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 *
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12 * about the suitability of this software for any purpose. It is *
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14 **************************************************************************/
16 //////////////////////////////////////////////////////////////////////////////
18 // AliTPCBoundaryVoltError class //
19 // The class calculates the space point distortions due to residual voltage //
20 // errors on the main boundaries of the TPC. For example, the inner vessel //
21 // of the TPC is shifted by a certain amount, whereas the ROCs on the A side//
22 // and the ROCs on the C side follow this mechanical shift (at the inner //
23 // vessel) in z direction (see example below). This example is commonly //
24 // named "conical deformation" of the TPC field cage. //
26 // The class allows "effective Omega Tau" corrections. //
28 // NOTE: This class is capable of calculating z distortions due to //
29 // drift velocity change in dependence of the electric field!!! //
31 // date: 01/06/2010 //
32 // Authors: Jim Thomas, Stefan Rossegger //
34 // Example usage (e.g +1mm shift of "conical deformation") //
35 // AliTPCBoundaryVoltError bve; //
36 // Float_t boundA[8] = {-40,-40,-40,0,0,0,0,-40}; // voltages A-side //
37 // Float_t boundC[6] = { 40, 40, 40,0,0,0}; // voltages C-side //
38 // bve.SetBoundariesA(boundA); //
39 // bve.SetBoundariesC(boundC); //
40 // bve.SetOmegaTauT1T2(0.32,1.,1.); // values ideally from OCDB //
41 // // initialization of the look up //
42 // bve.InitBoundaryVoltErrorDistortion(); //
43 // // plot dRPhi distortions ... //
44 // bve.CreateHistoDRPhiinZR(1.,100,100)->Draw("surf2"); //
45 //////////////////////////////////////////////////////////////////////////////
48 #include "TGeoGlobalMagField.h"
49 #include "AliTPCcalibDB.h"
50 #include "AliTPCParam.h"
55 #include "AliTPCROC.h"
56 #include "AliTPCBoundaryVoltError.h"
58 ClassImp(AliTPCBoundaryVoltError)
60 AliTPCBoundaryVoltError::AliTPCBoundaryVoltError()
61 : AliTPCCorrection("BoundaryVoltError","Boundary Voltage Error"),
63 fROCdisplacement(kTRUE),
67 // default constructor
69 for (Int_t i=0; i<8; i++){
71 if (i<6) fBoundariesC[i]= 0;
75 AliTPCBoundaryVoltError::~AliTPCBoundaryVoltError() {
83 void AliTPCBoundaryVoltError::Init() {
85 // Initialization funtion
88 AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
89 if (!magF) AliError("Magneticd field - not initialized");
90 Double_t bzField = magF->SolenoidField()/10.; //field in T
91 AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
92 if (!param) AliError("Parameters - not initialized");
93 Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally)
94 Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
95 Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
96 // Correction Terms for effective omegaTau; obtained by a laser calibration run
97 SetOmegaTauT1T2(wt,fT1,fT2);
99 InitBoundaryVoltErrorDistortion();
102 void AliTPCBoundaryVoltError::Update(const TTimeStamp &/*timeStamp*/) {
106 AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
107 if (!magF) AliError("Magneticd field - not initialized");
108 Double_t bzField = magF->SolenoidField()/10.; //field in T
109 AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
110 if (!param) AliError("Parameters - not initialized");
111 Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally)
112 Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
113 Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
114 // Correction Terms for effective omegaTau; obtained by a laser calibration run
115 SetOmegaTauT1T2(wt,fT1,fT2);
121 void AliTPCBoundaryVoltError::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) {
123 // Calculates the correction due e.g. residual voltage errors on the TPC boundaries
127 AliInfo("Lookup table was not initialized! Perform the inizialisation now ...");
128 InitBoundaryVoltErrorDistortion();
131 Int_t order = 1 ; // FIXME: hardcoded? Linear interpolation = 1, Quadratic = 2
132 // note that the poisson solution was linearly mirroed on this grid!
133 Double_t intEr, intEphi, intdEz ;
137 r = TMath::Sqrt( x[0]*x[0] + x[1]*x[1] ) ;
138 phi = TMath::ATan2(x[1],x[0]) ;
139 if ( phi < 0 ) phi += TMath::TwoPi() ; // Table uses phi from 0 to 2*Pi
140 z = x[2] ; // Create temporary copy of x[2]
142 if ( (roc%36) < 18 ) {
143 sign = 1; // (TPC A side)
145 sign = -1; // (TPC C side)
148 if ( sign==1 && z < fgkZOffSet ) z = fgkZOffSet; // Protect against discontinuity at CE
149 if ( sign==-1 && z > -fgkZOffSet ) z = -fgkZOffSet; // Protect against discontinuity at CE
152 intEphi = 0.0; // Efield is symmetric in phi - 2D calculation
154 if ( (sign==1 && z<0) || (sign==-1 && z>0) ) // just a consistency check
155 AliError("ROC number does not correspond to z coordinate! Calculation of distortions is most likely wrong!");
157 // Get the E field integral
158 Interpolate2DEdistortion( order, r, z, fLookUpErOverEz, intEr );
159 // Get DeltaEz field integral
160 Interpolate2DEdistortion( order, r, z, fLookUpDeltaEz, intdEz );
162 // Calculate distorted position
164 phi = phi + ( fC0*intEphi - fC1*intEr ) / r;
165 r = r + ( fC0*intEr + fC1*intEphi );
168 // Calculate correction in cartesian coordinates
169 dx[0] = r * TMath::Cos(phi) - x[0];
170 dx[1] = r * TMath::Sin(phi) - x[1];
171 dx[2] = intdEz; // z distortion - (internally scaled with driftvelocity dependency
172 // on the Ez field plus the actual ROC misalignment (if set TRUE)
177 void AliTPCBoundaryVoltError::InitBoundaryVoltErrorDistortion() {
179 // Initialization of the Lookup table which contains the solutions of the
180 // Dirichlet boundary problem
183 const Float_t gridSizeR = (fgkOFCRadius-fgkIFCRadius) / (kRows-1) ;
184 const Float_t gridSizeZ = fgkTPCZ0 / (kColumns-1) ;
186 TMatrixD voltArrayA(kRows,kColumns), voltArrayC(kRows,kColumns); // boundary vectors
187 TMatrixD chargeDensity(kRows,kColumns); // dummy charge
188 TMatrixD arrayErOverEzA(kRows,kColumns), arrayErOverEzC(kRows,kColumns); // solution
189 TMatrixD arrayDeltaEzA(kRows,kColumns), arrayDeltaEzC(kRows,kColumns); // solution
191 Double_t rList[kRows], zedList[kColumns] ;
193 // Fill arrays with initial conditions. V on the boundary and ChargeDensity in the volume.
194 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
195 Double_t zed = j*gridSizeZ ;
197 for ( Int_t i = 0 ; i < kRows ; i++ ) {
198 Double_t radius = fgkIFCRadius + i*gridSizeR ;
200 voltArrayA(i,j) = 0; // Initialize voltArrayA to zero
201 voltArrayC(i,j) = 0; // Initialize voltArrayC to zero
202 chargeDensity(i,j) = 0; // Initialize ChargeDensity to zero - not used in this class
207 // check if boundary values are the same for the C side (for later, saving some calculation time)
209 Int_t symmetry = -1; // assume that A and C side are identical (but anti-symmetric!) // e.g conical deformation
212 // check if boundaries are different (regardless the sign)
213 for (Int_t i=0; i<8; i++) {
214 if (TMath::Abs(TMath::Abs(fBoundariesA[i]) - TMath::Abs(fBoundariesC[i])) > 1e-5)
216 sVec[i] = (Int_t)( TMath::Sign((Float_t)1.,fBoundariesA[i]) * TMath::Sign((Float_t)1.,fBoundariesC[i]));
218 if (symmetry==-1) { // still the same values?
219 // check the kind of symmetry , if even ...
220 if (sVec[0]==1 && sVec[1]==1 && sVec[2]==1 && sVec[3]==1 && sVec[4]==1 && sVec[5]==1 && sVec[6]==1 && sVec[7]==1 )
222 else if (sVec[0]==-1 && sVec[1]==-1 && sVec[2]==-1 && sVec[3]==-1 && sVec[4]==-1 && sVec[5]==-1 && sVec[6]==-1 && sVec[7]==-1 )
225 symmetry = 0; // some of the values differ in the sign -> neither symmetric nor antisymmetric
230 // Solve the electrosatic problem in 2D
232 // Fill the complete Boundary vectors
233 // Start at IFC at CE and work anti-clockwise through IFC, ROC, OFC, and CE (clockwise for C side)
234 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
235 Double_t zed = j*gridSizeZ ;
236 for ( Int_t i = 0 ; i < kRows ; i++ ) {
237 Double_t radius = fgkIFCRadius + i*gridSizeR ;
239 // A side boundary vectors
240 if ( i == 0 ) voltArrayA(i,j) += zed *((fBoundariesA[1]-fBoundariesA[0])/((kColumns-1)*gridSizeZ))
241 + fBoundariesA[0] ; // IFC
242 if ( j == kColumns-1 ) voltArrayA(i,j) += (radius-fgkIFCRadius)*((fBoundariesA[3]-fBoundariesA[2])/((kRows-1)*gridSizeR))
243 + fBoundariesA[2] ; // ROC
244 if ( i == kRows-1 ) voltArrayA(i,j) += zed *((fBoundariesA[4]-fBoundariesA[5])/((kColumns-1)*gridSizeZ))
245 + fBoundariesA[5] ; // OFC
246 if ( j == 0 ) voltArrayA(i,j) += (radius-fgkIFCRadius)*((fBoundariesA[6]-fBoundariesA[7])/((kRows-1)*gridSizeR))
247 + fBoundariesA[7] ; // CE
250 // C side boundary vectors
251 if ( i == 0 ) voltArrayC(i,j) += zed *((fBoundariesC[1]-fBoundariesC[0])/((kColumns-1)*gridSizeZ))
252 + fBoundariesC[0] ; // IFC
253 if ( j == kColumns-1 ) voltArrayC(i,j) += (radius-fgkIFCRadius)*((fBoundariesC[3]-fBoundariesC[2])/((kRows-1)*gridSizeR))
254 + fBoundariesC[2] ; // ROC
255 if ( i == kRows-1 ) voltArrayC(i,j) += zed *((fBoundariesC[4]-fBoundariesC[5])/((kColumns-1)*gridSizeZ))
256 + fBoundariesC[5] ; // OFC
257 if ( j == 0 ) voltArrayC(i,j) += (radius-fgkIFCRadius)*((fBoundariesC[6]-fBoundariesC[7])/((kRows-1)*gridSizeR))
258 + fBoundariesC[7] ; // CE
264 voltArrayA(0,0) *= 0.5 ; // Use average boundary condition at corner
265 voltArrayA(kRows-1,0) *= 0.5 ; // Use average boundary condition at corner
266 voltArrayA(0,kColumns-1) *= 0.5 ; // Use average boundary condition at corner
267 voltArrayA(kRows-1,kColumns-1)*= 0.5 ; // Use average boundary condition at corner
270 voltArrayC(0,0) *= 0.5 ; // Use average boundary condition at corner
271 voltArrayC(kRows-1,0) *= 0.5 ; // Use average boundary condition at corner
272 voltArrayC(0,kColumns-1) *= 0.5 ; // Use average boundary condition at corner
273 voltArrayC(kRows-1,kColumns-1)*= 0.5 ; // Use average boundary condition at corner
277 // always solve the problem on the A side
278 PoissonRelaxation2D( voltArrayA, chargeDensity, arrayErOverEzA, arrayDeltaEzA,
279 kRows, kColumns, kIterations, fROCdisplacement ) ;
281 if (symmetry!=0) { // A and C side are the same ("anti-symmetric" or "symmetric")
282 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
283 for ( Int_t i = 0 ; i < kRows ; i++ ) {
284 arrayErOverEzC(i,j) = symmetry*arrayErOverEzA(i,j);
285 arrayDeltaEzC(i,j) = -symmetry*arrayDeltaEzA(i,j);
288 } else if (symmetry==0) { // A and C side are different - Solve the problem on the C side too
289 PoissonRelaxation2D( voltArrayC, chargeDensity, arrayErOverEzC, arrayDeltaEzC,
290 kRows, kColumns, kIterations, fROCdisplacement ) ;
291 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
292 for ( Int_t i = 0 ; i < kRows ; i++ ) {
293 arrayDeltaEzC(i,j) = -arrayDeltaEzC(i,j); // negative z coordinate!
298 // Interpolate results onto standard grid for Electric Fields
299 Int_t ilow=0, jlow=0 ;
303 for ( Int_t i = 0 ; i < kNZ ; ++i ) {
304 z = TMath::Abs( fgkZList[i] ) ;
305 for ( Int_t j = 0 ; j < kNR ; ++j ) {
306 // Linear interpolation !!
308 Search( kRows, rList, r, ilow ) ; // Note switch - R in rows and Z in columns
309 Search( kColumns, zedList, z, jlow ) ;
310 if ( ilow < 0 ) ilow = 0 ; // check if out of range
311 if ( jlow < 0 ) jlow = 0 ;
312 if ( ilow + 1 >= kRows - 1 ) ilow = kRows - 2 ;
313 if ( jlow + 1 >= kColumns - 1 ) jlow = kColumns - 2 ;
315 if (fgkZList[i]>0) { // A side solution
316 saveEr[0] = arrayErOverEzA(ilow,jlow) +
317 (arrayErOverEzA(ilow,jlow+1)-arrayErOverEzA(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
318 saveEr[1] = arrayErOverEzA(ilow+1,jlow) +
319 (arrayErOverEzA(ilow+1,jlow+1)-arrayErOverEzA(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
320 saveEz[0] = arrayDeltaEzA(ilow,jlow) +
321 (arrayDeltaEzA(ilow,jlow+1)-arrayDeltaEzA(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
322 saveEz[1] = arrayDeltaEzA(ilow+1,jlow) +
323 (arrayDeltaEzA(ilow+1,jlow+1)-arrayDeltaEzA(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
325 } else if (fgkZList[i]<0) { // C side solution
326 saveEr[0] = arrayErOverEzC(ilow,jlow) +
327 (arrayErOverEzC(ilow,jlow+1)-arrayErOverEzC(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
328 saveEr[1] = arrayErOverEzC(ilow+1,jlow) +
329 (arrayErOverEzC(ilow+1,jlow+1)-arrayErOverEzC(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
330 saveEz[0] = arrayDeltaEzC(ilow,jlow) +
331 (arrayDeltaEzC(ilow,jlow+1)-arrayDeltaEzC(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
332 saveEz[1] = arrayDeltaEzC(ilow+1,jlow) +
333 (arrayDeltaEzC(ilow+1,jlow+1)-arrayDeltaEzC(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
336 AliWarning("Field calculation at z=0 (CE) is not allowed!");
337 saveEr[0]=0; saveEr[1]=0;
338 saveEz[0]=0; saveEz[1]=0;
340 fLookUpErOverEz[i][j] = saveEr[0] + (saveEr[1]-saveEr[0])*(r-rList[ilow])/gridSizeR ;
341 fLookUpDeltaEz[i][j] = saveEz[0] + (saveEz[1]-saveEz[0])*(r-rList[ilow])/gridSizeR ;
347 chargeDensity.Clear();
348 arrayErOverEzA.Clear();
349 arrayErOverEzC.Clear();
350 arrayDeltaEzA.Clear();
351 arrayDeltaEzC.Clear();
357 void AliTPCBoundaryVoltError::Print(const Option_t* option) const {
359 // Print function to check the settings of the boundary vectors
360 // option=="a" prints the C0 and C1 coefficents for calibration purposes
363 TString opt = option; opt.ToLower();
364 printf("%s\n",GetTitle());
365 printf(" - Voltage settings (on the TPC boundaries) - linearly interpolated\n");
366 printf(" : A-side (anti-clockwise)\n");
367 printf(" (0,1):\t IFC (CE) : %3.1f V \t IFC (ROC): %3.1f V \n",fBoundariesA[0],fBoundariesA[1]);
368 printf(" (2,3):\t ROC (IFC): %3.1f V \t ROC (OFC): %3.1f V \n",fBoundariesA[2],fBoundariesA[3]);
369 printf(" (4,5):\t OFC (ROC): %3.1f V \t OFC (CE) : %3.1f V \n",fBoundariesA[4],fBoundariesA[5]);
370 printf(" (6,7):\t CE (OFC): %3.1f V \t CE (IFC): %3.1f V \n",fBoundariesA[6],fBoundariesA[7]);
371 printf(" : C-side (clockwise)\n");
372 printf(" (0,1):\t IFC (CE) : %3.1f V \t IFC (ROC): %3.1f V \n",fBoundariesC[0],fBoundariesC[1]);
373 printf(" (2,3):\t ROC (IFC): %3.1f V \t ROC (OFC): %3.1f V \n",fBoundariesC[2],fBoundariesC[3]);
374 printf(" (4,5):\t OFC (ROC): %3.1f V \t OFC (CE) : %3.1f V \n",fBoundariesC[4],fBoundariesC[5]);
375 printf(" (6,7):\t CE (OFC): %3.1f V \t CE (IFC): %3.1f V \n",fBoundariesC[6],fBoundariesC[7]);
377 // Check wether the settings of the Central Electrode agree (on the A and C side)
378 // Note: they have to be antisymmetric!
379 if (( TMath::Abs(fBoundariesA[6]+fBoundariesC[6])>1e-5) || ( TMath::Abs(fBoundariesA[7]+fBoundariesC[7])>1e-5 ) ){
380 AliWarning("Boundary parameters for the Central Electrode (CE) are not anti-symmetric! HOW DID YOU MANAGE THAT?");
381 AliWarning("Congratulations, you just splitted the Central Electrode of the TPC!");
382 AliWarning("Non-physical settings of the boundary parameter at the Central Electrode");
385 if (opt.Contains("a")) { // Print all details
386 printf(" - T1: %1.4f, T2: %1.4f \n",fT1,fT2);
387 printf(" - C1: %1.4f, C0: %1.4f \n",fC1,fC0);
391 AliError("Lookup table was not initialized! You should do InitBoundaryVoltErrorDistortion() ...");
396 void AliTPCBoundaryVoltError::SetBoundariesA(Float_t boundariesA[8]){
398 // set voltage errors on the TPC boundaries - A side
400 // Start at IFC at the Central electrode and work anti-clockwise (clockwise for C side) through
401 // IFC, ROC, OFC, and CE. The boundary conditions are currently defined to be a linear
402 // interpolation between pairs of numbers in the Boundary (e.g. fBoundariesA) vector.
403 // The first pair of numbers represent the beginning and end of the Inner Field cage, etc.
404 // The unit of the error potential vector is [Volt], whereas 1mm shift of the IFC would
405 // correspond to ~ 40 V
407 // Note: The setting for the CE will be passed to the C side!
409 for (Int_t i=0; i<8; i++) {
410 fBoundariesA[i]= boundariesA[i];
411 if (i>5) fBoundariesC[i]= -boundariesA[i]; // setting for the CE is passed to C side
415 void AliTPCBoundaryVoltError::SetBoundariesC(Float_t boundariesC[6]){
417 // set voltage errors on the TPC boundaries - C side
419 // Start at IFC at the Central electrode and work clockwise (for C side) through
420 // IFC, ROC and OFC. The boundary conditions are currently defined to be a linear
421 // interpolation between pairs of numbers in the Boundary (e.g. fBoundariesC) vector.
422 // The first pair of numbers represent the beginning and end of the Inner Field cage, etc.
423 // The unit of the error potential vector is [Volt], whereas 1mm shift of the IFC would
424 // correspond to ~ 40 V
426 // Note: The setting for the CE will be taken from the A side (pos 6 and 7)!
428 for (Int_t i=0; i<6; i++) {
429 fBoundariesC[i]= boundariesC[i];