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 **************************************************************************/
20 #include <Riostream.h>
21 #include <TObjArray.h>
22 #include "AliITSmodule.h"
23 #include "AliITSMapA2.h"
24 #include "AliITSpList.h"
25 #include "AliITSresponseSSD.h"
26 #include "AliITSsegmentationSSD.h"
27 #include "AliITSdcsSSD.h"
29 #include "AliITShit.h"
30 #include "AliITSdigitSSD.h"
32 #include "AliITSgeom.h"
33 #include "AliITSsimulationSSD.h"
34 #include "AliITSTableSSD.h"
36 ClassImp(AliITSsimulationSSD)
37 ////////////////////////////////////////////////////////////////////////
39 // Written by Enrico Fragiacomo //
42 // AliITSsimulationSSD is the simulation of SSDs. //
43 ////////////////////////////////////////////////////////////////////////
45 //----------------------------------------------------------------------
46 AliITSsimulationSSD::AliITSsimulationSSD():AliITSsimulation(),
58 // A default construction AliITSsimulationSSD class
60 //----------------------------------------------------------------------
61 AliITSsimulationSSD::AliITSsimulationSSD(AliITSDetTypeSim* dettyp):
62 AliITSsimulation(dettyp),
70 // AliITSsegmentationSSD *seg Pointer to the SSD segmentation to be used
71 // AliITSresponseSSD *resp Pointer to the SSD responce class to be used
75 // A standard constructed AliITSsimulationSSD class
79 //----------------------------------------------------------------------
80 void AliITSsimulationSSD::Init(){
81 // Inilizer, Inilizes all of the variable as needed in a standard place.
83 // AliITSsegmentationSSD *seg Pointer to the SSD segmentation to be used
84 // AliITSresponseSSD *resp Pointer to the SSD responce class to be used
89 AliITSresponseSSD* res =(AliITSresponseSSD*)GetResponseModel(fDetType->GetITSgeom()->GetStartSSD());
90 AliITSsegmentationSSD* seg = (AliITSsegmentationSSD*)GetSegmentationModel(2);
91 Double_t noise[2] = {0.,0.};
92 res->GetNoiseParam(noise[0],noise[1]); // retrieves noise parameters
93 fDCS = new AliITSdcsSSD(seg,res);
95 SetDriftVelocity(); // use default values in .h file
96 SetIonizeE(); // use default values in .h file
97 SetDiffConst(); // use default values in .h file
98 fpList = new AliITSpList(2,GetNStrips());
99 fMapA2 = new AliITSMapA2(seg);
101 //______________________________________________________________________
102 AliITSsimulationSSD& AliITSsimulationSSD::operator=(
103 const AliITSsimulationSSD &s){
106 if(this==&s) return *this;
108 this->fDCS = new AliITSdcsSSD(*(s.fDCS));
109 this->fMapA2 = s.fMapA2;
110 this->fIonE = s.fIonE;
111 this->fDifConst[0] = s.fDifConst[0];
112 this->fDifConst[1] = s.fDifConst[1];
113 this->fDriftVel[0] = s.fDriftVel[0];
114 this->fDriftVel[1] = s.fDriftVel[1];
117 //______________________________________________________________________
118 AliITSsimulation& AliITSsimulationSSD::operator=(
119 const AliITSsimulation &s){
122 if(this==&s) return *this;
123 Error("AliITSsimulationSSD","Not allowed to make a = with "
124 "AliITSsimulationSSD Using default creater instead");
128 //______________________________________________________________________
129 AliITSsimulationSSD::AliITSsimulationSSD(const AliITSsimulationSSD &source):
130 AliITSsimulation(source){
135 //______________________________________________________________________
136 AliITSsimulationSSD::~AliITSsimulationSSD() {
141 //______________________________________________________________________
142 void AliITSsimulationSSD::InitSimulationModule(Int_t module,Int_t event){
143 // Creates maps to build the list of tracks for each sumable digit
145 // Int_t module // Module number to be simulated
146 // Int_t event // Event number to be simulated
152 SetModuleNumber(module);
153 SetEventNumber(event);
157 //______________________________________________________________________
158 void AliITSsimulationSSD::FinishSDigitiseModule(){
159 // Does the Sdigits to Digits work
167 FillMapFrompList(fpList); // need to check if needed here or not????
168 SDigitToDigit(fModule,fpList);
172 //______________________________________________________________________
173 void AliITSsimulationSSD::DigitiseModule(AliITSmodule *mod,Int_t,Int_t) {
174 // Digitizes hits for one SSD module
175 SetModuleNumber(mod->GetIndex());
177 HitsToAnalogDigits(mod,fpList);
178 SDigitToDigit(GetModuleNumber(),fpList);
183 //______________________________________________________________________
184 void AliITSsimulationSSD::SDigitiseModule(AliITSmodule *mod,Int_t,Int_t) {
185 // Produces Summable/Analog digits and writes them to the SDigit tree.
187 HitsToAnalogDigits(mod,fpList);
189 WriteSDigits(fpList);
194 //______________________________________________________________________
195 void AliITSsimulationSSD::SDigitToDigit(Int_t module,AliITSpList *pList){
196 // Takes the pList and finishes the digitization.
198 ApplyNoise(pList,module);
199 ApplyCoupling(pList,module);
201 ChargeToSignal(module,pList);
203 //______________________________________________________________________
204 void AliITSsimulationSSD::HitsToAnalogDigits(AliITSmodule *mod,
206 // Loops over all hits to produce Analog/floating point digits. This
207 // is also the first task in producing standard digits.
208 Int_t lasttrack = -2;
210 Double_t x0=0.0, y0=0.0, z0=0.0;
211 Double_t x1=0.0, y1=0.0, z1=0.0;
213 Int_t module = mod->GetIndex();
215 AliITSsegmentationSSD* seg = (AliITSsegmentationSSD*)GetSegmentationModel(2);
217 TObjArray *hits = mod->GetHits();
218 Int_t nhits = hits->GetEntriesFast();
219 if (nhits<=0) return;
220 AliITSTableSSD * tav = new AliITSTableSSD(GetNStrips());
221 module = mod->GetIndex();
222 if ( mod->GetLayer() == 6 ) seg->SetLayer(6);
223 if ( mod->GetLayer() == 5 ) seg->SetLayer(5);
224 for(Int_t i=0; i<nhits; i++) {
225 // LineSegmentL returns 0 if the hit is entering
226 // If hits is exiting returns positions of entering and exiting hits
227 // Returns also energy loss
230 cout << mod->GetHit(i)->GetXL() << " "<<mod->GetHit(i)->GetYL();
231 cout << " " << mod->GetHit(i)->GetZL();
234 if (mod->LineSegmentL(i, x0, x1, y0, y1, z0, z1, de, idtrack)) {
235 HitToDigit(module, x0, y0, z0, x1, y1, z1, de,tav);
236 if (lasttrack != idtrack || i==(nhits-1)) {
237 GetList(idtrack,i,module,pList,tav);
241 } // end loop over hits
245 //----------------------------------------------------------------------
246 void AliITSsimulationSSD::HitToDigit(Int_t module, Double_t x0, Double_t y0,
247 Double_t z0, Double_t x1, Double_t y1,
248 Double_t z1, Double_t de,
249 AliITSTableSSD *tav) {
251 // hit to digit conversion
253 AliITSsegmentationSSD* seg = (AliITSsegmentationSSD*)GetSegmentationModel(2);
254 // Turns hits in SSD module into one or more digits.
255 Float_t tang[2] = {0.0,0.0};
256 seg->Angles(tang[0], tang[1]);//stereo<<->tan(stereo)~=stereo
258 Double_t dex=0.0, dey=0.0, dez=0.0;
259 Double_t pairs; // pair generation energy per step.
260 Double_t sigma[2] = {0.,0.};// standard deviation of the diffusion gaussian
261 Double_t tdrift[2] = {0.,0.}; // time of drift
263 Double_t inf[2], sup[2], par0[2];
265 // Steps in the module are determined "manually" (i.e. No Geant)
266 // NumOfSteps divide path between entering and exiting hits in steps
267 Int_t numOfSteps = NumOfSteps(x1, y1, z1, dex, dey, dez);
268 // Enery loss is equally distributed among steps
270 pairs = de/GetIonizeE(); // e-h pairs generated
271 for(Int_t j=0; j<numOfSteps; j++) { // stepping
272 x = x0 + (j+0.5)*dex;
273 y = y0 + (j+0.5)*dey;
274 if ( y > (seg->Dy()/2+10)*1.0E-4 ) {
275 // check if particle is within the detector
276 Warning("HitToDigit",
277 "hit out of detector y0=%e,y=%e,dey=%e,j =%e module=%d",
281 z = z0 + (j+0.5)*dez;
282 if(GetDebug(4)) cout <<"HitToDigit "<<x<<" "<<y<<" "<<z<< " "
283 <<dex<<" "<<dey<<" "<<dez<<endl;
284 // calculate drift time
285 // y is the minimum path
286 tdrift[0] = (y+(seg->Dy()*1.0E-4)/2)/GetDriftVelocity(0);
287 tdrift[1] = ((seg->Dy()*1.0E-4)/2-y)/GetDriftVelocity(1);
289 for(Int_t k=0; k<2; k++) { // both sides remember: 0=Pside 1=Nside
291 tang[k]=TMath::Tan(tang[k]);
293 // w is the coord. perpendicular to the strips
296 w = (x+(GetSegmentation()->Dx()*1.0E-4)/2) -
297 (z+(GetSegmentation()->Dz()*1.0E-4)/2)*tang[k];
299 w = (x+(GetSegmentation()->Dx()*1.0E-4)/2) +
300 (z-(GetSegmentation()->Dz()*1.0E-4)/2)*tang[k];
302 w /= (GetStripPitch()*1.0E-4); //w is converted in units of pitch
304 { // replacement block for the above.
305 Float_t xp=x*1.e+4,zp=z*1.e+4; // microns
306 seg->GetPadTxz(xp,zp);
307 if(k==0) w = xp; // P side strip number
308 else w = zp; // N side strip number
311 if((w<(-0.5)) || (w>(GetNStrips()-0.5))) {
312 // this check rejects hits in regions not covered by strips
313 // 0.5 takes into account boundaries
314 if(GetDebug(4)) cout << "x,z="<<x<<","<<z<<" w="<<w
315 <<" Nstrips="<<GetNStrips()<<endl;
316 return; // There are dead region on the SSD sensitive volume.
319 // sigma is the standard deviation of the diffusion gaussian
320 if(tdrift[k]<0) return;
321 sigma[k] = TMath::Sqrt(2*GetDiffConst(k)*tdrift[k]);
322 sigma[k] /= (GetStripPitch()*1.0E-4); //units of Pitch
324 Error("HitToDigit"," sigma[%d]=0",k);
329 // we integrate the diffusion gaussian from -3sigma to 3sigma
330 inf[k] = w - 3*sigma[k]; // 3 sigma from the gaussian average
331 sup[k] = w + 3*sigma[k]; // 3 sigma from the gaussian average
332 // IntegrateGaussian does the actual
333 // integration of diffusion gaussian
334 IntegrateGaussian(k, par0[k], w, sigma[k], inf[k], sup[k],tav);
335 } // end for loop over side (0=Pside, 1=Nside)
338 //______________________________________________________________________
339 void AliITSsimulationSSD::ApplyNoise(AliITSpList *pList,Int_t module){
342 Double_t signal,noise;
343 Double_t noiseP[2] = {0.,0.};
345 AliITSresponseSSD* res =(AliITSresponseSSD*)GetResponseModel(module);
346 res->GetNoiseParam(a,b); // retrieves noise parameters
347 noiseP[0] = a; noiseP[1] = b;
348 for(k=0;k<2;k++){ // both sides (0=Pside, 1=Nside)
349 for(ix=0;ix<GetNStrips();ix++){ // loop over strips
350 noise = gRandom->Gaus(0,noiseP[k]);// get noise to signal
351 signal = noise + fMapA2->GetSignal(k,ix);//get signal from map
352 if(signal<0.) signal=0.0; // in case noise is negative...
353 fMapA2->SetHit(k,ix,signal); // give back signal to map
354 if(signal>0.0) pList->AddNoise(k,ix,module,noise);
356 } // loop over k (P or N side)
358 //______________________________________________________________________
359 void AliITSsimulationSSD::ApplyCoupling(AliITSpList *pList,Int_t module) {
360 // Apply the effect of electronic coupling between channels
362 Double_t signalLeft=0, signalRight=0,signal=0;
364 for(ix=0;ix<GetNStrips();ix++){
366 if(ix>0.)signalLeft = fMapA2->GetSignal(0,ix-1)*fDCS->GetCouplingPL();
367 else signalLeft = 0.0;
368 if(ix<(GetNStrips()-1)) signalRight = fMapA2->GetSignal(0,ix+1)*
369 fDCS->GetCouplingPR();
370 else signalRight = 0.0;
371 signal = signalLeft + signalRight;
372 fMapA2->AddSignal(0,ix,signal);
373 if(signal>0.0) pList->AddNoise(0,ix,module,signal);
375 signalLeft = signalRight = signal = 0.0;
377 if(ix>0.) signalLeft = fMapA2->GetSignal(1,ix-1)*fDCS->GetCouplingNL();
378 else signalLeft = 0.0;
379 if(ix<(GetNStrips()-1)) signalRight = fMapA2->GetSignal(1,ix+1)*
380 fDCS->GetCouplingNR();
381 else signalRight = 0.0;
382 signal = signalLeft + signalRight;
383 fMapA2->AddSignal(1,ix,signal);
384 if(signal>0.0) pList->AddNoise(1,ix,module,signal);
385 } // loop over strips
387 //______________________________________________________________________
388 Float_t AliITSsimulationSSD::F(Float_t av, Float_t x, Float_t s) {
389 // Computes the integral of a gaussian using Error Function
390 Float_t sqrt2 = TMath::Sqrt(2.0);
391 Float_t sigm2 = sqrt2*s;
394 integral = 0.5 * TMath::Erf( (x - av) / sigm2);
397 //______________________________________________________________________
398 void AliITSsimulationSSD::IntegrateGaussian(Int_t k,Double_t par, Double_t w,
400 Double_t inf, Double_t sup,
401 AliITSTableSSD *tav) {
402 // integrate the diffusion gaussian
403 // remind: inf and sup are w-3sigma and w+3sigma
404 // we could define them here instead of passing them
405 // this way we are free to introduce asimmetry
407 Double_t a=0.0, b=0.0;
408 Double_t dXCharge1 = 0.0, dXCharge2 = 0.0;
409 // dXCharge1 and 2 are the charge to two neighbouring strips
410 // Watch that we only involve at least two strips
411 // Numbers greater than 2 of strips in a cluster depend on
412 // geometry of the track and delta rays, not charge diffusion!
414 Double_t strip = TMath::Floor(w); // closest strip on the left
416 if ( TMath::Abs((strip - w)) < 0.5) {
417 // gaussian mean is closer to strip on the left
418 a = inf; // integration starting point
419 if((strip+0.5)<=sup) {
420 // this means that the tail of the gaussian goes beyond
421 // the middle point between strips ---> part of the signal
422 // is given to the strip on the right
423 b = strip + 0.5; // integration stopping point
424 dXCharge1 = F( w, b, sigma) - F(w, a, sigma);
425 dXCharge2 = F( w, sup, sigma) - F(w ,b, sigma);
427 // this means that all the charge is given to the strip on the left
429 dXCharge1 = 0.9973; // gaussian integral at 3 sigmas
432 dXCharge1 = par * dXCharge1;// normalize by mean of number of carriers
433 dXCharge2 = par * dXCharge2;
435 // for the time being, signal is the charge
436 // in ChargeToSignal signal is converted in ADC channel
437 fMapA2->AddSignal(k,(Int_t)strip,dXCharge1);
438 tav->Add(k,(Int_t)strip);
439 if(((Int_t) strip) < (GetNStrips()-1)) {
440 // strip doesn't have to be the last (remind: last=GetNStrips()-1)
441 // otherwise part of the charge is lost
442 fMapA2->AddSignal(k,((Int_t)strip+1),dXCharge2);
443 tav->Add(k,((Int_t)(strip+1)));
446 // gaussian mean is closer to strip on the right
447 strip++; // move to strip on the rigth
448 b = sup; // now you know where to stop integrating
449 if((strip-0.5)>=inf) {
450 // tail of diffusion gaussian on the left goes left of
451 // middle point between strips
452 a = strip - 0.5; // integration starting point
453 dXCharge1 = F(w, b, sigma) - F(w, a, sigma);
454 dXCharge2 = F(w, a, sigma) - F(w, inf, sigma);
457 dXCharge1 = 0.9973; // gaussian integral at 3 sigmas
460 dXCharge1 = par * dXCharge1; // normalize by means of carriers
461 dXCharge2 = par * dXCharge2;
462 // for the time being, signal is the charge
463 // in ChargeToSignal signal is converted in ADC channel
464 fMapA2->AddSignal(k,(Int_t)strip,dXCharge1);
465 tav->Add(k,(Int_t)strip);
466 if(((Int_t) strip) > 0) {
467 // strip doesn't have to be the first
468 // otherwise part of the charge is lost
469 fMapA2->AddSignal(k,((Int_t)strip-1),dXCharge2);
470 tav->Add(k,((Int_t)(strip-1)));
474 //______________________________________________________________________
475 Int_t AliITSsimulationSSD::NumOfSteps(Double_t x, Double_t y, Double_t z,
476 Double_t &dex,Double_t &dey,
479 // it also returns steps for each coord
480 //AliITSsegmentationSSD *seg = new AliITSsegmentationSSD();
482 Double_t step = 25E-4;
483 //step = (Double_t) seg->GetStepSize(); // step size (cm)
484 Int_t numOfSteps = (Int_t) (TMath::Sqrt(x*x+y*y+z*z)/step);
486 if (numOfSteps < 1) numOfSteps = 1; // one step, at least
488 // we could condition the stepping depending on the incident angle
496 //----------------------------------------------------------------------
497 void AliITSsimulationSSD::GetList(Int_t label,Int_t hit,Int_t mod,
498 AliITSpList *pList,AliITSTableSSD *tav) {
499 // loop over nonzero digits
503 for(Int_t k=0; k<2; k++) {
506 signal = fMapA2->GetSignal(k,ix);
510 } // end if signal==0.0
511 // check the signal magnitude
512 for(i=0;i<pList->GetNSignals(k,ix);i++){
513 signal -= pList->GetTSignal(k,ix,i);
515 // compare the new signal with already existing list
516 if(signal>0)pList->AddSignal(k,ix,label,hit,mod,signal);
518 } // end of loop on strips
519 } // end of loop on P/N side
522 //----------------------------------------------------------------------
523 void AliITSsimulationSSD::ChargeToSignal(Int_t module,AliITSpList *pList) {
525 static AliITS *aliITS = (AliITS*)gAlice->GetModule("ITS");
526 Float_t threshold = 0.;
527 Int_t size = AliITSdigitSSD::GetNTracks();
528 Int_t * digits = new Int_t[size];
529 Int_t * tracks = new Int_t[size];
530 Int_t * hits = new Int_t[size];
532 Float_t charges[3] = {0.0,0.0,0.0};
534 Double_t noise[2] = {0.,0.};
535 AliITSresponseSSD* res =(AliITSresponseSSD*)GetResponseModel(module);
536 res->GetNoiseParam(noise[0],noise[1]);
538 for(Int_t k=0;k<2;k++){ // both sides (0=Pside, 1=Nside)
539 // Threshold for zero-suppression
540 // It can be defined in AliITSresponseSSD
541 // threshold = (Float_t)GetResp()->MinVal(k);
542 // I prefer to think adjusting the threshold "manually", looking
543 // at the scope, and considering noise standard deviation
544 threshold = 4.0*noise[k]; // 4 times noise is a choice
545 for(Int_t ix=0;ix<GetNStrips();ix++){ // loop over strips
546 if(fMapA2->GetSignal(k,ix) <= threshold)continue;
547 // convert to ADC signal
548 signal = res->DEvToADC(
549 fMapA2->GetSignal(k,ix));
550 if(signal>1024.) signal = 1024.;//if exceeding, accumulate last one
553 digits[2] = (Int_t) signal;
554 for(j1=0;j1<size;j1++)if(j1<pList->GetNEnteries()){
555 // only three in digit.
556 tracks[j1] = pList->GetTrack(k,ix,j1);
557 hits[j1] = pList->GetHit(k,ix,j1);
563 aliITS->AddSimDigit(2,0,digits,tracks,hits,charges);
570 //______________________________________________________________________
571 void AliITSsimulationSSD::WriteSDigits(AliITSpList *pList){
572 // Fills the Summable digits Tree
574 static AliITS *aliITS = (AliITS*)gAlice->GetModule("ITS");
576 pList->GetMaxMapIndex(ni,nj);
577 for(i=0;i<ni;i++)for(j=0;j<nj;j++){
578 if(pList->GetSignalOnly(i,j)>0.0){
579 aliITS->AddSumDigit(*(pList->GetpListItem(i,j)));
580 if(GetDebug(4)) cout << "pListSSD: "<<*(pList->GetpListItem(i,j))
586 //______________________________________________________________________
587 void AliITSsimulationSSD::FillMapFrompList(AliITSpList *pList){
588 // Fills fMap2A from the pList of Summable digits
591 for(k=0;k<2;k++)for(ix=0;ix<GetNStrips();ix++)
592 fMapA2->AddSignal(k,ix,pList->GetSignal(k,ix));
595 //______________________________________________________________________
596 void AliITSsimulationSSD::Print(ostream *os){
597 //Standard output format for this class
599 //AliITSsimulation::Print(os);
601 *os << fDifConst[0] <<","<< fDifConst[1] <<",";
602 *os << fDriftVel[0] <<","<< fDriftVel[1];
603 //*os <<","; fDCS->Print(os);
604 //*os <<","; fMapA2->Print(os);
606 //______________________________________________________________________
607 void AliITSsimulationSSD::Read(istream *is){
608 // Standard output streaming function.
610 //AliITSsimulation::Read(is);
612 *is >> fDifConst[0] >> fDifConst[1];
613 *is >> fDriftVel[0] >> fDriftVel[1];
617 //______________________________________________________________________
618 ostream &operator<<(ostream &os,AliITSsimulationSSD &source){
619 // Standard output streaming function.
624 //______________________________________________________________________
625 istream &operator>>(istream &os,AliITSsimulationSSD &source){
626 // Standard output streaming function.
631 //______________________________________________________________________