fix for pid in pr task: sjena
[u/mrichter/AliRoot.git] / FMD / AliFMDBaseDigitizer.h
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02a27b50 1#ifndef ALIFMDBASEDIGITIZER_H
2#define ALIFMDBASEDIGITIZER_H
3/* Copyright(c) 1998-2000, ALICE Experiment at CERN, All rights
4 * reserved.
5 *
6 * See cxx source for full Copyright notice
7 */
8// Classses to make Hits into digits and summable digits.
9//
10// Digits consists of
11// - Detector #
12// - Ring ID
13// - Sector #
14// - Strip #
15// - ADC count in this channel
16//
17// Summable digits consists of
18// - Detector #
19// - Ring ID
20// - Sector #
21// - Strip #
22// - Total energy deposited in the strip
23// - ADC count in this channel
24//
25/** @file AliFMDBaseDigitizer.h
26 @author Christian Holm Christensen <cholm@nbi.dk>
27 @date Mon Mar 27 12:38:26 2006
28 @brief FMD Digitizers declaration
29 @ingroup FMD_sim
30*/
31#ifndef ALIDIGITIZER_H
32# include <AliDigitizer.h>
33#endif
34#ifndef ALIRUNDIGITIZER_H
f21fc003 35# include <AliDigitizationInput.h>
02a27b50 36#endif
37#ifndef ALIFMDEdepMAP_H
38# include "AliFMDEdepMap.h"
39#endif
40//====================================================================
41class TClonesArray;
42class AliFMD;
43class AliLoader;
44class AliRunLoader;
45class AliFMDDigit;
46
47
48//====================================================================
49/** @class AliFMDBaseDigitizer AliFMDDigitizer.h <FMD/AliFMDDigitizer>
50 @brief Base class for digitizers.
51
52 This class contains the procedures simulation ADC signal for the
53 Forward Multiplicity detector : Hits->Digits and Hits->SDigits
54
55 Digits consists of
56 - Detector #
57 - Ring ID
58 - Sector #
59 - Strip #
60 - ADC count in this channel
61
62 Summable digits consists of
63 - Detector #
64 - Ring ID
65 - Sector #
66 - Strip #
67 - Total energy deposited in the strip
68 - ADC count in this channel
69
70 As the Digits and SDigits have so much in common, the classes
71 AliFMDDigitizer and AliFMDSDigitizer are implemented via a base
72 class AliFMDBaseDigitizer.
73 @verbatim
74 +---------------------+
75 | AliFMDBaseDigitizer |
76 +---------------------+
77 ^
78 |
79 +----------+---------+
80 | |
81 +-----------------+ +------------------+
82 | AliFMDDigitizer | | AliFMDSDigitizer |
83 +-----------------+ +------------------+
84 @endverbatim
85 These classes uses parameters fetched from the AliFMDParameters
86 manager.
87
88 The shaping function of the VA1 is generally given by
89 @f[
90 f(x) = A(1 - \exp(-Bx))
91 @f]
92 where A is the total charge collected in the pre-amp., and B is a
93 paramter that depends on the shaping time of the VA1 circut.
94
95 When simulating the shaping function of the VA1 pre-amp. chip, we
96 have to take into account, that the shaping function depends on
97 the previous value of read from the pre-amp.
98
99 That results in the following algorithm:
100 @code
101 last = 0;
102 for (i=0; i < n_pre_amp_charge; i++) {
103 charge = GetCharge(i);
104 if (last < charge)
105 f(t) = (charge - last) * (1 - exp(-B * t)) + last
106 else
107 f(t) = (last - charge) * exp(-B * t) + charge)
108 for (j=0; j < sample_rate; j++)
109 adc[j] = f(i / (# samples))
110 last = charge
111 }
112 @endcode
113 Here, the first loop is over all charges collected by the VA1
114 chip, and the @c sample_rate is how many times the ALTRO ADC
115 samples each of the 128 charges from the pre-amp.
116
117 The @c charge is the total charge @f$ Q@f$ collected by the VA1
118 pre-amplifier for a strip. @f$ Q@f$ is then given by
119 @f[
120 Q = \frac{E}{e}\frac{S}{r}
121 @f]
122 where @f$ E@f$ is the total energy deposited in a silicon strip,
123 @f$ R@f$ is the dynamic range of the VA1 pre-amp, @f$ e@f$ is the
124 energy deposited by a single MIP, and @f$ S@f$ ALTRO channel size
125 in each time step.
126
127 The energy deposited per MIP is given by
128 @f$
129 e = M \rho w
130 @f$
131 where @f$ M@f$ is the universal number
132 @f$ 1.664 \mbox{keV}\mbox{cm}^{2}\mbox{g}^{-1}@f$, @f$ \rho@f$ is
133 the density of silicon, and @f$ w@f$ is the depth of the silicon
134 sensor.
135
136 The final ADC count is given by
137 @f[
138 C' = C + P
139 @f]
140 where @f$ P@f$ is the (randomized) pedestal.
141
142 This class uses the class template AliFMDEdepMap to make an
143 internal cache of the energy deposted of the hits. The class
144 template is instantasized as
145
146 The first member of the values is the summed energy deposition in a
147 given strip, while the second member of the values is the number of
148 hits in a given strip. Using the second member, it's possible to
149 do some checks on just how many times a strip got hit, and what
150 kind of error we get in our reconstructed hits. Note, that this
151 information is currently not written to the digits tree. I think a
152 QA (Quality Assurance) digit tree is better suited for that task.
153 However, the information is there to be used in the future.
154 @ingroup FMD_sim
155 */
156class AliFMDBaseDigitizer : public AliDigitizer
157{
158public:
159 /** CTOR */
160 AliFMDBaseDigitizer();
161 /** Normal CTOR
162 @param manager Manager of digitization */
f21fc003 163 AliFMDBaseDigitizer(AliDigitizationInput * digInp);
02a27b50 164 /** Normal ctor
165 @param name Name
166 @param title Title */
167 AliFMDBaseDigitizer(const Char_t* name, const Char_t* title);
168 /** DTOR */
169 virtual ~AliFMDBaseDigitizer();
170
171 /** Initialize */
172 virtual Bool_t Init();
42f1b2f5 173
02a27b50 174 /** The response shape of the VA1 shaping circuit is approximently
175 given by
176 @f[
177 f(x) = A(1 - \exp(-Bx))
178 @f]
179 where @f$ A@f$ is the total charge collected by the pre-amp.,
180 and @f$ B@f$ is parameter that depends on the shaping time of
181 the @b VA1 pre-amp. This member function sets the parameter @f$
182 B@f$
183 @param B */
184 void SetShapingTime(Float_t B=10) { fShapingTime = B; }
185 /** @return Get the shaping time */
186 Float_t GetShapingTime() const { return fShapingTime; }
b2e6f0b0 187
188 void SetStoreTrackRefs(Bool_t store=kTRUE) { fStoreTrackRefs = store; }
189 Bool_t IsStoreTrackRefs() const { return fStoreTrackRefs; }
190
02a27b50 191protected:
02a27b50 192 /** For the stored energy contributions in the cache, convert the
193 energy signal to ADC counts, and store the created digit in
194 the digits array
195 @param fmd Pointer to detector */
ef8e8623 196 virtual void DigitizeHits() const;
02a27b50 197 /** Convert the total energy deposited to a (set of) ADC count(s).
198 See also the class description for more details.
199 @param edep Total energy deposited in detector
200 @param last Last charge collected in previous VA1 channnel
201 @param detector Detector #
202 @param ring Ring ID
203 @param sector Sector #
204 @param strip Strip #
205 @param counts Array holding the counts on return */
206 virtual void ConvertToCount(Float_t edep,
207 Float_t last,
208 UShort_t detector,
209 Char_t ring,
210 UShort_t sector,
211 UShort_t strip,
212 TArrayI& counts) const;
213 /** Make a pedestal
214 @param detector Detector #
215 @param ring Ring ID
216 @param sector Sector #
217 @param strip Strip #
218 @return Pedestal value */
219 virtual UShort_t MakePedestal(UShort_t detector,
220 Char_t ring,
221 UShort_t sector,
222 UShort_t strip) const;
223 /** Add noise to each sample */
224 virtual void AddNoise(TArrayI&) const {}
ef8e8623 225
226 /** Add edep contribution from (detector,ring,sector,strip) to cache */
227 virtual void AddContribution(UShort_t detector,
228 Char_t ring,
229 UShort_t sector,
230 UShort_t strip,
83ad576a 231 Float_t edep,
b2e6f0b0 232 Bool_t isPrimary,
faf80567 233 Int_t nTrackno,
234 Int_t* tracknos);
02a27b50 235 /** Add a digit to output */
b2e6f0b0 236 virtual void AddDigit(UShort_t detector,
237 Char_t ring,
238 UShort_t sector,
239 UShort_t strip,
240 Float_t edep,
241 UShort_t count1,
242 Short_t count2,
243 Short_t count3,
244 Short_t count4,
245 UShort_t ntot,
246 UShort_t nprim,
247 const TArrayI& refs) const;
ef8e8623 248 /** Make the output tree using the passed loader
249 @param loader
250 @return The generated tree. */
251 virtual TTree* MakeOutputTree(AliLoader* loader);
252 /** Store the data using the loader
253 @param loader The loader */
ab114bf9 254 virtual void StoreDigits(const AliLoader* loader);
02a27b50 255
b2e6f0b0 256 AliFMD* fFMD; // Detector object
257 AliRunLoader* fRunLoader; //! Run loader
258 AliFMDEdepMap fEdep; // Cache of Energy from hits
259 Float_t fShapingTime; // Shaping profile parameter
260 Bool_t fStoreTrackRefs; // Wether to store track references
2180cab3 261 mutable Int_t fIgnoredLabels; //! Number of labels not assigned
02a27b50 262
263 /** Copy CTOR
264 @param o object to copy from */
265 AliFMDBaseDigitizer(const AliFMDBaseDigitizer& o)
b5ee4425 266 : AliDigitizer(o),
ef8e8623 267 fFMD(o.fFMD),
b5ee4425 268 fRunLoader(0),
ef8e8623 269 fEdep(o.fEdep),
b2e6f0b0 270 fShapingTime(o.fShapingTime),
2180cab3 271 fStoreTrackRefs(o.fStoreTrackRefs),
272 fIgnoredLabels(o.fIgnoredLabels)
b5ee4425 273 {}
09b6c804 274 /**
275 * Assignment operator
276 *
277 * @return Reference to this object
278 */
279 AliFMDBaseDigitizer& operator=(const AliFMDBaseDigitizer& o);
2180cab3 280
f21fc003 281 ClassDef(AliFMDBaseDigitizer,5) // Base class for FMD digitizers
02a27b50 282};
283
284
285#endif
286//____________________________________________________________________
287//
288// Local Variables:
289// mode: C++
290// End:
291//
292//
293// EOF
294//
295