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 // Class AliMUONResponseV0
20 // --------------------------
24 #include "AliMUONResponseV0.h"
26 #include "AliMUONConstants.h"
27 #include "AliMUONDigit.h"
28 #include "AliMUONGeometrySegmentation.h"
29 #include "AliMUONGeometryTransformer.h"
30 #include "AliMUONHit.h"
31 #include "AliMUONSegmentation.h"
33 #include "AliMpArea.h"
34 #include "AliMpDEManager.h"
35 #include "AliMpVPadIterator.h"
36 #include "AliMpSegmentation.h"
37 #include "AliMpVSegmentation.h"
42 #include "Riostream.h"
48 ClassImp(AliMUONResponseV0)
53 return static_cast<AliMUON*>(gAlice->GetModule("MUON"));
56 void Global2Local(Int_t detElemId, Double_t xg, Double_t yg, Double_t zg,
57 Double_t& xl, Double_t& yl, Double_t& zl)
59 /// ideally should be :
61 /// AliMUONGeometry::Global2Local(detElemId,xg,yg,zg,x,y,z);
62 /// but while waiting for this geometry singleton, let's go through
65 const AliMUONGeometryTransformer* transformer = muon()->GetGeometryTransformer();
66 transformer->Global2Local(detElemId,xg,yg,zg,xl,yl,zl);
69 AliMUONSegmentation* Segmentation()
71 static AliMUONSegmentation* segmentation = muon()->GetSegmentation();
75 //__________________________________________________________________________
76 AliMUONResponseV0::AliMUONResponseV0()
81 fSigmaIntegration(0.0),
86 fMathieson(new AliMUONMathieson),
87 fChargeThreshold(1e-4)
89 /// Normal constructor
90 AliDebug(1,Form("Default ctor"));
93 //__________________________________________________________________________
94 AliMUONResponseV0::~AliMUONResponseV0()
102 //______________________________________________________________________________
104 AliMUONResponseV0::Print(Option_t*) const
108 cout << " ChargeSlope=" << fChargeSlope
109 << " ChargeSpreadX,Y=" << fChargeSpreadX
111 << " ChargeCorrelation=" << fChargeCorrel
115 //__________________________________________________________________________
116 void AliMUONResponseV0::SetSqrtKx3AndDeriveKx2Kx4(Float_t SqrtKx3)
118 /// Set to "SqrtKx3" the Mathieson parameter K3 ("fSqrtKx3")
119 /// in the X direction, perpendicular to the wires,
120 /// and derive the Mathieson parameters K2 ("fKx2") and K4 ("fKx4")
121 /// in the same direction
122 fMathieson->SetSqrtKx3AndDeriveKx2Kx4(SqrtKx3);
125 //__________________________________________________________________________
126 void AliMUONResponseV0::SetSqrtKy3AndDeriveKy2Ky4(Float_t SqrtKy3)
128 /// Set to "SqrtKy3" the Mathieson parameter K3 ("fSqrtKy3")
129 /// in the Y direction, along the wires,
130 /// and derive the Mathieson parameters K2 ("fKy2") and K4 ("fKy4")
131 /// in the same direction
132 fMathieson->SetSqrtKy3AndDeriveKy2Ky4(SqrtKy3);
134 //__________________________________________________________________________
135 Float_t AliMUONResponseV0::IntPH(Float_t eloss) const
137 /// Calculate charge from given ionization energy loss
139 nel= Int_t(eloss*1.e9/27.4);
142 for (Int_t i=1;i<=nel;i++) {
144 while(!arg) arg = gRandom->Rndm();
145 charge -= fChargeSlope*TMath::Log(arg);
150 //-------------------------------------------
151 Float_t AliMUONResponseV0::IntXY(Int_t idDE,
152 AliMUONGeometrySegmentation* segmentation)
155 /// Calculate charge on current pad according to Mathieson distribution
157 return fMathieson->IntXY(idDE, segmentation);
161 //_____________________________________________________________________________
163 AliMUONResponseV0::GetAnod(Float_t x) const
165 /// Return wire coordinate closest to x.
167 Int_t n = Int_t(x/Pitch());
168 Float_t wire = (x>0) ? n+0.5 : n-0.5;
172 //______________________________________________________________________________
174 AliMUONResponseV0::DisIntegrate(const AliMUONHit& hit, TList& digits)
176 /// Go from 1 hit to a list of digits.
177 /// The energy deposition of that hit is first converted into charge
178 /// (in IntPH() method), and then this charge is dispatched on several
179 /// pads, according to the Mathieson distribution.
183 Int_t detElemId = hit.DetElemId();
185 // Width of the integration area
186 Double_t dx = SigmaIntegration()*ChargeSpreadX();
187 Double_t dy = SigmaIntegration()*ChargeSpreadY();
189 // Use that (dx,dy) to specify the area upon which
190 // we will iterate to spread charge into.
192 Global2Local(detElemId,hit.X(),hit.Y(),hit.Z(),x,y,z);
194 TVector2 hitPosition(x,y);
195 AliMpArea area(hitPosition,TVector2(dx,dy));
197 // Get pulse height from energy loss.
198 Float_t qtot = IntPH(hit.Eloss());
200 // Get the charge correlation between cathodes.
201 Float_t currentCorrel = TMath::Exp(gRandom->Gaus(0.0,ChargeCorrel()/2.0));
203 for ( Int_t cath = 0; cath < 2; ++cath )
205 Float_t qcath = qtot * ( cath == 0 ? currentCorrel : 1.0/currentCorrel);
207 // Get an iterator to loop over pads, within the given area.
208 const AliMpVSegmentation* seg =
209 AliMpSegmentation::Instance()->GetMpSegmentation(detElemId,cath);
211 AliMpVPadIterator* it = seg->CreateIterator(area);
215 AliError(Form("Could not get iterator for detElemId %d",detElemId));
219 // Start loop over pads.
224 // Exceptional case : iterator is built, but is invalid from the start.
225 AliMpPad pad = seg->PadByPosition(area.Position(),kFALSE);
228 AliWarning(Form("Got an invalid iterator bug (area.Position() is within "
229 " DE but the iterator is void) for detElemId %d cath %d",
234 AliError(Form("Got an invalid iterator bug for detElemId %d cath %d."
235 "Might be a bad hit ? area.Position()=(%e,%e) "
236 "Dimensions()=(%e,%e)",
237 detElemId,cath,area.Position().X(),area.Position().Y(),
238 area.Dimensions().X(),area.Dimensions().Y()));
244 while ( !it->IsDone() )
246 // For each pad given by the iterator, compute the charge of that
247 // pad, according to the Mathieson distribution.
248 AliMpPad pad = it->CurrentItem();
249 TVector2 lowerLeft(hitPosition-pad.Position()-pad.Dimensions());
250 TVector2 upperRight(lowerLeft + pad.Dimensions()*2.0);
251 Float_t qp = TMath::Abs(fMathieson->IntXY(lowerLeft.X(),lowerLeft.Y(),
252 upperRight.X(),upperRight.Y()));
254 Int_t icharge = Int_t(qp*qcath);
256 if ( qp > fChargeThreshold )
258 // If we're above threshold, then we create a digit,
259 // and fill it with relevant information, including electronics.
260 AliMUONDigit* d = new AliMUONDigit;
261 d->SetDetElemId(detElemId);
262 d->SetPadX(pad.GetIndices().GetFirst());
263 d->SetPadY(pad.GetIndices().GetSecond());
264 d->SetSignal(icharge);
265 d->AddPhysicsSignal(d->Signal());
267 d->SetElectronics(pad.GetLocation().GetFirst(),
268 pad.GetLocation().GetSecond());