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4347b38f | 1 | /************************************************************************** |
2 | * Copyright(c) 2004, ALICE Experiment at CERN, All rights reserved. * | |
66d2ede1 | 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 | **************************************************************************/ | |
4347b38f | 15 | /* $Id$ */ |
c2fc1258 | 16 | /** @file AliFMDDigitizer.cxx |
17 | @author Christian Holm Christensen <cholm@nbi.dk> | |
18 | @date Mon Mar 27 12:38:26 2006 | |
19 | @brief FMD Digitizers implementation | |
02a27b50 | 20 | @ingroup FMD_sim |
c2fc1258 | 21 | */ |
4347b38f | 22 | ////////////////////////////////////////////////////////////////////////////// |
23 | // | |
24 | // This class contains the procedures simulation ADC signal for the | |
25 | // Forward Multiplicity detector : Hits->Digits and Hits->SDigits | |
26 | // | |
27 | // Digits consists of | |
28 | // - Detector # | |
29 | // - Ring ID | |
30 | // - Sector # | |
31 | // - Strip # | |
32 | // - ADC count in this channel | |
33 | // | |
34 | // Digits consists of | |
35 | // - Detector # | |
36 | // - Ring ID | |
37 | // - Sector # | |
38 | // - Strip # | |
39 | // - Total energy deposited in the strip | |
40 | // - ADC count in this channel | |
41 | // | |
42 | // As the Digits and SDigits have so much in common, the classes | |
43 | // AliFMDDigitizer and AliFMDSDigitizer are implemented via a base | |
44 | // class AliFMDBaseDigitizer. | |
45 | // | |
46 | // +---------------------+ | |
47 | // | AliFMDBaseDigitizer | | |
48 | // +---------------------+ | |
49 | // ^ | |
50 | // | | |
51 | // +----------+---------+ | |
52 | // | | | |
53 | // +-----------------+ +------------------+ | |
54 | // | AliFMDDigitizer | | AliFMDSDigitizer | | |
55 | // +-----------------+ +------------------+ | |
56 | // | |
57 | // These classes has several paramters: | |
58 | // | |
59 | // fPedestal | |
60 | // fPedestalWidth | |
61 | // (Only AliFMDDigitizer) | |
62 | // Mean and width of the pedestal. The pedestal is simulated | |
63 | // by a Guassian, but derived classes my override MakePedestal | |
64 | // to simulate it differently (or pick it up from a database). | |
65 | // | |
66 | // fVA1MipRange | |
67 | // The dymamic MIP range of the VA1_ALICE pre-amplifier chip | |
68 | // | |
69 | // fAltroChannelSize | |
70 | // The largest number plus one that can be stored in one | |
71 | // channel in one time step in the ALTRO ADC chip. | |
72 | // | |
73 | // fSampleRate | |
74 | // How many times the ALTRO ADC chip samples the VA1_ALICE | |
75 | // pre-amplifier signal. The VA1_ALICE chip is read-out at | |
76 | // 10MHz, while it's possible to drive the ALTRO chip at | |
77 | // 25MHz. That means, that the ALTRO chip can have time to | |
78 | // sample each VA1_ALICE signal up to 2 times. Although it's | |
79 | // not certain this feature will be used in the production, | |
80 | // we'd like have the option, and so it should be reflected in | |
81 | // the code. | |
82 | // | |
4347b38f | 83 | // |
e802be3e | 84 | // The shaping function of the VA1_ALICE is generally given by |
4347b38f | 85 | // |
e802be3e | 86 | // f(x) = A(1 - exp(-Bx)) |
4347b38f | 87 | // |
e802be3e | 88 | // where A is the total charge collected in the pre-amp., and B is a |
89 | // paramter that depends on the shaping time of the VA1_ALICE circut. | |
90 | // | |
91 | // When simulating the shaping function of the VA1_ALICe | |
92 | // pre-amp. chip, we have to take into account, that the shaping | |
93 | // function depends on the previous value of read from the pre-amp. | |
94 | // | |
95 | // That results in the following algorithm: | |
96 | // | |
97 | // last = 0; | |
98 | // FOR charge IN pre-amp. charge train DO | |
99 | // IF last < charge THEN | |
100 | // f(t) = (charge - last) * (1 - exp(-B * t)) + last | |
101 | // ELSE | |
102 | // f(t) = (last - charge) * exp(-B * t) + charge) | |
103 | // ENDIF | |
104 | // FOR i IN # samples DO | |
105 | // adc_i = f(i / (# samples)) | |
106 | // DONE | |
107 | // last = charge | |
108 | // DONE | |
109 | // | |
110 | // Here, | |
111 | // | |
112 | // pre-amp. charge train | |
113 | // is a series of 128 charges read from the VA1_ALICE chip | |
114 | // | |
115 | // # samples | |
116 | // is the number of times the ALTRO ADC samples each of the 128 | |
117 | // charges from the pre-amp. | |
4347b38f | 118 | // |
119 | // Where Q is the total charge collected by the VA1_ALICE | |
120 | // pre-amplifier. Q is then given by | |
121 | // | |
122 | // E S | |
123 | // Q = - - | |
124 | // e R | |
125 | // | |
126 | // where E is the total energy deposited in a silicon strip, R is the | |
127 | // dynamic range of the VA1_ALICE pre-amp (fVA1MipRange), e is the | |
128 | // energy deposited by a single MIP, and S ALTRO channel size in each | |
129 | // time step (fAltroChannelSize). | |
130 | // | |
131 | // The energy deposited per MIP is given by | |
132 | // | |
133 | // e = M * rho * w | |
134 | // | |
135 | // where M is the universal number 1.664, rho is the density of | |
136 | // silicon, and w is the depth of the silicon sensor. | |
137 | // | |
138 | // The final ADC count is given by | |
139 | // | |
140 | // C' = C + P | |
141 | // | |
142 | // where P is the (randomized) pedestal (see MakePedestal) | |
143 | // | |
144 | // This class uses the class template AliFMDMap<Type> to make an | |
145 | // internal cache of the energy deposted of the hits. The class | |
146 | // template is instantasized as | |
147 | // | |
148 | // typedef AliFMDMap<std::pair<Float_t, UShort_t> > AliFMDEdepMap; | |
149 | // | |
150 | // The first member of the values is the summed energy deposition in a | |
151 | // given strip, while the second member of the values is the number of | |
152 | // hits in a given strip. Using the second member, it's possible to | |
153 | // do some checks on just how many times a strip got hit, and what | |
154 | // kind of error we get in our reconstructed hits. Note, that this | |
155 | // information is currently not written to the digits tree. I think a | |
156 | // QA (Quality Assurance) digit tree is better suited for that task. | |
157 | // However, the information is there to be used in the future. | |
158 | // | |
159 | // | |
160 | // Latest changes by Christian Holm Christensen | |
161 | // | |
162 | ////////////////////////////////////////////////////////////////////////////// | |
163 | ||
e802be3e | 164 | // /1 |
165 | // | A(-1 + B + exp(-B)) | |
166 | // | f(x) dx = ------------------- = 1 | |
167 | // | B | |
168 | // / 0 | |
169 | // | |
170 | // and B is the a parameter defined by the shaping time (fShapingTime). | |
171 | // | |
172 | // Solving the above equation, for A gives | |
173 | // | |
174 | // B | |
175 | // A = ---------------- | |
176 | // -1 + B + exp(-B) | |
177 | // | |
178 | // So, if we define the function g: [0,1] -> [0:1] by | |
179 | // | |
180 | // / v | |
181 | // | Bu + exp(-Bu) - Bv - exp(-Bv) | |
182 | // g(u,v) = | f(x) dx = -A ----------------------------- | |
183 | // | B | |
184 | // / u | |
185 | // | |
186 | // we can evaluate the ALTRO sample of the VA1_ALICE pre-amp between | |
187 | // any two times (u, v), by | |
188 | // | |
189 | // | |
190 | // B Bu + exp(-Bu) - Bv - exp(-Bv) | |
191 | // C = Q g(u,v) = - Q ---------------- ----------------------------- | |
192 | // -1 + B + exp(-B) B | |
193 | // | |
194 | // Bu + exp(-Bu) - Bv - exp(-Bv) | |
195 | // = - Q ----------------------------- | |
196 | // -1 + B + exp(-B) | |
197 | // | |
198 | ||
56b1929b | 199 | #include <TTree.h> // ROOT_TTree |
e939a978 | 200 | #include <TRandom.h> // ROOT_TRandom |
f95a63c4 | 201 | // #include <AliLog.h> // ALILOG_H |
202 | #include "AliFMDDebug.h" // Better debug macros | |
e802be3e | 203 | #include "AliFMDDigitizer.h" // ALIFMDDIGITIZER_H |
204 | #include "AliFMD.h" // ALIFMD_H | |
6169f936 | 205 | // #include "AliFMDGeometry.h" // ALIFMDGEOMETRY_H |
206 | // #include "AliFMDDetector.h" // ALIFMDDETECTOR_H | |
207 | // #include "AliFMDRing.h" // ALIFMDRING_H | |
208 | // #include "AliFMDHit.h" // ALIFMDHIT_H | |
e802be3e | 209 | #include "AliFMDDigit.h" // ALIFMDDIGIT_H |
8f6ee336 | 210 | #include "AliFMDParameters.h" // ALIFMDPARAMETERS_H |
56b1929b | 211 | #include <AliRunDigitizer.h> // ALIRUNDIGITIZER_H |
212 | #include <AliRun.h> // ALIRUN_H | |
213 | #include <AliLoader.h> // ALILOADER_H | |
214 | #include <AliRunLoader.h> // ALIRUNLOADER_H | |
4347b38f | 215 | |
4347b38f | 216 | //==================================================================== |
925e6570 | 217 | ClassImp(AliFMDDigitizer) |
66d2ede1 | 218 | |
4347b38f | 219 | //____________________________________________________________________ |
220 | AliFMDDigitizer::AliFMDDigitizer() | |
221 | : AliFMDBaseDigitizer() | |
222 | { | |
223 | // Default ctor - don't use it | |
224 | } | |
66d2ede1 | 225 | |
4347b38f | 226 | //____________________________________________________________________ |
227 | AliFMDDigitizer::AliFMDDigitizer(AliRunDigitizer* manager) | |
228 | : AliFMDBaseDigitizer(manager) | |
229 | { | |
230 | // Normal CTOR | |
f95a63c4 | 231 | AliFMDDebug(1, (" processed")); |
4347b38f | 232 | } |
66d2ede1 | 233 | |
4347b38f | 234 | //____________________________________________________________________ |
235 | void | |
236 | AliFMDDigitizer::Exec(Option_t*) | |
237 | { | |
238 | // Get the output manager | |
239 | TString outFolder(fManager->GetOutputFolderName()); | |
240 | AliRunLoader* out = | |
241 | AliRunLoader::GetRunLoader(outFolder.Data()); | |
242 | // Get the FMD output manager | |
243 | AliLoader* outFMD = out->GetLoader("FMDLoader"); | |
244 | ||
245 | // Get the input loader | |
246 | TString inFolder(fManager->GetInputFolderName(0)); | |
247 | fRunLoader = | |
a3537838 | 248 | AliRunLoader::GetRunLoader(inFolder.Data()); |
4347b38f | 249 | if (!fRunLoader) { |
250 | AliError("Can not find Run Loader for input stream 0"); | |
251 | return; | |
252 | } | |
253 | // Get the AliRun object | |
254 | if (!fRunLoader->GetAliRun()) fRunLoader->LoadgAlice(); | |
255 | ||
256 | // Get the AliFMD object | |
8f6ee336 | 257 | AliFMD* fmd = |
258 | static_cast<AliFMD*>(fRunLoader->GetAliRun()->GetDetector("FMD")); | |
4347b38f | 259 | if (!fmd) { |
260 | AliError("Can not get FMD from gAlice"); | |
261 | return; | |
262 | } | |
263 | ||
264 | Int_t nFiles= fManager->GetNinputs(); | |
265 | for (Int_t inputFile = 0; inputFile < nFiles; inputFile++) { | |
f95a63c4 | 266 | AliFMDDebug(1, (" Digitizing event number %d", |
4347b38f | 267 | fManager->GetOutputEventNr())); |
268 | // Get the current loader | |
269 | fRunLoader = | |
270 | AliRunLoader::GetRunLoader(fManager->GetInputFolderName(inputFile)); | |
271 | if (!fRunLoader) Fatal("Exec", "no run loader"); | |
272 | // Cache contriutions | |
273 | SumContributions(fmd); | |
274 | } | |
275 | // Digitize the event | |
276 | DigitizeHits(fmd); | |
277 | ||
278 | // Load digits from the tree | |
279 | outFMD->LoadDigits("update"); | |
280 | // Get the tree of digits | |
281 | TTree* digitTree = outFMD->TreeD(); | |
282 | if (!digitTree) { | |
283 | outFMD->MakeTree("D"); | |
284 | digitTree = outFMD->TreeD(); | |
285 | } | |
286 | digitTree->Reset(); | |
287 | // Make a branch in the tree | |
288 | TClonesArray* digits = fmd->Digits(); | |
289 | fmd->MakeBranchInTree(digitTree, fmd->GetName(), &(digits), 4000, 0); | |
290 | // TBranch* digitBranch = digitTree->GetBranch(fmd->GetName()); | |
291 | // Fill the tree | |
a1f80595 | 292 | Int_t write = 0; |
293 | write = digitTree->Fill(); | |
f95a63c4 | 294 | AliFMDDebug(1, ("Wrote %d bytes to digit tree", write)); |
66d2ede1 | 295 | |
4347b38f | 296 | // Write the digits to disk |
297 | outFMD->WriteDigits("OVERWRITE"); | |
298 | outFMD->UnloadHits(); | |
299 | outFMD->UnloadDigits(); | |
4110645f | 300 | |
4347b38f | 301 | // Reset the digits in the AliFMD object |
302 | fmd->ResetDigits(); | |
303 | } | |
3d44ce66 | 304 | |
88cb7938 | 305 | |
4347b38f | 306 | //____________________________________________________________________ |
307 | UShort_t | |
8f6ee336 | 308 | AliFMDDigitizer::MakePedestal(UShort_t detector, |
309 | Char_t ring, | |
310 | UShort_t sector, | |
311 | UShort_t strip) const | |
4347b38f | 312 | { |
088f8e79 | 313 | // Make a pedestal |
8f6ee336 | 314 | AliFMDParameters* param =AliFMDParameters::Instance(); |
315 | Float_t mean =param->GetPedestal(detector,ring,sector,strip); | |
316 | Float_t width =param->GetPedestalWidth(detector,ring,sector,strip); | |
317 | return UShort_t(TMath::Max(gRandom->Gaus(mean, width), 0.)); | |
4347b38f | 318 | } |
88cb7938 | 319 | |
4347b38f | 320 | //____________________________________________________________________ |
321 | void | |
322 | AliFMDDigitizer::AddDigit(AliFMD* fmd, | |
323 | UShort_t detector, | |
324 | Char_t ring, | |
325 | UShort_t sector, | |
326 | UShort_t strip, | |
327 | Float_t /* edep */, | |
328 | UShort_t count1, | |
329 | Short_t count2, | |
330 | Short_t count3) const | |
331 | { | |
088f8e79 | 332 | // Add a digit |
69b696b9 | 333 | fmd->AddDigitByFields(detector, ring, sector, strip, count1, count2, count3); |
4347b38f | 334 | } |
3d44ce66 | 335 | |
4347b38f | 336 | //____________________________________________________________________ |
337 | void | |
8f6ee336 | 338 | AliFMDDigitizer::CheckDigit(AliFMDDigit* digit, |
4347b38f | 339 | UShort_t nhits, |
340 | const TArrayI& counts) | |
341 | { | |
088f8e79 | 342 | // Check that digit is consistent |
8f6ee336 | 343 | AliFMDParameters* param = AliFMDParameters::Instance(); |
344 | UShort_t det = digit->Detector(); | |
345 | Char_t ring = digit->Ring(); | |
346 | UShort_t sec = digit->Sector(); | |
347 | UShort_t str = digit->Strip(); | |
348 | Float_t mean = param->GetPedestal(det,ring,sec,str); | |
349 | Float_t width = param->GetPedestalWidth(det,ring,sec,str); | |
350 | UShort_t range = param->GetVA1MipRange(); | |
351 | UShort_t size = param->GetAltroChannelSize(); | |
352 | Int_t integral = counts[0]; | |
4347b38f | 353 | if (counts[1] >= 0) integral += counts[1]; |
354 | if (counts[2] >= 0) integral += counts[2]; | |
8f6ee336 | 355 | integral -= Int_t(mean + 2 * width); |
4347b38f | 356 | if (integral < 0) integral = 0; |
357 | ||
8f6ee336 | 358 | Float_t convF = Float_t(range) / size; |
088f8e79 | 359 | Float_t mips = integral * convF; |
4347b38f | 360 | if (mips > Float_t(nhits) + .5 || mips < Float_t(nhits) - .5) |
361 | Warning("CheckDigit", "Digit -> %4.2f MIPS != %d +/- .5 hits", | |
362 | mips, nhits); | |
363 | } | |
66d2ede1 | 364 | |
4347b38f | 365 | //____________________________________________________________________ |
366 | // | |
367 | // EOF | |
368 | // | |
88cb7938 | 369 | |
370 | ||
371 | ||
66d2ede1 | 372 |