add photons from delta rays to likelihood calculation

This commit updates the likelihood function to take into account Cerenkov light
produced from delta rays produced by muons. The angular distribution of this
light is currently assumed to be constant along the track and parameterized in
the same way as the Cerenkov light from an electromagnetic shower. Currently I
assume the light is produced uniformly along the track which isn't exactly
correct, but should be good enough.

1 files changed, 4 insertions, 8 deletions

diff --git a/src/likelihood.h b/src/likelihood.h
index 84fa7ff..4b72742 100644
--- a/src/likelihood.h
+++ b/src/likelihood.h
@@ -45,13 +45,6 @@
 #define GTVALID 400.0
 #define BETA_MIN 0.8
 
-/* Number of photons in the range 200 nm - 800 nm generated per MeV of energy
- * lost to radiation for electrons.
- *
- * FIXME: This is just a rough estimate, should use an energy dependent
- * quantity from simulation. */
-#define PHOTONS_PER_MEV 400.0
-
 /* Maximum number of vertices to fit. */
 #define MAX_VERTICES 10
 
@@ -70,12 +63,15 @@ typedef struct particle {
     int id;
     double mass;
     double range;
-    double rad;
     double *x;
     double *T;
     size_t n;
     double a;
     double b;
+    double shower_photons;
+    double delta_ray_a;
+    double delta_ray_b;
+    double delta_ray_photons;
 } particle;
 
 particle *particle_init(int id, double T0, size_t n);