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#include <math.h>
#include "optics.h"
#include "misc.h"
/* Absorption coefficients for H2O and D2O as a function of wavelength from
* SNOMAN.
*
* Note: These numbers come from prod/media.dat.
*
* FIXME: Should I be using the values from media_2_09.dat or media_qoca_*.cmd? */
static double absorption_coefficient_h2o_wavelengths[7] = {250.0, 350.0, 400.0, 450.0, 500.0, 548.0, 578.0};
static double absorption_coefficient_h2o[7] = {1e-5, 1e-5, 1.3e-5, 6.0e-5, 2.0e-4, 5.8e-4, 9.2e-4};
static double absorption_coefficient_d2o_wavelengths[7] = {254.0, 313.0, 366.0, 406.0, 436.0, 548.0, 578.0};
static double absorption_coefficient_d2o[7] = {1e-5, 1e-5, 1e-5, 1e-5, 1e-5, 1e-5, 1e-5};
/* From Table 4 in the paper. */
static double A0 = 0.243905091;
static double A1 = 9.53518094e-3;
static double A2 = -3.64358110e-3;
static double A3 = 2.65666426e-4;
static double A4 = 1.59189325e-3;
static double A5 = 2.45733798e-3;
static double A6 = 0.897478251;
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_absorption_length_snoman_h2o(double wavelength)
{
/* Returns the absorption length in H2O in cm. */
return 1.0/interp1d(wavelength, absorption_coefficient_h2o_wavelengths, absorption_coefficient_h2o, sizeof(absorption_coefficient_h2o_wavelengths)/sizeof(absorption_coefficient_h2o_wavelengths[0]));
}
double get_absorption_length_snoman_d2o(double wavelength)
{
/* Returns the absorption length in D2O in cm. */
return 1.0/interp1d(wavelength, absorption_coefficient_d2o_wavelengths, absorption_coefficient_d2o, sizeof(absorption_coefficient_d2o_wavelengths)/sizeof(absorption_coefficient_d2o_wavelengths[0]));
}
double get_index(double p, double wavelength, double T)
{
/* Returns the index of refraction of pure water for a given density,
* wavelength, and temperature. The density should be in units of g/cm^3,
* the wavelength in nm, and the temperature in Celsius.
*
* See "Refractive Index of Water and Steam as a function of Wavelength,
* Temperature, and Density" by Schiebener et al. 1990. */
/* normalize the temperature and pressure */
wavelength = wavelength/589.0;
T = (T+273.15)/273.15;
/* first we compute the right hand side of Equation 7 */
double c = A0 + A1*p + A2*T + A3*pow(wavelength,2)*T + A4/pow(wavelength,2) + A5/(pow(wavelength,2)-pow(UV,2)) + A6/(pow(wavelength,2)-pow(IR,2)) + A7*pow(p,2);
c *= p;
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);
}
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