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EDepInGas Class Reference

The Class for Energy deposit in the gas. More...

#include <EDepInGas.h>

Public Member Functions

virtual ~EDepInGas ()
 Destructor.
 
void initialize ()
 Initialize theclass.
 
double getEDepInGas (int mode, int pdg, double p, double dx, double e3) const
 Return the energy deosite in the gas.
 
double getMostProbabEDep (double p, double mass, double zi, double dx, double z, double a, double i, double rho) const
 Return the energy deosite in the material.
 

Static Public Member Functions

static EDepInGas & getInstance ()
 Static method to get a reference to the EDepInGas instance.
 

Private Member Functions

 EDepInGas ()
 Singleton class.
 
 EDepInGas (const EDepInGas &)
 Singleton class.
 
EDepInGas & operator= (const EDepInGas &)
 Singleton class.
 

Private Attributes

double m_z1 = 0
 Z of He-C2H6 gas.
 
double m_a1 = 0
 A of He-C2H6 gas.
 
double m_i1 = 0
 I of He-C2H6 gas.
 
double m_rho1 = 0
 rho of He-C2H6 gas
 
double m_z2 = 0
 Z of "wire gas".
 
double m_a2 = 0
 A of "wire gas".
 
double m_i2 = 0
 I of "wire gas".
 
double m_rho2 = 0
 rho of "wire gas"
 
double m_z0 = 0
 Z of wire+gas.
 
double m_a0 = 0
 A of wire+gas.
 
double m_i0 = 0
 I of wire+gas.
 
double m_rho0 = 0
 rho of wire+gas
 
const double m_massE = 0.51099895e6
 electron mass
 
double m_ak1 [6][2] = {{ }}
 coeffs a for density effect
 
double m_bk1 [6][2] = {{ }}
 coeffs b for density effect
 
double m_ck1 [6][2] = {{ }}
 coeffs c for density effect
 

Static Private Attributes

static EDepInGas * m_pntr = 0
 Pointer that saves the instance of this class.
 

Detailed Description

The Class for Energy deposit in the gas.

This class provides the energy deposit in the gas.

Definition at line 20 of file EDepInGas.h.

Constructor & Destructor Documentation

◆ ~EDepInGas()

~EDepInGas ( )
virtual

Destructor.

Definition at line 32 of file EDepInGas.cc.

32{}

◆ EDepInGas()

EDepInGas ( )
private

Singleton class.

Definition at line 30 of file EDepInGas.cc.

30{}

Member Function Documentation

◆ getEDepInGas()

double getEDepInGas ( int mode,
int pdg,
double p,
double dx,
double e3 ) const

Return the energy deosite in the gas.

Parameters
mode0: simple scaling; 1: scaling based on mpe; 2: based on probab.
pdgpdg code of incoming particle
pabsolute momentum (GeV)
dxthickness of material (cm)
e3energy deposit in gas+wire

Definition at line 135 of file EDepInGas.cc.

136{
137 double xi1 = m_rho1 * (m_z1 / m_a1);
138 double xi2 = m_rho2 * (m_z2 / m_a2);
139 // B2DEBUG(m_dbg, (xi1+xi2)/xi1 <<" "<< e3);
140 if (mode == 0) return e3 * xi1 / (xi1 + xi2);
141
142 static TDatabasePDG* ptrTDatabasePDG = TDatabasePDG::Instance();
143 const double mass = ptrTDatabasePDG->GetParticle(pdg)->Mass();
144 const double chrg = fabs(ptrTDatabasePDG->GetParticle(pdg)->Charge() / 3);
145
146 const double me1 = getMostProbabEDep(mom, mass, chrg, dx, m_z1, m_a1, m_i1, m_rho1);
147 if (mode == 2) {
148 const double me0 = getMostProbabEDep(mom, mass, chrg, dx, m_z0, m_a0, m_i0, m_rho0);
149 return e3 * me1 / me0;
150 }
151 const double me2 = getMostProbabEDep(mom, mass, chrg, dx, m_z2, m_a2, m_i2, m_rho2);
152 if (mode == 1) return e3 * me1 / (me1 + me2);
153
154 // extract energy deposit (e1) based on probab., L(e1)*L(e3-e1),
155 // where L is the analytic approx. of Landau dist.
156 // find lm1 which maximizes probability
157 const double mom2 = mom * mom;
158 const double beta2 = mom2 / (mass * mass + mom2);
159 const double buf = 0.1535e-3 * dx * chrg * chrg / beta2;
160 xi1 *= buf;
161 xi2 *= buf;
162 const double xi1i = 1 / xi1;
163 const double xi2i = 1 / xi2;
164 const double lm1min = -me1 * xi1i;
165 const double lm1max = (e3 - me1) * xi1i;
166 double lm1 = (e3 * me1 / (me1 + me2) - me1) * xi1i; // initial guess
167 lm1 = min(lm1, lm1max);
168 lm1 = max(lm1, lm1min);
169 // double edm = 1;
170 int itry = 0;
171 // B2DEBUG(m_dbg, "e3,me1,me2,xi1i=" << e3 <<" "<< me1 <<" "<< me2 <<" "<< xi1i);
172 // B2DEBUG(m_dbg, "lm1min,lm1max,lm1=" << lm1min <<" "<< lm1max <<" "<< lm1);
173 const double lm2b = (e3 - me1 - me2) * xi2i;
174 const double r = xi1 * xi2i;
175 double deltal = 0;
176 double lm1old = lm1;
177 while (itry <= 2 || fabs(lm1 - lm1old) > 0.001) {
178 ++itry;
179 lm1old = lm1;
180 if (itry > 50) {
181 // B2DEBUG(m_dbg, "itry > 50" << "itry,lm1min,lm1max,lm1,edm=" << itry <<" "<< lm1min <<" "<< lm1max <<" "<< lm1);
182 break;
183 }
184 lm1 -= deltal;
185 lm1 = max(lm1min, lm1);
186 lm1 = min(lm1max, lm1);
187 double lm2 = lm2b - r * lm1;
188 double emlm1 = exp(-lm1);
189 double emlm2 = exp(-lm2);
190 double dldlm1 = 1 - emlm1 - r + r * emlm2;
191 double dl2dlm12 = emlm1 + r * r * emlm2;
192 deltal = dldlm1 / dl2dlm12;
193 // edm = dldlm1 * deltal; //drop 0.5* for speed up
194 }
195
196 if (mode == 3) return xi1 * lm1 + me1;
197
198 double lm2 = lm2b - r * lm1;
199 double lmin = 0.5 * (lm1 + lm2 + exp(-lm1) + exp(-lm2));
200 const double ymax = exp(-lmin);
201 // if (ymax < 1.e-10) return e3*me1/(me1+me2);
202
203 // generate e1 according to probab.
204 const double lm1w = lm1max - lm1min;
205 double y = 10;
206 double p = 1;
207 int jtry = 0;
208 double urndm[2];
209 while (y > p) {
210 ++jtry;
211 if (jtry > 500) {
212 // B2DEBUG(m_dbg, "jtry > 500" <<"ymax" << ymax);
213 lm1 = (e3 * me1 / (me1 + me2) - me1) * xi1i;
214 break;
215 }
216 gRandom->RndmArray(2, urndm);
217 lm1 = lm1min + lm1w * urndm[0];
218 lm2 = lm2b - r * lm1;
219 double l = 0.5 * (lm1 + lm2 + exp(-lm1) + exp(-lm2));
220 p = exp(-l);
221 y = ymax * urndm[1];
222 }
223
224 return xi1 * lm1 + me1;
225}
Belle2::CDC::EDepInGas::m_i1
double m_i1
I of He-C2H6 gas.
Definition EDepInGas.h:71
Belle2::CDC::EDepInGas::m_i0
double m_i0
I of wire+gas.
Definition EDepInGas.h:81
Belle2::CDC::EDepInGas::m_z1
double m_z1
Z of He-C2H6 gas.
Definition EDepInGas.h:69
Belle2::CDC::EDepInGas::m_i2
double m_i2
I of "wire gas".
Definition EDepInGas.h:76
Belle2::CDC::EDepInGas::m_rho0
double m_rho0
rho of wire+gas
Definition EDepInGas.h:82
Belle2::CDC::EDepInGas::m_rho1
double m_rho1
rho of He-C2H6 gas
Definition EDepInGas.h:72
Belle2::CDC::EDepInGas::m_rho2
double m_rho2
rho of "wire gas"
Definition EDepInGas.h:77
Belle2::CDC::EDepInGas::m_a1
double m_a1
A of He-C2H6 gas.
Definition EDepInGas.h:70
Belle2::CDC::EDepInGas::m_z2
double m_z2
Z of "wire gas".
Definition EDepInGas.h:74
Belle2::CDC::EDepInGas::m_z0
double m_z0
Z of wire+gas.
Definition EDepInGas.h:79
Belle2::CDC::EDepInGas::m_a0
double m_a0
A of wire+gas.
Definition EDepInGas.h:80
Belle2::CDC::EDepInGas::getMostProbabEDep
double getMostProbabEDep(double p, double mass, double zi, double dx, double z, double a, double i, double rho) const
Return the energy deosite in the material.
Definition EDepInGas.cc:227
Belle2::CDC::EDepInGas::m_a2
double m_a2
A of "wire gas".
Definition EDepInGas.h:75

◆ getInstance()

EDepInGas & getInstance ( )
static

Static method to get a reference to the EDepInGas instance.

Returns
A reference to an instance of this class.

Definition at line 21 of file EDepInGas.cc.

22{
23 if (!m_pntr) {
24 m_pntr = new EDepInGas();
25 m_pntr->initialize();
26 }
27 return *m_pntr;
28}
Belle2::CDC::EDepInGas::EDepInGas
EDepInGas()
Singleton class.
Definition EDepInGas.cc:30
Belle2::CDC::EDepInGas::m_pntr
static EDepInGas * m_pntr
Pointer that saves the instance of this class.
Definition EDepInGas.h:89

◆ getMostProbabEDep()

double getMostProbabEDep ( double p,
double mass,
double zi,
double dx,
double z,
double a,
double i,
double rho ) const

Return the energy deosite in the material.

Parameters
pabsolute momentum (GeV)
masslmass of incoming particle (GeV)
ziz of incoming particle
dxthickness of material (cm)
zatomic number of material
aatomic weight of material
iionization potential of material (eV)
rhodensity of material

Definition at line 227 of file EDepInGas.cc.

229{
230// Calculate most probable energy deposit in GeV.
231// Ref. J.Va'vra et al., NIM 203 (1982) 109.
232// ----------------------------------------------------------------------
233// <Input>
234// p : total momentum (GeV)
235// mass : mass of particle (GeV)
236// zi : charge of particle (e)
237// dx : thickness of gas (cm)
238// Z : atomic no. of gas
239// A : atomic weight of gas
240// I : mean ionization potential of gas (eV)
241// rho : density of gas (g/cm**3)
242// ----------------------------------------------------------------------
243 const double psq = p * p;
244 const double masq = mass * mass;
245 const double tote = psq + masq;
246 const double beta2 = psq / tote;
247 const double bgam2 = psq / masq;
248 const double gamma = sqrt(tote) / mass;
249 const double alft = 0.1535e6 * rho * dx * Z / A;
250 const double k = log(m_massE * alft / I / I) + 0.891;
251 const double k1 = k - log(dx);
252 const double alngam = log(gamma);
253 const double alggam = log10(gamma);
254 // calculate density correction term
255 int irgn = 0;
256 double aa, bb, cc;
257 if (k1 < 6.) {
258 if (alggam > 3.6) irgn = 1;
259 aa = (m_ak1[1][irgn] - m_ak1[0][irgn]) * (6. - k1) + m_ak1[0][irgn];
260 bb = (m_bk1[1][irgn] - m_bk1[0][irgn]) * (6. - k1) + m_bk1[0][irgn];
261 cc = (m_ck1[1][irgn] - m_ck1[0][irgn]) * (6. - k1) + m_ck1[0][irgn];
262 } else if (k1 < 7.) {
263 if (alggam > 3.6) irgn = 1;
264 aa = (m_ak1[1][irgn] - m_ak1[0][irgn]) * (k1 - 6.) + m_ak1[0][irgn];
265 bb = (m_bk1[1][irgn] - m_bk1[0][irgn]) * (k1 - 6.) + m_bk1[0][irgn];
266 cc = (m_ck1[1][irgn] - m_ck1[0][irgn]) * (k1 - 6.) + m_ck1[0][irgn];
267 } else if (k1 < 8.) {
268 if (alggam > 3.6) irgn = 1;
269 aa = (m_ak1[2][irgn] - m_ak1[1][irgn]) * (k1 - 7.) + m_ak1[1][irgn];
270 bb = (m_bk1[2][irgn] - m_bk1[1][irgn]) * (k1 - 7.) + m_bk1[1][irgn];
271 cc = (m_ck1[2][irgn] - m_ck1[1][irgn]) * (k1 - 7.) + m_ck1[1][irgn];
272 } else if (k1 < 9.) {
273 if (alggam > 3.6) irgn = 1;
274 aa = (m_ak1[3][irgn] - m_ak1[2][irgn]) * (k1 - 8.) + m_ak1[2][irgn];
275 bb = (m_bk1[3][irgn] - m_bk1[2][irgn]) * (k1 - 8.) + m_bk1[2][irgn];
276 cc = (m_ck1[3][irgn] - m_ck1[2][irgn]) * (k1 - 8.) + m_ck1[2][irgn];
277 } else if (k1 < 10.) {
278 if (alggam > 3.6) irgn = 1;
279 aa = (m_ak1[4][irgn] - m_ak1[3][irgn]) * (k1 - 9.) + m_ak1[3][irgn];
280 bb = (m_bk1[4][irgn] - m_bk1[3][irgn]) * (k1 - 9.) + m_bk1[3][irgn];
281 cc = (m_ck1[4][irgn] - m_ck1[3][irgn]) * (k1 - 9.) + m_ck1[3][irgn];
282 } else if (k1 < 11.) {
283 if (alggam > 4.0) irgn = 1;
284 aa = (m_ak1[5][irgn] - m_ak1[4][irgn]) * (k1 - 10.) + m_ak1[4][irgn];
285 bb = (m_bk1[5][irgn] - m_bk1[4][irgn]) * (k1 - 10.) + m_bk1[4][irgn];
286 cc = (m_ck1[5][irgn] - m_ck1[4][irgn]) * (k1 - 10.) + m_ck1[4][irgn];
287 } else {
288 if (alggam > 4.0) irgn = 1;
289 aa = (m_ak1[5][irgn] - m_ak1[4][irgn]) * (k1 - 11.) + m_ak1[5][irgn];
290 bb = (m_bk1[5][irgn] - m_bk1[4][irgn]) * (k1 - 11.) + m_bk1[5][irgn];
291 cc = (m_ck1[5][irgn] - m_ck1[4][irgn]) * (k1 - 11.) + m_ck1[5][irgn];
292 }
293
294 double delta = aa + alggam * (bb + cc * alggam);
295 delta = max(delta, 0.);
296 delta = min(delta, fabs(log(bgam2)));
297
298 double val = zi * zi * alft * (k + 2 * alngam - beta2 - delta) / beta2;
299 val = max(val, 0.);
300 val *= Unit::eV;
301 return val;
302}
Belle2::CDC::EDepInGas::m_bk1
double m_bk1[6][2]
coeffs b for density effect
Definition EDepInGas.h:86
Belle2::CDC::EDepInGas::m_ak1
double m_ak1[6][2]
coeffs a for density effect
Definition EDepInGas.h:85
Belle2::CDC::EDepInGas::m_massE
const double m_massE
electron mass
Definition EDepInGas.h:84
Belle2::CDC::EDepInGas::m_ck1
double m_ck1[6][2]
coeffs c for density effect
Definition EDepInGas.h:87
Belle2::Unit::eV
static const double eV
[electronvolt]
Definition Unit.h:112
Belle2::sqrt
double sqrt(double a)
sqrt for double
Definition beamHelpers.h:28

◆ initialize()

void initialize ( )

Initialize theclass.

Definition at line 34 of file EDepInGas.cc.

35{
36// gas
37 const double zHe = 2;
38 const double aHe = 4.003;
39 double fHe = 0.1108;
40
41 const double zC = 6;
42 const double aC = 12.011;
43 double fC = 0.2223;
44
45 const double zH = 1;
46 const double aH = 1.008;
47 double fH = 0.6669;
48
49 double f = fHe + fC + fH;
50 fHe /= f;
51 fC /= f;
52 fH /= f;
53 m_z1 = fHe * zHe + fC * zC + fH * zH;
54 m_a1 = fHe * aHe + fC * aC + fH * aH;
55 m_i1 = 49.229;
56 m_rho1 = 0.703e-3;
57 // B2DEBUG(m_dbg, m_z1 <<" "<< m_a1 <<" "<< m_i1 <<" "<< m_rho1*m_z1/m_a1);
58
59 // wire
60 const double zW = 74;
61 const double aW = 183.842;
62 double fW = 0.0198;
63
64 const double zAl = 13;
65 const double aAl = 26.982;
66 double fAl = 0.9802;
67
68 f = fW + fAl;
69 fW /= f;
70 fAl /= f;
71 m_z2 = fW * zW + fAl * zAl;
72 m_a2 = fW * aW + fAl * aAl;
73 m_i2 = 193.301;
74 m_rho2 = 0.419e-3;
75 // B2DEBUG(m_dbg, m_z2 <<" "<< m_a2 <<" "<< m_i2 <<" "<< m_rho2*m_z2/m_a2);
76
77 fHe = 0.01031;
78 fC = 0.02068;
79 fH = 0.06204;
80 fW = 0.0014;
81 fAl = 0.0684;
82 f = fHe + fC + fH + fW + fAl;
83 fHe /= f;
84 fC /= f;
85 fH /= f;
86 fW /= f;
87 fAl /= f;
88 m_z0 = fHe * zHe + fC * zC + fH * zH + fW * zW + fAl * zAl;
89 m_a0 = fHe * aHe + fC * aC + fH * aH + fW * aW + fAl * aAl;
90 m_i0 = 76.693;
91 // m_rho0 = m_rho1 + m_rho2;
92 m_rho0 = 1.121e-3;
93
94 //Define coefficients of density correction term
95 m_ak1[0][0] = 10.065;
96 m_ak1[0][1] = -13.63;
97 m_ak1[1][0] = 4.1334;
98 m_ak1[1][1] = -12.4;
99 m_ak1[2][0] = 0.8135;
100 m_ak1[2][1] = -11.33;
101 m_ak1[3][0] = 0.00402;
102 m_ak1[3][1] = -10.36;
103 m_ak1[4][0] = - 1.7564;
104 m_ak1[4][1] = - 9.611;
105 m_ak1[5][0] = - 1.5065;
106 m_ak1[5][1] = - 8.6753;
107
108 m_bk1[0][0] = - 8.5619;
109 m_bk1[0][1] = 4.6;
110 m_bk1[1][0] = - 4.5857;
111 m_bk1[1][1] = 4.6;
112 m_bk1[2][0] = - 2.1447;
113 m_bk1[2][1] = 4.6;
114 m_bk1[3][0] = - 1.1582;
115 m_bk1[3][1] = 4.6;
116 m_bk1[4][0] = 0.67256;
117 m_bk1[4][1] = 4.6;
118 m_bk1[5][0] = 1.0156;
119 m_bk1[5][1] = 4.6;
120
121 m_ck1[0][0] = 1.82804;
122 m_ck1[0][1] = 0.0;
123 m_ck1[1][0] = 1.27579;
124 m_ck1[1][1] = 0.0;
125 m_ck1[2][0] = 0.93676;
126 m_ck1[2][1] = 0.0;
127 m_ck1[3][0] = 0.79975;
128 m_ck1[3][1] = 0.0;
129 m_ck1[4][0] = 0.49093;
130 m_ck1[4][1] = 0.0;
131 m_ck1[5][0] = 0.44805;
132 m_ck1[5][1] = 0.0;
133}

Member Data Documentation

◆ m_a0

double m_a0 = 0
private

A of wire+gas.

Definition at line 80 of file EDepInGas.h.

◆ m_a1

double m_a1 = 0
private

A of He-C2H6 gas.

Definition at line 70 of file EDepInGas.h.

◆ m_a2

double m_a2 = 0
private

A of "wire gas".

Definition at line 75 of file EDepInGas.h.

◆ m_ak1

double m_ak1[6][2] = {{ }}
private

coeffs a for density effect

Definition at line 85 of file EDepInGas.h.

85{{ }};

◆ m_bk1

double m_bk1[6][2] = {{ }}
private

coeffs b for density effect

Definition at line 86 of file EDepInGas.h.

86{{ }};

◆ m_ck1

double m_ck1[6][2] = {{ }}
private

coeffs c for density effect

Definition at line 87 of file EDepInGas.h.

87{{ }};

◆ m_i0

double m_i0 = 0
private

I of wire+gas.

Definition at line 81 of file EDepInGas.h.

◆ m_i1

double m_i1 = 0
private

I of He-C2H6 gas.

Definition at line 71 of file EDepInGas.h.

◆ m_i2

double m_i2 = 0
private

I of "wire gas".

Definition at line 76 of file EDepInGas.h.

◆ m_massE

const double m_massE = 0.51099895e6
private

electron mass

Definition at line 84 of file EDepInGas.h.

◆ m_pntr

EDepInGas * m_pntr = 0
staticprivate

Pointer that saves the instance of this class.

Definition at line 89 of file EDepInGas.h.

◆ m_rho0

double m_rho0 = 0
private

rho of wire+gas

Definition at line 82 of file EDepInGas.h.

◆ m_rho1

double m_rho1 = 0
private

rho of He-C2H6 gas

Definition at line 72 of file EDepInGas.h.

◆ m_rho2

double m_rho2 = 0
private

rho of "wire gas"

Definition at line 77 of file EDepInGas.h.

◆ m_z0

double m_z0 = 0
private

Z of wire+gas.

Definition at line 79 of file EDepInGas.h.

◆ m_z1

double m_z1 = 0
private

Z of He-C2H6 gas.

Definition at line 69 of file EDepInGas.h.

◆ m_z2

double m_z2 = 0
private

Z of "wire gas".

Definition at line 74 of file EDepInGas.h.

The documentation for this class was generated from the following files: