Merge pull request #110 from fusion-energy/improve-energy-spectrum

Improve energy spectrum plotting

.github/workflows/ci.yml

@@ -50,3 +50,4 @@ jobs:
           python examples/plot_tokamak_ion_temperature.py
           python examples/plot_tokamak_neutron_source_density.py
           python examples/plot_tokamak_neutron_source_strengths.py
+          python examples/plot_energy_spectra.py

examples/plot_energy_spectra.py

@@ -0,0 +1,39 @@
+import matplotlib.pyplot as plt
+from openmc_plasma_source import fusion_point_source
+
+import numpy as np
+
+tritium_factions = np.linspace(0, 1, 3)
+tritium_factions = np.concatenate([tritium_factions, [0.99]])
+tritium_factions = np.sort(tritium_factions)
+
+for tritium_fraction in tritium_factions:
+    fuel = {"D": 1 - tritium_fraction, "T": tritium_fraction}
+
+    if fuel["D"] == 0:
+        fuel = {"T": 1}
+    if fuel["T"] == 0:
+        fuel = {"D": 1}
+    my_source = fusion_point_source(
+        coordinate=(0, 0, 0), temperature=20000.0, fuel=fuel
+    )
+
+    # Plot the source energy distribution
+    energies = my_source[0].energy.sample(n_samples=int(5e6))
+
+    data, bins, _ = plt.hist(
+        energies / 1e6,
+        bins=1000,
+        histtype="step",
+        label=f"{1-tritium_fraction:.0%} D - {tritium_fraction:.0%} T",
+        density=True,
+        # alpha=0.5,
+    )
+
+plt.xlabel("Energy (MeV)")
+plt.ylabel("Neturon energy distribution")
+plt.yscale("log")
+plt.legend()
+plt.ylim(bottom=1e-3)
+plt.savefig("energy_spectra.svg")
+plt.show()

examples/point_source_example.py

@@ -23,6 +23,7 @@
     },  # note this is mainly tritium fuel so that TT reactions are more likely
 )
 
+
 # Tell OpenMC we're going to use our custom source
 settings = openmc.Settings()
 settings.run_mode = "fixed source"
@@ -34,16 +35,10 @@
 
 model.run()
 
+# Plot the source energy distribution
+energies = my_source[0].energy.sample(n_samples=10000)
+import matplotlib.pyplot as plt
 
-# optionally if you would like to plot the energy of particles then another package can be used
-# https://github.com/fusion-energy/openmc_source_plotter
-
-from openmc_source_plotter import plot_source_energy
-
-plot = plot_source_energy(
-    this=settings,
-    n_samples=2000000,  # increase this value for a smoother plot
-    energy_bins=np.linspace(0, 16e6, 1000),
-    yaxis_type="log",
-)
-plot.show()
+plt.hist(energies, bins=1000)
+plt.xlim(14e6 - 2e6, 14e6 + 2e6)
+plt.show()

src/openmc_plasma_source/fuel_types.py

@@ -153,7 +153,7 @@ def get_neutron_energy_distribution(
     # 1.0 neutron yield, all reactions scaled by this value
     num_of_vals = 100
     # single grid for TT neutrons
-    E_pspec = np.linspace(0, 12e6, num_of_vals)  # E_pspec is exspected in MeV units
+    E_pspec = np.linspace(0, 12e6, num_of_vals)  # E_pspec is exspected in eV units
 
     DDmean = neutron_energy_mean(ion_temperature=ion_temperature, reaction="DD")
     DTmean = neutron_energy_mean(ion_temperature=ion_temperature, reaction="DT")
@@ -165,7 +165,7 @@ def get_neutron_energy_distribution(
     if reactions == ["TT"]:
         strength_TT = 1.0
         dNdE_TT = strength_TT * nst.dNdE_TT(E_pspec, ion_temperature)
-        tt_source = openmc.stats.Tabular(E_pspec * 1e6, dNdE_TT)
+        tt_source = openmc.stats.Tabular(E_pspec, dNdE_TT)
         return tt_source
 
     elif reactions == ["DD"]: