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source: svn/trunk/Utilities/CLHEP/Units/PhysicalConstants.h@ 642

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1// -*- C++ -*-
2// $Id: PhysicalConstants.h,v 1.1 2009-03-08 23:28:09 rouby Exp $
3// ----------------------------------------------------------------------
4// HEP coherent Physical Constants
5//
6// This file has been provided by Geant4 (simulation toolkit for HEP).
7//
8// The basic units are :
9// millimeter
10// nanosecond
11// Mega electron Volt
12// positon charge
13// degree Kelvin
14// amount of substance (mole)
15// luminous intensity (candela)
16// radian
17// steradian
18//
19// Below is a non exhaustive list of Physical CONSTANTS,
20// computed in the Internal HEP System Of Units.
21//
22// Most of them are extracted from the Particle Data Book :
23// Phys. Rev. D volume 50 3-1 (1994) page 1233
24//
25// ...with a meaningful (?) name ...
26//
27// You can add your own constants.
28//
29// Author: M.Maire
30//
31// History:
32//
33// 23.02.96 Created
34// 26.03.96 Added constants for standard conditions of temperature
35// and pressure; also added Gas threshold.
36
37#ifndef HEP_PHYSICAL_CONSTANTS_H
38#define HEP_PHYSICAL_CONSTANTS_H
39
40#include "SystemOfUnits.h"
41
42
43//
44//
45//
46//static const double pi = 3.14159265358979323846;
47static const double twopi = 2*pi;
48static const double halfpi = pi/2;
49static const double pi2 = pi*pi;
50
51//
52//
53//
54static const double Avogadro = 6.0221367e+23/mole;
55
56//
57// c = 299.792458 mm/ns
58// c^2 = 898.7404 (mm/ns)^2
59//
60static const double c_light = 2.99792458e+8 * m/s;
61static const double c_squared = c_light * c_light;
62
63//
64// h = 4.13566e-12 MeV*ns
65// hbar = 6.58212e-13 MeV*ns
66// hbarc = 197.32705e-12 MeV*mm
67//
68static const double h_Planck = 6.6260755e-34 * joule*s;
69static const double hbar_Planck = h_Planck/twopi;
70static const double hbarc = hbar_Planck * c_light;
71static const double hbarc_squared = hbarc * hbarc;
72
73//
74//
75//
76static const double electron_charge = - eplus; // see SystemOfUnits.h
77static const double e_squared = eplus * eplus;
78
79//
80// amu_c2 - atomic equivalent mass unit
81// amu - atomic mass unit
82//
83static const double electron_mass_c2 = 0.51099906 * MeV;
84static const double proton_mass_c2 = 938.27231 * MeV;
85static const double neutron_mass_c2 = 939.56563 * MeV;
86static const double amu_c2 = 931.49432 * MeV;
87static const double amu = amu_c2/c_squared;
88
89//
90// permeability of free space mu0 = 2.01334e-16 Mev*(ns*eplus)^2/mm
91// permittivity of free space epsil0 = 5.52636e+10 eplus^2/(MeV*mm)
92//
93static const double mu0 = 4*pi*1.e-7 * henry/m;
94static const double epsilon0 = 1./(c_squared*mu0);
95
96//
97// electromagnetic coupling = 1.43996e-12 MeV*mm/(eplus^2)
98//
99static const double elm_coupling = e_squared/(4*pi*epsilon0);
100static const double fine_structure_const = elm_coupling/hbarc;
101static const double classic_electr_radius = elm_coupling/electron_mass_c2;
102static const double electron_Compton_length = hbarc/electron_mass_c2;
103static const double Bohr_radius = electron_Compton_length/fine_structure_const;
104
105static const double alpha_rcl2 = fine_structure_const
106 *classic_electr_radius
107 *classic_electr_radius;
108
109static const double twopi_mc2_rcl2 = twopi*electron_mass_c2
110 *classic_electr_radius
111 *classic_electr_radius;
112//
113//
114//
115static const double k_Boltzmann = 8.617385e-11 * MeV/kelvin;
116
117//
118//
119//
120static const double STP_Temperature = 273.15*kelvin;
121static const double STP_Pressure = 1.*atmosphere;
122static const double kGasThreshold = 10.*mg/cm3;
123
124//
125//
126//
127static const double universe_mean_density = 1.e-25*g/cm3;
128
129#endif /* HEP_PHYSICAL_CONSTANTS_H */
130
131
132
133
134
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