Source code for irfpy.vels.bible.energy_resolution

''' The module to calculate energy resolution.

Energy resolution is discussed in Section 5 of :ref:`vexelsbible`.
There is also a table 2 showing raw data of the resolution,
but I skipped the implementation.
'''

import math
import numpy as np

def __m0():
    ''' return the fitting parameter m0 in Table 3.
    '''
    return np.array([4.969, 4.749, 5.507, 6.063, 4.293, 5.366, 5.780, 5.735,
            5.991, 4.928, 5.302, 6.190, 5.141, 5.943, 6.469, 6.347])

def __m1():
    ''' return the fitting parameter m1 in Table 3.
    '''
    return np.array([1.211, 0.998, 0.528, 0.555, 1.143, 0.724, 0.585, 0.533,
            0.394, 1.098, 0.516, 0.256, 0.805, 0.626, 0.475, 0.339])

def energy_resolution(anode, energy):
    ''' Return the energy resolution, Delta(E)/E, for each anode and energy.

    :param anode: Integer specifying the anode.
    :param energy: Central energy in electron volts (eV).
    :returns: Energy resultion. (Fraction.  Not per-cent)

    >>> print('%.3f' % energy_resolution(7, 970.000))
    0.073
    >>> print('%.3f' % energy_resolution(0, 11997.000))
    0.099

    '''
    m0 = __m0()[anode]
    m1 = __m1()[anode]
    loge = math.log10(energy)
    return (m0 + m1 * loge) / 100.


import unittest,doctest
def doctests():
    return unittest.TestSuite((
        doctest.DocTestSuite(),
        ))
if __name__=='__main__':
        unittest.main(defaultTest='doctests')