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14 **************************************************************************/
17 //////////////////////////////////////////////////////
18 // Calibration class for set:ITS //
19 // Specific subdetector implementation is done in //
20 // AliITSCalibrationSPD //
21 // AliITSCalibrationSDD //
22 // AliITSCalibrationSSD //
23 //////////////////////////////////////////////////////
25 #include "Riostream.h"
26 #include "AliITSCalibration.h"
29 ClassImp(AliITSCalibration)
31 //______________________________________________________________________
32 AliITSCalibration::AliITSCalibration():
40 // Default Constructor (300 microns and 80 volts)
45 //______________________________________________________________________
46 AliITSCalibration::AliITSCalibration(Double_t thickness):
54 // Default Constructor
56 fdv = thickness/80.0; // 80 volts.
61 //______________________________________________________________________
62 AliITSCalibration::AliITSCalibration(const AliITSCalibration &ob):
64 fDataType(ob.fDataType),
68 fGeVcharge(ob.fGeVcharge),
69 fResponse(ob.fResponse)
75 //______________________________________________________________________________
76 AliITSCalibration& AliITSCalibration::operator= (const AliITSCalibration& source)
80 this->~AliITSCalibration();
81 new(this) AliITSCalibration(source);
87 //______________________________________________________________________
88 Double_t AliITSCalibration::MobilityElectronSiEmp() const {
89 // Computes the electron mobility in cm^2/volt-sec. Taken from SILVACO
90 // International ATLAS II, 2D Device Simulation Framework, User Manual
91 // Chapter 5 Equation 5-6. An empirical function for low-field mobiliity
92 // in silicon at different tempeatures.
98 // The Mobility of electrons in Si at a give temprature and impurity
99 // concentration. [cm^2/Volt-sec]
100 const Double_t km0 = 55.24; // cm^2/Volt-sec
101 const Double_t km1 = 7.12E+08; // cm^2 (degree K)^2.3 / Volt-sec
102 const Double_t kN0 = 1.072E17; // #/cm^3
103 const Double_t kT0 = 300.; // degree K.
104 const Double_t keT0 = -2.3; // Power of Temp.
105 const Double_t keT1 = -3.8; // Power of Temp.
106 const Double_t keN = 0.73; // Power of Dopent Consentrations
108 Double_t tT = fT,nN = fN;
110 if(nN<=0.0){ // Simple case.
111 if(tT==300.) return 1350.0; // From Table 5-1 at consentration 1.0E14.
112 m = km1*TMath::Power(tT,keT0);
115 m = km1*TMath::Power(tT,keT0) - km0;
116 m /= 1.0 + TMath::Power(tT/kT0,keT1)*TMath::Power(nN/kN0,keN);
120 //______________________________________________________________________
121 Double_t AliITSCalibration::MobilityHoleSiEmp() const {
122 // Computes the Hole mobility in cm^2/volt-sec. Taken from SILVACO
123 // International ATLAS II, 2D Device Simulation Framework, User Manual
124 // Chapter 5 Equation 5-7 An empirical function for low-field mobiliity
125 // in silicon at different tempeatures.
131 // The Mobility of Hole in Si at a give temprature and impurity
132 // concentration. [cm^2/Volt-sec]
133 const Double_t km0a = 49.74; // cm^2/Volt-sec
134 const Double_t km0b = 49.70; // cm^2/Volt-sec
135 const Double_t km1 = 1.35E+08; // cm^2 (degree K)^2.3 / Volt-sec
136 const Double_t kN0 = 1.606E17; // #/cm^3
137 const Double_t kT0 = 300.; // degree K.
138 const Double_t keT0 = -2.2; // Power of Temp.
139 const Double_t keT1 = -3.7; // Power of Temp.
140 const Double_t keN = 0.70; // Power of Dopent Consentrations
142 Double_t tT = fT,nN = fN;
144 if(nN<=0.0){ // Simple case.
145 if(tT==300.) return 495.0; // From Table 5-1 at consentration 1.0E14.
146 m = km1*TMath::Power(tT,keT0) + km0a-km0b;
149 m = km1*TMath::Power(tT,keT0) - km0b;
150 m /= 1.0 + TMath::Power(tT/kT0,keT1)*TMath::Power(nN/kN0,keN);
154 //______________________________________________________________________
155 Double_t AliITSCalibration::DiffusionCoefficientElectron() const {
156 // Computes the Diffusion coefficient for electrons in cm^2/sec. Taken
157 // from SILVACO International ATLAS II, 2D Device Simulation Framework,
158 // User Manual Chapter 5 Equation 5-53. Einstein relations for diffusion
159 // coefficient. Note: 1 cm^2/sec = 10 microns^2/nanosec.
165 // The Diffusion Coefficient of electrons in Si at a give temprature
166 // and impurity concentration. [cm^2/sec]
167 // const Double_t kb = 1.3806503E-23; // Joules/degree K
168 // const Double_t qe = 1.60217646E-19; // Coulumbs.
169 const Double_t kbqe = 8.617342312E-5; // Volt/degree K
170 Double_t m = MobilityElectronSiEmp();
173 return m*kbqe*tT; // [cm^2/sec]
175 //______________________________________________________________________
176 Double_t AliITSCalibration::DiffusionCoefficientHole() const {
177 // Computes the Diffusion coefficient for Holes in cm^2/sec. Taken
178 // from SILVACO International ATLAS II, 2D Device Simulation Framework,
179 // User Manual Chapter 5 Equation 5-53. Einstein relations for diffusion
180 // coefficient. Note: 1 cm^2/sec = 10 microns^2/nanosec.
186 // The Defusion Coefficient of Hole in Si at a give temprature and
187 // impurity concentration. [cm^2/sec]
188 // and impurity concentration. [cm^2/sec]
189 // const Double_t kb = 1.3806503E-23; // Joules/degree K
190 // const Double_t qe = 1.60217646E-19; // Coulumbs.
191 const Double_t kbqe = 8.617342312E-5; // Volt/degree K
192 Double_t m = MobilityHoleSiEmp();
195 return m*kbqe*tT; // [cm^2/sec]
197 //______________________________________________________________________
198 Double_t AliITSCalibration::SpeedElectron() const {
199 // Computes the average speed for electrons in Si under the low-field
200 // approximation. [cm/sec].
206 // The speed the holes are traveling at due to the low field applied.
208 Double_t m = MobilityElectronSiEmp();
210 return m/fdv; // [cm/sec]
212 //______________________________________________________________________
213 Double_t AliITSCalibration::SpeedHole() const {
214 // Computes the average speed for Holes in Si under the low-field
215 // approximation.[cm/sec].
221 // The speed the holes are traveling at due to the low field applied.
223 Double_t m = MobilityHoleSiEmp();
225 return m/fdv; // [cm/sec]
227 //______________________________________________________________________
228 Double_t AliITSCalibration::SigmaDiffusion3D(Double_t l) const {
229 // Returns the Gaussian sigma^2 == <x^2+y^2+z^2> [cm^2] due to the
230 // defusion of electrons or holes through a distance l [cm] caused
231 // by an applied voltage v [volt] through a distance d [cm] in any
232 // material at a temperature T [degree K]. The sigma diffusion when
233 // expressed in terms of the distance over which the diffusion
234 // occures, l=time/speed, is independent of the mobility and therefore
235 // the properties of the material. The charge distributions is given by
236 // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 6Dt where D=mkT/e
237 // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
238 // charge. and vel=m*v/d. consiquently sigma^2=6kTdl/ev.
240 // Double_t l Distance the charge has to travel.
244 // The Sigma due to the diffution of electrons. [cm]
245 const Double_t kcon = 5.17040258E-04; // == 6k/e [J/col or volts]
247 return TMath::Sqrt(kcon*fT*fdv*l); // [cm]
249 //______________________________________________________________________
250 Double_t AliITSCalibration::SigmaDiffusion2D(Double_t l) const {
251 // Returns the Gaussian sigma^2 == <x^2+z^2> [cm^2] due to the defusion
252 // of electrons or holes through a distance l [cm] caused by an applied
253 // voltage v [volt] through a distance d [cm] in any material at a
254 // temperature T [degree K]. The sigma diffusion when expressed in terms
255 // of the distance over which the diffusion occures, l=time/speed, is
256 // independent of the mobility and therefore the properties of the
257 // material. The charge distributions is given by
258 // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <x^2+z^2> = 4Dt where D=mkT/e
259 // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
260 // charge. and vel=m*v/d. consiquently sigma^2=4kTdl/ev.
262 // Double_t l Distance the charge has to travel.
266 // The Sigma due to the diffution of electrons. [cm]
267 const Double_t kcon = 3.446935053E-04; // == 4k/e [J/col or volts]
269 return TMath::Sqrt(kcon*fT*fdv*l); // [cm]
271 //______________________________________________________________________
272 Double_t AliITSCalibration::SigmaDiffusion1D(Double_t l) const {
273 // Returns the Gaussian sigma^2 == <x^2> [cm^2] due to the defusion
274 // of electrons or holes through a distance l [cm] caused by an applied
275 // voltage v [volt] through a distance d [cm] in any material at a
276 // temperature T [degree K]. The sigma diffusion when expressed in terms
277 // of the distance over which the diffusion occures, l=time/speed, is
278 // independent of the mobility and therefore the properties of the
279 // material. The charge distributions is given by
280 // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 2Dt where D=mkT/e
281 // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
282 // charge. and vel=m*v/d. consiquently sigma^2=2kTdl/ev.
284 // Double_t l Distance the charge has to travel.
288 // The Sigma due to the diffution of electrons. [cm]
289 const Double_t kcon = 1.723467527E-04; // == 2k/e [J/col or volts]
291 return TMath::Sqrt(kcon*fT*fdv*l); // [cm]
293 //----------------------------------------------------------------------
294 Double_t AliITSCalibration::DepletedRegionThicknessA(Double_t dopCons,
297 Double_t voltBuiltIn)const{
298 // Computes the thickness of the depleted region in Si due to the
299 // application of an external bias voltage. From the Particle Data
300 // Book, 28.8 Silicon semiconductor detectors equation 28.19 (2004)
301 // Physics Letters B "Review of Particle Physics" Volume 592, Issue 1-4
302 // July 15 2004, ISSN 0370-2693 page 263. First equation.
304 // Double_t dopCons "N" doping concentration
305 // Double_t voltage "V" external bias voltage
306 // Double_t elecCharge "e" electronic charge
307 // Double_t voltBuiltIn=0.5 "V_bi" "built-in" Voltage (~0.5V for
308 // resistivities typically used in detectors)
312 // The thickness of the depleted region
314 return TMath::Sqrt(2.0*(voltage+voltBuiltIn)/(dopCons*elecCharge));
316 //----------------------------------------------------------------------
317 Double_t AliITSCalibration::DepletedRegionThicknessB(Double_t resist,
320 Double_t voltBuiltIn,
321 Double_t dielConst)const{
322 // Computes the thickness of the depleted region in Si due to the
323 // application of an external bias voltage. From the Particle Data
324 // Book, 28.8 Silicon semiconductor detectors equation 28.19 (2004)
325 // Physics Letters B "Review of Particle Physics" Volume 592, Issue 1-4
326 // July 15 2004, ISSN 0370-2693 page 263. Second Equation.
328 // Double_t resist "rho" resistivity (typically 1-10 kOhm cm)
329 // Double_t voltage "V" external bias voltage
330 // Double_t mobility "mu" charge carrier mobility
331 // (electons 1350, holes 450 cm^2/V/s)
332 // Double_t voltBuiltIn=0.5 "V_bi" "built-in" Voltage (~0.5V for
333 // resistivities typically used in detectors)
334 // Double_t dielConst=1.E-12 "epsilon" dielectric constant = 11.9 *
335 // (permittivity of free space) or ~ 1 pF/cm
339 // The thickness of the depleted region
341 return TMath::Sqrt(2.8*resist*mobility*dielConst*(voltage+voltBuiltIn));
343 //----------------------------------------------------------------------
344 Double_t AliITSCalibration::ReverseBiasCurrent(Double_t temp,
345 Double_t revBiasCurT1,
347 Double_t energy)const{
348 // Computes the temperature dependance of the reverse bias current
349 // of Si detectors. From the Particle Data
350 // Book, 28.8 Silicon semiconductor detectors equation 28.21 (2004)
351 // Physics Letters B "Review of Particle Physics" Volume 592, Issue 1-4
352 // July 15 2004, ISSN 0370-2693 page 263.
354 // Double_t temp The temperature at which the current is wanted
355 // Double_t revBiasCurT1 The reference bias current at temp T1
356 // Double_t tempT1 The temperature correstponding to revBiasCurT1
357 // Double_t energy=1.2 Some energy [eV]
361 // The reverse bias current at the tempeature temp.
362 const Double_t kBoltz = 8.617343E-5; //[eV/K]
364 return revBiasCurT1*(temp*temp/(tempT1*tempT1))*
365 TMath::Exp(-0.5*energy*(tempT1-temp)/(kBoltz*tempT1*temp));
367 //----------------------------------------------------------------------
368 void AliITSCalibration::Print(ostream *os) const {
369 // Standard output format for this class.
371 *os << fdv << " " << fN << " " << fT << " ";
373 // printf("%-10.6e %-10.6e %-10.6e %-10.6e \n",fdv,fN,fT,fGeVcharge);
376 //----------------------------------------------------------------------
377 void AliITSCalibration::Read(istream *is) {
378 // Standard input format for this class.
380 // ostream *is Pointer to the output stream
386 *is >> fdv >> fN >> fT >> fGeVcharge;
389 //----------------------------------------------------------------------
391 ostream &operator<<(ostream &os,AliITSCalibration &p){
392 // Standard output streaming function.
394 // ostream *os Pointer to the output stream
404 //----------------------------------------------------------------------
405 istream &operator>>(istream &is,AliITSCalibration &r){
406 // Standard input streaming function.
408 // ostream *os Pointer to the output stream
417 //----------------------------------------------------------------------