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18 //////////////////////////////////////////////////////
19 // Response class for set:ITS //
20 // Specific subdetector implementation is done in //
21 // AliITSresponseSPD //
22 // AliITSresponseSDD //
23 // AliITSresponseSSD //
24 //////////////////////////////////////////////////////
25 #include <Riostream.h>
27 #include "AliITSresponse.h"
29 ClassImp(AliITSresponse)
31 //______________________________________________________________________
32 AliITSresponse::AliITSresponse(){
33 // Default Constructor
35 fdv = 0.000375; // 300 microns and 80 volts.
41 //______________________________________________________________________
42 AliITSresponse::AliITSresponse(Double_t thickness){
43 // Default Constructor
45 fdv = thickness/80.0; // 80 volts.
51 //______________________________________________________________________
52 Double_t AliITSresponse::MobilityElectronSiEmp() const {
53 // Computes the electron mobility in cm^2/volt-sec. Taken from SILVACO
54 // International ATLAS II, 2D Device Simulation Framework, User Manual
55 // Chapter 5 Equation 5-6. An empirical function for low-field mobiliity
56 // in silicon at different tempeatures.
62 // The Mobility of electrons in Si at a give temprature and impurity
63 // concentration. [cm^2/Volt-sec]
64 const Double_t km0 = 55.24; // cm^2/Volt-sec
65 const Double_t km1 = 7.12E+08; // cm^2 (degree K)^2.3 / Volt-sec
66 const Double_t kN0 = 1.072E17; // #/cm^3
67 const Double_t kT0 = 300.; // degree K.
68 const Double_t keT0 = -2.3; // Power of Temp.
69 const Double_t keT1 = -3.8; // Power of Temp.
70 const Double_t keN = 0.73; // Power of Dopent Consentrations
72 Double_t tT = fT,nN = fN;
74 if(nN<=0.0){ // Simple case.
75 if(tT==300.) return 1350.0; // From Table 5-1 at consentration 1.0E14.
76 m = km1*TMath::Power(tT,keT0);
79 m = km1*TMath::Power(tT,keT0) - km0;
80 m /= 1.0 + TMath::Power(tT/kT0,keT1)*TMath::Power(nN/kN0,keN);
84 //______________________________________________________________________
85 Double_t AliITSresponse::MobilityHoleSiEmp() const {
86 // Computes the Hole mobility in cm^2/volt-sec. Taken from SILVACO
87 // International ATLAS II, 2D Device Simulation Framework, User Manual
88 // Chapter 5 Equation 5-7 An empirical function for low-field mobiliity
89 // in silicon at different tempeatures.
95 // The Mobility of Hole in Si at a give temprature and impurity
96 // concentration. [cm^2/Volt-sec]
97 const Double_t km0a = 49.74; // cm^2/Volt-sec
98 const Double_t km0b = 49.70; // cm^2/Volt-sec
99 const Double_t km1 = 1.35E+08; // cm^2 (degree K)^2.3 / Volt-sec
100 const Double_t kN0 = 1.606E17; // #/cm^3
101 const Double_t kT0 = 300.; // degree K.
102 const Double_t keT0 = -2.2; // Power of Temp.
103 const Double_t keT1 = -3.7; // Power of Temp.
104 const Double_t keN = 0.70; // Power of Dopent Consentrations
106 Double_t tT = fT,nN = fN;
108 if(nN<=0.0){ // Simple case.
109 if(tT==300.) return 495.0; // From Table 5-1 at consentration 1.0E14.
110 m = km1*TMath::Power(tT,keT0) + km0a-km0b;
113 m = km1*TMath::Power(tT,keT0) - km0b;
114 m /= 1.0 + TMath::Power(tT/kT0,keT1)*TMath::Power(nN/kN0,keN);
118 //______________________________________________________________________
119 Double_t AliITSresponse::DiffusionCoefficientElectron() const {
120 // Computes the Diffusion coefficient for electrons in cm^2/sec. Taken
121 // from SILVACO International ATLAS II, 2D Device Simulation Framework,
122 // User Manual Chapter 5 Equation 5-53. Einstein relations for diffusion
123 // coefficient. Note: 1 cm^2/sec = 10 microns^2/nanosec.
129 // The Diffusion Coefficient of electrons in Si at a give temprature
130 // and impurity concentration. [cm^2/sec]
131 // const Double_t kb = 1.3806503E-23; // Joules/degree K
132 // const Double_t qe = 1.60217646E-19; // Coulumbs.
133 const Double_t kbqe = 8.617342312E-5; // Volt/degree K
134 Double_t m = MobilityElectronSiEmp();
137 return m*kbqe*tT; // [cm^2/sec]
139 //______________________________________________________________________
140 Double_t AliITSresponse::DiffusionCoefficientHole() const {
141 // Computes the Diffusion coefficient for Holes in cm^2/sec. Taken
142 // from SILVACO International ATLAS II, 2D Device Simulation Framework,
143 // User Manual Chapter 5 Equation 5-53. Einstein relations for diffusion
144 // coefficient. Note: 1 cm^2/sec = 10 microns^2/nanosec.
150 // The Defusion Coefficient of Hole in Si at a give temprature and
151 // impurity concentration. [cm^2/sec]
152 // and impurity concentration. [cm^2/sec]
153 // const Double_t kb = 1.3806503E-23; // Joules/degree K
154 // const Double_t qe = 1.60217646E-19; // Coulumbs.
155 const Double_t kbqe = 8.617342312E-5; // Volt/degree K
156 Double_t m = MobilityHoleSiEmp();
159 return m*kbqe*tT; // [cm^2/sec]
161 //______________________________________________________________________
162 Double_t AliITSresponse::SpeedElectron() const {
163 // Computes the average speed for electrons in Si under the low-field
164 // approximation. [cm/sec].
170 // The speed the holes are traveling at due to the low field applied.
172 Double_t m = MobilityElectronSiEmp();
174 return m/fdv; // [cm/sec]
176 //______________________________________________________________________
177 Double_t AliITSresponse::SpeedHole() const {
178 // Computes the average speed for Holes in Si under the low-field
179 // approximation.[cm/sec].
185 // The speed the holes are traveling at due to the low field applied.
187 Double_t m = MobilityHoleSiEmp();
189 return m/fdv; // [cm/sec]
191 //______________________________________________________________________
192 Double_t AliITSresponse::SigmaDiffusion3D(Double_t l) const {
193 // Returns the Gaussian sigma^2 == <x^2+y^2+z^2> [cm^2] due to the
194 // defusion of electrons or holes through a distance l [cm] caused
195 // by an applied voltage v [volt] through a distance d [cm] in any
196 // material at a temperature T [degree K]. The sigma diffusion when
197 // expressed in terms of the distance over which the diffusion
198 // occures, l=time/speed, is independent of the mobility and therefore
199 // the properties of the material. The charge distributions is given by
200 // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 6Dt where D=mkT/e
201 // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
202 // charge. and vel=m*v/d. consiquently sigma^2=6kTdl/ev.
204 // Double_t l Distance the charge has to travel.
208 // The Sigma due to the diffution of electrons. [cm]
209 const Double_t kcon = 5.17040258E-04; // == 6k/e [J/col or volts]
211 return TMath::Sqrt(kcon*fT*fdv*l); // [cm]
213 //______________________________________________________________________
214 Double_t AliITSresponse::SigmaDiffusion2D(Double_t l) const {
215 // Returns the Gaussian sigma^2 == <x^2+z^2> [cm^2] due to the defusion
216 // of electrons or holes through a distance l [cm] caused by an applied
217 // voltage v [volt] through a distance d [cm] in any material at a
218 // temperature T [degree K]. The sigma diffusion when expressed in terms
219 // of the distance over which the diffusion occures, l=time/speed, is
220 // independent of the mobility and therefore the properties of the
221 // material. The charge distributions is given by
222 // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <x^2+z^2> = 4Dt where D=mkT/e
223 // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
224 // charge. and vel=m*v/d. consiquently sigma^2=4kTdl/ev.
226 // Double_t l Distance the charge has to travel.
230 // The Sigma due to the diffution of electrons. [cm]
231 const Double_t kcon = 3.446935053E-04; // == 4k/e [J/col or volts]
233 return TMath::Sqrt(kcon*fT*fdv*l); // [cm]
235 //______________________________________________________________________
236 Double_t AliITSresponse::SigmaDiffusion1D(Double_t l) const {
237 // Returns the Gaussian sigma^2 == <x^2> [cm^2] due to the defusion
238 // of electrons or holes through a distance l [cm] caused by an applied
239 // voltage v [volt] through a distance d [cm] in any material at a
240 // temperature T [degree K]. The sigma diffusion when expressed in terms
241 // of the distance over which the diffusion occures, l=time/speed, is
242 // independent of the mobility and therefore the properties of the
243 // material. The charge distributions is given by
244 // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 2Dt where D=mkT/e
245 // (m==mobility, k==Boltzman's constant, T==temparature, e==electric
246 // charge. and vel=m*v/d. consiquently sigma^2=2kTdl/ev.
248 // Double_t l Distance the charge has to travel.
252 // The Sigma due to the diffution of electrons. [cm]
253 const Double_t kcon = 1.723467527E-04; // == 2k/e [J/col or volts]
255 return TMath::Sqrt(kcon*fT*fdv*l); // [cm]
257 //----------------------------------------------------------------------
258 Double_t AliITSresponse::DepletedRegionThicknessA(Double_t dopCons,
261 Double_t voltBuiltIn)const{
262 // Computes the thickness of the depleted region in Si due to the
263 // application of an external bias voltage. From the Particle Data
264 // Book, 28.8 Silicon semiconductor detectors equation 28.19 (2004)
265 // Physics Letters B "Review of Particle Physics" Volume 592, Issue 1-4
266 // July 15 2004, ISSN 0370-2693 page 263. First equation.
268 // Double_t dopCons "N" doping concentration
269 // Double_t voltage "V" external bias voltage
270 // Double_t elecCharge "e" electronic charge
271 // Double_t voltBuiltIn=0.5 "V_bi" "built-in" Voltage (~0.5V for
272 // resistivities typically used in detectors)
276 // The thickness of the depleted region
278 return TMath::Sqrt(2.0*(voltage+voltBuiltIn)/(dopCons*elecCharge));
280 //----------------------------------------------------------------------
281 Double_t AliITSresponse::DepletedRegionThicknessB(Double_t resist,
284 Double_t voltBuiltIn,
285 Double_t dielConst)const{
286 // Computes the thickness of the depleted region in Si due to the
287 // application of an external bias voltage. From the Particle Data
288 // Book, 28.8 Silicon semiconductor detectors equation 28.19 (2004)
289 // Physics Letters B "Review of Particle Physics" Volume 592, Issue 1-4
290 // July 15 2004, ISSN 0370-2693 page 263. Second Equation.
292 // Double_t resist "rho" resistivity (typically 1-10 kOhm cm)
293 // Double_t voltage "V" external bias voltage
294 // Double_t mobility "mu" charge carrier mobility
295 // (electons 1350, holes 450 cm^2/V/s)
296 // Double_t voltBuiltIn=0.5 "V_bi" "built-in" Voltage (~0.5V for
297 // resistivities typically used in detectors)
298 // Double_t dielConst=1.E-12 "epsilon" dielectric constant = 11.9 *
299 // (permittivity of free space) or ~ 1 pF/cm
303 // The thickness of the depleted region
305 return TMath::Sqrt(2.8*resist*mobility*dielConst*(voltage+voltBuiltIn));
307 //----------------------------------------------------------------------
308 Double_t AliITSresponse::ReverseBiasCurrent(Double_t temp,
309 Double_t revBiasCurT1,
311 Double_t energy)const{
312 // Computes the temperature dependance of the reverse bias current
313 // of Si detectors. From the Particle Data
314 // Book, 28.8 Silicon semiconductor detectors equation 28.21 (2004)
315 // Physics Letters B "Review of Particle Physics" Volume 592, Issue 1-4
316 // July 15 2004, ISSN 0370-2693 page 263.
318 // Double_t temp The temperature at which the current is wanted
319 // Double_t revBiasCurT1 The reference bias current at temp T1
320 // Double_t tempT1 The temperature correstponding to revBiasCurT1
321 // Double_t energy=1.2 Some energy [eV]
325 // The reverse bias current at the tempeature temp.
326 const Double_t kBoltz = 8.617343E-5; //[eV/K]
328 return revBiasCurT1*(temp*temp/(tempT1*tempT1))*
329 TMath::Exp(-0.5*energy*(tempT1-temp)/(kBoltz*tempT1*temp));
331 //----------------------------------------------------------------------
332 void AliITSresponse::Print(ostream *os) const {
333 // Standard output format for this class.
335 *os << fdv << " " << fN << " " << fT << " ";
337 // printf("%-10.6e %-10.6e %-10.6e %-10.6e \n",fdv,fN,fT,fGeVcharge);
340 //----------------------------------------------------------------------
341 void AliITSresponse::Read(istream *is) {
342 // Standard input format for this class.
344 // ostream *is Pointer to the output stream
350 *is >> fdv >> fN >> fT >> fGeVcharge;
353 //----------------------------------------------------------------------
355 ostream &operator<<(ostream &os,AliITSresponse &p){
356 // Standard output streaming function.
358 // ostream *os Pointer to the output stream
368 //----------------------------------------------------------------------
369 istream &operator>>(istream &is,AliITSresponse &r){
370 // Standard input streaming function.
372 // ostream *os Pointer to the output stream
381 //----------------------------------------------------------------------