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451f5018 | 1 | /************************************************************************** |
2 | * Copyright(c) 2007-2009, 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 | /* $Id: AliITSUSimuParam.cxx 48165 2011-03-07 17:48:57Z masera $ */ | |
17 | ||
18 | /////////////////////////////////////////////////////////////////// | |
19 | // // | |
20 | // Implementation of the class to store the parameters used in // | |
21 | // the simulation of SPD, SDD and SSD detectors // | |
22 | // Origin: F.Prino, Torino, prino@to.infn.it // | |
23 | // // | |
24 | /////////////////////////////////////////////////////////////////// | |
25 | #include "AliITSUSimuParam.h" | |
26 | #include "AliLog.h" | |
27 | ||
28 | ||
29 | const Double_t AliITSUSimuParam::fgkPixUpgBiasVoltageDefault = 18.182; | |
30 | const Double_t AliITSUSimuParam::fgkPixUpgThreshDefault = 3000.; | |
31 | const Double_t AliITSUSimuParam::fgkPixUpgThrSigmaDefault = 250.; | |
32 | const UInt_t AliITSUSimuParam::fgkPixUpgCouplingOptDefault = AliITSUSimuParam::kOldCouplingPixUpg; | |
33 | const Double_t AliITSUSimuParam::fgkPixUpgCouplColDefault = 0.; | |
34 | const Double_t AliITSUSimuParam::fgkPixUpgCouplRowDefault = 0.055; | |
35 | const Double_t AliITSUSimuParam::fgkPixUpgEccDiffDefault = 0.85; | |
36 | const Double_t AliITSUSimuParam::fgkPixUpgLorentzHoleWeightDefault = 1.0; | |
37 | const Double_t AliITSUSimuParam::fgkGeVtoChargeDefault = 3.6e-9; | |
38 | const Double_t AliITSUSimuParam::fgkDOverVDefault = 0.000375; | |
39 | const Double_t AliITSUSimuParam::fgkTDefault = 300; | |
40 | ||
41 | const Double_t AliITSUSimuParam::fgkNsigmasDefault = 3.; | |
42 | const Int_t AliITSUSimuParam::fgkNcompsDefault = 121; | |
43 | ||
44 | ClassImp(AliITSUSimuParam) | |
45 | ||
46 | //______________________________________________________________________ | |
47 | AliITSUSimuParam::AliITSUSimuParam() | |
48 | : fGeVcharge(fgkGeVtoChargeDefault) | |
49 | ,fDOverV(fgkDOverVDefault) | |
50 | ,fT(fgkTDefault) | |
51 | // | |
52 | ,fNPixUpg(0) | |
53 | ,fPixUpgCouplOpt(kOldCouplingPixUpg) | |
54 | ,fPixUpgCouplCol(fgkPixUpgCouplColDefault) | |
55 | ,fPixUpgCouplRow(fgkPixUpgCouplRowDefault) | |
56 | ,fPixUpgEccDiff(fgkPixUpgEccDiffDefault) | |
57 | ,fPixUpgLorentzDrift(kTRUE) | |
58 | ,fPixUpgLorentzHoleWeight(fgkPixUpgLorentzHoleWeightDefault) | |
59 | ,fPixUpgAddNoisyFlag(kFALSE) | |
60 | ,fPixUpgRemoveDeadFlag(kFALSE) | |
61 | // | |
62 | ,fPixUpgThreshDef(fgkPixUpgThreshDefault) | |
63 | ,fPixUpgThrSigmaDef(fgkPixUpgThrSigmaDefault) | |
64 | ,fPixUpgBiasVoltageDef(fgkPixUpgBiasVoltageDefault) | |
65 | ,fPixUpgNoiseDef(0) | |
66 | ,fPixUpgBaselineDef(0) | |
67 | // | |
68 | ,fPixUpgThresh(0) | |
69 | ,fPixUpgThrSigma(0) | |
70 | ,fPixUpgBiasVoltage(0) | |
71 | ,fPixUpgSigma(0) | |
72 | ,fPixUpgNoise(0) | |
73 | ,fPixUpgBaseline(0) | |
74 | { | |
75 | // default constructor | |
76 | } | |
77 | ||
78 | //______________________________________________________________________ | |
79 | AliITSUSimuParam::AliITSUSimuParam(UInt_t nPixUpg) | |
80 | :fGeVcharge(fgkGeVtoChargeDefault) | |
81 | ,fDOverV(fgkDOverVDefault) | |
82 | ,fT(fgkTDefault) | |
83 | // | |
84 | ,fNPixUpg(nPixUpg) | |
85 | ,fPixUpgCouplOpt(kOldCouplingPixUpg) | |
86 | ,fPixUpgCouplCol(fgkPixUpgCouplColDefault) | |
87 | ,fPixUpgCouplRow(fgkPixUpgCouplRowDefault) | |
88 | ,fPixUpgEccDiff(fgkPixUpgEccDiffDefault) | |
89 | ,fPixUpgLorentzDrift(kTRUE) | |
90 | ,fPixUpgLorentzHoleWeight(fgkPixUpgLorentzHoleWeightDefault) | |
91 | ,fPixUpgAddNoisyFlag(kFALSE) | |
92 | ,fPixUpgRemoveDeadFlag(kFALSE) | |
93 | // | |
94 | ,fPixUpgThreshDef(fgkPixUpgThreshDefault) | |
95 | ,fPixUpgThrSigmaDef(fgkPixUpgThrSigmaDefault) | |
96 | ,fPixUpgBiasVoltageDef(fgkPixUpgBiasVoltageDefault) | |
97 | ,fPixUpgNoiseDef(0) | |
98 | ,fPixUpgBaselineDef(0) | |
99 | // | |
100 | ,fPixUpgThresh(0) | |
101 | ,fPixUpgThrSigma(0) | |
102 | ,fPixUpgBiasVoltage(0) | |
103 | ,fPixUpgSigma(0) | |
104 | ,fPixUpgNoise(0) | |
105 | ,fPixUpgBaseline(0) | |
106 | { | |
107 | // regular constructor | |
108 | if (fNPixUpg>0) { | |
109 | fPixUpgBiasVoltage = new Double_t[fNPixUpg]; | |
110 | fPixUpgThresh = new Double_t[fNPixUpg]; | |
111 | fPixUpgThrSigma = new Double_t[fNPixUpg]; | |
112 | fPixUpgNoise = new Double_t[fNPixUpg]; | |
113 | fPixUpgBaseline = new Double_t[fNPixUpg]; | |
114 | } | |
115 | SetPixUpgThreshold(fgkPixUpgThreshDefault,fgkPixUpgThrSigmaDefault); | |
116 | SetPixUpgNoise(0.,0.); | |
117 | SetPixUpgBiasVoltage(fgkPixUpgBiasVoltageDefault); | |
118 | // | |
119 | } | |
120 | ||
121 | //______________________________________________________________________ | |
122 | AliITSUSimuParam::AliITSUSimuParam(const AliITSUSimuParam &simpar) | |
123 | :TObject(simpar) | |
124 | ,fGeVcharge(simpar.fGeVcharge) | |
125 | ,fDOverV(simpar.fDOverV) | |
126 | ,fT(simpar.fT) | |
127 | // | |
128 | ,fNPixUpg(simpar.fNPixUpg) | |
129 | ,fPixUpgCouplOpt(simpar.fPixUpgCouplOpt) | |
130 | ,fPixUpgCouplCol(simpar.fPixUpgCouplCol) | |
131 | ,fPixUpgCouplRow(simpar.fPixUpgCouplRow) | |
132 | ,fPixUpgEccDiff(simpar.fPixUpgEccDiff) | |
133 | ,fPixUpgLorentzDrift(simpar.fPixUpgLorentzDrift) | |
134 | ,fPixUpgLorentzHoleWeight(simpar.fPixUpgLorentzHoleWeight) | |
135 | ,fPixUpgAddNoisyFlag(simpar.fPixUpgAddNoisyFlag) | |
136 | ,fPixUpgRemoveDeadFlag(simpar.fPixUpgRemoveDeadFlag) | |
137 | // | |
138 | ,fPixUpgThreshDef(simpar.fPixUpgThreshDef) | |
139 | ,fPixUpgThrSigmaDef(simpar.fPixUpgThrSigmaDef) | |
140 | ,fPixUpgBiasVoltageDef(simpar.fPixUpgBiasVoltageDef) | |
141 | ,fPixUpgNoiseDef(simpar.fPixUpgNoiseDef) | |
142 | ,fPixUpgBaselineDef(simpar.fPixUpgBaselineDef) | |
143 | // | |
144 | ,fPixUpgThresh(0) | |
145 | ,fPixUpgThrSigma(0) | |
146 | ,fPixUpgBiasVoltage(0) | |
147 | ,fPixUpgSigma(0) | |
148 | ,fPixUpgNoise(0) | |
149 | ,fPixUpgBaseline(0) | |
150 | // | |
151 | { | |
152 | // copy constructor | |
153 | if (fNPixUpg) { | |
154 | fPixUpgBiasVoltage = new Double_t[fNPixUpg]; | |
155 | fPixUpgThresh = new Double_t[fNPixUpg]; | |
156 | fPixUpgThrSigma = new Double_t[fNPixUpg]; | |
157 | fPixUpgNoise = new Double_t[fNPixUpg]; | |
158 | fPixUpgBaseline = new Double_t[fNPixUpg]; | |
159 | } | |
160 | for (Int_t i=fNPixUpg;i--;) { | |
161 | fPixUpgBiasVoltage[i] = simpar.fPixUpgBiasVoltage[i]; | |
162 | fPixUpgThresh[i] = simpar.fPixUpgThresh[i]; | |
163 | fPixUpgThrSigma[i] = simpar.fPixUpgThrSigma[i]; | |
164 | fPixUpgNoise[i] = simpar.fPixUpgNoise[i]; | |
165 | fPixUpgBaseline[i] = simpar.fPixUpgBaseline[i]; | |
166 | } | |
167 | // | |
168 | } | |
169 | ||
170 | //______________________________________________________________________ | |
171 | AliITSUSimuParam& AliITSUSimuParam::operator=(const AliITSUSimuParam& source) | |
172 | { | |
173 | // Assignment operator. | |
174 | if (this==&source) return *this; | |
175 | this->~AliITSUSimuParam(); | |
176 | new(this) AliITSUSimuParam(source); | |
177 | return *this; | |
178 | // | |
179 | } | |
180 | ||
181 | //______________________________________________________________________ | |
182 | AliITSUSimuParam::~AliITSUSimuParam() | |
183 | { | |
184 | // destructor | |
185 | delete[] fPixUpgBiasVoltage; | |
186 | delete[] fPixUpgThresh; | |
187 | delete[] fPixUpgThrSigma; | |
188 | delete[] fPixUpgNoise; | |
189 | delete[] fPixUpgBaseline; | |
190 | } | |
191 | ||
192 | //________________________________________________________________________ | |
193 | void AliITSUSimuParam::Print(Option_t *) const | |
194 | { | |
195 | // Dump all parameters | |
196 | Dump(); | |
197 | } | |
198 | ||
199 | //_______________________________________________________________________ | |
200 | Double_t AliITSUSimuParam::ApplyPixUpgBaselineAndNoise(UInt_t mod) const | |
201 | { | |
202 | // generate random noise | |
203 | double base,noise; | |
204 | if (mod>=fNPixUpg) { | |
205 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
206 | base = fPixUpgBaselineDef; | |
207 | noise = fPixUpgNoiseDef; | |
208 | } | |
209 | else { | |
210 | base = fPixUpgBaseline[mod]; | |
211 | noise = fPixUpgNoise[mod]; | |
212 | } | |
213 | return base+noise*gRandom->Gaus(); | |
214 | } | |
215 | ||
216 | //_______________________________________________________________________ | |
217 | Double_t AliITSUSimuParam::CalcProbNoiseOverThreshold(UInt_t mod) const | |
218 | { | |
219 | // calculate probability of noise exceeding the threshold | |
220 | double base,noise,thresh; | |
221 | if (mod>=fNPixUpg) { | |
222 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
223 | base = fPixUpgBaselineDef; | |
224 | noise = fPixUpgNoiseDef; | |
225 | thresh = fPixUpgThreshDef; | |
226 | } | |
227 | else { | |
228 | base = fPixUpgBaseline[mod]; | |
229 | noise = fPixUpgNoise[mod]; | |
230 | thresh = fPixUpgThresh[mod]; | |
231 | } | |
232 | if (noise<1e-12) { | |
233 | if (base>thresh) return 1; | |
234 | else return 0; | |
235 | } | |
236 | return CalcProbNoiseOverThreshold(base, noise, thresh); | |
237 | } | |
238 | ||
239 | //_______________________________________________________________________ | |
240 | void AliITSUSimuParam::SetPixUpgThreshold(Double_t thresh, Double_t sigma, int mod) | |
241 | { | |
242 | // set threshold params | |
243 | if (mod<0) { | |
244 | fPixUpgThreshDef = thresh; | |
245 | fPixUpgThrSigmaDef = sigma; | |
246 | for (int i=fNPixUpg;i--;) { | |
247 | fPixUpgThresh[i] = thresh; | |
248 | fPixUpgThrSigma[i] = sigma; | |
249 | } | |
250 | } | |
251 | else if (mod>=(int)fNPixUpg) { | |
252 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
253 | fPixUpgThreshDef = thresh; | |
254 | fPixUpgThrSigmaDef = sigma; | |
255 | } | |
256 | else { | |
257 | fPixUpgThresh[mod] = thresh; | |
258 | fPixUpgThrSigma[mod] = sigma; | |
259 | } | |
260 | // | |
261 | } | |
262 | ||
263 | //_______________________________________________________________________ | |
264 | Double_t AliITSUSimuParam::GetPixUpgThreshold(UInt_t mod) const | |
265 | { | |
266 | // obtain threshold | |
267 | if (mod>=fNPixUpg) { | |
268 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
269 | return fPixUpgThreshDef; | |
270 | } | |
271 | else return fPixUpgThresh[mod]; | |
272 | } | |
273 | ||
274 | //_______________________________________________________________________ | |
275 | void AliITSUSimuParam::GetPixUpgThreshold(UInt_t mod, Double_t &thresh, Double_t &sigma) const | |
276 | { | |
277 | // obtain thresholds | |
278 | if (mod>=fNPixUpg) { | |
279 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
280 | thresh = fPixUpgThreshDef; | |
281 | sigma = fPixUpgThrSigmaDef; | |
282 | } | |
283 | else { | |
284 | thresh = fPixUpgThresh[mod]; | |
285 | sigma = fPixUpgThrSigma[mod]; | |
286 | } | |
287 | } | |
288 | ||
289 | //_______________________________________________________________________ | |
290 | void AliITSUSimuParam::SetPixUpgBiasVoltage(Double_t val, int mod) | |
291 | { | |
292 | // set threshold params | |
293 | if (mod<0) { | |
294 | fPixUpgBiasVoltageDef = val; | |
295 | for (int i=fNPixUpg;i--;) fPixUpgBiasVoltage[i] = val; | |
296 | } | |
297 | else if (mod>=(int)fNPixUpg) { | |
298 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
299 | fPixUpgBiasVoltageDef = val; | |
300 | } | |
301 | else fPixUpgBiasVoltage[mod] = val; | |
302 | // | |
303 | } | |
304 | ||
305 | //_______________________________________________________________________ | |
306 | Double_t AliITSUSimuParam::GetPixUpgBiasVoltage(UInt_t mod) const | |
307 | { | |
308 | // obtain threshold | |
309 | if (mod>=fNPixUpg) { | |
310 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
311 | return fPixUpgBiasVoltageDef; | |
312 | } | |
313 | else return fPixUpgBiasVoltage[mod]; | |
314 | } | |
315 | ||
316 | //_______________________________________________________________________ | |
317 | void AliITSUSimuParam::SetPixUpgNoise(Double_t noise, Double_t baseline, int mod) | |
318 | { | |
319 | // set noise params | |
320 | if (mod<0) { | |
321 | fPixUpgNoiseDef = noise; | |
322 | fPixUpgBaselineDef = baseline; | |
323 | for (int i=fNPixUpg;i--;) { | |
324 | fPixUpgNoise[i] = noise; | |
325 | fPixUpgBaseline[i] = baseline; | |
326 | } | |
327 | } | |
328 | else if (mod>=(int)fNPixUpg) { | |
329 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
330 | fPixUpgNoiseDef = noise; | |
331 | fPixUpgBaselineDef = baseline; | |
332 | } | |
333 | else { | |
334 | fPixUpgNoise[mod] = noise; | |
335 | fPixUpgBaseline[mod] = baseline; | |
336 | } | |
337 | // | |
338 | } | |
339 | ||
340 | //_______________________________________________________________________ | |
341 | void AliITSUSimuParam::GetPixUpgNoise(UInt_t mod, Double_t &noise, Double_t &baseline) const | |
342 | { | |
343 | // obtain noise | |
344 | if (mod>=fNPixUpg) { | |
345 | if (fNPixUpg>0) {AliFatal(Form("Wrong module %d, NPidUpg=%d",mod,fNPixUpg));} | |
346 | noise = fPixUpgNoiseDef; | |
347 | baseline = fPixUpgBaselineDef; | |
348 | } | |
349 | else { | |
350 | noise = fPixUpgNoise[mod]; | |
351 | baseline = fPixUpgBaseline[mod]; | |
352 | } | |
353 | } | |
354 | ||
355 | //_______________________________________________________________________ | |
356 | void AliITSUSimuParam::SetPixUpgCouplingOption(UInt_t opt) | |
357 | { | |
358 | // set coupling option | |
359 | if (opt>=kMaxCouplingOptPixUpg) AliFatal(Form("Coupling option %d should be less than %d",opt,kMaxCouplingOptPixUpg)); | |
360 | fPixUpgCouplOpt = opt; | |
361 | } | |
362 | ||
363 | ||
364 | //______________________________________________________________________ | |
365 | Double_t AliITSUSimuParam::LorentzAngleHole(Double_t B) const | |
366 | { | |
367 | // Computes the Lorentz angle for electrons in Si | |
368 | // Input: magnetic Field in KGauss | |
369 | // Output: Lorentz angle in radians (positive if Bz is positive) | |
370 | // Main Reference: NIM A 497 (2003) 389–396. | |
371 | // "An algorithm for calculating the Lorentz angle in silicon detectors", V. Bartsch et al. | |
372 | // | |
373 | const Double_t krH=0.70; // Hall scattering factor for Hole | |
374 | const Double_t kT0 = 300.; // reference Temperature (degree K). | |
375 | const Double_t kmulow0 = 470.5; // cm^2/Volt-sec | |
376 | const Double_t keT0 = -2.5; // Power of Temp. | |
377 | const Double_t beta0 = 1.213; // beta coeff. at T0=300K | |
378 | const Double_t keT1 = 0.17; // Power of Temp. for beta | |
379 | const Double_t kvsat0 = 8.37E+06; // saturated velocity at T0=300K (cm/sec) | |
380 | const Double_t keT2 = 0.52; // Power of Temp. for vsat | |
381 | Double_t tT = fT; | |
382 | Double_t eE= 1./fDOverV; | |
383 | Double_t muLow=kmulow0*TMath::Power(tT/kT0,keT0); | |
384 | Double_t beta=beta0*TMath::Power(tT/kT0,keT1); | |
385 | Double_t vsat=kvsat0*TMath::Power(tT/kT0,keT2); | |
386 | Double_t mu=muLow/TMath::Power(1+TMath::Power(muLow*eE/vsat,beta),1/beta); | |
387 | Double_t angle=TMath::ATan(krH*mu*B*1.E-05); // Conversion Factor | |
388 | return angle; | |
389 | } | |
390 | ||
391 | //______________________________________________________________________ | |
392 | Double_t AliITSUSimuParam::LorentzAngleElectron(Double_t B) const | |
393 | { | |
394 | // Computes the Lorentz angle for electrons in Si | |
395 | // Input: magnetic Field in KGauss | |
396 | // Output: Lorentz angle in radians (positive if Bz is positive) | |
397 | // Main Reference: NIM A 497 (2003) 389–396. | |
398 | // "An algorithm for calculating the Lorentz angle in silicon detectors", V. Bartsch et al. | |
399 | // | |
400 | const Double_t krH=1.15; // Hall scattering factor for Electron | |
401 | const Double_t kT0 = 300.; // reference Temperature (degree K). | |
402 | const Double_t kmulow0 = 1417.0; // cm^2/Volt-sec | |
403 | const Double_t keT0 = -2.2; // Power of Temp. | |
404 | const Double_t beta0 = 1.109; // beta coeff. at T0=300K | |
405 | const Double_t keT1 = 0.66; // Power of Temp. for beta | |
406 | const Double_t kvsat0 = 1.07E+07; // saturated velocity at T0=300K (cm/sec) | |
407 | const Double_t keT2 = 0.87; // Power of Temp. for vsat | |
408 | Double_t tT = fT; | |
409 | Double_t eE= 1./fDOverV; | |
410 | Double_t muLow=kmulow0*TMath::Power(tT/kT0,keT0); | |
411 | Double_t beta=beta0*TMath::Power(tT/kT0,keT1); | |
412 | Double_t vsat=kvsat0*TMath::Power(tT/kT0,keT2); | |
413 | Double_t mu=muLow/TMath::Power(1+TMath::Power(muLow*eE/vsat,beta),1/beta); | |
414 | Double_t angle=TMath::ATan(krH*mu*B*1.E-05); | |
415 | return angle; | |
416 | } | |
417 | ||
418 | //______________________________________________________________________ | |
02d6eccc | 419 | Double_t AliITSUSimuParam::SigmaDiffusion3D(Double_t l) const |
451f5018 | 420 | { |
421 | // Returns the Gaussian sigma^2 == <x^2+y^2+z^2> [cm^2] due to the | |
422 | // defusion of electrons or holes through a distance l [cm] caused | |
423 | // by an applied voltage v [volt] through a distance d [cm] in any | |
424 | // material at a temperature T [degree K]. The sigma diffusion when | |
425 | // expressed in terms of the distance over which the diffusion | |
426 | // occures, l=time/speed, is independent of the mobility and therefore | |
427 | // the properties of the material. The charge distributions is given by | |
428 | // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 6Dt where D=mkT/e | |
429 | // (m==mobility, k==Boltzman's constant, T==temparature, e==electric | |
430 | // charge. and vel=m*v/d. consiquently sigma^2=6kTdl/ev. | |
431 | // Inputs: | |
432 | // Double_t l Distance the charge has to travel. | |
433 | // Output: | |
434 | // none. | |
435 | // Return: | |
436 | // The Sigma due to the diffution of electrons. [cm] | |
437 | const Double_t kcon = 5.17040258E-04; // == 6k/e [J/col or volts] | |
438 | return TMath::Sqrt(kcon*fT*fDOverV*l); // [cm] | |
439 | } | |
440 | ||
441 | //______________________________________________________________________ | |
442 | Double_t AliITSUSimuParam::SigmaDiffusion2D(Double_t l) const | |
443 | { | |
444 | // Returns the Gaussian sigma^2 == <x^2+z^2> [cm^2] due to the defusion | |
445 | // of electrons or holes through a distance l [cm] caused by an applied | |
446 | // voltage v [volt] through a distance d [cm] in any material at a | |
447 | // temperature T [degree K]. The sigma diffusion when expressed in terms | |
448 | // of the distance over which the diffusion occures, l=time/speed, is | |
449 | // independent of the mobility and therefore the properties of the | |
450 | // material. The charge distributions is given by | |
451 | // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <x^2+z^2> = 4Dt where D=mkT/e | |
452 | // (m==mobility, k==Boltzman's constant, T==temparature, e==electric | |
453 | // charge. and vel=m*v/d. consiquently sigma^2=4kTdl/ev. | |
454 | // Inputs: | |
455 | // Double_t l Distance the charge has to travel. | |
456 | // Output: | |
457 | // none. | |
458 | // Return: | |
459 | // The Sigma due to the diffution of electrons. [cm] | |
460 | const Double_t kcon = 3.446935053E-04; // == 4k/e [J/col or volts] | |
461 | return TMath::Sqrt(kcon*fT*fDOverV*l); // [cm] | |
462 | } | |
463 | ||
464 | //______________________________________________________________________ | |
02d6eccc | 465 | Double_t AliITSUSimuParam::SigmaDiffusion1D(Double_t l) const |
451f5018 | 466 | { |
467 | // Returns the Gaussian sigma^2 == <x^2> [cm^2] due to the defusion | |
468 | // of electrons or holes through a distance l [cm] caused by an applied | |
469 | // voltage v [volt] through a distance d [cm] in any material at a | |
470 | // temperature T [degree K]. The sigma diffusion when expressed in terms | |
471 | // of the distance over which the diffusion occures, l=time/speed, is | |
472 | // independent of the mobility and therefore the properties of the | |
473 | // material. The charge distributions is given by | |
474 | // n = exp(-r^2/4Dt)/(4piDt)^1.5. From this <r^2> = 2Dt where D=mkT/e | |
475 | // (m==mobility, k==Boltzman's constant, T==temparature, e==electric | |
476 | // charge. and vel=m*v/d. consiquently sigma^2=2kTdl/ev. | |
477 | // Inputs: | |
478 | // Double_t l Distance the charge has to travel. | |
479 | // Output: | |
480 | // none. | |
481 | // Return: | |
482 | // The Sigma due to the diffution of electrons. [cm] | |
483 | const Double_t kcon = 1.723467527E-04; // == 2k/e [J/col or volts] | |
484 | return TMath::Sqrt(kcon*fT*fDOverV*l); // [cm] | |
485 | } |