[u/mrichter/AliRoot.git] / TPC / AliTPCGGVoltError.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

////////////////////////////////////////////////////////////////////////////
//                                                                        //
// AliTPCGGVoltError class                                                //
// The class calculates the electric field and space point distortions    //
// due a Gating Grid (GG) Error voltage. It uses the exact calculation    //
// technique based on bessel functions. (original code from STAR)         //
// The class allows "effective Omega Tau" corrections.                    // 
//                                                                        //
// date: 27/04/2010                                                       //
// Authors: Jim Thomas, Stefan Rossegger, Magnus Mager                    //
//                                                                        //
// Example usage:                                                         //
//  AliTPCGGVoltError GGerror;                                            //
//  GGerror.SetOmegaTauT1T2(0.32,1.,1.); // values ideally from OCDB      //
//  GGerror.SetDeltaVGGA(50.);           // voltage offset A-side         //
//  GGerror.SetDeltaVGGC(50.);           // voltage offset C-side         //
//  GGerror.InitGGVoltErrorDistortion(); // initialization of the look up //
//  // plot dRPhi distortions ...                                         //
//  GGerror.CreateHistoDRPhiinZR(1.,100,100)->Draw("surf2");              //
////////////////////////////////////////////////////////////////////////////


#include "AliTPCGGVoltError.h"
#include <TMath.h>

AliTPCGGVoltError::AliTPCGGVoltError()
  : AliTPCCorrection("GGVoltError","GatingGrid (GG) Voltage Error"),
    fC0(0.),fC1(0.),
    fDeltaVGGA(0.),fDeltaVGGC(0.)
{
  //
  // default constructor
  //
}

AliTPCGGVoltError::~AliTPCGGVoltError() {
  //
  // default destructor
  //
}

void AliTPCGGVoltError::Init() {
  //
  // Initialization funtion (not used at the moment)
  //
  
  // Set default parameters
  // FIXME: Ask the database for these entries
  
  Double_t vdrift = 2.6; // [cm/us]   // From dataBase: to be updated: per second (ideally)
  Double_t bzField = -0.5; // [Tesla] // From dataBase: to be updated: per run

  Double_t ezField = 400; // [V/cm]   // to be updated: never (hopefully)
  Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ; 

  // Correction Terms for effective omegaTau; obtained by a laser calibration run
  Double_t t1 = 0.9;   // ideally from database
  Double_t t2 = 1.5;   // ideally from database

  SetOmegaTauT1T2(wt,t1,t2);

  SetDeltaVGGA(0.0);//  ideally from the database
  SetDeltaVGGC(0.0);//  ideally from the database
}

void AliTPCGGVoltError::Update(const TTimeStamp &/*timeStamp*/) {
  //
  // Update function 
  //

  Double_t vdrift = 2.6; // [cm/us]   // From dataBase: to be updated: per second (ideally)
  Double_t bzField = -0.5; // [Tesla] // From dataBase: to be updated: per run

  Double_t ezField = 400; // [V/cm]   // to be updated: never (hopefully)
  Double_t wt = -10.0 * (bzField*10) * vdrift / ezField ; 

  // Correction Terms for effective omegaTau; obtained by a laser calibration run
  Double_t t1 = 0.9;   // ideally from database
  Double_t t2 = 1.5;   // ideally from database

  SetOmegaTauT1T2(wt,t1,t2);
}


void AliTPCGGVoltError::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) {

  //
  // Gated Grid Voltage Error
  //
  // Calculates the effect of having an incorrect voltage on the A or C end plate Gated Grids.
  //
  // Electrostatic Equations from StarNote SN0253 by Howard Wieman.
  //
  
  Int_t   order     = 1 ;               // FIXME: hardcoded? Linear interpolation = 1, Quadratic = 2         
 
  Double_t intEr, intEphi ;
  Double_t r, phi, z ;
  Int_t    sign ;

  Double_t deltaVGG;
  
  r   = TMath::Sqrt( x[0]*x[0] + x[1]*x[1] );
  phi = TMath::ATan2(x[1],x[0]);
  if ( phi < 0 ) phi += TMath::TwoPi();                   // Table uses phi from 0 to 2*Pi
  z   = x[2] ;

  if ( (roc%36) < 18 ) {
    sign =  1; 
    deltaVGG = fDeltaVGGA;           // (TPC End A)
  } else {
    sign = -1;                       // (TPC End C)
    deltaVGG = fDeltaVGGC; 
  }

  if ( sign==1  && z <  fgkZOffSet ) z =  fgkZOffSet;    // Protect against discontinuity at CE
  if ( sign==-1 && z > -fgkZOffSet ) z = -fgkZOffSet;    // Protect against discontinuity at CE

  Interpolate2DEdistortion( order, r, z, fGGVoltErrorER, intEr );
  intEphi = 0.0;  // Efield is symmetric in phi

  // Calculate distorted position
  if ( r > 0.0 ) {
    phi =  phi + deltaVGG*( fC0*intEphi - fC1*intEr ) / r;      
    r   =  r   + deltaVGG*( fC0*intEr   + fC1*intEphi );  
  }
  
  // Calculate correction in cartesian coordinates
  dx[0] = r * TMath::Cos(phi) - x[0];
  dx[1] = r * TMath::Sin(phi) - x[1]; 
  dx[2] = 0.; // z distortion not implemented (1st order distortions)

}


Float_t AliTPCGGVoltError::GetIntErOverEz(const Float_t x[],const Short_t roc) {
  //
  // This function is purely for calibration purposes
  // Calculates the integral (int Er/Ez dz) for the setted GG voltage offset 
  // 
  
  Int_t   order     = 1 ;     // FIXME: so far hardcoded? Linear interpolation = 1, Quadratic = 2         
  
  Double_t intEr;
  Double_t r, phi, z ;
  Int_t    sign ;
  
  Double_t deltaVGG;
  
  r   = TMath::Sqrt( x[0]*x[0] + x[1]*x[1] );
  phi = TMath::ATan2(x[1],x[0]);
  if ( phi < 0 ) phi += TMath::TwoPi();        // Table uses phi from 0 to 2*Pi
  z   = x[2] ;

  if ( (roc%36) < 18 ) {
    sign =  1; 
    deltaVGG = fDeltaVGGA;           // (TPC End A)
  } else {
    sign = -1;                       // (TPC End C)
    deltaVGG = fDeltaVGGC; 
  }

  if ( sign==1  && z <  fgkZOffSet ) z =  fgkZOffSet;    // Protect against discontinuity at CE
  if ( sign==-1 && z > -fgkZOffSet ) z = -fgkZOffSet;    // Protect against discontinuity at CE

  Interpolate2DEdistortion(order, r, z, fGGVoltErrorER, intEr );

  return (intEr*deltaVGG);

}

void AliTPCGGVoltError::InitGGVoltErrorDistortion() {
  //
  // Initialization of the Lookup table which contains the solutions of the GG Error problem
  //

  Double_t r,z;
  Int_t nterms = 100 ;
  for ( Int_t i = 0 ; i < kNZ ; ++i ) {
    z = fgkZList[i] ;
    for ( Int_t j = 0 ; j < kNR ; ++j ) {
      r = fgkRList[j] ;
      fGGVoltErrorER[i][j] = 0.0 ; 	    
      Double_t intz = 0.0 ;
      for ( Int_t n = 1 ; n < nterms ; ++n ) {
	Double_t k    =  n * TMath::Pi() / fgkTPC_Z0 ;
	Double_t ein  =  0 ;                    // Error potential on the IFC
	Double_t eout =  0 ;                    // Error potential on the OFC
	if ( z < 0 ) {
	  ein   =  -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;       
	  eout  =  -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;       
	}
	if ( z == 0 ) continue ;
	if ( z > 0 ) {
	  ein   =  -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;       
	  eout  =  -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;       
	}
	Double_t an   =  ein  * TMath::BesselK0( k*fgkOFCRadius ) - eout * TMath::BesselK0( k*fgkIFCRadius ) ;
	Double_t bn   =  eout * TMath::BesselI0( k*fgkIFCRadius ) - ein  * TMath::BesselI0( k*fgkOFCRadius ) ;
	Double_t numerator =
	  an * TMath::BesselI1( k*r ) - bn * TMath::BesselK1( k*r ) ;
	Double_t denominator =
	  TMath::BesselK0( k*fgkOFCRadius ) * TMath::BesselI0( k*fgkIFCRadius ) -
	  TMath::BesselK0( k*fgkIFCRadius ) * TMath::BesselI0( k*fgkOFCRadius ) ;
	Double_t zterm = TMath::Cos( k*(fgkTPC_Z0-TMath::Abs(z)) ) - 1 ;
	intz += zterm * numerator / denominator ;
	// Assume series converges, break if small terms
	if ( n>10 && TMath::Abs(intz)*1.e-10 > TMath::Abs(numerator/denominator) ) break;   
      }
      fGGVoltErrorER[i][j] = (Double_t) intz ;

    }
  }
}


void AliTPCGGVoltError::Print(Option_t* option) const {
  //
  // Print function to check the settings (e.g. voltage offsets)
  // option=="a" prints the C0 and C1 coefficents for calibration purposes
  //

  TString opt = option; opt.ToLower();
  printf("%s\n",GetTitle());
  printf(" - GG Voltage offset: A-side: %3.1f V, C-side: %3.1f V \n",fDeltaVGGA,fDeltaVGGC);  
  if (opt.Contains("a")) { // Print all details
    printf(" - C1: %1.4f, C0: %1.4f \n",fC1,fC0);
  }    


}
Commit	Line	Data
0116859c	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	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	**************************************************************************/
	15
	16	////////////////////////////////////////////////////////////////////////////
	17	// //
	18	// AliTPCGGVoltError class //
	19	// The class calculates the electric field and space point distortions //
	20	// due a Gating Grid (GG) Error voltage. It uses the exact calculation //
	21	// technique based on bessel functions. (original code from STAR) //
	22	// The class allows "effective Omega Tau" corrections. //
	23	// //
	24	// date: 27/04/2010 //
	25	// Authors: Jim Thomas, Stefan Rossegger, Magnus Mager //
	26	// //
	27	// Example usage: //
	28	// AliTPCGGVoltError GGerror; //
	29	// GGerror.SetOmegaTauT1T2(0.32,1.,1.); // values ideally from OCDB //
	30	// GGerror.SetDeltaVGGA(50.); // voltage offset A-side //
	31	// GGerror.SetDeltaVGGC(50.); // voltage offset C-side //
	32	// GGerror.InitGGVoltErrorDistortion(); // initialization of the look up //
	33	// // plot dRPhi distortions ... //
	34	// GGerror.CreateHistoDRPhiinZR(1.,100,100)->Draw("surf2"); //
	35	////////////////////////////////////////////////////////////////////////////
	36
	37
	38
	39	#include "AliTPCGGVoltError.h"
	40	#include <TMath.h>
	41
	42	AliTPCGGVoltError::AliTPCGGVoltError()
	43	: AliTPCCorrection("GGVoltError","GatingGrid (GG) Voltage Error"),
	44	fC0(0.),fC1(0.),
	45	fDeltaVGGA(0.),fDeltaVGGC(0.)
	46	{
	47	//
	48	// default constructor
	49	//
	50	}
	51
	52	AliTPCGGVoltError::~AliTPCGGVoltError() {
	53	//
	54	// default destructor
	55	//
	56	}
	57
e527a1b9	58	void AliTPCGGVoltError::Init() {
	59	//
	60	// Initialization funtion (not used at the moment)
	61	//
	62
	63	// Set default parameters
	64	// FIXME: Ask the database for these entries
	65
	66	Double_t vdrift = 2.6; // [cm/us] // From dataBase: to be updated: per second (ideally)
	67	Double_t bzField = -0.5; // [Tesla] // From dataBase: to be updated: per run
	68
	69	Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
	70	Double_t wt = -10.0 * (bzField10) vdrift / ezField ;
	71
	72	// Correction Terms for effective omegaTau; obtained by a laser calibration run
	73	Double_t t1 = 0.9; // ideally from database
	74	Double_t t2 = 1.5; // ideally from database
	75
	76	SetOmegaTauT1T2(wt,t1,t2);
	77
	78	SetDeltaVGGA(0.0);// ideally from the database
	79	SetDeltaVGGC(0.0);// ideally from the database
	80	}
	81
	82	void AliTPCGGVoltError::Update(const TTimeStamp &/timeStamp/) {
	83	//
	84	// Update function
	85	//
	86
	87	Double_t vdrift = 2.6; // [cm/us] // From dataBase: to be updated: per second (ideally)
	88	Double_t bzField = -0.5; // [Tesla] // From dataBase: to be updated: per run
	89
	90	Double_t ezField = 400; // [V/cm] // to be updated: never (hopefully)
	91	Double_t wt = -10.0 * (bzField10) vdrift / ezField ;
	92
	93	// Correction Terms for effective omegaTau; obtained by a laser calibration run
	94	Double_t t1 = 0.9; // ideally from database
	95	Double_t t2 = 1.5; // ideally from database
	96
	97	SetOmegaTauT1T2(wt,t1,t2);
	98	}
	99
	100
	101
0116859c	102	void AliTPCGGVoltError::GetCorrection(const Float_t x[],const Short_t roc,Float_t dx[]) {
	103
	104	//
	105	// Gated Grid Voltage Error
	106	//
	107	// Calculates the effect of having an incorrect voltage on the A or C end plate Gated Grids.
	108	//
	109	// Electrostatic Equations from StarNote SN0253 by Howard Wieman.
	110	//
	111
	112	Int_t order = 1 ; // FIXME: hardcoded? Linear interpolation = 1, Quadratic = 2
	113
	114	Double_t intEr, intEphi ;
	115	Double_t r, phi, z ;
	116	Int_t sign ;
	117
	118	Double_t deltaVGG;
	119
	120	r = TMath::Sqrt( x[0]x[0] + x[1]x[1] );
	121	phi = TMath::ATan2(x[1],x[0]);
	122	if ( phi < 0 ) phi += TMath::TwoPi(); // Table uses phi from 0 to 2*Pi
	123	z = x[2] ;
	124
	125	if ( (roc%36) < 18 ) {
	126	sign = 1;
	127	deltaVGG = fDeltaVGGA; // (TPC End A)
	128	} else {
	129	sign = -1; // (TPC End C)
	130	deltaVGG = fDeltaVGGC;
	131	}
	132
	133	if ( sign==1 && z < fgkZOffSet ) z = fgkZOffSet; // Protect against discontinuity at CE
	134	if ( sign==-1 && z > -fgkZOffSet ) z = -fgkZOffSet; // Protect against discontinuity at CE
	135
	136	Interpolate2DEdistortion( order, r, z, fGGVoltErrorER, intEr );
	137	intEphi = 0.0; // Efield is symmetric in phi
	138
	139	// Calculate distorted position
	140	if ( r > 0.0 ) {
	141	phi = phi + deltaVGG( fC0intEphi - fC1*intEr ) / r;
	142	r = r + deltaVGG( fC0intEr + fC1*intEphi );
	143	}
	144
	145	// Calculate correction in cartesian coordinates
	146	dx[0] = r * TMath::Cos(phi) - x[0];
	147	dx[1] = r * TMath::Sin(phi) - x[1];
	148	dx[2] = 0.; // z distortion not implemented (1st order distortions)
	149
	150	}
	151
	152
	153	Float_t AliTPCGGVoltError::GetIntErOverEz(const Float_t x[],const Short_t roc) {
	154	//
	155	// This function is purely for calibration purposes
	156	// Calculates the integral (int Er/Ez dz) for the setted GG voltage offset
	157	//
	158
	159	Int_t order = 1 ; // FIXME: so far hardcoded? Linear interpolation = 1, Quadratic = 2
	160
	161	Double_t intEr;
	162	Double_t r, phi, z ;
	163	Int_t sign ;
	164
	165	Double_t deltaVGG;
166
167	r = TMath::Sqrt( x[0]x[0] + x[1]x[1] );
168	phi = TMath::ATan2(x[1],x[0]);
169	if ( phi < 0 ) phi += TMath::TwoPi(); // Table uses phi from 0 to 2*Pi
170	z = x[2] ;
171
172	if ( (roc%36) < 18 ) {
173	sign = 1;
174	deltaVGG = fDeltaVGGA; // (TPC End A)
175	} else {
176	sign = -1; // (TPC End C)
177	deltaVGG = fDeltaVGGC;
178	}
179
180	if ( sign==1 && z < fgkZOffSet ) z = fgkZOffSet; // Protect against discontinuity at CE
181	if ( sign==-1 && z > -fgkZOffSet ) z = -fgkZOffSet; // Protect against discontinuity at CE
182
183	Interpolate2DEdistortion(order, r, z, fGGVoltErrorER, intEr );
184
185	return (intEr*deltaVGG);
186
187	}
188
189	void AliTPCGGVoltError::InitGGVoltErrorDistortion() {
190	//
191	// Initialization of the Lookup table which contains the solutions of the GG Error problem
192	//
193
194	Double_t r,z;
195	Int_t nterms = 100 ;
196	for ( Int_t i = 0 ; i < kNZ ; ++i ) {
197	z = fgkZList[i] ;
198	for ( Int_t j = 0 ; j < kNR ; ++j ) {
199	r = fgkRList[j] ;
200	fGGVoltErrorER[i][j] = 0.0 ;
201	Double_t intz = 0.0 ;
202	for ( Int_t n = 1 ; n < nterms ; ++n ) {
203	Double_t k = n * TMath::Pi() / fgkTPC_Z0 ;
204	Double_t ein = 0 ; // Error potential on the IFC
205	Double_t eout = 0 ; // Error potential on the OFC
206	if ( z < 0 ) {
207	ein = -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;
208	eout = -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;
209	}
210	if ( z == 0 ) continue ;
211	if ( z > 0 ) {
212	ein = -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;
213	eout = -2.0 / ( k * (fgkCathodeV - fgkGG) ) ;
214	}
215	Double_t an = ein * TMath::BesselK0( kfgkOFCRadius ) - eout TMath::BesselK0( k*fgkIFCRadius ) ;
216	Double_t bn = eout * TMath::BesselI0( kfgkIFCRadius ) - ein TMath::BesselI0( k*fgkOFCRadius ) ;
217	Double_t numerator =
218	an * TMath::BesselI1( kr ) - bn TMath::BesselK1( k*r ) ;
219	Double_t denominator =
220	TMath::BesselK0( kfgkOFCRadius ) TMath::BesselI0( k*fgkIFCRadius ) -
221	TMath::BesselK0( kfgkIFCRadius ) TMath::BesselI0( k*fgkOFCRadius ) ;
222	Double_t zterm = TMath::Cos( k*(fgkTPC_Z0-TMath::Abs(z)) ) - 1 ;
223	intz += zterm * numerator / denominator ;
224	// Assume series converges, break if small terms
b9f518ba	225	if ( n>10 && TMath::Abs(intz)*1.e-10 > TMath::Abs(numerator/denominator) ) break;
0116859c	226	}
	227	fGGVoltErrorER[i][j] = (Double_t) intz ;
	228
	229	}
	230	}
	231	}
	232
	233
	234
	235	void AliTPCGGVoltError::Print(Option_t* option) const {
	236	//
	237	// Print function to check the settings (e.g. voltage offsets)
	238	// option=="a" prints the C0 and C1 coefficents for calibration purposes
	239	//
	240
	241	TString opt = option; opt.ToLower();
	242	printf("%s\n",GetTitle());
	243	printf(" - GG Voltage offset: A-side: %3.1f V, C-side: %3.1f V \n",fDeltaVGGA,fDeltaVGGC);
	244	if (opt.Contains("a")) { // Print all details
	245	printf(" - C1: %1.4f, C0: %1.4f \n",fC1,fC0);
	246	}
	247
	248
	249
	250	}