5 #include "AliTRDltuParam.h"
7 // definition of geometry constants
8 Float_t AliTRDltuParam::fgZrow[6][5] = {
9 {301, 177, 53, -57, -181},
10 {301, 177, 53, -57, -181},
11 {315, 184, 53, -57, -188},
12 {329, 191, 53, -57, -195},
13 {343, 198, 53, -57, -202},
14 {347, 200, 53, -57, -204}};
15 Float_t AliTRDltuParam::fgX[6] =
16 {300.65, 313.25, 325.85, 338.45, 351.05, 363.65};
17 Float_t AliTRDltuParam::fgTiltingAngle[6] =
18 {-2., 2., -2., 2., -2., 2.};
19 Int_t AliTRDltuParam::fgDyMax = 63;
20 Int_t AliTRDltuParam::fgDyMin = -64;
21 Float_t AliTRDltuParam::fgBinDy = 140e-4;
22 Float_t AliTRDltuParam::fgWidthPad[6] =
23 {0.635, 0.665, 0.695, 0.725, 0.755, 0.785};
24 Float_t AliTRDltuParam::fgLengthInnerPadC1[6] =
25 {7.5, 7.5, 8.0, 8.5, 9.0, 9.0};
26 Float_t AliTRDltuParam::fgLengthOuterPadC1[6] =
27 {7.5, 7.5, 7.5, 7.5, 7.5, 8.5};
28 Float_t AliTRDltuParam::fgLengthInnerPadC0 = 9.0;
29 Float_t AliTRDltuParam::fgLengthOuterPadC0 = 8.0;
30 Float_t AliTRDltuParam::fgScalePad = 256. * 32.;
31 Float_t AliTRDltuParam::fgDriftLength = 3.;
33 AliTRDltuParam::AliTRDltuParam() :
41 fPidTracklengthCorr(kFALSE),
45 // default constructor
48 AliTRDltuParam::~AliTRDltuParam()
53 Int_t AliTRDltuParam::GetDyCorrection(Int_t det, Int_t rob, Int_t mcm) const
55 // calculate the correction of the deflection
56 // i.e. Lorentz angle and tilt correction (if active)
58 Int_t layer = det % 6;
60 Float_t dyTilt = ( fgDriftLength * TMath::Tan(fgTiltingAngle[layer] * TMath::Pi()/180.) *
61 GetLocalZ(det, rob, mcm) / fgX[layer] );
63 // calculate Lorentz correction
64 Float_t dyCorr = - fOmegaTau * fgDriftLength;
67 dyCorr += dyTilt; // add tilt correction
69 return (int) TMath::Nint(dyCorr * fgScalePad / fgWidthPad[layer]);
72 void AliTRDltuParam::GetDyRange(Int_t det, Int_t rob, Int_t mcm, Int_t ch,
73 Int_t &dyMinInt, Int_t &dyMaxInt) const
75 // calculate the deflection range in which tracklets are accepted
80 // deflection cut is considered for |B| > 0.1 T only
81 if (TMath::Abs(fMagField) < 0.1)
86 Float_t maxDeflTemp = GetPerp(det, rob, mcm, ch)/2. * // Sekante/2 (cm)
87 (e * 1e-2 * TMath::Abs(fMagField) / fPtMin); // 1/R (1/cm)
89 Float_t maxDeflAngle = 0.;
91 Float_t phi = GetPhi(det, rob, mcm, ch);
92 if (maxDeflTemp < TMath::Cos(phi)) {
93 maxDeflAngle = TMath::ASin(maxDeflTemp);
95 Float_t dyMin = ( fgDriftLength *
96 TMath::Tan(phi - maxDeflAngle) );
98 dyMinInt = Int_t(dyMin / fgBinDy);
99 // clipping to allowed range
100 if (dyMinInt < fgDyMin)
102 else if (dyMinInt > fgDyMax)
105 Float_t dyMax = ( fgDriftLength *
106 TMath::Tan(phi + maxDeflAngle) );
108 dyMaxInt = Int_t(dyMax / fgBinDy);
109 // clipping to allowed range
110 if (dyMaxInt > fgDyMax)
112 else if (dyMaxInt < fgDyMin)
115 else if (maxDeflTemp < 0.) {
116 // this must not happen
117 printf("Inconsistent calculation of sin(alpha): %f\n", maxDeflTemp);
120 // TRD is not reached at the given pt threshold
124 if ((dyMaxInt - dyMinInt) <= 0) {
125 printf("strange dy range: [%i,%i], using max range now\n", dyMinInt, dyMaxInt);
131 Float_t AliTRDltuParam::GetElongation(Int_t det, Int_t rob, Int_t mcm, Int_t ch) const
133 // calculate the ratio of the distance to the primary vertex and the
134 // distance in x-direction for the given ADC channel
136 Int_t layer = det % 6;
138 Float_t elongation = TMath::Abs(GetDist(det, rob, mcm, ch) / fgX[layer]);
141 if(elongation<0.001) {
147 void AliTRDltuParam::GetCorrectionFactors(Int_t det, Int_t rob, Int_t mcm, Int_t ch,
148 UInt_t &cor0, UInt_t &cor1, Float_t gain) const
150 // calculate the gain correction factors for the given ADC channel
152 if (fPidGainCorr==kFALSE)
155 if (fPidTracklengthCorr == kTRUE ) {
156 cor0 = UInt_t ((1.0*fScaleQ0* (1./GetElongation(det, rob, mcm, ch))) / gain );
157 cor1 = UInt_t ((1.0*fScaleQ1* (1./GetElongation(det, rob, mcm, ch))) / gain );
160 cor0 = UInt_t (fScaleQ0 / gain);
161 cor1 = UInt_t ( fScaleQ1 / gain);
165 Int_t AliTRDltuParam::GetNtimebins() const
167 // return the number of timebins used
172 Float_t AliTRDltuParam::GetX(Int_t det, Int_t /* rob */, Int_t /* mcm */) const
174 // return the distance to the beam axis in x-direction
180 Float_t AliTRDltuParam::GetLocalY(Int_t det, Int_t rob, Int_t mcm, Int_t ch) const
182 // get local y-position (r-phi) w.r.t. the chamber centre
185 // calculate the pad position as in the TRAP
186 Float_t ypos = (-4 + 1 + (rob&0x1) * 4 + (mcm&0x3)) * 18 - ch - 0.5; // y position in bins of pad widths
187 return ypos*fgWidthPad[layer];
190 Float_t AliTRDltuParam::GetLocalZ(Int_t det, Int_t rob, Int_t mcm) const
192 // get local z-position w.r.t. to the chamber boundary
194 Int_t stack = (det%30) / 6;
195 Int_t layer = det % 6;
196 Int_t row = (rob/2) * 4 + mcm/4;
200 return (fgZrow[layer][stack] - 0.5 * fgLengthOuterPadC0);
202 return (fgZrow[layer][stack] - 1.5 * fgLengthOuterPadC0 - (row - 1) * fgLengthInnerPadC0);
204 return (fgZrow[layer][stack] - fgLengthOuterPadC0 - (row - 0.5) * fgLengthInnerPadC0);
208 return (fgZrow[layer][stack] - 0.5 * fgLengthOuterPadC1[layer]);
210 return (fgZrow[layer][stack] - 1.5 * fgLengthOuterPadC1[layer] - (row - 1) * fgLengthInnerPadC1[layer]);
212 return (fgZrow[layer][stack] - fgLengthOuterPadC1[layer] - (row - 0.5) * fgLengthInnerPadC1[layer]);
216 Float_t AliTRDltuParam::GetPerp(Int_t det, Int_t rob, Int_t mcm, Int_t ch) const
218 // get transverse distance to the beam axis
220 return TMath::Sqrt(GetLocalY(det, rob, mcm, ch)*GetLocalY(det, rob, mcm, ch) +
221 GetX(det, rob, mcm)*GetX(det, rob, mcm) );
224 Float_t AliTRDltuParam::GetPhi(Int_t det, Int_t rob, Int_t mcm, Int_t ch) const
226 // calculate the azimuthal angle for the given ADC channel
228 return TMath::ATan2(GetLocalY(det, rob, mcm, ch), GetX(det, rob, mcm));
231 Float_t AliTRDltuParam::GetDist(Int_t det, Int_t rob, Int_t mcm, Int_t ch) const
233 // calculate the distance from the origin for the given ADC channel
235 return TMath::Sqrt(GetLocalY(det, rob, mcm, ch)*GetLocalY(det, rob, mcm, ch) +
236 GetX(det, rob, mcm)*GetX(det, rob, mcm) +
237 GetLocalZ(det, rob, mcm)*GetLocalZ(det, rob, mcm) );