diff options
Diffstat (limited to 'src/optics.c')
| -rw-r--r-- | src/optics.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/src/optics.c b/src/optics.c index 23e043d..dd9b82d 100644 --- a/src/optics.c +++ b/src/optics.c @@ -13,6 +13,19 @@ static double A7 = -1.63066183e-2; static double UV = 0.2292020; static double IR = 5.432937; +static double RIND_H2O_C1 = 1.302; +static double RIND_H2O_C2 = 0.01562; +static double RIND_H2O_C3 = 0.32; + +static double RIND_D2O_C1 = 1.302; +static double RIND_D2O_C2 = 0.01333; +static double RIND_D2O_C3 = 0.32; + +/* Wavelength of 1 eV particle in nm. + * + * From http://pdg.lbl.gov/2018/reviews/rpp2018-rev-phys-constants.pdf. */ +static double HC = 1.239841973976e3; + double get_index(double p, double wavelength, double T) { /* Returns the index of refraction of pure water for a given density, @@ -31,3 +44,35 @@ double get_index(double p, double wavelength, double T) return sqrt((2*c+1)/(1-c)); } + +double get_index_snoman_h2o(double wavelength) +{ + /* Returns the index of refraction of light water that SNOMAN uses for a + * given wavelength. The wavelength should be in units of nm. + * + * The coefficients come from media.dat in SNOMAN version 5.0294 and the + * formula used to compute the index of refraction comes from the SNOMAN + * companion page for titles MEDA. */ + double E; + + /* Calculate the energy of the photon in eV. */ + E = HC/wavelength; + + return RIND_H2O_C1 + RIND_H2O_C2*exp(RIND_H2O_C3*E); +} + +double get_index_snoman_d2o(double wavelength) +{ + /* Returns the index of refraction of heavy water that SNOMAN uses for a + * given wavelength. The wavelength should be in units of nm. + * + * The coefficients come from media.dat in SNOMAN version 5.0294 and the + * formula used to compute the index of refraction comes from the SNOMAN + * companion page for titles MEDA. */ + double E; + + /* Calculate the energy of the photon in eV. */ + E = HC/wavelength; + + return RIND_D2O_C1 + RIND_D2O_C2*exp(RIND_D2O_C3*E); +} |