include/Evaluator/DD4hepUnits.h

0001 //==========================================================================
0002 //  AIDA Detector description implementation
0003 //--------------------------------------------------------------------------
0004 // Copyright (C) Organisation europeenne pour la Recherche nucleaire (CERN)
0005 // All rights reserved.
0006 //
0007 // For the licensing terms see $DD4hepINSTALL/LICENSE.
0008 // For the list of contributors see $DD4hepINSTALL/doc/CREDITS.
0009 //
0010 // Author     : M.Frank
0011 //
0012 //==========================================================================
0013
0014 //
0015 // System of Units for dd4hep - similar to Geant3 and TGeo/ROOT
0016 //
0017 // Taken from CLHEP with the following basic translations:
0018 //
0019 // Geant4                                   dd4hep
0020 // ----------------------------------------------------------------
0021 // millimeter         mm=1,cm=10            centimeter  mm=0.1,cm=1
0022 // nanosecond         s=1e9                 second      ns=1e-9,s=1
0023 // Mega electron Volt GeV=1e3               GeV         GeV=1
0024 // radian             rad=1                 rad = 1  //NB: different from TGeo
0025 //
0026 //
0027 #ifndef EVALUATOR_DD4HEPUNITS_H
0028 #define EVALUATOR_DD4HEPUNITS_H
0029
0030 /// Main dd4hep namespace. We must import here the ROOT TGeo units
0031 namespace dd4hep {
0032
0033   //namespace units  {
0034     //
0035     // Length [L]
0036     //
0037 #ifdef DD4HEP_USE_GEANT4_UNITS
0038     static constexpr double millimeter = 1.0;
0039 #else
0040     static constexpr double millimeter = 0.1;
0041 #endif
0042     static constexpr double millimeter2 = millimeter * millimeter;
0043     static constexpr double millimeter3 = millimeter * millimeter * millimeter;
0044
0045     static constexpr double centimeter = 10. * millimeter;
0046     static constexpr double centimeter2 = centimeter * centimeter;
0047     static constexpr double centimeter3 = centimeter * centimeter * centimeter;
0048
0049     static constexpr double meter = 1000. * millimeter;
0050     static constexpr double meter2 = meter * meter;
0051     static constexpr double meter3 = meter * meter * meter;
0052
0053     static constexpr double kilometer = 1000. * meter;
0054     static constexpr double kilometer2 = kilometer * kilometer;
0055     static constexpr double kilometer3 = kilometer * kilometer * kilometer;
0056
0057     static constexpr double parsec = 3.0856775807e+16 * meter;
0058
0059     static constexpr double micrometer = 1.e-6 * meter;
0060     static constexpr double nanometer = 1.e-9 * meter;
0061     static constexpr double angstrom = 1.e-10 * meter;
0062     static constexpr double fermi = 1.e-15 * meter;
0063
0064     static constexpr double barn = 1.e-28 * meter2;
0065     static constexpr double millibarn = 1.e-3 * barn;
0066     static constexpr double microbarn = 1.e-6 * barn;
0067     static constexpr double nanobarn = 1.e-9 * barn;
0068     static constexpr double picobarn = 1.e-12 * barn;
0069
0070     // symbols
0071     static constexpr double nm = nanometer;
0072     static constexpr double um = micrometer;
0073
0074     static constexpr double mm = millimeter;
0075     static constexpr double mm2 = millimeter2;
0076     static constexpr double mm3 = millimeter3;
0077
0078     static constexpr double cm = centimeter;
0079     static constexpr double cm2 = centimeter2;
0080     static constexpr double cm3 = centimeter3;
0081
0082     static constexpr double m = meter;
0083     static constexpr double m2 = meter2;
0084     static constexpr double m3 = meter3;
0085
0086     static constexpr double km = kilometer;
0087     static constexpr double km2 = kilometer2;
0088     static constexpr double km3 = kilometer3;
0089
0090     static constexpr double pc = parsec;
0091
0092     //
0093     // Angle
0094     //
0095     // static constexpr double radian = 180. / 3.14159265358979323846;   // => degree=1
0096     // static constexpr double milliradian = 1.e-3 * radian;
0097     // static constexpr double degree = 1.;   //= (3.14159265358979323846/180.0)*radian;
0098
0099     //fg: use radians as default unit as this is needed for all math functions
0100     //    and everywhere else, except in TGeo shapes -> this is taken care of in shape Handles ....
0101     static constexpr double radian = 1. ;
0102     static constexpr double milliradian = 1.e-3 * radian;
0103     static constexpr double degree = (3.14159265358979323846/180.0)*radian;
0104
0105     static constexpr double steradian = 1.;
0106
0107     // symbols
0108     static constexpr double rad = radian;
0109     static constexpr double mrad = milliradian;
0110     static constexpr double sr = steradian;
0111     static constexpr double deg = degree;
0112
0113     //
0114     // Time [T]
0115     //
0116 #ifdef DD4HEP_USE_GEANT4_UNITS
0117     static constexpr double nanosecond = 1.0;
0118 #else
0119     static constexpr double nanosecond = 1.e-9;
0120 #endif
0121     static constexpr double second = 1.e+9 * nanosecond;
0122     static constexpr double millisecond = 1.e-3 * second;
0123     static constexpr double microsecond = 1.e-6 * second;
0124     static constexpr double picosecond = 1.e-12 * second;
0125
0126     static constexpr double hertz = 1. / second;
0127     static constexpr double kilohertz = 1.e+3 * hertz;
0128     static constexpr double megahertz = 1.e+6 * hertz;
0129
0130     // symbols
0131     static constexpr double ns = nanosecond;
0132     static constexpr double s = second;
0133     static constexpr double ms = millisecond;
0134
0135     //
0136     // Electric charge [Q]
0137     //
0138     static constexpr double eplus = 1.;   // positron charge
0139     static constexpr double e_SI = 1.602176487e-19;   // positron charge in coulomb
0140     static constexpr double coulomb = eplus / e_SI;   // coulomb = 6.24150 e+18 * eplus
0141
0142     //
0143     // Energy [E]
0144     //
0145 #ifdef DD4HEP_USE_GEANT4_UNITS
0146     static constexpr double megaelectronvolt = 1.0;
0147 #else
0148     static constexpr double megaelectronvolt = 1.e-3;
0149 #endif
0150     static constexpr double electronvolt = 1.e-6 * megaelectronvolt;
0151     static constexpr double kiloelectronvolt = 1.e-3 * megaelectronvolt;
0152     static constexpr double gigaelectronvolt = 1.e+3 * megaelectronvolt;
0153     static constexpr double teraelectronvolt = 1.e+6 * megaelectronvolt;
0154     static constexpr double petaelectronvolt = 1.e+9 * megaelectronvolt;
0155
0156     static constexpr double joule = electronvolt / e_SI;   // joule = 6.24150 e+12 * MeV
0157     static constexpr double kilojoule = 1.e3*joule;
0158
0159     // symbols
0160     static constexpr double eV  = electronvolt;
0161     static constexpr double keV = kiloelectronvolt;
0162     static constexpr double MeV = megaelectronvolt;
0163     static constexpr double GeV = gigaelectronvolt;
0164     static constexpr double TeV = teraelectronvolt;
0165     static constexpr double PeV = petaelectronvolt;
0166
0167     //
0168     // Mass [E][T^2][L^-2]
0169     //
0170     static constexpr double kilogram = joule * second * second / (meter * meter);
0171     static constexpr double gram = 1.e-3 * kilogram;
0172     static constexpr double milligram = 1.e-3 * gram;
0173
0174     // symbols
0175     static constexpr double kg = kilogram;
0176     static constexpr double g = gram;
0177     static constexpr double mg = milligram;
0178
0179     //
0180     // Power [E][T^-1]
0181     //
0182     static constexpr double watt = joule / second;   // watt = 6.24150 e+3 * MeV/ns
0183     static constexpr double kilowatt = 1.e3*watt;
0184     static constexpr double megawatt = 1.e6*watt;
0185
0186     //
0187     // Force [E][L^-1]
0188     //
0189     static constexpr double newton = joule / meter;   // newton = 6.24150 e+9 * MeV/mm
0190
0191     //
0192     // Pressure [E][L^-3]
0193     //
0194 #define pascal hep_pascal                               // a trick to avoid warnings
0195     static constexpr double hep_pascal = newton / m2;   // pascal = 6.24150 e+3 * MeV/mm3
0196     static constexpr double bar = 100000 * pascal;      // bar    = 6.24150 e+8 * MeV/mm3
0197     static constexpr double atmosphere = 101325 * pascal;   // atm    = 6.32420 e+8 * MeV/mm3
0198
0199     //
0200     // Electric current [Q][T^-1]
0201     //
0202     static constexpr double ampere = coulomb / second;   // ampere = 6.24150 e+9 * eplus/ns
0203     static constexpr double milliampere = 1.e-3 * ampere;
0204     static constexpr double microampere = 1.e-6 * ampere;
0205     static constexpr double nanoampere = 1.e-9 * ampere;
0206
0207     //
0208     // Electric potential [E][Q^-1]
0209     //
0210     static constexpr double megavolt = megaelectronvolt / eplus;
0211     static constexpr double kilovolt = 1.e-3 * megavolt;
0212     static constexpr double volt = 1.e-6 * megavolt;
0213
0214     //
0215     // Electric resistance [E][T][Q^-2]
0216     //
0217     static constexpr double ohm = volt / ampere;   // ohm = 1.60217e-16*(MeV/eplus)/(eplus/ns)
0218
0219     //
0220     // Electric capacitance [Q^2][E^-1]
0221     //
0222     static constexpr double farad = coulomb / volt;   // farad = 6.24150e+24 * eplus/Megavolt
0223     static constexpr double millifarad = 1.e-3 * farad;
0224     static constexpr double microfarad = 1.e-6 * farad;
0225     static constexpr double nanofarad = 1.e-9 * farad;
0226     static constexpr double picofarad = 1.e-12 * farad;
0227
0228     //
0229     // Magnetic Flux [T][E][Q^-1]
0230     //
0231     static constexpr double weber = volt * second;   // weber = 1000*megavolt*ns
0232
0233     //
0234     // Magnetic Field [T][E][Q^-1][L^-2]
0235     //
0236     static constexpr double tesla = volt * second / meter2;   // tesla =0.001*megavolt*ns/mm2
0237
0238     static constexpr double gauss = 1.e-4 * tesla;
0239     static constexpr double kilogauss = 1.e-1 * tesla;
0240
0241     //
0242     // Inductance [T^2][E][Q^-2]
0243     //
0244     static constexpr double henry = weber / ampere;   // henry = 1.60217e-7*MeV*(ns/eplus)**2
0245
0246     //
0247     // Temperature
0248     //
0249     static constexpr double kelvin = 1.;
0250
0251     //
0252     // Amount of substance
0253     //
0254     static constexpr double mole = 1.;
0255
0256     //
0257     // Activity [T^-1]
0258     //
0259     static constexpr double becquerel = 1. / second;
0260     static constexpr double curie = 3.7e+10 * becquerel;
0261
0262     //
0263     // Absorbed dose [L^2][T^-2]
0264     //
0265     static constexpr double gray = joule / kilogram;
0266     static constexpr double kilogray = 1.e+3 * gray;
0267     static constexpr double milligray = 1.e-3 * gray;
0268     static constexpr double microgray = 1.e-6 * gray;
0269
0270     //
0271     // Luminous intensity [I]
0272     //
0273     static constexpr double candela = 1.;
0274
0275     //
0276     // Luminous flux [I]
0277     //
0278     static constexpr double lumen = candela * steradian;
0279
0280     //
0281     // Illuminance [I][L^-2]
0282     //
0283     static constexpr double lux = lumen / meter2;
0284
0285     //
0286     // Miscellaneous
0287     //
0288     static constexpr double perCent = 0.01;
0289     static constexpr double perThousand = 0.001;
0290     static constexpr double perMillion = 0.000001;
0291
0292     // -*- C++ -*-
0293     // ----------------------------------------------------------------------
0294     // HEP coherent Physical Constants
0295     //
0296     // This file has been provided by Geant4 (simulation toolkit for HEP).
0297     //
0298     // The basic units are :
0299     //            millimeter
0300     //            nanosecond
0301     //            Mega electron Volt
0302     //            positon charge
0303     //            degree Kelvin
0304     //              amount of substance (mole)
0305     //              luminous intensity (candela)
0306     //            radian
0307     //              steradian
0308     //
0309     // Below is a non exhaustive list of Physical CONSTANTS,
0310     // computed in the Internal HEP System Of Units.
0311     //
0312     // Most of them are extracted from the Particle Data Book :
0313     //        Phys. Rev. D  volume 50 3-1 (1994) page 1233
0314     //
0315     //        ...with a meaningful (?) name ...
0316     //
0317     // You can add your own constants.
0318     //
0319     // Author: M.Maire
0320     //
0321     // History:
0322     //
0323     // 23.02.96 Created
0324     // 26.03.96 Added constants for standard conditions of temperature
0325     //          and pressure; also added Gas threshold.
0326     // 29.04.08   use PDG 2006 values
0327     // 03.11.08   use PDG 2008 values
0328
0329     static constexpr double pi = 3.14159265358979323846;
0330     static constexpr double twopi = 2 * pi;
0331     static constexpr double halfpi = pi / 2;
0332     static constexpr double pi2 = pi * pi;
0333
0334     //
0335     //
0336     //
0337     static constexpr double Avogadro = 6.02214179e+23 / mole;
0338
0339     //
0340     // c   = 299.792458 mm/ns
0341     // c^2 = 898.7404 (mm/ns)^2
0342     //
0343     static constexpr double c_light = 2.99792458e+8 * m / s;
0344     static constexpr double c_squared = c_light * c_light;
0345
0346     //
0347     // h     = 4.13566e-12 MeV*ns
0348     // hbar  = 6.58212e-13 MeV*ns
0349     // hbarc = 197.32705e-12 MeV*mm
0350     //
0351     static constexpr double h_Planck = 6.62606896e-34 * joule * s;
0352     static constexpr double hbar_Planck = h_Planck / twopi;
0353     static constexpr double hbarc = hbar_Planck * c_light;
0354     static constexpr double hbarc_squared = hbarc * hbarc;
0355
0356     //
0357     //
0358     //
0359     static constexpr double electron_charge = -eplus;   // see SystemOfUnits.h
0360     static constexpr double e_squared = eplus * eplus;
0361
0362     //
0363     // amu_c2 - atomic equivalent mass unit
0364     //        - AKA, unified atomic mass unit (u)
0365     // amu    - atomic mass unit
0366     //
0367     static constexpr double electron_mass_c2 = 0.510998910 * MeV;
0368     static constexpr double proton_mass_c2 = 938.272013 * MeV;
0369     static constexpr double neutron_mass_c2 = 939.56536 * MeV;
0370     static constexpr double amu_c2 = 931.494028 * MeV;
0371     static constexpr double amu = amu_c2 / c_squared;
0372
0373     //
0374     // permeability of free space mu0    = 2.01334e-16 Mev*(ns*eplus)^2/mm
0375     // permittivity of free space epsil0 = 5.52636e+10 eplus^2/(MeV*mm)
0376     //
0377     static constexpr double mu0 = 4 * pi * 1.e-7 * henry / m;
0378     static constexpr double epsilon0 = 1. / (c_squared * mu0);
0379
0380     //
0381     // electromagnetic coupling = 1.43996e-12 MeV*mm/(eplus^2)
0382     //
0383     static constexpr double elm_coupling = e_squared / (4 * pi * epsilon0);
0384     static constexpr double fine_structure_const = elm_coupling / hbarc;
0385     static constexpr double classic_electr_radius = elm_coupling / electron_mass_c2;
0386     static constexpr double electron_Compton_length = hbarc / electron_mass_c2;
0387     static constexpr double Bohr_radius = electron_Compton_length / fine_structure_const;
0388
0389     static constexpr double alpha_rcl2 = fine_structure_const * classic_electr_radius * classic_electr_radius;
0390
0391     static constexpr double twopi_mc2_rcl2 = twopi * electron_mass_c2 * classic_electr_radius * classic_electr_radius;
0392     //
0393     //
0394     //
0395     static constexpr double k_Boltzmann = 8.617343e-11 * MeV / kelvin;
0396
0397     //
0398     // IUPAC standard temperature and pressure (STP)
0399     // STP uses 273.15 K (0 °C, 32 °F) and (since 1982) 1 bar (100 kPa) and not 1 atm!
0400     static constexpr double Temperature_STP = 273.15 * kelvin;
0401     static constexpr double Pressure_STP    = 1. * bar;
0402     //
0403     // NTP uses the NIST convention: 20 °C (293.15 K, 68 °F), 1 atm (14.696 psi, 101.325 kPa)
0404     static constexpr double Temperature_NTP = 293.15 * kelvin;
0405     static constexpr double Pressure_NTP    = 1. * atmosphere;
0406     //
0407     static constexpr double kGasThreshold   = 10. * mg / cm3;
0408     //
0409     //
0410     //
0411     static constexpr double universe_mean_density = 1.e-25 * g / cm3;
0412   //}
0413 }
0414 #endif // EVALUATOR_DD4HEPUNITS_H