1 /**************************************************************************
2 * Copyright(c) 2004, 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 **************************************************************************/
16 /** @file AliFMDRing.cxx
17 @author Christian Holm Christensen <cholm@nbi.dk>
18 @date Mon Mar 27 12:47:43 2006
19 @brief FMD ring geometry parameters
21 //__________________________________________________________________
23 // Utility class to help implement collection of FMD modules into
24 // rings. This is used by AliFMDDetector and AliFMDGeometry.
25 // The AliFMDGeometry object owns the AliFMDRing objects, and the
26 // AliFMDDetector objects reference these. That is, the AliFMDRing
27 // objects are share amoung the AliFMDDetector objects.
29 // Latest changes by Christian Holm Christensen
32 #include <TMath.h> // ROOT_TMath
33 #include <TVector2.h> // ROOT_TVector2
35 // #include <AliLog.h> // ALILOG_H
36 #include "AliFMDRing.h" // ALIFMDRING_H
38 //====================================================================
41 ; // This is here to keep Emacs for indenting the next line
44 //____________________________________________________________________
45 AliFMDRing::AliFMDRing(Char_t id)
46 : TNamed(Form("FMD%c", id), "Forward multiplicity ring"),
62 fPrintboardThickness(0),
76 SetPrintboardThickness();
81 if (fId == 'I' || fId == 'i') {
87 else if (fId == 'O' || fId == 'o') {
95 //____________________________________________________________________
100 Double_t tanTheta = TMath::Tan(fTheta * TMath::Pi() / 180.);
101 Double_t tanTheta2 = TMath::Power(tanTheta,2);
102 Double_t r2 = TMath::Power(fWaferRadius,2);
103 Double_t yA = tanTheta * fLowR;
104 Double_t lr2 = TMath::Power(fLowR, 2);
105 Double_t hr2 = TMath::Power(fHighR,2);
106 Double_t xD = fLowR + TMath::Sqrt(r2 - tanTheta2 * lr2);
107 Double_t xD2 = TMath::Power(xD,2);
108 Double_t yB = TMath::Sqrt(r2 - hr2 + 2 * fHighR * xD - xD2);
109 Double_t xC = ((xD + TMath::Sqrt(-tanTheta2 * xD2 + r2
112 Double_t yC = tanTheta * xC;
114 fVerticies.Expand(6);
115 fVerticies.AddAt(new TVector2(fLowR, -yA), 0);
116 fVerticies.AddAt(new TVector2(xC, -yC), 1);
117 fVerticies.AddAt(new TVector2(fHighR, -yB), 2);
118 fVerticies.AddAt(new TVector2(fHighR, yB), 3);
119 fVerticies.AddAt(new TVector2(xC, yC), 4);
120 fVerticies.AddAt(new TVector2(fLowR, yA), 5);
122 // A's length. Corresponds to distance from nominal beam line to the
123 // cornor of the active silicon element.
124 fMinR = GetVertex(5)->Mod();
125 // A's length. Corresponds to distance from nominal beam line to the
126 // cornor of the active silicon element.
129 fRingDepth = (fSiThickness + fPrintboardThickness
130 + fCopperThickness + fChipThickness
131 + fLegLength + fModuleSpacing + fSpacing);
134 //____________________________________________________________________
136 AliFMDRing::GetVertex(Int_t i) const
138 // Get the i'th vertex of polygon shape
139 return static_cast<TVector2*>(fVerticies.At(i));
142 //____________________________________________________________________
144 AliFMDRing::GetStripRadius(UShort_t strip) const
146 // Return the nominal strip radius
147 Double_t rmax = GetMaxR();
148 Double_t stripoff = GetMinR();
149 Double_t dstrip = (rmax - stripoff) / GetNStrips();
150 return (strip + .5) * dstrip + stripoff; // fLowR
153 //____________________________________________________________________
155 AliFMDRing::Detector2XYZ(UShort_t sector,
161 // Translate detector coordinates (this,sector,strip) to global
162 // coordinates (x,y,z)
163 if (sector >= GetNSectors()) {
164 Error("Detector2XYZ", "Invalid sector number %d (>=%d) in ring %c",
165 sector, GetNSectors(), fId);
168 if (strip >= GetNStrips()) {
169 Error("Detector2XYZ", "Invalid strip number %d (>=%d)",
170 strip, GetNStrips(), fId);
173 Double_t phi = Float_t(sector + .5) / GetNSectors() * 2 * TMath::Pi();
174 Double_t r = Float_t(strip + .5) / GetNStrips() * (fHighR - fLowR) + fLowR;
175 x = r * TMath::Cos(phi);
176 y = r * TMath::Sin(phi);
177 if (((sector / 2) % 2) == 1)
178 z += TMath::Sign(fModuleSpacing, z);
181 //____________________________________________________________________
183 AliFMDRing::XYZ2Detector(Double_t x,
187 UShort_t& strip) const
189 // Translate global coordinates (x,y,z) to detector coordinates
190 // (this,sector,strip)
192 Double_t r = TMath::Sqrt(x * x + y * y);
193 Int_t str = Int_t((r - fMinR) / GetPitch());
194 if (str < 0 || str >= GetNStrips()) return kFALSE;
196 Double_t phi = TMath::ATan2(y, x) * 180. / TMath::Pi();
197 if (phi < 0) phi = 360. + phi;
198 Int_t sec = Int_t(phi / fTheta);
199 if (sec < 0 || sec >= GetNSectors()) return kFALSE;
200 if ((sec / 2) % 2 == 1) {
201 if (TMath::Abs(z - TMath::Sign(fModuleSpacing, z)) >= 0.01)
204 else if (TMath::Abs(z) >= 0.01) return kFALSE;