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e802be3e | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, 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 | /* $Id$ */ | |
17 | ||
18 | //____________________________________________________________________ | |
19 | // | |
20 | // Base class for FMD naiive algorithms. | |
21 | // | |
22 | // Derived classes will implement various ways of reconstructing the | |
23 | // charge particle multiplicity in the FMD. | |
24 | // | |
25 | #include "AliFMDNaiiveAlgorithm.h" // ALIFMDNAIIVEALGORITHM_H | |
26 | #include "AliFMDDigit.h" // ALIFMDDIGIT_H | |
27 | ||
28 | //____________________________________________________________________ | |
29 | ClassImp(AliFMDNaiiveAlgorithm); | |
30 | ||
31 | //____________________________________________________________________ | |
32 | AliFMDNaiiveAlgorithm::AliFMDNaiiveAlgorithm() | |
33 | : AliFMDReconstructionAlgorithm("Naiive", "Naiive") | |
34 | {} | |
35 | ||
36 | ||
37 | //____________________________________________________________________ | |
38 | void | |
39 | AliFMDNaiiveAlgorithm::Reset() | |
40 | { | |
41 | // Reset internal data | |
42 | fTotal = 0; | |
43 | fEdep.Clear(0); | |
44 | fMultiplicity.Clear(0); | |
45 | } | |
46 | ||
47 | //____________________________________________________________________ | |
48 | void | |
49 | AliFMDNaiiveAlgorithm::ProcessDigit(AliFMDDigit* digit, | |
50 | Float_t eta, | |
51 | Float_t phi, | |
52 | UShort_t count) | |
53 | { | |
54 | // Process one digit. | |
55 | // | |
56 | // Parameters: | |
57 | // | |
58 | // digit Digit to process | |
59 | // eta Pseudo-rapidity of digit | |
60 | // phi Azimuthal angle of digit | |
61 | // count ADC (corrected for the pedestal) | |
62 | // | |
63 | // This calculates the energy deposited and the number of MIPs that | |
64 | // this energy deposition corresponds to | |
65 | // | |
66 | // EnergyDeposited = cos(theta) * gain * count | |
67 | // Multiplicity = EnergyDeposited / EnergyDepositedPerMIP | |
68 | // | |
69 | // where gain is a conversion factor from number of counts to an | |
70 | // energy: | |
71 | // Pre_Amp_MIP_Range 1 | |
72 | // gain = ----------------- * --------------------- | |
73 | // ADC_channel_size EnergyDepositedPerMip | |
74 | // | |
75 | // and theta is the particles incident angle on the strip, given by | |
76 | // | |
77 | // theta = 2 * atan * exp(-eta) | |
78 | // | |
79 | // The cos(theta) factor corrects for the fact that the particle may | |
80 | // traverse the strip at an angle, and therefor have a longer flight | |
81 | // length, leading to a larger energy deposition. | |
82 | // | |
83 | if (!digit) return; | |
84 | Double_t theta = 2 * TMath::Tan(TMath::Exp(- eta)); | |
85 | Double_t edep = TMath::Cos(theta) * fGain * count; | |
86 | Double_t mult = edep / fEdepMip; | |
87 | fEdep(digit->Detector() - 1, digit->Ring(), | |
88 | digit->Setctor(), digit->Strip()) = edep; | |
89 | fMultiplicity(digit->Detector() - 1, digit->Ring(), | |
90 | digit->Setctor(), digit->Strip()) = mult; | |
91 | } | |
92 | ||
93 | ||
94 | //____________________________________________________________________ | |
95 | // | |
96 | // EOF | |
97 | // |