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 *
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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 /// \class AliTPCBoundaryVoltError
18 /// <h2> AliTPCBoundaryVoltError class </h2>
19 /// This class calculates the space point distortions due to residual voltage errors on
20 /// the main boundaries of the TPC. For example, the inner vessel of the TPC is shifted
21 /// by a certain amount, whereas the ROCs on the A side and the C side follow this mechanical
22 /// shift (at the inner vessel) in z direction. This example can be named "conical deformation"
23 /// of the TPC field cage (see example below).
25 /// The boundary conditions can be set via two arrays (A and C side) which contain the
26 /// residual voltage setting modeling a possible shift or an inhomogeneity on the TPC field
27 /// cage. In order to avoid that the user splits the Central Electrode (CE), the settings for
28 /// the C side is taken from the array on the A side (points: A.6 and A.7). The region betweem
29 /// the points is interpolated linearly onto the boundaries.
31 /// The class uses the PoissonRelaxation2D (see AliTPCCorrection) to calculate the resulting
32 /// electrical field inhomogeneities in the (r,z)-plane. Then, the Langevin-integral formalism
33 /// is used to calculate the space point distortions.
34 /// Note: This class assumes a homogeneous magnetic field.
36 /// One has two possibilities when calculating the $dz$ distortions. The resulting distortions
37 /// are purely due to the change of the drift velocity (along with the change of the drift field)
38 /// when the SetROCDisplacement is FALSE. This emulates for example a Gating-Grid Voltage offset
39 /// without moving the ROCs. When the flag is set to TRUE, the ROCs are assumed to be misaligned
40 /// and the corresponding offset in z is added.
41 /// ![Picture from ROOT macro](AliTPCBoundaryVoltError_cxx_1511bb7.png)
43 /// \author Jim Thomas, Stefan Rossegger
48 #include "TGeoGlobalMagField.h"
49 #include "AliTPCcalibDB.h"
50 #include "AliTPCParam.h"
55 #include "AliTPCROC.h"
56 #include "AliTPCBoundaryVoltError.h"
59 ClassImp(AliTPCBoundaryVoltError)
62 AliTPCBoundaryVoltError::AliTPCBoundaryVoltError()
63 : AliTPCCorrection("BoundaryVoltError","Boundary Voltage Error"),
65 fROCdisplacement(kTRUE),
69 // default constructor
71 for (Int_t i=0; i<8; i++){
73 if (i<6) fBoundariesC[i]= 0;
77 AliTPCBoundaryVoltError::~AliTPCBoundaryVoltError() {
78 /// default destructor
85 Bool_t AliTPCBoundaryVoltError::AddCorrectionCompact(AliTPCCorrection* corr, Double_t weight){
86 /// Add correction and make them compact
88 /// - origin of distortion/correction are additive
89 /// - only correction ot the same type supported ()
92 AliError("Zerro pointer - correction");
95 AliTPCBoundaryVoltError* corrC = dynamic_cast<AliTPCBoundaryVoltError *>(corr);
97 AliError(TString::Format("Inconsistent class types: %s\%s",IsA()->GetName(),corr->IsA()->GetName()).Data());
100 if (fROCdisplacement!=corrC->fROCdisplacement){
101 AliError(TString::Format("Inconsistent fROCdisplacement : %s\%s",IsA()->GetName(),corr->IsA()->GetName()).Data());
104 for (Int_t i=0;i <8; i++){
105 fBoundariesA[i]+= corrC->fBoundariesA[i]*weight;
106 fBoundariesC[i]+= corrC->fBoundariesC[i]*weight;
115 void AliTPCBoundaryVoltError::Init() {
116 /// Initialization funtion
118 AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
119 if (!magF) AliError("Magneticd field - not initialized");
120 Double_t bzField = magF->SolenoidField()/10.; //field in T
121 AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
122 if (!param) AliError("Parameters - not initialized");
123 Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally)
124 Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
125 Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
126 // Correction Terms for effective omegaTau; obtained by a laser calibration run
127 SetOmegaTauT1T2(wt,fT1,fT2);
129 InitBoundaryVoltErrorDistortion();
132 void AliTPCBoundaryVoltError::Update(const TTimeStamp &/*timeStamp*/) {
135 AliMagF* magF= (AliMagF*)TGeoGlobalMagField::Instance()->GetField();
136 if (!magF) AliError("Magneticd field - not initialized");
137 Double_t bzField = magF->SolenoidField()/10.; //field in T
138 AliTPCParam *param= AliTPCcalibDB::Instance()->GetParameters();
139 if (!param) AliError("Parameters - not initialized");
140 Double_t vdrift = param->GetDriftV()/1000000.; // [cm/us] // From dataBase: to be updated: per second (ideally)
141 Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
142 Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ;
143 // Correction Terms for effective omegaTau; obtained by a laser calibration run
144 SetOmegaTauT1T2(wt,fT1,fT2);
150 void AliTPCBoundaryVoltError::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) {
151 /// Calculates the correction due e.g. residual voltage errors on the TPC boundaries
154 AliInfo("Lookup table was not initialized! Perform the inizialisation now ...");
155 InitBoundaryVoltErrorDistortion();
158 Int_t order = 1 ; // FIXME: hardcoded? Linear interpolation = 1, Quadratic = 2
159 // note that the poisson solution was linearly mirroed on this grid!
160 Double_t intEr, intEphi, intdEz ;
164 r = TMath::Sqrt( x[0]*x[0] + x[1]*x[1] ) ;
165 phi = TMath::ATan2(x[1],x[0]) ;
166 if ( phi < 0 ) phi += TMath::TwoPi() ; // Table uses phi from 0 to 2*Pi
167 z = x[2] ; // Create temporary copy of x[2]
169 if ( (roc%36) < 18 ) {
170 sign = 1; // (TPC A side)
172 sign = -1; // (TPC C side)
175 if ( sign==1 && z < fgkZOffSet ) z = fgkZOffSet; // Protect against discontinuity at CE
176 if ( sign==-1 && z > -fgkZOffSet ) z = -fgkZOffSet; // Protect against discontinuity at CE
179 intEphi = 0.0; // Efield is symmetric in phi - 2D calculation
181 if ( (sign==1 && z<0) || (sign==-1 && z>0) ) // just a consistency check
182 AliError("ROC number does not correspond to z coordinate! Calculation of distortions is most likely wrong!");
184 // Get the E field integral
185 Interpolate2DEdistortion( order, r, z, fLookUpErOverEz, intEr );
186 // Get DeltaEz field integral
187 Interpolate2DEdistortion( order, r, z, fLookUpDeltaEz, intdEz );
189 // Calculate distorted position
191 phi = phi + ( fC0*intEphi - fC1*intEr ) / r;
192 r = r + ( fC0*intEr + fC1*intEphi );
195 // Calculate correction in cartesian coordinates
196 dx[0] = r * TMath::Cos(phi) - x[0];
197 dx[1] = r * TMath::Sin(phi) - x[1];
198 dx[2] = intdEz; // z distortion - (internally scaled with driftvelocity dependency
199 // on the Ez field plus the actual ROC misalignment (if set TRUE)
204 void AliTPCBoundaryVoltError::InitBoundaryVoltErrorDistortion() {
205 /// Initialization of the Lookup table which contains the solutions of the
206 /// Dirichlet boundary problem
208 const Float_t gridSizeR = (fgkOFCRadius-fgkIFCRadius) / (kRows-1) ;
209 const Float_t gridSizeZ = fgkTPCZ0 / (kColumns-1) ;
211 TMatrixD voltArrayA(kRows,kColumns), voltArrayC(kRows,kColumns); // boundary vectors
212 TMatrixD chargeDensity(kRows,kColumns); // dummy charge
213 TMatrixD arrayErOverEzA(kRows,kColumns), arrayErOverEzC(kRows,kColumns); // solution
214 TMatrixD arrayDeltaEzA(kRows,kColumns), arrayDeltaEzC(kRows,kColumns); // solution
216 Double_t rList[kRows], zedList[kColumns] ;
218 // Fill arrays with initial conditions. V on the boundary and ChargeDensity in the volume.
219 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
220 Double_t zed = j*gridSizeZ ;
222 for ( Int_t i = 0 ; i < kRows ; i++ ) {
223 Double_t radius = fgkIFCRadius + i*gridSizeR ;
225 voltArrayA(i,j) = 0; // Initialize voltArrayA to zero
226 voltArrayC(i,j) = 0; // Initialize voltArrayC to zero
227 chargeDensity(i,j) = 0; // Initialize ChargeDensity to zero - not used in this class
232 // check if boundary values are the same for the C side (for later, saving some calculation time)
234 Int_t symmetry = -1; // assume that A and C side are identical (but anti-symmetric!) // e.g conical deformation
237 // check if boundaries are different (regardless the sign)
238 for (Int_t i=0; i<8; i++) {
239 if (TMath::Abs(TMath::Abs(fBoundariesA[i]) - TMath::Abs(fBoundariesC[i])) > 1e-5)
241 sVec[i] = (Int_t)( TMath::Sign((Float_t)1.,fBoundariesA[i]) * TMath::Sign((Float_t)1.,fBoundariesC[i]));
243 if (symmetry==-1) { // still the same values?
244 // check the kind of symmetry , if even ...
245 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 )
247 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 )
250 symmetry = 0; // some of the values differ in the sign -> neither symmetric nor antisymmetric
255 // Solve the electrosatic problem in 2D
257 // Fill the complete Boundary vectors
258 // Start at IFC at CE and work anti-clockwise through IFC, ROC, OFC, and CE (clockwise for C side)
259 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
260 Double_t zed = j*gridSizeZ ;
261 for ( Int_t i = 0 ; i < kRows ; i++ ) {
262 Double_t radius = fgkIFCRadius + i*gridSizeR ;
264 // A side boundary vectors
265 if ( i == 0 ) voltArrayA(i,j) += zed *((fBoundariesA[1]-fBoundariesA[0])/((kColumns-1)*gridSizeZ))
266 + fBoundariesA[0] ; // IFC
267 if ( j == kColumns-1 ) voltArrayA(i,j) += (radius-fgkIFCRadius)*((fBoundariesA[3]-fBoundariesA[2])/((kRows-1)*gridSizeR))
268 + fBoundariesA[2] ; // ROC
269 if ( i == kRows-1 ) voltArrayA(i,j) += zed *((fBoundariesA[4]-fBoundariesA[5])/((kColumns-1)*gridSizeZ))
270 + fBoundariesA[5] ; // OFC
271 if ( j == 0 ) voltArrayA(i,j) += (radius-fgkIFCRadius)*((fBoundariesA[6]-fBoundariesA[7])/((kRows-1)*gridSizeR))
272 + fBoundariesA[7] ; // CE
275 // C side boundary vectors
276 if ( i == 0 ) voltArrayC(i,j) += zed *((fBoundariesC[1]-fBoundariesC[0])/((kColumns-1)*gridSizeZ))
277 + fBoundariesC[0] ; // IFC
278 if ( j == kColumns-1 ) voltArrayC(i,j) += (radius-fgkIFCRadius)*((fBoundariesC[3]-fBoundariesC[2])/((kRows-1)*gridSizeR))
279 + fBoundariesC[2] ; // ROC
280 if ( i == kRows-1 ) voltArrayC(i,j) += zed *((fBoundariesC[4]-fBoundariesC[5])/((kColumns-1)*gridSizeZ))
281 + fBoundariesC[5] ; // OFC
282 if ( j == 0 ) voltArrayC(i,j) += (radius-fgkIFCRadius)*((fBoundariesC[6]-fBoundariesC[7])/((kRows-1)*gridSizeR))
283 + fBoundariesC[7] ; // CE
289 voltArrayA(0,0) *= 0.5 ; // Use average boundary condition at corner
290 voltArrayA(kRows-1,0) *= 0.5 ; // Use average boundary condition at corner
291 voltArrayA(0,kColumns-1) *= 0.5 ; // Use average boundary condition at corner
292 voltArrayA(kRows-1,kColumns-1)*= 0.5 ; // Use average boundary condition at corner
295 voltArrayC(0,0) *= 0.5 ; // Use average boundary condition at corner
296 voltArrayC(kRows-1,0) *= 0.5 ; // Use average boundary condition at corner
297 voltArrayC(0,kColumns-1) *= 0.5 ; // Use average boundary condition at corner
298 voltArrayC(kRows-1,kColumns-1)*= 0.5 ; // Use average boundary condition at corner
302 // always solve the problem on the A side
303 PoissonRelaxation2D( voltArrayA, chargeDensity, arrayErOverEzA, arrayDeltaEzA,
304 kRows, kColumns, kIterations, fROCdisplacement ) ;
306 if (symmetry!=0) { // A and C side are the same ("anti-symmetric" or "symmetric")
307 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
308 for ( Int_t i = 0 ; i < kRows ; i++ ) {
309 arrayErOverEzC(i,j) = symmetry*arrayErOverEzA(i,j);
310 arrayDeltaEzC(i,j) = -symmetry*arrayDeltaEzA(i,j);
313 } else if (symmetry==0) { // A and C side are different - Solve the problem on the C side too
314 PoissonRelaxation2D( voltArrayC, chargeDensity, arrayErOverEzC, arrayDeltaEzC,
315 kRows, kColumns, kIterations, fROCdisplacement ) ;
316 for ( Int_t j = 0 ; j < kColumns ; j++ ) {
317 for ( Int_t i = 0 ; i < kRows ; i++ ) {
318 arrayDeltaEzC(i,j) = -arrayDeltaEzC(i,j); // negative z coordinate!
323 // Interpolate results onto standard grid for Electric Fields
324 Int_t ilow=0, jlow=0 ;
328 for ( Int_t i = 0 ; i < kNZ ; ++i ) {
329 z = TMath::Abs( fgkZList[i] ) ;
330 for ( Int_t j = 0 ; j < kNR ; ++j ) {
331 // Linear interpolation !!
333 Search( kRows, rList, r, ilow ) ; // Note switch - R in rows and Z in columns
334 Search( kColumns, zedList, z, jlow ) ;
335 if ( ilow < 0 ) ilow = 0 ; // check if out of range
336 if ( jlow < 0 ) jlow = 0 ;
337 if ( ilow + 1 >= kRows - 1 ) ilow = kRows - 2 ;
338 if ( jlow + 1 >= kColumns - 1 ) jlow = kColumns - 2 ;
340 if (fgkZList[i]>0) { // A side solution
341 saveEr[0] = arrayErOverEzA(ilow,jlow) +
342 (arrayErOverEzA(ilow,jlow+1)-arrayErOverEzA(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
343 saveEr[1] = arrayErOverEzA(ilow+1,jlow) +
344 (arrayErOverEzA(ilow+1,jlow+1)-arrayErOverEzA(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
345 saveEz[0] = arrayDeltaEzA(ilow,jlow) +
346 (arrayDeltaEzA(ilow,jlow+1)-arrayDeltaEzA(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
347 saveEz[1] = arrayDeltaEzA(ilow+1,jlow) +
348 (arrayDeltaEzA(ilow+1,jlow+1)-arrayDeltaEzA(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
350 } else if (fgkZList[i]<0) { // C side solution
351 saveEr[0] = arrayErOverEzC(ilow,jlow) +
352 (arrayErOverEzC(ilow,jlow+1)-arrayErOverEzC(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
353 saveEr[1] = arrayErOverEzC(ilow+1,jlow) +
354 (arrayErOverEzC(ilow+1,jlow+1)-arrayErOverEzC(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
355 saveEz[0] = arrayDeltaEzC(ilow,jlow) +
356 (arrayDeltaEzC(ilow,jlow+1)-arrayDeltaEzC(ilow,jlow))*(z-zedList[jlow])/gridSizeZ ;
357 saveEz[1] = arrayDeltaEzC(ilow+1,jlow) +
358 (arrayDeltaEzC(ilow+1,jlow+1)-arrayDeltaEzC(ilow+1,jlow))*(z-zedList[jlow])/gridSizeZ ;
361 AliWarning("Field calculation at z=0 (CE) is not allowed!");
362 saveEr[0]=0; saveEr[1]=0;
363 saveEz[0]=0; saveEz[1]=0;
365 fLookUpErOverEz[i][j] = saveEr[0] + (saveEr[1]-saveEr[0])*(r-rList[ilow])/gridSizeR ;
366 fLookUpDeltaEz[i][j] = saveEz[0] + (saveEz[1]-saveEz[0])*(r-rList[ilow])/gridSizeR ;
372 chargeDensity.Clear();
373 arrayErOverEzA.Clear();
374 arrayErOverEzC.Clear();
375 arrayDeltaEzA.Clear();
376 arrayDeltaEzC.Clear();
382 void AliTPCBoundaryVoltError::Print(const Option_t* option) const {
383 /// Print function to check the settings of the boundary vectors
384 /// option=="a" prints the C0 and C1 coefficents for calibration purposes
386 TString opt = option; opt.ToLower();
387 printf("%s\n",GetTitle());
388 printf(" - Voltage settings (on the TPC boundaries) - linearly interpolated\n");
389 printf(" : A-side (anti-clockwise)\n");
390 printf(" (0,1):\t IFC (CE) : %3.1f V \t IFC (ROC): %3.1f V \n",fBoundariesA[0],fBoundariesA[1]);
391 printf(" (2,3):\t ROC (IFC): %3.1f V \t ROC (OFC): %3.1f V \n",fBoundariesA[2],fBoundariesA[3]);
392 printf(" (4,5):\t OFC (ROC): %3.1f V \t OFC (CE) : %3.1f V \n",fBoundariesA[4],fBoundariesA[5]);
393 printf(" (6,7):\t CE (OFC): %3.1f V \t CE (IFC): %3.1f V \n",fBoundariesA[6],fBoundariesA[7]);
394 printf(" : C-side (clockwise)\n");
395 printf(" (0,1):\t IFC (CE) : %3.1f V \t IFC (ROC): %3.1f V \n",fBoundariesC[0],fBoundariesC[1]);
396 printf(" (2,3):\t ROC (IFC): %3.1f V \t ROC (OFC): %3.1f V \n",fBoundariesC[2],fBoundariesC[3]);
397 printf(" (4,5):\t OFC (ROC): %3.1f V \t OFC (CE) : %3.1f V \n",fBoundariesC[4],fBoundariesC[5]);
398 printf(" (6,7):\t CE (OFC): %3.1f V \t CE (IFC): %3.1f V \n",fBoundariesC[6],fBoundariesC[7]);
400 // Check wether the settings of the Central Electrode agree (on the A and C side)
401 // Note: they have to be antisymmetric!
402 if (( TMath::Abs(fBoundariesA[6]+fBoundariesC[6])>1e-5) || ( TMath::Abs(fBoundariesA[7]+fBoundariesC[7])>1e-5 ) ){
403 AliWarning("Boundary parameters for the Central Electrode (CE) are not anti-symmetric! HOW DID YOU MANAGE THAT?");
404 AliWarning("Congratulations, you just splitted the Central Electrode of the TPC!");
405 AliWarning("Non-physical settings of the boundary parameter at the Central Electrode");
408 if (opt.Contains("a")) { // Print all details
409 printf(" - T1: %1.4f, T2: %1.4f \n",fT1,fT2);
410 printf(" - C1: %1.4f, C0: %1.4f \n",fC1,fC0);
414 AliError("Lookup table was not initialized! You should do InitBoundaryVoltErrorDistortion() ...");
419 void AliTPCBoundaryVoltError::SetBoundariesA(Float_t boundariesA[8]){
420 /// set voltage errors on the TPC boundaries - A side
422 /// Start at IFC at the Central electrode and work anti-clockwise (clockwise for C side) through
423 /// IFC, ROC, OFC, and CE. The boundary conditions are currently defined to be a linear
424 /// interpolation between pairs of numbers in the Boundary (e.g. fBoundariesA) vector.
425 /// The first pair of numbers represent the beginning and end of the Inner Field cage, etc.
426 /// The unit of the error potential vector is [Volt], whereas 1mm shift of the IFC would
427 /// correspond to ~ 40 V
429 /// Note: The setting for the CE will be passed to the C side!
431 for (Int_t i=0; i<8; i++) {
432 fBoundariesA[i]= boundariesA[i];
433 if (i>5) fBoundariesC[i]= -boundariesA[i]; // setting for the CE is passed to C side
437 void AliTPCBoundaryVoltError::SetBoundariesC(Float_t boundariesC[6]){
438 /// set voltage errors on the TPC boundaries - C side
440 /// Start at IFC at the Central electrode and work clockwise (for C side) through
441 /// IFC, ROC and OFC. The boundary conditions are currently defined to be a linear
442 /// interpolation between pairs of numbers in the Boundary (e.g. fBoundariesC) vector.
443 /// The first pair of numbers represent the beginning and end of the Inner Field cage, etc.
444 /// The unit of the error potential vector is [Volt], whereas 1mm shift of the IFC would
445 /// correspond to ~ 40 V
447 /// Note: The setting for the CE will be taken from the A side (pos 6 and 7)!
449 for (Int_t i=0; i<6; i++) {
450 fBoundariesC[i]= boundariesC[i];