1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
18 //_________________________________________________________________________
19 // Implementation version v1 of PHOS Manager class
22 // Layout EMC + CPV has name IHEP:
23 // Produces hits for CPV, cumulated hits
26 //*-- Author: Yves Schutz (SUBATECH)
29 // --- ROOT system ---
30 #include <TParticle.h>
31 #include <TVirtualMC.h>
33 // --- Standard library ---
36 // --- AliRoot header files ---
37 #include "AliPHOSCPVDigit.h"
38 #include "AliPHOSGeometry.h"
39 #include "AliPHOSHit.h"
40 #include "AliPHOSv1.h"
46 //____________________________________________________________________________
47 AliPHOSv1::AliPHOSv1():
51 fLightYieldMean = 0. ;
52 fIntrinsicPINEfficiency = 0. ;
53 fLightYieldAttenuation = 0. ;
54 fRecalibrationFactor = 0. ;
55 fElectronsPerGeV = 0. ;
62 //____________________________________________________________________________
63 AliPHOSv1::AliPHOSv1(const char *name, const char *title):
68 // - fHits (the "normal" one), which retains the hits associated with
69 // the current primary particle being tracked
70 // (this array is reset after each primary has been tracked).
75 // We do not want to save in TreeH the raw hits
76 // But save the cumulated hits instead (need to create the branch myself)
77 // It is put in the Digit Tree because the TreeH is filled after each primary
78 // and the TreeD at the end of the event (branch is set in FinishEvent() ).
80 fHits= new TClonesArray("AliPHOSHit",1000) ;
81 gAlice->GetMCApp()->AddHitList(fHits) ;
85 fIshunt = 2 ; // All hits are associated with primary particles
87 //Photoelectron statistics:
88 // The light yield is a poissonian distribution of the number of
89 // photons created in the PbWo4 crystal, calculated using following formula
90 // NumberOfPhotons = EnergyLost * LightYieldMean* APDEfficiency *
91 // exp (-LightYieldAttenuation * DistanceToPINdiodeFromTheHit);
92 // LightYieldMean is parameter calculated to be over 47000 photons per GeV
93 // APDEfficiency is 0.02655
94 // k_0 is 0.0045 from Valery Antonenko
95 // The number of electrons created in the APD is
96 // NumberOfElectrons = APDGain * LightYield
97 // The APD Gain is 300
98 fLightYieldMean = 47000;
99 fIntrinsicPINEfficiency = 0.02655 ; //APD= 0.1875/0.1271 * 0.018 (PIN)
100 fLightYieldAttenuation = 0.0045 ;
101 fRecalibrationFactor = 13.418/ fLightYieldMean ;
102 fElectronsPerGeV = 2.77e+8 ;
104 fLightFactor = fLightYieldMean * fIntrinsicPINEfficiency ;
105 fAPDFactor = (fRecalibrationFactor/100.) * fAPDGain ;
108 //____________________________________________________________________________
109 AliPHOSv1::~AliPHOSv1()
119 //____________________________________________________________________________
120 void AliPHOSv1::Copy(AliPHOSv1 & phos)
122 TObject::Copy(phos) ;
123 AliPHOSv0::Copy(phos) ;
124 phos.fLightYieldMean = fLightYieldMean ;
125 phos.fIntrinsicPINEfficiency = fIntrinsicPINEfficiency ;
126 phos.fLightYieldAttenuation = fLightYieldAttenuation ;
127 phos.fRecalibrationFactor = fRecalibrationFactor ;
128 phos.fElectronsPerGeV = fElectronsPerGeV ;
129 phos.fAPDGain = fAPDGain ;
130 phos.fLightFactor = fLightFactor ;
131 phos.fAPDFactor = fAPDFactor ;
134 //____________________________________________________________________________
135 void AliPHOSv1::AddHit(Int_t shunt, Int_t primary, Int_t Id, Float_t * hits)
137 // Add a hit to the hit list.
138 // A PHOS hit is the sum of all hits in a single crystal from one primary and within some time gate
143 Bool_t deja = kFALSE ;
144 AliPHOSGeometry * geom = GetGeometry() ;
146 newHit = new AliPHOSHit(shunt, primary, Id, hits) ;
148 for ( hitCounter = fNhits-1 ; hitCounter >= 0 && !deja ; hitCounter-- ) {
149 curHit = dynamic_cast<AliPHOSHit*>((*fHits)[hitCounter]) ;
150 if(curHit->GetPrimary() != primary) break ;
151 // We add hits with the same primary, while GEANT treats primaries succesively
152 if( *curHit == *newHit ) {
159 new((*fHits)[fNhits]) AliPHOSHit(*newHit) ;
160 // get the block Id number
162 geom->AbsToRelNumbering(Id, relid) ;
170 //____________________________________________________________________________
171 void AliPHOSv1::FinishPrimary()
173 // called at the end of each track (primary) by AliRun
174 // hits are reset for each new track
175 // accumulate the total hit-multiplicity
179 //____________________________________________________________________________
180 void AliPHOSv1::FinishEvent()
182 // called at the end of each event by AliRun
183 // accumulate the hit-multiplicity and total energy per block
184 // if the values have been updated check it
186 AliDetector::FinishEvent();
188 //____________________________________________________________________________
189 void AliPHOSv1::StepManager(void)
191 // Accumulates hits as long as the track stays in a single crystal or CPV gas Cell
193 Int_t relid[4] ; // (box, layer, row, column) indices
194 Int_t absid ; // absolute cell ID number
195 Float_t xyzte[5]={-1000.,-1000.,-1000.,0.,0.} ; // position wrt MRS, time and energy deposited
196 TLorentzVector pos ; // Lorentz vector of the track current position
199 TString name = GetGeometry()->GetName() ;
203 static Int_t idPCPQ = gMC->VolId("PCPQ");
204 if( gMC->CurrentVolID(copy) == idPCPQ &&
205 (gMC->IsTrackEntering() ) &&
206 gMC->TrackCharge() != 0) {
208 gMC -> TrackPosition(pos);
210 Float_t xyzm[3], xyzd[3] ;
212 for (i=0; i<3; i++) xyzm[i] = pos[i];
213 gMC -> Gmtod (xyzm, xyzd, 1); // transform coordinate from master to daughter system
215 Float_t xyd[3]={0,0,0} ; //local position of the entering
220 // Current momentum of the hit's track in the local ref. system
221 TLorentzVector pmom ; //momentum of the particle initiated hit
222 gMC -> TrackMomentum(pmom);
223 Float_t pm[3], pd[3];
227 gMC -> Gmtod (pm, pd, 2); // transform 3-momentum from master to daughter system
232 // Digitize the current CPV hit:
234 // 1. find pad response and
235 gMC->CurrentVolOffID(3,moduleNumber);
238 TClonesArray *cpvDigits = new TClonesArray("AliPHOSCPVDigit",0); // array of digits for current hit
239 CPVDigitize(pmom,xyd,cpvDigits);
244 Int_t idigit,ndigits;
246 // 2. go through the current digit list and sum digits in pads
248 ndigits = cpvDigits->GetEntriesFast();
249 for (idigit=0; idigit<ndigits-1; idigit++) {
250 AliPHOSCPVDigit *cpvDigit1 = dynamic_cast<AliPHOSCPVDigit*>(cpvDigits->UncheckedAt(idigit));
251 Float_t x1 = cpvDigit1->GetXpad() ;
252 Float_t z1 = cpvDigit1->GetYpad() ;
253 for (Int_t jdigit=idigit+1; jdigit<ndigits; jdigit++) {
254 AliPHOSCPVDigit *cpvDigit2 = dynamic_cast<AliPHOSCPVDigit*>(cpvDigits->UncheckedAt(jdigit));
255 Float_t x2 = cpvDigit2->GetXpad() ;
256 Float_t z2 = cpvDigit2->GetYpad() ;
257 if (x1==x2 && z1==z2) {
258 Float_t qsum = cpvDigit1->GetQpad() + cpvDigit2->GetQpad() ;
259 cpvDigit2->SetQpad(qsum) ;
260 cpvDigits->RemoveAt(idigit) ;
264 cpvDigits->Compress() ;
266 // 3. add digits to temporary hit list fTmpHits
268 ndigits = cpvDigits->GetEntriesFast();
269 for (idigit=0; idigit<ndigits; idigit++) {
270 AliPHOSCPVDigit *cpvDigit = dynamic_cast<AliPHOSCPVDigit*>(cpvDigits->UncheckedAt(idigit));
271 relid[0] = moduleNumber + 1 ; // CPV (or PHOS) module number
272 relid[1] =-1 ; // means CPV
273 relid[2] = cpvDigit->GetXpad() ; // column number of a pad
274 relid[3] = cpvDigit->GetYpad() ; // row number of a pad
276 // get the absolute Id number
277 GetGeometry()->RelToAbsNumbering(relid, absid) ;
279 // add current digit to the temporary hit list
281 xyzte[3] = gMC->TrackTime() ;
282 xyzte[4] = cpvDigit->GetQpad() ; // amplitude in a pad
284 Int_t primary = gAlice->GetMCApp()->GetPrimary( gAlice->GetMCApp()->GetCurrentTrackNumber() );
285 AddHit(fIshunt, primary, absid, xyzte);
287 if (cpvDigit->GetQpad() > 0.02) {
288 xmean += cpvDigit->GetQpad() * (cpvDigit->GetXpad() + 0.5);
289 zmean += cpvDigit->GetQpad() * (cpvDigit->GetYpad() + 0.5);
290 qsum += cpvDigit->GetQpad();
301 static Int_t idPXTL = gMC->VolId("PXTL");
302 if(gMC->CurrentVolID(copy) == idPXTL ) { // We are inside a PBWO crystal
304 gMC->TrackPosition(pos) ;
309 Float_t global[3], local[3] ;
313 Float_t lostenergy = gMC->Edep();
315 //Put in the TreeK particle entering PHOS and all its parents
316 if ( gMC->IsTrackEntering() ){
318 gMC -> Gmtod (xyzte, xyzd, 1); // transform coordinate from master to daughter system
319 if (xyzd[1] < -GetGeometry()->GetCrystalSize(1)/2.+0.1){ //Entered close to forward surface
320 Int_t parent = gAlice->GetMCApp()->GetCurrentTrackNumber() ;
321 TParticle * part = gAlice->GetMCApp()->Particle(parent) ;
322 Float_t vert[3],vertd[3] ;
326 gMC -> Gmtod (vert, vertd, 1); // transform coordinate from master to daughter system
327 if(vertd[1]<-GetGeometry()->GetCrystalSize(1)/2.-0.1){ //Particle is created in foront of PHOS
328 //0.1 to get rid of numerical errors
329 part->SetBit(kKeepBit);
330 while ( parent != -1 ) {
331 part = gAlice->GetMCApp()->Particle(parent) ;
332 part->SetBit(kKeepBit);
333 parent = part->GetFirstMother() ;
338 if ( lostenergy != 0 ) { // Track is inside the crystal and deposits some energy
339 xyzte[3] = gMC->TrackTime() ;
341 gMC->CurrentVolOffID(10, moduleNumber) ; // get the PHOS module number ;
344 gMC->CurrentVolOffID(3, strip);
346 gMC->CurrentVolOffID(2, cell);
348 Int_t row = 1 + GetGeometry()->GetNZ() - strip % GetGeometry()->GetNZ() ;
349 Int_t col = (Int_t) TMath::Ceil((Double_t) strip/GetGeometry()->GetNZ()) -1 ;
351 absid = (moduleNumber-1)*GetGeometry()->GetNCristalsInModule() +
352 row + (col*GetGeometry()->GetEMCAGeometry()->GetNCellsInStrip() + cell-1)*GetGeometry()->GetNZ() ;
354 gMC->Gmtod(global, local, 1) ;
356 //Calculates the light yield, the number of photons produced in the
358 Float_t lightYield = gRandom->Poisson(fLightFactor * lostenergy *
359 exp(-fLightYieldAttenuation *
360 (local[1]+GetGeometry()->GetCrystalSize(1)/2.0 ))
363 //Calculates de energy deposited in the crystal
364 xyzte[4] = fAPDFactor * lightYield ;
368 primary = gAlice->GetMCApp()->GetCurrentTrackNumber() ;
369 TParticle * part = gAlice->GetMCApp()->Particle(primary) ;
370 while ( !part->TestBit(kKeepBit) ) {
371 primary = part->GetFirstMother() ;
373 primary = gAlice->GetMCApp()->GetPrimary( gAlice->GetMCApp()->GetCurrentTrackNumber() );
374 break ; //there is a possibility that particle passed e.g. thermal isulator and hits a side
375 //surface of the crystal. In this case it may have no primary at all.
376 //We can not easily separate this case from the case when this is part of the shower,
377 //developed in the neighboring crystal.
379 part = gAlice->GetMCApp()->Particle(primary) ;
383 primary = gAlice->GetMCApp()->GetPrimary( gAlice->GetMCApp()->GetCurrentTrackNumber() );
387 // add current hit to the hit list
388 // Info("StepManager","%d %d", primary, tracknumber) ;
389 AddHit(fIshunt, primary, absid, xyzte);
391 } // there is deposited energy
392 } // we are inside a PHOS Xtal
396 //____________________________________________________________________________
397 void AliPHOSv1::CPVDigitize (TLorentzVector p, Float_t *zxhit, TClonesArray *cpvDigits)
399 // ------------------------------------------------------------------------
400 // Digitize one CPV hit:
401 // On input take exact 4-momentum p and position zxhit of the hit,
402 // find the pad response around this hit and
403 // put the amplitudes in the pads into array digits
405 // Author: Yuri Kharlov (after Serguei Sadovsky)
407 // ------------------------------------------------------------------------
409 const Float_t kCelWr = GetGeometry()->GetPadSizePhi()/2; // Distance between wires (2 wires above 1 pad)
410 const Float_t kDetR = 0.1; // Relative energy fluctuation in track for 100 e-
411 const Float_t kdEdx = 4.0; // Average energy loss in CPV;
412 const Int_t kNgamz = 5; // Ionization size in Z
413 const Int_t kNgamx = 9; // Ionization size in Phi
414 const Float_t kNoise = 0.03; // charge noise in one pad
418 // Just a reminder on axes notation in the CPV module:
419 // axis Z goes along the beam
420 // axis X goes across the beam in the module plane
421 // axis Y is a normal to the module plane showing from the IP
423 Float_t hitX = zxhit[0];
424 Float_t hitZ =-zxhit[1];
427 Float_t pNorm = p.Py();
428 Float_t eloss = kdEdx;
430 //Info("CPVDigitize", "YVK : %f %f | %f %f %d", hitX, hitZ, pX, pZ, pNorm) ;
432 Float_t dZY = pZ/pNorm * GetGeometry()->GetCPVGasThickness();
433 Float_t dXY = pX/pNorm * GetGeometry()->GetCPVGasThickness();
434 gRandom->Rannor(rnor1,rnor2);
435 eloss *= (1 + kDetR*rnor1) *
436 TMath::Sqrt((1 + ( pow(dZY,2) + pow(dXY,2) ) / pow(GetGeometry()->GetCPVGasThickness(),2)));
437 Float_t zhit1 = hitZ + GetGeometry()->GetCPVActiveSize(1)/2 - dZY/2;
438 Float_t xhit1 = hitX + GetGeometry()->GetCPVActiveSize(0)/2 - dXY/2;
439 Float_t zhit2 = zhit1 + dZY;
440 Float_t xhit2 = xhit1 + dXY;
442 Int_t iwht1 = (Int_t) (xhit1 / kCelWr); // wire (x) coordinate "in"
443 Int_t iwht2 = (Int_t) (xhit2 / kCelWr); // wire (x) coordinate "out"
447 if (iwht1==iwht2) { // incline 1-wire hit
449 zxe[0][0] = (zhit1 + zhit2 - dZY*0.57735) / 2;
450 zxe[1][0] = (iwht1 + 0.5) * kCelWr;
452 zxe[0][1] = (zhit1 + zhit2 + dZY*0.57735) / 2;
453 zxe[1][1] = (iwht1 + 0.5) * kCelWr;
456 else if (TMath::Abs(iwht1-iwht2) != 1) { // incline 3-wire hit
458 Int_t iwht3 = (iwht1 + iwht2) / 2;
459 Float_t xwht1 = (iwht1 + 0.5) * kCelWr; // wire 1
460 Float_t xwht2 = (iwht2 + 0.5) * kCelWr; // wire 2
461 Float_t xwht3 = (iwht3 + 0.5) * kCelWr; // wire 3
462 Float_t xwr13 = (xwht1 + xwht3) / 2; // center 13
463 Float_t xwr23 = (xwht2 + xwht3) / 2; // center 23
464 Float_t dxw1 = xhit1 - xwr13;
465 Float_t dxw2 = xhit2 - xwr23;
466 Float_t egm1 = TMath::Abs(dxw1) / ( TMath::Abs(dxw1) + TMath::Abs(dxw2) + kCelWr );
467 Float_t egm2 = TMath::Abs(dxw2) / ( TMath::Abs(dxw1) + TMath::Abs(dxw2) + kCelWr );
468 Float_t egm3 = kCelWr / ( TMath::Abs(dxw1) + TMath::Abs(dxw2) + kCelWr );
469 zxe[0][0] = (dXY*(xwr13-xwht1)/dXY + zhit1 + zhit1) / 2;
471 zxe[2][0] = eloss * egm1;
472 zxe[0][1] = (dXY*(xwr23-xwht1)/dXY + zhit1 + zhit2) / 2;
474 zxe[2][1] = eloss * egm2;
475 zxe[0][2] = dXY*(xwht3-xwht1)/dXY + zhit1;
477 zxe[2][2] = eloss * egm3;
479 else { // incline 2-wire hit
481 Float_t xwht1 = (iwht1 + 0.5) * kCelWr;
482 Float_t xwht2 = (iwht2 + 0.5) * kCelWr;
483 Float_t xwr12 = (xwht1 + xwht2) / 2;
484 Float_t dxw1 = xhit1 - xwr12;
485 Float_t dxw2 = xhit2 - xwr12;
486 Float_t egm1 = TMath::Abs(dxw1) / ( TMath::Abs(dxw1) + TMath::Abs(dxw2) );
487 Float_t egm2 = TMath::Abs(dxw2) / ( TMath::Abs(dxw1) + TMath::Abs(dxw2) );
488 zxe[0][0] = (zhit1 + zhit2 - dZY*egm1) / 2;
490 zxe[2][0] = eloss * egm1;
491 zxe[0][1] = (zhit1 + zhit2 + dZY*egm2) / 2;
493 zxe[2][1] = eloss * egm2;
496 // Finite size of ionization region
498 Int_t nCellZ = GetGeometry()->GetNumberOfCPVPadsZ();
499 Int_t nCellX = GetGeometry()->GetNumberOfCPVPadsPhi();
500 Int_t nz3 = (kNgamz+1)/2;
501 Int_t nx3 = (kNgamx+1)/2;
502 cpvDigits->Expand(nIter*kNgamx*kNgamz);
503 TClonesArray &ldigits = *(static_cast<TClonesArray *>(cpvDigits));
505 for (Int_t iter=0; iter<nIter; iter++) {
507 Float_t zhit = zxe[0][iter];
508 Float_t xhit = zxe[1][iter];
509 Float_t qhit = zxe[2][iter];
510 Float_t zcell = zhit / GetGeometry()->GetPadSizeZ();
511 Float_t xcell = xhit / GetGeometry()->GetPadSizePhi();
512 if ( zcell<=0 || xcell<=0 ||
513 zcell>=nCellZ || xcell>=nCellX) return;
514 Int_t izcell = (Int_t) zcell;
515 Int_t ixcell = (Int_t) xcell;
516 Float_t zc = zcell - izcell - 0.5;
517 Float_t xc = xcell - ixcell - 0.5;
518 for (Int_t iz=1; iz<=kNgamz; iz++) {
519 Int_t kzg = izcell + iz - nz3;
520 if (kzg<=0 || kzg>nCellZ) continue;
521 Float_t zg = (Float_t)(iz-nz3) - zc;
522 for (Int_t ix=1; ix<=kNgamx; ix++) {
523 Int_t kxg = ixcell + ix - nx3;
524 if (kxg<=0 || kxg>nCellX) continue;
525 Float_t xg = (Float_t)(ix-nx3) - xc;
527 // Now calculate pad response
528 Float_t qpad = CPVPadResponseFunction(qhit,zg,xg);
529 qpad += kNoise*rnor2;
530 if (qpad<0) continue;
532 // Fill the array with pad response ID and amplitude
533 new(ldigits[cpvDigits->GetEntriesFast()]) AliPHOSCPVDigit(kxg,kzg,qpad);
539 //____________________________________________________________________________
540 Float_t AliPHOSv1::CPVPadResponseFunction(Float_t qhit, Float_t zhit, Float_t xhit) {
541 // ------------------------------------------------------------------------
542 // Calculate the amplitude in one CPV pad using the
543 // cumulative pad response function
544 // Author: Yuri Kharlov (after Serguei Sadovski)
546 // ------------------------------------------------------------------------
548 Double_t dz = GetGeometry()->GetPadSizeZ() / 2;
549 Double_t dx = GetGeometry()->GetPadSizePhi() / 2;
550 Double_t z = zhit * GetGeometry()->GetPadSizeZ();
551 Double_t x = xhit * GetGeometry()->GetPadSizePhi();
552 Double_t amplitude = qhit *
553 (CPVCumulPadResponse(z+dz,x+dx) - CPVCumulPadResponse(z+dz,x-dx) -
554 CPVCumulPadResponse(z-dz,x+dx) + CPVCumulPadResponse(z-dz,x-dx));
555 return (Float_t)amplitude;
558 //____________________________________________________________________________
559 Double_t AliPHOSv1::CPVCumulPadResponse(Double_t x, Double_t y) {
560 // ------------------------------------------------------------------------
561 // Cumulative pad response function
562 // It includes several terms from the CF decomposition in electrostatics
563 // Note: this cumulative function is wrong since omits some terms
564 // but the cell amplitude obtained with it is correct because
565 // these omitting terms cancel
566 // Author: Yuri Kharlov (after Serguei Sadovski)
568 // ------------------------------------------------------------------------
570 const Double_t kA=1.0;
571 const Double_t kB=0.7;
573 Double_t r2 = x*x + y*y;
575 Double_t cumulPRF = 0;
576 for (Int_t i=0; i<=4; i++) {
577 Double_t b1 = (2*i + 1) * kB;
578 cumulPRF += TMath::Power(-1,i) * TMath::ATan( xy / (b1*TMath::Sqrt(b1*b1 + r2)) );
580 cumulPRF *= kA/(2*TMath::Pi());