3 degres
+// static Double_t z1[10] = { 90, 315, 467, 472, 477, 482, 487, 492, 497, 502 };
+// // inner part theta < 3 degres
+// static Double_t z2[4] = { 90, 315, 467, 503 };
+// static Bool_t first = kTRUE;
+// static Double_t zBP1, zBP2, rLimit;
+// // Calculates z positions of the Branson's planes: zBP1 for outer part and zBP2 for inner part (only at the first call)
+// if (first) {
+// first = kFALSE;
+// Double_t aNBP = 0.0;
+// Double_t aDBP = 0.0;
+// Int_t iBound;
+
+// for (iBound = 0; iBound < 9; iBound++) {
+// aNBP = aNBP +
+// (z1[iBound+1] * z1[iBound+1] * z1[iBound+1] -
+// z1[iBound] * z1[iBound] * z1[iBound] ) / x01[iBound];
+// aDBP = aDBP +
+// (z1[iBound+1] * z1[iBound+1] - z1[iBound] * z1[iBound] ) / x01[iBound];
+// }
+// zBP1 = (2.0 * aNBP) / (3.0 * aDBP);
+// aNBP = 0.0;
+// aDBP = 0.0;
+// for (iBound = 0; iBound < 3; iBound++) {
+// aNBP = aNBP +
+// (z2[iBound+1] * z2[iBound+1] * z2[iBound+1] -
+// z2[iBound] * z2[iBound ] * z2[iBound] ) / x02[iBound];
+// aDBP = aDBP +
+// (z2[iBound+1] * z2[iBound+1] - z2[iBound] * z2[iBound]) / x02[iBound];
+// }
+// zBP2 = (2.0 * aNBP) / (3.0 * aDBP);
+// rLimit = z2[3] * TMath::Tan(3.0 * (TMath::Pi()) / 180.);
+// }
+
+// pYZ = TMath::Abs(1.0 / fInverseBendingMomentum);
+// sign = 1;
+// if (fInverseBendingMomentum < 0) sign = -1;
+// pZ = pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope));
+// pX = pZ * fNonBendingSlope;
+// pY = pZ * fBendingSlope;
+// pTotal = TMath::Sqrt(pYZ *pYZ + pX * pX);
+// xEndAbsorber = fNonBendingCoor;
+// yEndAbsorber = fBendingCoor;
+// radiusEndAbsorber2 = xEndAbsorber * xEndAbsorber + yEndAbsorber * yEndAbsorber;
+
+// if (radiusEndAbsorber2 > rLimit*rLimit) {
+// zEndAbsorber = z1[9];
+// zBP = zBP1;
+// } else {
+// zEndAbsorber = z2[3];
+// zBP = zBP2;
+// }
+
+// xBP = xEndAbsorber - (pX / pZ) * (zEndAbsorber - zBP);
+// yBP = yEndAbsorber - (pY / pZ) * (zEndAbsorber - zBP);
+
+// // new parameters after Branson and energy loss corrections
+// pZ = pTotal * zBP / TMath::Sqrt(xBP * xBP + yBP * yBP + zBP * zBP);
+// pX = pZ * xBP / zBP;
+// pY = pZ * yBP / zBP;
+// fBendingSlope = pY / pZ;
+// fNonBendingSlope = pX / pZ;
+
+// pT = TMath::Sqrt(pX * pX + pY * pY);
+// theta = TMath::ATan2(pT, pZ);
+// pTotal =
+// TotalMomentumEnergyLoss(rLimit, pTotal, theta, xEndAbsorber, yEndAbsorber);
+
+// fInverseBendingMomentum = (sign / pTotal) *
+// TMath::Sqrt(1.0 +
+// fBendingSlope * fBendingSlope +
+// fNonBendingSlope * fNonBendingSlope) /
+// TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope);
+
+// // vertex position at (0,0,0)
+// // should be taken from vertex measurement ???
+// fBendingCoor = 0.0;
+// fNonBendingCoor = 0;
+// fZ= 0;
+// }
+
void AliMUONTrackParam::BransonCorrection()
{
// Branson correction of track parameters
// the entry parameters have to be calculated at the end of the absorber
- Double_t zEndAbsorber, zBP, xBP, yBP;
- Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta;
- Int_t sign;
+ // simplified version: the z positions of Branson's planes are no longer calculated
+ // but are given as inputs. One can use the macros MUONTestAbso.C and DrawTestAbso.C
+ // to test this correction.
// Would it be possible to calculate all that from Geant configuration ????
// and to get the Branson parameters from a function in ABSO module ????
// with an eventual contribution from other detectors like START ????
- // Radiation lengths outer part theta > 3 degres
- static Double_t x01[9] = { 18.8, // C (cm)
- 10.397, // Concrete (cm)
- 0.56, // Plomb (cm)
- 47.26, // Polyethylene (cm)
- 0.56, // Plomb (cm)
- 47.26, // Polyethylene (cm)
- 0.56, // Plomb (cm)
- 47.26, // Polyethylene (cm)
- 0.56 }; // Plomb (cm)
- // inner part theta < 3 degres
- static Double_t x02[3] = { 18.8, // C (cm)
- 10.397, // Concrete (cm)
- 0.35 }; // W (cm)
- // z positions of the materials inside the absober outer part theta > 3 degres
- static Double_t z1[10] = { 90, 315, 467, 472, 477, 482, 487, 492, 497, 502 };
- // inner part theta < 3 degres
- static Double_t z2[4] = { 90, 315, 467, 503 };
+ Double_t zBP, xBP, yBP;
+ Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta;
+ Int_t sign;
static Bool_t first = kTRUE;
- static Double_t zBP1, zBP2, rLimit;
- // Calculates z positions of the Branson's planes: zBP1 for outer part and zBP2 for inner part (only at the first call)
+ static Double_t zBP1, zBP2, rLimit, zEndAbsorber;
+ // zBP1 for outer part and zBP2 for inner part (only at the first call)
if (first) {
first = kFALSE;
- Double_t aNBP = 0.0;
- Double_t aDBP = 0.0;
- Int_t iBound;
-
- for (iBound = 0; iBound < 9; iBound++) {
- aNBP = aNBP +
- (z1[iBound+1] * z1[iBound+1] * z1[iBound+1] -
- z1[iBound] * z1[iBound] * z1[iBound] ) / x01[iBound];
- aDBP = aDBP +
- (z1[iBound+1] * z1[iBound+1] - z1[iBound] * z1[iBound] ) / x01[iBound];
- }
- zBP1 = (2.0 * aNBP) / (3.0 * aDBP);
- aNBP = 0.0;
- aDBP = 0.0;
- for (iBound = 0; iBound < 3; iBound++) {
- aNBP = aNBP +
- (z2[iBound+1] * z2[iBound+1] * z2[iBound+1] -
- z2[iBound] * z2[iBound ] * z2[iBound] ) / x02[iBound];
- aDBP = aDBP +
- (z2[iBound+1] * z2[iBound+1] - z2[iBound] * z2[iBound]) / x02[iBound];
- }
- zBP2 = (2.0 * aNBP) / (3.0 * aDBP);
- rLimit = z2[3] * TMath::Tan(3.0 * (TMath::Pi()) / 180.);
+
+ zEndAbsorber = 503;
+ rLimit = zEndAbsorber * TMath::Tan(3.0 * (TMath::Pi()) / 180.);
+ zBP1 = 450;
+ zBP2 = 480;
}
pYZ = TMath::Abs(1.0 / fInverseBendingMomentum);
radiusEndAbsorber2 = xEndAbsorber * xEndAbsorber + yEndAbsorber * yEndAbsorber;
if (radiusEndAbsorber2 > rLimit*rLimit) {
- zEndAbsorber = z1[9];
zBP = zBP1;
} else {
- zEndAbsorber = z2[3];
zBP = zBP2;
}
fNonBendingCoor = 0;
fZ= 0;
}
-
//__________________________________________________________________________
Double_t AliMUONTrackParam::TotalMomentumEnergyLoss(Double_t rLimit, Double_t pTotal, Double_t theta, Double_t xEndAbsorber, Double_t yEndAbsorber)
{
// Returns the total momentum corrected from energy loss in the front absorber
+ // One can use the macros MUONTestAbso.C and DrawTestAbso.C
+ // to test this correction.
Double_t deltaP, pTotalCorrected;
Double_t radiusEndAbsorber2 =
} else {
deltaP = 3.0643 + 0.01346 *pTotal;
}
+ deltaP = 0.63 * deltaP; // !!!! changes in the absorber composition ????
} else {
if (pTotal < 15) {
deltaP = 2.1380 + 0.0351 * pTotal - 0.000853 * pTotal * pTotal;
} else {
deltaP = 2.407 + 0.00702 * pTotal;
}
+ deltaP = 0.67 * deltaP; // !!!! changes in the absorber composition ????
}
- deltaP = 0.88 * deltaP; // !!!! changes in the absorber composition ????
pTotalCorrected = pTotal + deltaP / TMath::Cos(theta);
return pTotalCorrected;
}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff