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SystemOfUnits.h
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1 // -*- C++ -*-
2 // $Id:$
3 // ----------------------------------------------------------------------
4 // HEP coherent system of Units
5 //
6 // This file has been provided to CLHEP by Geant4 (simulation toolkit for HEP).
7 //
8 // The basic units are :
9 // millimeter (millimeter)
10 // nanosecond (nanosecond)
11 // Mega electron Volt (MeV)
12 // positron charge (eplus)
13 // degree Kelvin (kelvin)
14 // the amount of substance (mole)
15 // luminous intensity (candela)
16 // radian (radian)
17 // steradian (steradian)
18 //
19 // Below is a non exhaustive list of derived and pratical units
20 // (i.e. mostly the SI units).
21 // You can add your own units.
22 //
23 // The SI numerical value of the positron charge is defined here,
24 // as it is needed for conversion factor : positron charge = e_SI (coulomb)
25 //
26 // The others physical constants are defined in the header file :
27 //PhysicalConstants.h
28 //
29 // Authors: M.Maire, S.Giani
30 //
31 // History:
32 //
33 // 06.02.96 Created.
34 // 28.03.96 Added miscellaneous constants.
35 // 05.12.97 E.Tcherniaev: Redefined pascal (to avoid warnings on WinNT)
36 // 20.05.98 names: meter, second, gram, radian, degree
37 // (from Brian.Lasiuk@yale.edu (STAR)). Added luminous units.
38 // 05.08.98 angstrom, picobarn, microsecond, picosecond, petaelectronvolt
39 // 01.03.01 parsec
40 // 31.01.06 kilogray, milligray, microgray
41 // 29.04.08 use PDG 2006 value of e_SI
42 // 03.11.08 use PDG 2008 value of e_SI
43 
44 #ifndef HEP_SYSTEM_OF_UNITS_H
45 #define HEP_SYSTEM_OF_UNITS_H
46 
47 namespace CLHEP {
48 
49  //
50  // Length [L]
51  //
52  static const double millimeter = 1.;
53  static const double millimeter2 = millimeter*millimeter;
54  static const double millimeter3 = millimeter*millimeter*millimeter;
55 
56  static const double centimeter = 10.*millimeter;
57  static const double centimeter2 = centimeter*centimeter;
58  static const double centimeter3 = centimeter*centimeter*centimeter;
59 
60  static const double meter = 1000.*millimeter;
61  static const double meter2 = meter*meter;
62  static const double meter3 = meter*meter*meter;
63 
64  static const double kilometer = 1000.*meter;
65  static const double kilometer2 = kilometer*kilometer;
66  static const double kilometer3 = kilometer*kilometer*kilometer;
67 
68  static const double parsec = 3.0856775807e+16*meter;
69 
70  static const double micrometer = 1.e-6 *meter;
71  static const double nanometer = 1.e-9 *meter;
72  static const double angstrom = 1.e-10*meter;
73  static const double fermi = 1.e-15*meter;
74 
75  static const double barn = 1.e-28*meter2;
76  static const double millibarn = 1.e-3 *barn;
77  static const double microbarn = 1.e-6 *barn;
78  static const double nanobarn = 1.e-9 *barn;
79  static const double picobarn = 1.e-12*barn;
80 
81  // symbols
82  static const double nm = nanometer;
83  static const double um = micrometer;
84 
85  static const double mm = millimeter;
86  static const double mm2 = millimeter2;
87  static const double mm3 = millimeter3;
88 
89  static const double cm = centimeter;
90  static const double cm2 = centimeter2;
91  static const double cm3 = centimeter3;
92 
93  static const double m = meter;
94  static const double m2 = meter2;
95  static const double m3 = meter3;
96 
97  static const double km = kilometer;
98  static const double km2 = kilometer2;
99  static const double km3 = kilometer3;
100 
101  static const double pc = parsec;
102 
103  //
104  // Angle
105  //
106  static const double radian = 1.;
107  static const double milliradian = 1.e-3*radian;
108  static const double degree = (3.14159265358979323846/180.0)*radian;
109 
110  static const double steradian = 1.;
111 
112  // symbols
113  static const double rad = radian;
114  static const double mrad = milliradian;
115  static const double sr = steradian;
116  static const double deg = degree;
117 
118  //
119  // Time [T]
120  //
121  static const double nanosecond = 1.;
122  static const double second = 1.e+9 *nanosecond;
123  static const double millisecond = 1.e-3 *second;
124  static const double microsecond = 1.e-6 *second;
125  static const double picosecond = 1.e-12*second;
126 
127  static const double hertz = 1./second;
128  static const double kilohertz = 1.e+3*hertz;
129  static const double megahertz = 1.e+6*hertz;
130 
131  // symbols
132  static const double ns = nanosecond;
133  static const double s = second;
134  static const double ms = millisecond;
135 
136  //
137  // Electric charge [Q]
138  //
139  static const double eplus = 1. ;// positron charge
140  static const double e_SI = 1.602176487e-19;// positron charge in coulomb
141  static const double coulomb = eplus/e_SI;// coulomb = 6.24150 e+18 * eplus
142 
143  //
144  // Energy [E]
145  //
146  static const double megaelectronvolt = 1. ;
147  static const double electronvolt = 1.e-6*megaelectronvolt;
148  static const double kiloelectronvolt = 1.e-3*megaelectronvolt;
149  static const double gigaelectronvolt = 1.e+3*megaelectronvolt;
150  static const double teraelectronvolt = 1.e+6*megaelectronvolt;
151  static const double petaelectronvolt = 1.e+9*megaelectronvolt;
152 
153  static const double joule = electronvolt/e_SI;// joule = 6.24150 e+12 * MeV
154 
155  // symbols
156  static const double MeV = megaelectronvolt;
157  static const double eV = electronvolt;
158  static const double keV = kiloelectronvolt;
159  static const double GeV = gigaelectronvolt;
160  static const double TeV = teraelectronvolt;
161  static const double PeV = petaelectronvolt;
162 
163  //
164  // Mass [E][T^2][L^-2]
165  //
166  static const double kilogram = joule*second*second/(meter*meter);
167  static const double gram = 1.e-3*kilogram;
168  static const double milligram = 1.e-3*gram;
169 
170  // symbols
171  static const double kg = kilogram;
172  static const double g = gram;
173  static const double mg = milligram;
174 
175  //
176  // Power [E][T^-1]
177  //
178  static const double watt = joule/second;// watt = 6.24150 e+3 * MeV/ns
179 
180  //
181  // Force [E][L^-1]
182  //
183  static const double newton = joule/meter;// newton = 6.24150 e+9 * MeV/mm
184 
185  //
186  // Pressure [E][L^-3]
187  //
188 #define pascal hep_pascal // a trick to avoid warnings
189  static const double hep_pascal = newton/m2; // pascal = 6.24150 e+3 * MeV/mm3
190  static const double bar = 100000*pascal; // bar = 6.24150 e+8 * MeV/mm3
191  static const double atmosphere = 101325*pascal; // atm = 6.32420 e+8 * MeV/mm3
192 
193  //
194  // Electric current [Q][T^-1]
195  //
196  static const double ampere = coulomb/second; // ampere = 6.24150 e+9 * eplus/ns
197  static const double milliampere = 1.e-3*ampere;
198  static const double microampere = 1.e-6*ampere;
199  static const double nanoampere = 1.e-9*ampere;
200 
201  //
202  // Electric potential [E][Q^-1]
203  //
204  static const double megavolt = megaelectronvolt/eplus;
205  static const double kilovolt = 1.e-3*megavolt;
206  static const double volt = 1.e-6*megavolt;
207 
208  //
209  // Electric resistance [E][T][Q^-2]
210  //
211  static const double ohm = volt/ampere;// ohm = 1.60217e-16*(MeV/eplus)/(eplus/ns)
212 
213  //
214  // Electric capacitance [Q^2][E^-1]
215  //
216  static const double farad = coulomb/volt;// farad = 6.24150e+24 * eplus/Megavolt
217  static const double millifarad = 1.e-3*farad;
218  static const double microfarad = 1.e-6*farad;
219  static const double nanofarad = 1.e-9*farad;
220  static const double picofarad = 1.e-12*farad;
221 
222  //
223  // Magnetic Flux [T][E][Q^-1]
224  //
225  static const double weber = volt*second;// weber = 1000*megavolt*ns
226 
227  //
228  // Magnetic Field [T][E][Q^-1][L^-2]
229  //
230  static const double tesla = volt*second/meter2;// tesla =0.001*megavolt*ns/mm2
231 
232  static const double gauss = 1.e-4*tesla;
233  static const double kilogauss = 1.e-1*tesla;
234 
235  //
236  // Inductance [T^2][E][Q^-2]
237  //
238  static const double henry = weber/ampere;// henry = 1.60217e-7*MeV*(ns/eplus)**2
239 
240  //
241  // Temperature
242  //
243  static const double kelvin = 1.;
244 
245  //
246  // Amount of substance
247  //
248  static const double mole = 1.;
249 
250  //
251  // Activity [T^-1]
252  //
253  static const double becquerel = 1./second ;
254  static const double curie = 3.7e+10 * becquerel;
255 
256  //
257  // Absorbed dose [L^2][T^-2]
258  //
259  static const double gray = joule/kilogram ;
260  static const double kilogray = 1.e+3*gray;
261  static const double milligray = 1.e-3*gray;
262  static const double microgray = 1.e-6*gray;
263 
264  //
265  // Luminous intensity [I]
266  //
267  static const double candela = 1.;
268 
269  //
270  // Luminous flux [I]
271  //
272  static const double lumen = candela*steradian;
273 
274  //
275  // Illuminance [I][L^-2]
276  //
277  static const double lux = lumen/meter2;
278 
279  //
280  // Miscellaneous
281  //
282  static const double perCent = 0.01 ;
283  static const double perThousand = 0.001;
284  static const double perMillion = 0.000001;
285 
286 } // namespace CLHEP
287 
288 #endif /* HEP_SYSTEM_OF_UNITS_H */
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