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ef8e8623 | 1 | /************************************************************************** |
2 | * Copyright(c) 2004, 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 | /* $Id: AliFMDHitDigitizer.cxx 28055 2008-08-18 00:33:20Z cholm $ */ | |
16 | /** @file AliFMDHitDigitizer.cxx | |
17 | @author Christian Holm Christensen <cholm@nbi.dk> | |
18 | @date Mon Mar 27 12:38:26 2006 | |
19 | @brief FMD Digitizers implementation | |
20 | @ingroup FMD_sim | |
21 | */ | |
22 | ////////////////////////////////////////////////////////////////////////////// | |
23 | // | |
24 | // This class contains the procedures simulation ADC signal for the | |
25 | // Forward Multiplicity detector : Hits->Digits | |
26 | // | |
27 | // Digits consists of | |
28 | // - Detector # | |
29 | // - Ring ID | |
30 | // - Sector # | |
31 | // - Strip # | |
32 | // - ADC count in this channel | |
33 | // | |
34 | // As the Digits and SDigits have so much in common, the classes | |
35 | // AliFMDHitDigitizer and AliFMDSDigitizer are implemented via a base | |
36 | // class AliFMDBaseDigitizer. | |
37 | // | |
38 | // +---------------------+ | |
39 | // | AliFMDBaseDigitizer | | |
40 | // +---------------------+ | |
41 | // ^ | |
42 | // | | |
43 | // +----------+---------+ | |
44 | // | | | |
45 | // +-----------------+ +------------------+ | |
46 | // | AliFMDHitDigitizer | | AliFMDSDigitizer | | |
47 | // +-----------------+ +------------------+ | |
48 | // | |
49 | // These classes has several paramters: | |
50 | // | |
51 | // fPedestal | |
52 | // fPedestalWidth | |
53 | // (Only AliFMDHitDigitizer) | |
54 | // Mean and width of the pedestal. The pedestal is simulated | |
55 | // by a Guassian, but derived classes my override MakePedestal | |
56 | // to simulate it differently (or pick it up from a database). | |
57 | // | |
58 | // fVA1MipRange | |
59 | // The dymamic MIP range of the VA1_ALICE pre-amplifier chip | |
60 | // | |
61 | // fAltroChannelSize | |
62 | // The largest number plus one that can be stored in one | |
63 | // channel in one time step in the ALTRO ADC chip. | |
64 | // | |
65 | // fSampleRate | |
66 | // How many times the ALTRO ADC chip samples the VA1_ALICE | |
67 | // pre-amplifier signal. The VA1_ALICE chip is read-out at | |
68 | // 10MHz, while it's possible to drive the ALTRO chip at | |
69 | // 25MHz. That means, that the ALTRO chip can have time to | |
70 | // sample each VA1_ALICE signal up to 2 times. Although it's | |
71 | // not certain this feature will be used in the production, | |
72 | // we'd like have the option, and so it should be reflected in | |
73 | // the code. | |
74 | // | |
75 | // These parameters are fetched from OCDB via the mananger AliFMDParameters. | |
76 | // | |
77 | // The shaping function of the VA1_ALICE is generally given by | |
78 | // | |
79 | // f(x) = A(1 - exp(-Bx)) | |
80 | // | |
81 | // where A is the total charge collected in the pre-amp., and B is a | |
82 | // paramter that depends on the shaping time of the VA1_ALICE circut. | |
83 | // | |
84 | // When simulating the shaping function of the VA1_ALICe | |
85 | // pre-amp. chip, we have to take into account, that the shaping | |
86 | // function depends on the previous value of read from the pre-amp. | |
87 | // | |
88 | // That results in the following algorithm: | |
89 | // | |
90 | // last = 0; | |
91 | // FOR charge IN pre-amp. charge train DO | |
92 | // IF last < charge THEN | |
93 | // f(t) = (charge - last) * (1 - exp(-B * t)) + last | |
94 | // ELSE | |
95 | // f(t) = (last - charge) * exp(-B * t) + charge) | |
96 | // ENDIF | |
97 | // FOR i IN # samples DO | |
98 | // adc_i = f(i / (# samples)) | |
99 | // DONE | |
100 | // last = charge | |
101 | // DONE | |
102 | // | |
103 | // Here, | |
104 | // | |
105 | // pre-amp. charge train | |
106 | // is a series of 128 charges read from the VA1_ALICE chip | |
107 | // | |
108 | // # samples | |
109 | // is the number of times the ALTRO ADC samples each of the 128 | |
110 | // charges from the pre-amp. | |
111 | // | |
112 | // Where Q is the total charge collected by the VA1_ALICE | |
113 | // pre-amplifier. Q is then given by | |
114 | // | |
115 | // E S | |
116 | // Q = - - | |
117 | // e R | |
118 | // | |
119 | // where E is the total energy deposited in a silicon strip, R is the | |
120 | // dynamic range of the VA1_ALICE pre-amp (fVA1MipRange), e is the | |
121 | // energy deposited by a single MIP, and S ALTRO channel size in each | |
122 | // time step (fAltroChannelSize). | |
123 | // | |
124 | // The energy deposited per MIP is given by | |
125 | // | |
126 | // e = M * rho * w | |
127 | // | |
128 | // where M is the universal number 1.664, rho is the density of | |
129 | // silicon, and w is the depth of the silicon sensor. | |
130 | // | |
131 | // The final ADC count is given by | |
132 | // | |
133 | // C' = C + P | |
134 | // | |
135 | // where P is the (randomized) pedestal (see MakePedestal) | |
136 | // | |
137 | // This class uses the class template AliFMDMap<Type> to make an | |
138 | // internal cache of the energy deposted of the hits. The class | |
139 | // template is instantasized as | |
140 | // | |
141 | // typedef AliFMDMap<std::pair<Float_t, UShort_t> > AliFMDEdepMap; | |
142 | // | |
143 | // The first member of the values is the summed energy deposition in a | |
144 | // given strip, while the second member of the values is the number of | |
145 | // hits in a given strip. Using the second member, it's possible to | |
146 | // do some checks on just how many times a strip got hit, and what | |
147 | // kind of error we get in our reconstructed hits. Note, that this | |
148 | // information is currently not written to the digits tree. I think a | |
149 | // QA (Quality Assurance) digit tree is better suited for that task. | |
150 | // However, the information is there to be used in the future. | |
151 | // | |
152 | // | |
153 | // Latest changes by Christian Holm Christensen | |
154 | // | |
155 | ////////////////////////////////////////////////////////////////////////////// | |
156 | ||
157 | // /1 | |
158 | // | A(-1 + B + exp(-B)) | |
159 | // | f(x) dx = ------------------- = 1 | |
160 | // | B | |
161 | // / 0 | |
162 | // | |
163 | // and B is the a parameter defined by the shaping time (fShapingTime). | |
164 | // | |
165 | // Solving the above equation, for A gives | |
166 | // | |
167 | // B | |
168 | // A = ---------------- | |
169 | // -1 + B + exp(-B) | |
170 | // | |
171 | // So, if we define the function g: [0,1] -> [0:1] by | |
172 | // | |
173 | // / v | |
174 | // | Bu + exp(-Bu) - Bv - exp(-Bv) | |
175 | // g(u,v) = | f(x) dx = -A ----------------------------- | |
176 | // | B | |
177 | // / u | |
178 | // | |
179 | // we can evaluate the ALTRO sample of the VA1_ALICE pre-amp between | |
180 | // any two times (u, v), by | |
181 | // | |
182 | // | |
183 | // B Bu + exp(-Bu) - Bv - exp(-Bv) | |
184 | // C = Q g(u,v) = - Q ---------------- ----------------------------- | |
185 | // -1 + B + exp(-B) B | |
186 | // | |
187 | // Bu + exp(-Bu) - Bv - exp(-Bv) | |
188 | // = - Q ----------------------------- | |
189 | // -1 + B + exp(-B) | |
190 | // | |
191 | ||
192 | #include <TTree.h> // ROOT_TTree | |
193 | #include "AliFMDDebug.h" // Better debug macros | |
194 | #include "AliFMDHitDigitizer.h" // ALIFMDDIGITIZER_H | |
195 | #include "AliFMD.h" // ALIFMD_H | |
196 | #include "AliFMDDigit.h" // ALIFMDDIGIT_H | |
197 | #include "AliFMDParameters.h" // ALIFMDPARAMETERS_H | |
198 | #include <AliRun.h> // ALIRUN_H | |
199 | #include <AliLoader.h> // ALILOADER_H | |
200 | #include <AliRunLoader.h> // ALIRUNLOADER_H | |
201 | #include <AliFMDHit.h> | |
202 | #include <TFile.h> | |
203 | ||
204 | //==================================================================== | |
205 | ClassImp(AliFMDHitDigitizer) | |
206 | #if 0 | |
207 | ; | |
208 | #endif | |
209 | ||
210 | //____________________________________________________________________ | |
211 | AliFMDHitDigitizer::AliFMDHitDigitizer(AliFMD* fmd, Output_t output) | |
212 | : AliFMDBaseDigitizer("FMD", (fOutput == kDigits ? | |
213 | "FMD Hit->Digit digitizer" : | |
214 | "FMD Hit->SDigit digitizer")), | |
215 | fOutput(output) | |
216 | { | |
217 | fFMD = fmd; | |
218 | } | |
219 | ||
220 | //____________________________________________________________________ | |
221 | void | |
222 | AliFMDHitDigitizer::Exec(Option_t* /*option*/) | |
223 | { | |
224 | // Run this digitizer | |
225 | // Get an inititialize parameter manager | |
226 | AliFMDParameters::Instance()->Init(); | |
227 | if (AliLog::GetDebugLevel("FMD","") >= 10) | |
228 | AliFMDParameters::Instance()->Print("ALL"); | |
229 | ||
230 | // Get loader, and ask it to read in the hits | |
231 | AliLoader* loader = fFMD->GetLoader(); | |
232 | if (!loader) { | |
233 | AliError("Failed to get loader from detector object"); | |
234 | return; | |
235 | } | |
236 | loader->LoadHits("READ"); | |
237 | ||
238 | // Get the run loader | |
239 | AliRunLoader* runLoader = loader->GetRunLoader(); | |
240 | if (!runLoader) { | |
241 | AliError("Failed to get run loader from loader"); | |
242 | return; | |
243 | } | |
244 | ||
245 | // Now loop over events | |
246 | Int_t nEvents = runLoader->GetNumberOfEvents(); | |
247 | for (Int_t event = 0; event < nEvents; event++) { | |
248 | // Get the current event folder. | |
249 | TFolder* folder = loader->GetEventFolder(); | |
250 | if (!folder) { | |
251 | AliError("Failed to get event folder from loader"); | |
252 | return; | |
253 | } | |
254 | ||
255 | // Get the run-loader of this event. | |
256 | const char* loaderName = AliRunLoader::GetRunLoaderName(); | |
257 | AliRunLoader* thisLoader = | |
258 | static_cast<AliRunLoader*>(folder->FindObject(loaderName)); | |
259 | if (!thisLoader) { | |
260 | AliError(Form("Failed to get loader '%s' from event folder", loaderName)); | |
261 | return; | |
262 | } | |
263 | ||
264 | // Read in the event | |
265 | AliFMDDebug(5, ("Now digitizing (Hits->%s) event # %d", | |
266 | (fOutput == kDigits ? "digits" : "sdigits"), event)); | |
267 | thisLoader->GetEvent(event); | |
268 | ||
269 | // Check that we have the hits | |
270 | if (!loader->TreeH() && loader->LoadHits()) { | |
271 | AliError("Failed to load hits"); | |
272 | return; | |
273 | } | |
274 | TTree* hitsTree = loader->TreeH(); | |
275 | TBranch* hitsBranch = hitsTree->GetBranch(fFMD->GetName()); | |
276 | if (!hitsBranch) { | |
277 | AliError("Failed to get hits branch in tree"); | |
278 | return; | |
279 | } | |
280 | // Check that we can make the output digits - This must come | |
281 | // before AliFMD::SetBranchAddress | |
282 | TTree* outTree = MakeOutputTree(loader); | |
283 | if (!outTree) { | |
284 | AliError("Failed to get output tree"); | |
285 | return; | |
286 | } | |
287 | AliFMDDebug(5, ("Output tree name for %s is '%s'", | |
288 | (fOutput == kDigits ? "digits" : "sdigits"), | |
289 | outTree->GetName())); | |
290 | if (AliLog::GetDebugLevel("FMD","") >= 5) { | |
291 | TFile* file = outTree->GetCurrentFile(); | |
292 | if (!file) { | |
293 | AliWarning("Output tree has no file!"); | |
294 | } | |
295 | else { | |
296 | AliFMDDebug(5, ("Output tree file %s content:", file->GetName())); | |
297 | file->ls(); | |
298 | } | |
299 | } | |
300 | ||
301 | // Set-up the branch addresses | |
302 | fFMD->SetTreeAddress(); | |
303 | ||
304 | // Now sum all contributions in cache | |
305 | SumContributions(hitsBranch); | |
306 | loader->UnloadHits(); | |
307 | ||
308 | // And now digitize the hits | |
309 | DigitizeHits(); | |
310 | ||
311 | // Write digits to tree | |
312 | Int_t write = outTree->Fill(); | |
313 | AliFMDDebug(1, ("Wrote %d bytes to digit tree", write)); | |
314 | ||
315 | // Store the digits | |
316 | StoreDigits(loader); | |
317 | ||
318 | } | |
319 | } | |
320 | ||
321 | //____________________________________________________________________ | |
322 | TTree* | |
323 | AliFMDHitDigitizer::MakeOutputTree(AliLoader* loader) | |
324 | { | |
325 | if (fOutput == kDigits) | |
326 | return AliFMDBaseDigitizer::MakeOutputTree(loader); | |
327 | ||
328 | AliFMDDebug(5, ("Making sdigits tree")); | |
329 | loader->LoadSDigits("UPDATE"); // RECREATE"); | |
330 | TTree* out = loader->TreeS(); | |
331 | if (!out) loader->MakeTree("S"); | |
332 | out = loader->TreeS(); | |
333 | if (out) { | |
334 | out->Reset(); | |
335 | fFMD->MakeBranch("S"); | |
336 | } | |
337 | return out; | |
338 | } | |
339 | ||
340 | ||
341 | //____________________________________________________________________ | |
342 | void | |
343 | AliFMDHitDigitizer::SumContributions(TBranch* hitsBranch) | |
344 | { | |
345 | // Sum energy deposited contributions from each hit in a cache | |
346 | // (fEdep). | |
347 | ||
348 | // Clear array of deposited energies | |
349 | fEdep.Reset(); | |
350 | ||
351 | // Get a list of hits from the FMD manager | |
352 | AliFMDDebug(5, ("Get array of FMD hits")); | |
353 | TClonesArray *fmdHits = fFMD->Hits(); | |
354 | ||
355 | ||
356 | // Get number of entries in the tree | |
357 | AliFMDDebug(5, ("Get # of tracks")); | |
358 | Int_t ntracks = Int_t(hitsBranch->GetEntries()); | |
359 | AliFMDDebug(5, ("We got %d tracks", ntracks)); | |
360 | ||
361 | Int_t read = 0; | |
362 | // Loop over the tracks in the | |
363 | for (Int_t track = 0; track < ntracks; track++) { | |
364 | // Read in entry number `track' | |
365 | read += hitsBranch->GetEntry(track); | |
366 | ||
367 | // Get the number of hits | |
368 | Int_t nhits = fmdHits->GetEntries (); | |
369 | for (Int_t hit = 0; hit < nhits; hit++) { | |
370 | // Get the hit number `hit' | |
371 | AliFMDHit* fmdHit = | |
372 | static_cast<AliFMDHit*>(fmdHits->UncheckedAt(hit)); | |
373 | ||
374 | // Extract parameters | |
375 | AddContribution(fmdHit->Detector(), | |
376 | fmdHit->Ring(), | |
377 | fmdHit->Sector(), | |
378 | fmdHit->Strip(), | |
379 | fmdHit->Edep()); | |
380 | } // hit loop | |
381 | } // track loop | |
382 | AliFMDDebug(5, ("Size of cache: %d bytes, read %d bytes", | |
383 | sizeof(fEdep), read)); | |
384 | } | |
385 | ||
386 | ||
387 | //____________________________________________________________________ | |
388 | UShort_t | |
389 | AliFMDHitDigitizer::MakePedestal(UShort_t detector, | |
390 | Char_t ring, | |
391 | UShort_t sector, | |
392 | UShort_t strip) const | |
393 | { | |
394 | // Make a pedestal | |
395 | if (fOutput == kSDigits) return 0; | |
396 | return AliFMDBaseDigitizer::MakePedestal(detector, ring, sector, strip); | |
397 | } | |
398 | ||
399 | ||
400 | ||
401 | //____________________________________________________________________ | |
402 | void | |
403 | AliFMDHitDigitizer::AddDigit(UShort_t detector, | |
404 | Char_t ring, | |
405 | UShort_t sector, | |
406 | UShort_t strip, | |
407 | Float_t edep, | |
408 | UShort_t count1, | |
409 | Short_t count2, | |
410 | Short_t count3, | |
411 | Short_t count4) const | |
412 | { | |
413 | // Add a digit or summable digit | |
414 | if (fOutput == kDigits) { | |
415 | AliFMDBaseDigitizer::AddDigit(detector, ring, sector, strip, 0, | |
416 | count1, count2, count3, count4); | |
417 | return; | |
418 | } | |
419 | if (edep <= 0) return; | |
420 | if (count1 == 0 && count2 <= 0 && count3 <= 0 && count4 <= 0) return; | |
421 | fFMD->AddSDigitByFields(detector, ring, sector, strip, edep, | |
422 | count1, count2, count3, count4); | |
423 | } | |
424 | ||
425 | //____________________________________________________________________ | |
426 | void | |
427 | AliFMDHitDigitizer::CheckDigit(AliFMDDigit* digit, | |
428 | UShort_t nhits, | |
429 | const TArrayI& counts) | |
430 | { | |
431 | // Check that digit is consistent | |
432 | AliFMDParameters* param = AliFMDParameters::Instance(); | |
433 | UShort_t det = digit->Detector(); | |
434 | Char_t ring = digit->Ring(); | |
435 | UShort_t sec = digit->Sector(); | |
436 | UShort_t str = digit->Strip(); | |
437 | Float_t mean = param->GetPedestal(det,ring,sec,str); | |
438 | Float_t width = param->GetPedestalWidth(det,ring,sec,str); | |
439 | UShort_t range = param->GetVA1MipRange(); | |
440 | UShort_t size = param->GetAltroChannelSize(); | |
441 | Int_t integral = counts[0]; | |
442 | if (counts[1] >= 0) integral += counts[1]; | |
443 | if (counts[2] >= 0) integral += counts[2]; | |
444 | if (counts[3] >= 0) integral += counts[3]; | |
445 | integral -= Int_t(mean + 2 * width); | |
446 | if (integral < 0) integral = 0; | |
447 | ||
448 | Float_t convF = Float_t(range) / size; | |
449 | Float_t mips = integral * convF; | |
450 | if (mips > Float_t(nhits) + .5 || mips < Float_t(nhits) - .5) | |
451 | Warning("CheckDigit", "Digit -> %4.2f MIPS != %d +/- .5 hits", | |
452 | mips, nhits); | |
453 | } | |
454 | ||
455 | //____________________________________________________________________ | |
456 | void | |
457 | AliFMDHitDigitizer::StoreDigits(AliLoader* loader) | |
458 | { | |
459 | if (fOutput == kDigits) { | |
460 | AliFMDBaseDigitizer::StoreDigits(loader); | |
461 | return; | |
462 | } | |
463 | AliFMDDebug(5, ("Storing %d sdigits", fFMD->SDigits()->GetEntries())); | |
464 | // Write the digits to disk | |
465 | loader->WriteSDigits("OVERWRITE"); | |
466 | loader->UnloadSDigits(); | |
467 | // Reset the digits in the AliFMD object | |
468 | fFMD->ResetSDigits(); | |
469 | } | |
470 | ||
471 | ||
472 | //____________________________________________________________________ | |
473 | // | |
474 | // EOF | |
475 | // | |
476 | ||
477 | ||
478 | ||
479 |