diff --git a/docs/source/methods/photon_physics.rst b/docs/source/methods/photon_physics.rst
index bde6d2a994..23809f6745 100644
--- a/docs/source/methods/photon_physics.rst
+++ b/docs/source/methods/photon_physics.rst
@@ -775,7 +775,7 @@ formula can be used to find the collision stopping power of the material:
:label: material-collision-stopping-power
S_{\text{col}}(T) = \frac{2 \pi r_e^2 m_e c^2}{\beta^2} N_A \frac{Z}{A_M}
- [\ln(T^2/I^2) + ln(1 + \tau/2) + F(\tau) - \delta_F(T)],
+ [\ln(T^2/I^2) + \ln(1 + \tau/2) + F(\tau) - \delta_F(T)],
where :math:`N_A` is Avogadro's number, :math:`A_M` is the molar mass,
:math:`\tau = T/m_e`, and :math:`F(\tau)` depends on the particle type. For
@@ -797,7 +797,7 @@ while for positrons
The density effect correction :math:`\delta_F` takes into account the reduction
of the collision stopping power due to the polarization of the material the
charged particle is passing through by the electric field of the particle.
-It can be evaluated using the method described by [Sternheimer]_, where the
+It can be evaluated using the method described by Sternheimer_, where the
equation for :math:`\delta_F` is
.. math::
@@ -821,14 +821,14 @@ where :math:`\bar{v}_i` is defined as
.. math::
:label: density-effect-nubar
- \bar{\nu}_i = \nu_i \rho / \nu_p.
+ \bar{\nu}_i = h\nu_i \rho / h\nu_p.
The plasma energy :math:`h\nu_p` of the medium is given by
.. math::
:label: plasma-frequency
- h\nu_p = \sqrt{(hc)^2/\pi r_e \rho_m N_A Z / A},
+ h\nu_p = \sqrt{\frac{(hc)^2 r_e \rho_m N_A Z}{\pi A}},
where :math:`A` is the atomic weight and :math:`\rho_m` is the density of the
material. In :eq:`density-effect-nubar`, :math:`h\nu_i` is the oscillator
@@ -840,8 +840,8 @@ defined as
.. math::
:label: density-effect-li
- l_i &= (\bar{v}_i^2 + 2/3f_i)^{1/2} ~~~~&\text{for}~~ \bar{v}_i > 0 \\
- l_n &= f_n^{1/2} ~~~~&\text{for}~~ \bar{v}_n = 0,
+ l_i &= (\bar{\nu}_i^2 + 2/3f_i)^{1/2} ~~~~&\text{for}~~ \bar{\nu}_i > 0 \\
+ l_n &= f_n^{1/2} ~~~~&\text{for}~~ \bar{\nu}_n = 0,
where the second case applies to conduction electrons. For a conductor,
:math:`f_n` is given by :math:`n_c/Z`, where :math:`n_c` is the effective
@@ -1047,8 +1047,4 @@ emitted photon.
.. _Salvat: http://www.oecd-nea.org/globalsearch/download.php?doc=77434
-.. _Sternheimer: https://journals.aps.org/prb/pdf/10.1103/PhysRevB.26.6067
-
-.. [Sternheimer] R. M. Sternheimer, S.M.Seltzer, and M.J.Berger, *Density
- effect for the ionization loss of charged particles in various substances*,
- Phys. Rev. B, 26, 6067–6076 (1982).
+.. _Sternheimer: https://doi.org/10.1103/PhysRevB.26.6067
diff --git a/src/material.cpp b/src/material.cpp
index 9ad0b8f0aa..da68a536dd 100644
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -505,11 +505,15 @@ void Material::collision_stopping_power(double* s_col, bool positron)
double rho = sternheimer_adjustment(f, e_b_sq, e_p_sq, n_conduction, log_I,
1.0e-6, 100);
- // Classical elctron radius in cm
- double r_e = PLANCK_C / (2.0e8 * PI * FINE_STRUCTURE * MASS_ELECTRON_EV);
+ // Classical electron radius in cm
+ constexpr double CM_PER_ANGSTROM {1.0e-8};
+ constexpr double r_e = CM_PER_ANGSTROM * PLANCK_C / (2.0 * PI *
+ FINE_STRUCTURE * MASS_ELECTRON_EV);
// Constant in expression for collision stopping power
- double c = 2.0e24 * PI * r_e * r_e * MASS_ELECTRON_EV * electron_density;
+ constexpr double BARN_PER_CM_SQ {1.0e24};
+ double c = BARN_PER_CM_SQ * 2.0 * PI * r_e * r_e * MASS_ELECTRON_EV *
+ electron_density;
// Loop over incident charged particle energies
for (int i = 0; i < data::ttb_e_grid.size(); ++i) {
diff --git a/tests/regression_tests/photon_production/inputs_true.dat b/tests/regression_tests/photon_production/inputs_true.dat
index 32e3bdcf38..427078c889 100644
--- a/tests/regression_tests/photon_production/inputs_true.dat
+++ b/tests/regression_tests/photon_production/inputs_true.dat
@@ -26,7 +26,7 @@
- 14.0 1.0
+ 14000000.0 1.0
ttb
diff --git a/tests/regression_tests/photon_production/results_true.dat b/tests/regression_tests/photon_production/results_true.dat
index 6f53e2d334..3d9cf68ede 100644
--- a/tests/regression_tests/photon_production/results_true.dat
+++ b/tests/regression_tests/photon_production/results_true.dat
@@ -1,3 +1,3 @@
tally 1:
-sum = 1.550000E-02
-sum_sq = 2.402500E-04
+sum = 7.938000E-01
+sum_sq = 6.301184E-01
diff --git a/tests/regression_tests/photon_production/test.py b/tests/regression_tests/photon_production/test.py
index 68992c867b..1abc184a2c 100644
--- a/tests/regression_tests/photon_production/test.py
+++ b/tests/regression_tests/photon_production/test.py
@@ -33,7 +33,7 @@ class SourceTestHarness(PyAPITestHarness):
source = openmc.Source()
source.space = openmc.stats.Point((0,0,0))
source.angle = openmc.stats.Monodirectional()
- source.energy = openmc.stats.Discrete([14.0], [1.0])
+ source.energy = openmc.stats.Discrete([14.0e6], [1.0])
source.particle = 'neutron'
settings = openmc.Settings()