-////////////////////////////////////////////////
-// Response class for set:ITS //
-////////////////////////////////////////////////
+/**************************************************************************
+ * 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. *
+ **************************************************************************/
+
+
+//////////////////////////////////////////////////////
+// Base Response class for ITS //
+// Specific subdetector implementation is done in //
+// AliITSresponseSPD //
+// AliITSresponseSDD //
+// AliITSresponseSSD //
+//////////////////////////////////////////////////////
-#include <TMath.h>
-#include <TF1.h>
-#include <TString.h>
#include "AliITSresponse.h"
ClassImp(AliITSresponse)
//______________________________________________________________________
-AliITSresponse::AliITSresponse(){
- // Default Constructor
+AliITSresponse::AliITSresponse():
+TObject(),
+fDiffCoeff(0.),
+fDiffCoeff1(0.){
+
+ // Default Constructor
- fdv = 0.000375; // 300 microns and 80 volts.
- fN = 0.0;
- fT = 300.0;
}
-//______________________________________________________________________
-AliITSresponse::AliITSresponse(Double_t thickness){
- // Default Constructor
-
- fdv = thickness/80.0; // 80 volts.
- fN = 0.0;
- fT = 300.0;
-}
-//______________________________________________________________________
-Double_t AliITSresponse::MobilityElectronSiEmp(){
- // Computes the electron mobility in cm^2/volt-sec. Taken from SILVACO
- // International ATLAS II, 2D Device Simulation Framework, User Manual
- // Chapter 5 Equation 5-6. An empirical function for low-field mobiliity
- // in silicon at different tempeatures.
- // Inputs:
- // none.
- // Output:
- // none.
- // Return:
- // The Mobility of electrons in Si at a give temprature and impurity
- // concentration. [cm^2/Volt-sec]
- const Double_t m0 = 55.24; // cm^2/Volt-sec
- const Double_t m1 = 7.12E+08; // cm^2 (degree K)^2.3 / Volt-sec
- const Double_t N0 = 1.072E17; // #/cm^3
- const Double_t T0 = 300.; // degree K.
- const Double_t eT0 = -2.3; // Power of Temp.
- const Double_t eT1 = -3.8; // Power of Temp.
- const Double_t eN = 0.73; // Power of Dopent Consentrations
- Double_t m;
- Double_t T = fT,N = fN;
- if(N<=0.0){ // Simple case.
- if(T==300.) return 1350.0; // From Table 5-1 at consentration 1.0E14.
- m = m1*TMath::Power(T,eT0);
- return m;
- } // if N<=0.0
- m = m1*TMath::Power(T,eT0) - m0;
- m /= 1.0 + TMath::Power(T/T0,eT1)*TMath::Power(N/N0,eN);
- m += m0;
- return m;
-}
-//______________________________________________________________________
-Double_t AliITSresponse::MobilityHoleSiEmp(){
- // Computes the Hole mobility in cm^2/volt-sec. Taken from SILVACO
- // International ATLAS II, 2D Device Simulation Framework, User Manual
- // Chapter 5 Equation 5-7 An empirical function for low-field mobiliity
- // in silicon at different tempeatures.
- // Inputs:
- // none.
- // Output:
- // none.
- // Return:
- // The Mobility of Hole in Si at a give temprature and impurity
- // concentration. [cm^2/Volt-sec]
- const Double_t m0a = 49.74; // cm^2/Volt-sec
- const Double_t m0b = 49.70; // cm^2/Volt-sec
- const Double_t m1 = 1.35E+08; // cm^2 (degree K)^2.3 / Volt-sec
- const Double_t N0 = 1.606E17; // #/cm^3
- const Double_t T0 = 300.; // degree K.
- const Double_t eT0 = -2.2; // Power of Temp.
- const Double_t eT1 = -3.7; // Power of Temp.
- const Double_t eN = 0.70; // Power of Dopent Consentrations
- Double_t m;
- Double_t T = fT,N = fN;
-
- if(N<=0.0){ // Simple case.
- if(T==300.) return 495.0; // From Table 5-1 at consentration 1.0E14.
- m = m1*TMath::Power(T,eT0) + m0a-m0b;
- return m;
- } // if N<=0.0
- m = m1*TMath::Power(T,eT0) - m0b;
- m /= 1.0 + TMath::Power(T/T0,eT1)*TMath::Power(N/N0,eN);
- m += m0a;
- return m;
-}
-//______________________________________________________________________
-Double_t AliITSresponse::DiffusionCoefficientElectron(){
- // Computes the Diffusion coefficient for electrons in cm^2/sec. Taken
- // from SILVACO International ATLAS II, 2D Device Simulation Framework,
- // User Manual Chapter 5 Equation 5-53. Einstein relations for diffusion
- // coefficient. Note: 1 cm^2/sec = 10 microns^2/nanosec.
- // Inputs:
- // none.
- // Output:
- // none.
- // Return:
- // The Diffusion Coefficient of electrons in Si at a give temprature
- // and impurity concentration. [cm^2/sec]
- // const Double_t kb = 1.3806503E-23; // Joules/degree K
- // const Double_t qe = 1.60217646E-19; // Coulumbs.
- const Double_t kbqe = 8.617342312E-5; // Volt/degree K
- Double_t m = MobilityElectronSiEmp();
- Double_t T = fT;
-
- return m*kbqe*T; // [cm^2/sec]
-}
-//______________________________________________________________________
-Double_t AliITSresponse::DiffusionCoefficientHole(){
- // Computes the Diffusion coefficient for Holes in cm^2/sec. Taken
- // from SILVACO International ATLAS II, 2D Device Simulation Framework,
- // User Manual Chapter 5 Equation 5-53. Einstein relations for diffusion
- // coefficient. Note: 1 cm^2/sec = 10 microns^2/nanosec.
- // Inputs:
- // none.
- // Output:
- // none.
- // Return:
- // The Defusion Coefficient of Hole in Si at a give temprature and
- // impurity concentration. [cm^2/sec]
- // and impurity concentration. [cm^2/sec]
- // const Double_t kb = 1.3806503E-23; // Joules/degree K
- // const Double_t qe = 1.60217646E-19; // Coulumbs.
- const Double_t kbqe = 8.617342312E-5; // Volt/degree K
- Double_t m = MobilityHoleSiEmp();
- Double_t T = fT;
-
- return m*kbqe*T; // [cm^2/sec]
-}
-//______________________________________________________________________
-Double_t AliITSresponse::SpeedElectron(){
- // Computes the average speed for electrons in Si under the low-field
- // approximation. [cm/sec].
- // Inputs:
- // none.
- // Output:
- // none.
- // Return:
- // The speed the holes are traveling at due to the low field applied.
- // [cm/sec]
- Double_t m = MobilityElectronSiEmp();
-
- return m/fdv; // [cm/sec]
-}
-//______________________________________________________________________
-Double_t AliITSresponse::SpeedHole(){
- // Computes the average speed for Holes in Si under the low-field
- // approximation.[cm/sec].
- // Inputs:
- // none.
- // Output:
- // none.
- // Return:
- // The speed the holes are traveling at due to the low field applied.
- // [cm/sec]
- Double_t m = MobilityHoleSiEmp();
-
- return m/fdv; // [cm/sec]
-}
-//______________________________________________________________________
-Double_t AliITSresponse::SigmaDiffusion3D(Double_t l){
- // Returns the Gaussian sigma^2 == <x^2+y^2+z^2> [cm^2] due to the defusion
- // of electrons or holes through a distance l [cm] caused by an applied
- // voltage v [volt] through a distance d [cm] in any material at a
- // temperature T [degree K]. The sigma diffusion when expressed in terms
- // of the distance over which the diffusion occures, l=time/speed, is
- // independent of the mobility and therefore the properties of the
- // material. The charge distributions is given by
- // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 6Dt where D=mkT/e
- // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
- // charge. and vel=m*v/d. consiquently sigma^2=6kTdl/ev.
- // Inputs:
- // Double_t l Distance the charge has to travel.
- // Output:
- // none.
- // Return:
- // The Sigma due to the diffution of electrons. [cm]
- const Double_t con = 5.17040258E-04; // == 6k/e [J/col or volts]
-
- return TMath::Sqrt(con*fT*fdv*l); // [cm]
-}
-//______________________________________________________________________
-Double_t AliITSresponse::SigmaDiffusion2D(Double_t l){
- // Returns the Gaussian sigma^2 == <x^2+z^2> [cm^2] due to the defusion
- // of electrons or holes through a distance l [cm] caused by an applied
- // voltage v [volt] through a distance d [cm] in any material at a
- // temperature T [degree K]. The sigma diffusion when expressed in terms
- // of the distance over which the diffusion occures, l=time/speed, is
- // independent of the mobility and therefore the properties of the
- // material. The charge distributions is given by
- // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <x^2+z^2> = 4Dt where D=mkT/e
- // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
- // charge. and vel=m*v/d. consiquently sigma^2=4kTdl/ev.
- // Inputs:
- // Double_t l Distance the charge has to travel.
- // Output:
- // none.
- // Return:
- // The Sigma due to the diffution of electrons. [cm]
- const Double_t con = 3.446935053E-04; // == 4k/e [J/col or volts]
-
- return TMath::Sqrt(con*fT*fdv*l); // [cm]
-}
-//______________________________________________________________________
-Double_t AliITSresponse::SigmaDiffusion1D(Double_t l){
- // Returns the Gaussian sigma^2 == <x^2> [cm^2] due to the defusion
- // of electrons or holes through a distance l [cm] caused by an applied
- // voltage v [volt] through a distance d [cm] in any material at a
- // temperature T [degree K]. The sigma diffusion when expressed in terms
- // of the distance over which the diffusion occures, l=time/speed, is
- // independent of the mobility and therefore the properties of the
- // material. The charge distributions is given by
- // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 2Dt where D=mkT/e
- // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
- // charge. and vel=m*v/d. consiquently sigma^2=2kTdl/ev.
- // Inputs:
- // Double_t l Distance the charge has to travel.
- // Output:
- // none.
- // Return:
- // The Sigma due to the diffution of electrons. [cm]
- const Double_t con = 1.723467527E-04; // == 2k/e [J/col or volts]
-
- return TMath::Sqrt(con*fT*fdv*l); // [cm]
-}
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