#!/usr/bin/env python
# this script requires Python3, numpy, scipy, matplotlib, and xraydb modules. Use:
#        pip install xraydb scipy matplotlib
import numpy as np
import matplotlib.pyplot as plt
import xraydb

# X-ray monochromator Darwin Width calculations
# inputs from web form
xtal    = 'Si'
h, k, l = (1, 1, 1)
polarization = 's'
energy = 10000

dw = xraydb.darwin_width(energy, xtal, (h, k, l), polarization=polarization)

print('Mono Angle: %.5f deg' % (dw.theta*180/np.pi))
print('Angular width : %.5f microrad' % (dw.theta_width*1.e6))
print('Energy width  : %.5f eV' % (dw.energy_width))

plt.plot(dw.denergy, dw.intensity)
plt.xlabel('Energy (eV)')
plt.ylabel('reflectivity')
plt.title(f'{xtal} {(h, k, l)}, "{polarization}" polar, E={energy} eV')
plt.show()

plt.plot(dw.dtheta*1e6, dw.intensity)
plt.xlabel('Angle (microrad)')
plt.ylabel('reflectivity')
plt.title(f'{xtal} {(h, k, l)}, "{polarization}" polar, E={energy} eV')
plt.show()