Using the new AliTracker::PropagateTrackTo
[u/mrichter/AliRoot.git] / TPC / AliL1Delay.C
CommitLineData
35d4a90a 1/////////////////////////////////////////////////////////////////////////////
2// //
3// This is a macro which measures the time delay of L1 trigger in TPC //
4// //
5// It reads the ESD tracks and fills histograms with the distance //
6// between the primary vertex and the Z position //
7// of the point of closest approach between the track and the beam axis. //
8// The processing of forward and backward tracks is done separately. //
9// The corresponding histograms are fitted with gaussian and the //
10// shifts of the Z positions are extracted. //
11// The L1 time delay is taken as an average of the forward and backward //
12// (with opposite sign) shifts divided by the drift velocity. //
13// We assume that the ESD tracks are obtained by the TPC tracking stand //
14// alone. //
15// The propagation to the vertex can be done either with or without //
16// TGeoManager. //
17// //
18// Cvetan.Cheshkov@cern.ch //
19// //
20/////////////////////////////////////////////////////////////////////////////
21
22#if !defined(__CINT__) || defined(__MAKECINT__)
23 #include <TMath.h>
24 #include <TError.h>
25 #include <Riostream.h>
26 #include <TH1F.h>
27 #include <TF1.h>
28 #include <TTree.h>
29 #include <TCanvas.h>
30 #include <TFile.h>
31 #include <TStyle.h>
32 #include <TGeoManager.h>
33 #include "AliRunLoader.h"
34 #include "AliRun.h"
35 #include "AliESD.h"
36 #include "AliTracker.h"
37 #include "AliTPCParam.h"
38 #include "AliMagFMaps.h"
39 #include "AliITStrackV2.h"
40#endif
41
42Int_t CorrectForDeadZoneMaterial(AliITStrackV2 *t);
43Bool_t PropagateToVertex(AliESDtrack *track, Float_t *vtxXYZ);
44Bool_t PropagateToVertexG(AliESDtrack *track, Float_t *vtxXYZ);
45
46void AliL1Delay(const Char_t *esdfilename = "./AliESDs.root", const Char_t *galicefilename = "./galice.root", Bool_t withTGeo = kFALSE, const Char_t *geomfilename = "./geometry.root")
47{
48 const Int_t kMinNClusters = 0;
49 const Double_t kPtMin = 0.5;
50 const Double_t kMaxImpact = 0.3;
51 const Double_t kDeltaZRes = 0.3;
52 const Double_t kZRange = 20.;
53
54 // Book histograms
55 Int_t NBins = (Int_t)(2.*kZRange/(0.5*kDeltaZRes));
56 TH1F *hDeltaZForward = new TH1F("hDeltaZForward","Longitudinal distance to the vertex (forward tracks)",NBins,-kZRange,kZRange);
57 TH1F *hDeltaZBackward = new TH1F("hDeltaZBackward","Longitudinal distance to the vertex (backward tracks)",NBins,-kZRange,kZRange);
58 TH1F *hTrImpact = new TH1F("hTrImpact","Transverse impact parameter (all tracks)",100,0,30.*kMaxImpact);
59
60 // Open RunLoader
61 AliRunLoader *rl = AliRunLoader::Open(galicefilename);
62 if (!rl) {
63 ::Error("AliL1Delay.C","Can't start session !");
64 return;
65 }
66 rl->LoadgAlice();
67 gAlice = rl->GetAliRun();
68
69 // Set magnetic field
70 AliMagF* field = gAlice->Field();
71 AliTracker::SetFieldMap(field,kTRUE);
72 AliExternalTrackParam::SetFieldMap(field);
73 AliExternalTrackParam::SetNonuniformFieldTracking();
74 const Float_t sfield = field->SolenoidField();
75
76 // GetGeo manager
77 if(withTGeo)
78 {
79 TFile *geoFile = TFile::Open(geomfilename);
80 if (!geoFile || !geoFile->IsOpen()) {
81 ::Error("AliL1Delay.C","Can't open %s !",geomfilename);
82 return;
83 }
84 gGeoManager = (TGeoManager *)geoFile->Get("Geo");
85 if(!gGeoManager) {
86 ::Error("AliL1Delay.C","Can't find TGeoManager !");
87 return;
88 }
89 }
90
91 // Get X positions of the pad-rows
92 TDirectory* saveDir = gDirectory;
93 rl->CdGAFile();
94 AliTPCParam* param = (AliTPCParam*) gDirectory->Get("75x40_100x60_150x60");
95 if (!param) {
96 ::Error("AliL1Delay.C","No TPC parameters found !");
97 return;
98 }
99 Int_t nRowLow = param->GetNRowLow();
100 Int_t nRowUp = param->GetNRowUp();
101 Float_t xRow[159];
102 for (Int_t i=0;i<nRowLow;i++){
103 xRow[i] = param->GetPadRowRadiiLow(i);
104 }
105 for (Int_t i=0;i<nRowUp;i++){
106 xRow[i+nRowLow] = param->GetPadRowRadiiUp(i);
107 }
108 saveDir->cd();
109
110 // Open file with ESDs
111 TFile *esdFile = TFile::Open(esdfilename);
112 if (!esdFile || !esdFile->IsOpen()) {
113 ::Error("AliL1Delay.C","Can't open %s !",esdfilename);
114 return;
115 }
116 AliESD* event = new AliESD;
117 TTree* esdTree = (TTree*) esdFile->Get("esdTree");
118 if (!esdTree) {
119 ::Error("AliL1Delay.C","No ESD tree found !");
120 return;
121 }
122 esdTree->SetBranchAddress("ESD", &event);
123
124 // Init PID
125 AliPID pid;
126
127 Int_t nEvent = esdTree->GetEntries();
128
129 // Loop over events
130 for(Int_t iEvent = 0; iEvent<nEvent; iEvent++)
131 {
132 esdTree->GetEvent(iEvent);
133 const AliESDVertex *esdVtx = event->GetVertex();
134 Double_t zVtx = esdVtx->GetZv();
135 if(zVtx == 0.) continue; // Vertex is not found. Skip the event.
136 Int_t nTrk=event->GetNumberOfTracks();
137
138 ::Info("AliL1Delay.C","Event %d : Z vertex = %f | Number of tracks = %d",iEvent,zVtx,nTrk);
139
140 for(Int_t iTrk=0; iTrk<nTrk; iTrk++)
141 {
142 AliESDtrack *track = event->GetTrack(iTrk);
143 if(!track) continue;
144
145 // Track selection
146 if((track->GetStatus()&AliESDtrack::kTPCrefit)==0) continue;
147 if(track->GetTPCclusters((Int_t)0x0)<(kMinNClusters*3)) continue;
148 if(track->GetP()<kPtMin) continue;
149
150 Int_t firstRow = (Int_t)(track->GetTPCPoints(0)+0.5);
151 Int_t lastRow = (Int_t)(track->GetTPCPoints(2)+0.5);
152 Double_t firstXYZ[3];
153 Double_t lastXYZ[3];
154 track->GetXYZAt(xRow[firstRow], sfield, firstXYZ);
155 track->GetXYZAt(xRow[lastRow], sfield, lastXYZ);
156
157 // Select if the track is forward or backward one
158 Bool_t IsForward;
159 if(firstXYZ[2] > 0 && lastXYZ[2] > 0)
160 IsForward = kTRUE;
161 else if(firstXYZ[2] < 0 && lastXYZ[2] < 0)
162 IsForward = kFALSE;
163 else
164 continue;
165
166 // Propagate the track to the vertex
167 Float_t vtxXYZ[3];
168 if(withTGeo) {
169 if(PropagateToVertexG(track,vtxXYZ) == 0) continue;
170 }
171 else {
172 if(PropagateToVertex(track,vtxXYZ) == 0) continue;
173 }
174
175 // Get the position at point of closest approach to the vertex
176 Float_t impact = TMath::Sqrt(vtxXYZ[0]*vtxXYZ[0]+vtxXYZ[1]*vtxXYZ[1]);
177 hTrImpact->Fill(impact);
178 // Select primary tracks
179 if(impact > kMaxImpact) continue;
180
181 if (IsForward)
182 hDeltaZForward->Fill(vtxXYZ[2]-zVtx);
183 else
184 hDeltaZBackward->Fill(vtxXYZ[2]-zVtx);
185 }
186 }
187
188 // delete event;
189 // esdFile->Close();
190
191 // Check track propagation
192 TF1 *fexpo = new TF1("fexpo","expo");
193 hTrImpact->Fit("fexpo","E");
194 Double_t slope = fexpo->GetParameter(1);
195 if(slope > 3.*kMaxImpact)
196 ::Warning("AliL1Delay.C","The transverse impact parameter distribution is too broad: %f +- %f",slope,fexpo->GetParError(1));
197 delete fexpo;
198
199 // Fit histograms and extract L1 time delay
200 Double_t shifts[2],shifterrs2[2];
201 {
202 Double_t params[3];
203 params[0] = hDeltaZForward->GetMaximumBin();
204 params[1] = hDeltaZForward->GetBinCenter(hDeltaZForward->GetMaximumBin());
205 params[2] = kDeltaZRes;
206 TF1 *fgaus = new TF1("fgaus","gaus");
207 fgaus->SetParameters(params);
208 hDeltaZForward->Fit("fgaus","E");
209 shifts[0] = fgaus->GetParameter(1);
210 shifterrs2[0] = fgaus->GetParError(1)*fgaus->GetParError(1);
211 delete fgaus;
212 }
213 {
214 Double_t params[3];
215 params[0] = hDeltaZBackward->GetMaximumBin();
216 params[1] = hDeltaZBackward->GetBinCenter(hDeltaZBackward->GetMaximumBin());
217 params[2] = kDeltaZRes;
218 TF1 *fgaus = new TF1("fgaus","gaus");
219 fgaus->SetParameters(params);
220 hDeltaZBackward->Fit("fgaus","E");
221 shifts[1] = -fgaus->GetParameter(1);
222 shifterrs2[1] = fgaus->GetParError(1)*fgaus->GetParError(1);
223 delete fgaus;
224 }
225
226 // Check the consistency of the two time delays
227 if(TMath::Abs(shifts[0]-shifts[1])>3.*TMath::Sqrt(shifterrs2[0]+shifterrs2[1]))
228 ::Warning("AliL1Delay.C","The extracted delays are more than 3 sigma away from each other: %f %f",shifts[0],shifts[1]);
229
230 // Calculated the overall time delay
231 Double_t shifterr = 1./TMath::Sqrt(1./shifterrs2[0]+1./shifterrs2[1]);
232 Double_t shift = (shifts[0]/shifterrs2[0]+shifts[1]/shifterrs2[1])*shifterr*shifterr;
233
234 ::Info("AliL1Delay.C","");
235 ::Info("AliL1Delay.C","=====================================================");
236 ::Info("AliL1Delay.C","The measured L1 delay is (%f +- %f) cm",shift,shifterr);
237 ::Info("AliL1Delay.C","The measured L1 delay is (%f +- %f) ns",shift*1.e9/param->GetDriftV(),shifterr*1.e9/param->GetDriftV());
238 ::Info("AliL1Delay.C","=====================================================");
239
240 delete event;
241 esdFile->Close();
242
243 gStyle->SetOptFit(1);
244
245 TCanvas *c1 = new TCanvas("c1","",0,0,700,850);
246
247 TPad *p1 = new TPad("p1","",0,0,1,0.5); p1->Draw();
248 p1->cd(); p1->SetFillColor(42); p1->SetFrameFillColor(10);
249 p1->SetLogy(1);
250 hTrImpact->SetFillColor(4); hTrImpact->SetXTitle("(cm)");
251 hTrImpact->SetStats(kTRUE); hTrImpact->Draw(); c1->cd();
252
253 TPad *p2 = new TPad("p2","",0,0.5,0.5,1); p2->Draw();
254 p2->cd(); p2->SetFillColor(42); p2->SetFrameFillColor(10);
255 hDeltaZForward->SetFillColor(4); hDeltaZForward->SetXTitle("(cm)");
256 hDeltaZForward->SetStats(kTRUE); hDeltaZForward->Draw(); c1->cd();
257
258 TPad *p3 = new TPad("p3","",0.5,0.5,1,1); p3->Draw();
259 p3->cd(); p3->SetFillColor(42); p3->SetFrameFillColor(10);
260 hDeltaZBackward->SetFillColor(4); hDeltaZBackward->SetXTitle("(cm)");
261 hDeltaZBackward->SetStats(kTRUE); hDeltaZBackward->Draw(); c1->cd();
262
263 TFile f("AliL1Delay.root","RECREATE");
264 c1->Write();
265 f.Close();
266
267 delete rl;
268}
269
270Int_t CorrectForDeadZoneMaterial(AliITStrackV2 *t) {
271 //--------------------------------------------------------------------
272 // Correction for the material between the TPC and the ITS
273 // (should it belong to the TPC code ?)
274 //--------------------------------------------------------------------
275 Double_t riw=80., diw=0.0053, x0iw=30; // TPC inner wall ?
276 Double_t rcd=61., dcd=0.0053, x0cd=30; // TPC "central drum" ?
277 Double_t yr=12.8, dr=0.03; // rods ?
278 Double_t zm=0.2, dm=0.40; // membrane
279 //Double_t rr=52., dr=0.19, x0r=24., yyr=7.77; //rails
280 Double_t rs=50., ds=0.001; // something belonging to the ITS (screen ?)
281
282 if (t->GetX() > riw) {
283 if (!t->PropagateTo(riw,diw,x0iw)) return 1;
284 if (TMath::Abs(t->GetY())>yr) t->CorrectForMaterial(dr);
285 if (TMath::Abs(t->GetZ())<zm) t->CorrectForMaterial(dm);
286 if (!t->PropagateTo(rcd,dcd,x0cd)) return 1;
287 //Double_t x,y,z; t->GetGlobalXYZat(rr,x,y,z);
288 //if (TMath::Abs(y)<yyr) t->PropagateTo(rr,dr,x0r);
289 if (!t->PropagateTo(rs,ds)) return 1;
290 } else if (t->GetX() < rs) {
291 if (!t->PropagateTo(rs,-ds)) return 1;
292 //Double_t x,y,z; t->GetGlobalXYZat(rr,x,y,z);
293 //if (TMath::Abs(y)<yyr) t->PropagateTo(rr,-dr,x0r);
294 if (!t->PropagateTo(rcd,-dcd,x0cd)) return 1;
295 if (!t->PropagateTo(riw+0.001,-diw,x0iw)) return 1;
296 } else {
297 ::Error("CorrectForDeadZoneMaterial","track is already in the dead zone !");
298 return 1;
299 }
300
301 return 0;
302}
303
304Bool_t PropagateToVertex(AliESDtrack *track, Float_t *vtxXYZ)
305{
306 // Make an ITS track and propagate it to the vertex
307 AliITStrackV2 itstrack(*track);
308 if (CorrectForDeadZoneMaterial(&itstrack) != 0) return 0;
309 if (!itstrack.PropagateTo(3.,0.0028,65.19)) return 0;
310 if (!itstrack.PropagateToVertex()) return 0;
311
312 itstrack.GetXYZ(vtxXYZ);
313
314 return 1;
315}
316
317Bool_t PropagateToVertexG(AliESDtrack *track, Float_t *vtxXYZ)
318{
319 // Make an ITS track and propagate it to the vertex using TGeoManager
320 AliITStrackV2 itstrack(*track);
321 AliExternalTrackParam etrack(itstrack);
322 Double_t r = 3.;
323 Double_t xyz0[3],xyz1[3],y,z;
324 Double_t param[7];
325 Double_t step = 2.;
326 for (Double_t x = etrack.X()-step; x > r; x -= step) {
327 etrack.GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
328 Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
329 etrack.RotateTo(alpha);
330 etrack.GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
331 if (!etrack.GetProlongationAt(x,y,z)) return 0;
332 xyz1[0] = x*TMath::Cos(alpha)-y*TMath::Sin(alpha);
333 xyz1[1] = x*TMath::Sin(alpha)+y*TMath::Cos(alpha);
334 xyz1[2] = z;
335 AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param);
336 if (!etrack.PropagateTo(x,param[1],param[0])) return 0;
337 }
338 etrack.PropagateTo(r,1,0);
339 if (!etrack.PropagateToDCA(0,0,param[1],0)) return 0;
340
341 etrack.GetXYZ(vtxXYZ);
342
343 return 1;
344}