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 <TParticle.h>
27 #include "AliITSmodule.h"
28 #include "AliITSMapA2.h"
29 #include "AliITSpList.h"
30 #include "AliITSresponseSSD.h"
31 #include "AliITSsegmentationSSD.h"
32 #include "AliITSdcsSSD.h"
34 #include "AliITShit.h"
35 #include "AliITSdigit.h"
37 #include "AliITSgeom.h"
38 #include "AliITSsimulationSSD.h"
39 #include "AliITSTableSSD.h"
41 ClassImp(AliITSsimulationSSD);
42 ////////////////////////////////////////////////////////////////////////
44 // Written by Enrico Fragiacomo
47 // AliITSsimulationSSD is the simulation of SSDs.
49 //----------------------------------------------------------------------
50 AliITSsimulationSSD::AliITSsimulationSSD(){
54 fDifConst[0] = fDifConst[1] = 0.0;
55 fDriftVel[0] = fDriftVel[1] = 0.0;
59 //----------------------------------------------------------------------
60 AliITSsimulationSSD::AliITSsimulationSSD(AliITSsegmentation *seg,
61 AliITSresponse *resp){
64 // AliITSsegmentationSSD *seg Pointer to the SSD segmentation to be used
65 // AliITSresponseSSD *resp Pointer to the SSD responce class to be used
72 fDifConst[0] = fDifConst[1] = 0.0;
73 fDriftVel[0] = fDriftVel[1] = 0.0;
76 Init((AliITSsegmentationSSD*)seg,(AliITSresponseSSD*)resp);
78 //----------------------------------------------------------------------
79 void AliITSsimulationSSD::Init(AliITSsegmentationSSD *seg,
80 AliITSresponseSSD *resp){
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
92 Float_t noise[2] = {0.,0.};
93 fResponse->GetNoiseParam(noise[0],noise[1]); // retrieves noise parameters
94 fDCS = new AliITSdcsSSD(seg,resp);
96 SetDriftVelocity(); // use default values in .h file
97 SetIonizeE(); // use default values in .h file
98 SetDiffConst(); // use default values in .h file
99 fpList = new AliITSpList(2,GetNStrips());
100 fMapA2 = new AliITSMapA2(fSegmentation);
102 //______________________________________________________________________
103 AliITSsimulationSSD& AliITSsimulationSSD::operator=(
104 const AliITSsimulationSSD &s){
107 if(this==&s) return *this;
109 this->fDCS = new AliITSdcsSSD(*(s.fDCS));
110 this->fMapA2 = s.fMapA2;
111 this->fIonE = s.fIonE;
112 this->fDifConst[0] = s.fDifConst[0];
113 this->fDifConst[1] = s.fDifConst[1];
114 this->fDriftVel[0] = s.fDriftVel[0];
115 this->fDriftVel[1] = s.fDriftVel[1];
118 //______________________________________________________________________
119 AliITSsimulationSSD::AliITSsimulationSSD(const AliITSsimulationSSD &source):
120 AliITSsimulation(source){
125 //______________________________________________________________________
126 AliITSsimulationSSD::~AliITSsimulationSSD() {
131 //______________________________________________________________________
132 void AliITSsimulationSSD::InitSimulationModule(Int_t module,Int_t event){
133 // Creates maps to build the list of tracks for each sumable digit
135 // Int_t module // Module number to be simulated
136 // Int_t event // Event number to be simulated
147 //______________________________________________________________________
148 void AliITSsimulationSSD::FinishSDigitiseModule(){
149 // Does the Sdigits to Digits work
157 FillMapFrompList(fpList); // need to check if needed here or not????
158 SDigitToDigit(fModule,fpList);
162 //______________________________________________________________________
163 void AliITSsimulationSSD::DigitiseModule(AliITSmodule *mod,
164 Int_t dummy0,Int_t dummy1) {
165 // Digitizes hits for one SSD module
166 Int_t module = mod->GetIndex();
168 dummy0 = dummy1 = 0; // remove unused variable warning.
169 HitsToAnalogDigits(mod,fpList);
170 SDigitToDigit(module,fpList);
175 //______________________________________________________________________
176 void AliITSsimulationSSD::SDigitiseModule(AliITSmodule *mod,Int_t dummy0,
178 // Produces Summable/Analog digits and writes them to the SDigit tree.
180 dummy0 = dummy1 = 0; // remove unused variable warning
181 HitsToAnalogDigits(mod,fpList);
183 WriteSDigits(fpList);
188 //______________________________________________________________________
189 void AliITSsimulationSSD::SDigitToDigit(Int_t module,AliITSpList *pList){
190 // Takes the pList and finishes the digitization.
192 // FillMapFrompList(pList); //commented out to avoid double counting of the
195 ApplyNoise(pList,module);
196 ApplyCoupling(pList,module);
198 ChargeToSignal(pList);
200 //______________________________________________________________________
201 void AliITSsimulationSSD::HitsToAnalogDigits(AliITSmodule *mod,
203 // Loops over all hits to produce Analog/floating point digits. This
204 // is also the first task in producing standard digits.
205 Int_t lasttrack = -2;
207 Double_t x0=0.0, y0=0.0, z0=0.0;
208 Double_t x1=0.0, y1=0.0, z1=0.0;
210 Int_t module = mod->GetIndex();
212 TObjArray *hits = mod->GetHits();
213 Int_t nhits = hits->GetEntriesFast();
214 if (nhits<=0) return;
215 AliITSTableSSD * tav = new AliITSTableSSD(GetNStrips());
216 module = mod->GetIndex();
217 if ( mod->GetLayer() == 6 ) GetSegmentation()->SetLayer(6);
218 if ( mod->GetLayer() == 5 ) GetSegmentation()->SetLayer(5);
219 for(Int_t i=0; i<nhits; i++) {
220 // LineSegmentL returns 0 if the hit is entering
221 // If hits is exiting returns positions of entering and exiting hits
222 // Returns also energy loss
224 // cout << mod->GetHit(i)->GetXL() << " "<<mod->GetHit(i)->GetYL();
225 // cout << " " << mod->GetHit(i)->GetZL();
227 if (mod->LineSegmentL(i, x0, x1, y0, y1, z0, z1, de, idtrack)) {
228 HitToDigit(module, x0, y0, z0, x1, y1, z1, de,tav);
229 if (lasttrack != idtrack || i==(nhits-1)) {
230 GetList(idtrack,i,module,pList,tav);
234 } // end loop over hits
238 //----------------------------------------------------------------------
239 void AliITSsimulationSSD::HitToDigit(Int_t module, Double_t x0, Double_t y0,
240 Double_t z0, Double_t x1, Double_t y1,
241 Double_t z1, Double_t de,
242 AliITSTableSSD *tav) {
243 // Turns hits in SSD module into one or more digits.
244 Float_t tang[2] = {0.0,0.0};
245 GetSegmentation()->Angles(tang[0], tang[1]);//stereo<<->tan(stereo)~=stereo
247 Double_t dex=0.0, dey=0.0, dez=0.0;
248 Double_t pairs; // pair generation energy per step.
249 Double_t sigma[2] = {0.,0.};// standard deviation of the diffusion gaussian
250 Double_t tdrift[2] = {0.,0.}; // time of drift
252 Double_t inf[2], sup[2], par0[2];
254 // Steps in the module are determined "manually" (i.e. No Geant)
255 // NumOfSteps divide path between entering and exiting hits in steps
256 Int_t numOfSteps = NumOfSteps(x1, y1, z1, dex, dey, dez);
257 // Enery loss is equally distributed among steps
259 pairs = de/GetIonizeE(); // e-h pairs generated
260 for(Int_t j=0; j<numOfSteps; j++) { // stepping
261 x = x0 + (j+0.5)*dex;
262 y = y0 + (j+0.5)*dey;
263 if ( y > (GetSegmentation()->Dy()/2+10)*1.0E-4 ) {
264 // check if particle is within the detector
265 Warning("HitToDigit",
266 "hit out of detector y0=%e,y=%e,dey=%e,j =%e module=%d",
270 z = z0 + (j+0.5)*dez;
271 // cout <<"HitToDigit "<<x<<" "<<y<<" "<<z<< " "<<dex<<" "<<dey<<" "<<dez<<endl;
272 // calculate drift time
273 // y is the minimum path
274 tdrift[0] = (y+(GetSegmentation()->Dy()*1.0E-4)/2)/GetDriftVelocity(0);
275 tdrift[1] = ((GetSegmentation()->Dy()*1.0E-4)/2-y)/GetDriftVelocity(1);
277 for(Int_t k=0; k<2; k++) { // both sides remember: 0=Pside 1=Nside
279 tang[k]=TMath::Tan(tang[k]);
281 // w is the coord. perpendicular to the strips
284 w = (x+(GetSegmentation()->Dx()*1.0E-4)/2) -
285 (z+(GetSegmentation()->Dz()*1.0E-4)/2)*tang[k];
287 w = (x+(GetSegmentation()->Dx()*1.0E-4)/2) +
288 (z-(GetSegmentation()->Dz()*1.0E-4)/2)*tang[k];
290 w /= (GetStripPitch()*1.0E-4); // w is converted in units of pitch
292 { // replacement block for the above.
293 Float_t xp=x*1.e+4,zp=z*1.e+4; // microns
294 GetSegmentation()->GetPadTxz(xp,zp);
295 if(k==0) w = xp; // P side strip number
296 else w = zp; // N side strip number
299 if((w<(-0.5)) || (w>(GetNStrips()-0.5))) {
300 // this check rejects hits in regions not covered by strips
301 // 0.5 takes into account boundaries
302 //cout << "x,z="<<x<<","<<z<<" w="<<w<<" Nstrips="<<GetNStrips()<<endl;
303 return; // There are dead region on the SSD sensitive volume.
306 // sigma is the standard deviation of the diffusion gaussian
307 if(tdrift[k]<0) return;
308 sigma[k] = TMath::Sqrt(2*GetDiffConst(k)*tdrift[k]);
309 sigma[k] /= (GetStripPitch()*1.0E-4); //units of Pitch
311 Error("HitToDigit"," sigma[%d]=0",k);
316 // we integrate the diffusion gaussian from -3sigma to 3sigma
317 inf[k] = w - 3*sigma[k]; // 3 sigma from the gaussian average
318 sup[k] = w + 3*sigma[k]; // 3 sigma from the gaussian average
319 // IntegrateGaussian does the actual
320 // integration of diffusion gaussian
321 IntegrateGaussian(k, par0[k], w, sigma[k], inf[k], sup[k],tav);
322 } // end for loop over side (0=Pside, 1=Nside)
325 //______________________________________________________________________
326 void AliITSsimulationSSD::ApplyNoise(AliITSpList *pList,Int_t module){
329 Double_t signal,noise;
330 Double_t noiseP[2] = {0.,0.};
333 fResponse->GetNoiseParam(a,b); // retrieves noise parameters
334 noiseP[0] = (Double_t) a; noiseP[1] = (Double_t) b;
335 for(k=0;k<2;k++){ // both sides (0=Pside, 1=Nside)
336 for(ix=0;ix<GetNStrips();ix++){ // loop over strips
337 noise = gRandom->Gaus(0,noiseP[k]);// get noise to signal
338 signal = noise + fMapA2->GetSignal(k,ix);//get signal from map
339 if(signal<0.) signal=0.0; // in case noise is negative...
340 fMapA2->SetHit(k,ix,signal); // give back signal to map
341 if(signal>0.0) pList->AddNoise(k,ix,module,noise);
343 } // loop over k (P or N side)
345 //______________________________________________________________________
346 void AliITSsimulationSSD::ApplyCoupling(AliITSpList *pList,Int_t module) {
347 // Apply the effect of electronic coupling between channels
349 Double_t signalLeft=0, signalRight=0,signal=0;
351 for(ix=0;ix<GetNStrips();ix++){
353 if(ix>0.)signalLeft = fMapA2->GetSignal(0,ix-1)*fDCS->GetCouplingPL();
354 else signalLeft = 0.0;
355 if(ix<(GetNStrips()-1)) signalRight = fMapA2->GetSignal(0,ix+1)*
356 fDCS->GetCouplingPR();
357 else signalRight = 0.0;
358 signal = signalLeft + signalRight;
359 fMapA2->AddSignal(0,ix,signal);
360 if(signal>0.0) pList->AddNoise(0,ix,module,signal);
362 signalLeft = signalRight = signal = 0.0;
364 if(ix>0.) signalLeft = fMapA2->GetSignal(1,ix-1)*fDCS->GetCouplingNL();
365 else signalLeft = 0.0;
366 if(ix<(GetNStrips()-1)) signalRight = fMapA2->GetSignal(1,ix+1)*
367 fDCS->GetCouplingNR();
368 else signalRight = 0.0;
369 signal = signalLeft + signalRight;
370 fMapA2->AddSignal(1,ix,signal);
371 if(signal>0.0) pList->AddNoise(1,ix,module,signal);
372 } // loop over strips
374 //______________________________________________________________________
375 Float_t AliITSsimulationSSD::F(Float_t av, Float_t x, Float_t s) {
376 // Computes the integral of a gaussian using Error Function
377 Float_t sqrt2 = TMath::Sqrt(2.0);
378 Float_t sigm2 = sqrt2*s;
381 integral = 0.5 * TMath::Erf( (x - av) / sigm2);
384 //______________________________________________________________________
385 void AliITSsimulationSSD::IntegrateGaussian(Int_t k,Double_t par, Double_t w,
387 Double_t inf, Double_t sup,
388 AliITSTableSSD *tav) {
389 // integrate the diffusion gaussian
390 // remind: inf and sup are w-3sigma and w+3sigma
391 // we could define them here instead of passing them
392 // this way we are free to introduce asimmetry
394 Double_t a=0.0, b=0.0;
395 Double_t dXCharge1 = 0.0, dXCharge2 = 0.0;
396 // dXCharge1 and 2 are the charge to two neighbouring strips
397 // Watch that we only involve at least two strips
398 // Numbers greater than 2 of strips in a cluster depend on
399 // geometry of the track and delta rays, not charge diffusion!
401 Double_t strip = TMath::Floor(w); // closest strip on the left
403 if ( TMath::Abs((strip - w)) < 0.5) {
404 // gaussian mean is closer to strip on the left
405 a = inf; // integration starting point
406 if((strip+0.5)<=sup) {
407 // this means that the tail of the gaussian goes beyond
408 // the middle point between strips ---> part of the signal
409 // is given to the strip on the right
410 b = strip + 0.5; // integration stopping point
411 dXCharge1 = F( w, b, sigma) - F(w, a, sigma);
412 dXCharge2 = F( w, sup, sigma) - F(w ,b, sigma);
414 // this means that all the charge is given to the strip on the left
416 dXCharge1 = 0.9973; // gaussian integral at 3 sigmas
419 dXCharge1 = par * dXCharge1;// normalize by mean of number of carriers
420 dXCharge2 = par * dXCharge2;
422 // for the time being, signal is the charge
423 // in ChargeToSignal signal is converted in ADC channel
424 fMapA2->AddSignal(k,(Int_t)strip,dXCharge1);
425 tav->Add(k,(Int_t)strip);
426 if(((Int_t) strip) < (GetNStrips()-1)) {
427 // strip doesn't have to be the last (remind: last=GetNStrips()-1)
428 // otherwise part of the charge is lost
429 fMapA2->AddSignal(k,((Int_t)strip+1),dXCharge2);
430 tav->Add(k,((Int_t)(strip+1)));
433 // gaussian mean is closer to strip on the right
434 strip++; // move to strip on the rigth
435 b = sup; // now you know where to stop integrating
436 if((strip-0.5)>=inf) {
437 // tail of diffusion gaussian on the left goes left of
438 // middle point between strips
439 a = strip - 0.5; // integration starting point
440 dXCharge1 = F(w, b, sigma) - F(w, a, sigma);
441 dXCharge2 = F(w, a, sigma) - F(w, inf, sigma);
444 dXCharge1 = 0.9973; // gaussian integral at 3 sigmas
447 dXCharge1 = par * dXCharge1; // normalize by means of carriers
448 dXCharge2 = par * dXCharge2;
449 // for the time being, signal is the charge
450 // in ChargeToSignal signal is converted in ADC channel
451 fMapA2->AddSignal(k,(Int_t)strip,dXCharge1);
452 tav->Add(k,(Int_t)strip);
453 if(((Int_t) strip) > 0) {
454 // strip doesn't have to be the first
455 // otherwise part of the charge is lost
456 fMapA2->AddSignal(k,((Int_t)strip-1),dXCharge2);
457 tav->Add(k,((Int_t)(strip-1)));
461 //______________________________________________________________________
462 Int_t AliITSsimulationSSD::NumOfSteps(Double_t x, Double_t y, Double_t z,
463 Double_t & dex,Double_t & dey,Double_t & dez){
465 // it also returns steps for each coord
466 //AliITSsegmentationSSD *seg = new AliITSsegmentationSSD();
468 Double_t step = 25E-4;
469 //step = (Double_t) seg->GetStepSize(); // step size (cm)
470 Int_t numOfSteps = (Int_t) (TMath::Sqrt(x*x+y*y+z*z)/step);
472 if (numOfSteps < 1) numOfSteps = 1; // one step, at least
474 // we could condition the stepping depending on the incident angle
482 //----------------------------------------------------------------------
483 void AliITSsimulationSSD::GetList(Int_t label,Int_t hit,Int_t mod,
484 AliITSpList *pList,AliITSTableSSD *tav) {
485 // loop over nonzero digits
489 for(Int_t k=0; k<2; k++) {
492 signal = fMapA2->GetSignal(k,ix);
496 } // end if signal==0.0
497 // check the signal magnitude
498 for(i=0;i<pList->GetNSignals(k,ix);i++){
499 signal -= pList->GetTSignal(k,ix,i);
501 // compare the new signal with already existing list
502 if(signal>0)pList->AddSignal(k,ix,label,hit,mod,signal);
504 } // end of loop on strips
505 } // end of loop on P/N side
508 //----------------------------------------------------------------------
509 void AliITSsimulationSSD::ChargeToSignal(AliITSpList *pList) {
511 static AliITS *aliITS = (AliITS*)gAlice->GetModule("ITS");
512 Float_t threshold = 0.;
513 Int_t size = AliITSdigitSSD::GetNTracks();
514 Int_t * digits = new Int_t[size];
515 Int_t * tracks = new Int_t[size];
516 Int_t * hits = new Int_t[size];
518 Float_t charges[3] = {0.0,0.0,0.0};
520 Float_t noise[2] = {0.,0.};
522 ((AliITSresponseSSD*)fResponse)->GetNoiseParam(noise[0],noise[1]);
524 for(Int_t k=0;k<2;k++){ // both sides (0=Pside, 1=Nside)
525 // Threshold for zero-suppression
526 // It can be defined in AliITSresponseSSD
527 // threshold = (Float_t)fResponse->MinVal(k);
528 // I prefer to think adjusting the threshold "manually", looking
529 // at the scope, and considering noise standard deviation
530 threshold = 4.0*noise[k]; // 4 times noise is a choice
531 for(Int_t ix=0;ix<GetNStrips();ix++){ // loop over strips
532 if(fMapA2->GetSignal(k,ix) <= threshold)continue;
533 // convert to ADC signal
534 signal = ((AliITSresponseSSD*)fResponse)->DEvToADC(
535 fMapA2->GetSignal(k,ix));
536 if(signal>1024.) signal = 1024.;//if exceeding, accumulate last one
539 digits[2] = (Int_t) signal;
540 for(j1=0;j1<size;j1++)if(j1<pList->GetNEnteries()){
541 // only three in digit.
542 tracks[j1] = pList->GetTrack(k,ix,j1);
543 hits[j1] = pList->GetHit(k,ix,j1);
549 aliITS->AddSimDigit(2,0,digits,tracks,hits,charges);
556 //______________________________________________________________________
557 void AliITSsimulationSSD::WriteSDigits(AliITSpList *pList){
558 // Fills the Summable digits Tree
560 static AliITS *aliITS = (AliITS*)gAlice->GetModule("ITS");
562 pList->GetMaxMapIndex(ni,nj);
563 for(i=0;i<ni;i++)for(j=0;j<nj;j++){
564 if(pList->GetSignalOnly(i,j)>0.0){
565 aliITS->AddSumDigit(*(pList->GetpListItem(i,j)));
566 // cout << "pListSSD: " << *(pList->GetpListItem(i,j)) << endl;
571 //______________________________________________________________________
572 void AliITSsimulationSSD::FillMapFrompList(AliITSpList *pList){
573 // Fills fMap2A from the pList of Summable digits
576 for(k=0;k<2;k++)for(ix=0;ix<GetNStrips();ix++)
577 fMapA2->AddSignal(k,ix,pList->GetSignal(k,ix));
580 //______________________________________________________________________
581 void AliITSsimulationSSD::Print(ostream *os){
582 //Standard output format for this class
584 //AliITSsimulation::Print(os);
586 *os << fDifConst[0] <<","<< fDifConst[1] <<",";
587 *os << fDriftVel[0] <<","<< fDriftVel[1];
588 //*os <<","; fDCS->Print(os);
589 //*os <<","; fMapA2->Print(os);
591 //______________________________________________________________________
592 void AliITSsimulationSSD::Read(istream *is){
593 // Standard output streaming function.
595 //AliITSsimulation::Read(is);
597 *is >> fDifConst[0] >> fDifConst[1];
598 *is >> fDriftVel[0] >> fDriftVel[1];
602 //______________________________________________________________________
603 ostream &operator<<(ostream &os,AliITSsimulationSSD &source){
604 // Standard output streaming function.
609 //______________________________________________________________________
610 istream &operator>>(istream &os,AliITSsimulationSSD &source){
611 // Standard output streaming function.
616 //______________________________________________________________________