diff --git a/.github/workflows/celeritas.json b/.github/workflows/celeritas.json
new file mode 100644
index 000000000..0bf684486
--- /dev/null
+++ b/.github/workflows/celeritas.json
@@ -0,0 +1,28 @@
+{
+    "geometry_file": "${config}.gdml",
+    "event_file": "root://dtn-eic.jlab.org//work/eic2/EPIC/EVGEN/CI/pythia8NCDIS_5x41_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_1_20ev.hepmc",
+    "output_file": "pythia8NCDIS_5x41_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_1_20ev.json",
+    "offload_output_file": "pythia8NCDIS_5x41_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_1_20ev.offloaded.hepmc",
+    "num_track_slots": 1024,
+    "initializer_capacity": 32768,
+    "secondary_stack_factor": 2,
+    "physics_list": "celer_ftfp_bert",
+    "field_type": "uniform",
+    "field": [
+        0.0,
+        0.0,
+        1.7
+    ],
+    "field_options": {
+        "minimum_step": 1e-06,
+        "delta_chord": 0.025,
+        "delta_intersection": 1e-05,
+        "epsilon_step": 1e-05
+    },
+    "use_device": false,
+    "sd_type": "simple_calo",
+    "step_diagnostic": false,
+    "step_diagnostic_bins": 8,
+    "slot_diagnostic": false,
+    "slot_diagnostic_prefix": "slot-diag-cpu-"
+}
\ No newline at end of file
diff --git a/.github/workflows/celeritas.yml b/.github/workflows/celeritas.yml
index 32212d929..168e5b190 100644
--- a/.github/workflows/celeritas.yml
+++ b/.github/workflows/celeritas.yml
@@ -28,36 +28,7 @@ jobs:
         run: |
           # convert to gdml, but with sensitive detectors included
           scripts/convert_to_gdml.py --compact $DETECTOR_PATH/${config}.xml --output ${config}.gdml
-          # create celeritas input file
-          cat <<EOF > ${config}.json
-{
-"geometry_file": "${config}.gdml",
-"event_file": "root://dtn-eic.jlab.org//work/eic2/EPIC/EVGEN/CI/pythia8NCDIS_5x41_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_1_20ev.hepmc",
-"output_file": "pythia8NCDIS_5x41_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_1_20ev.json",
-"offload_output_file": "pythia8NCDIS_5x41_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_1_20ev.offloaded.hepmc",
-"num_track_slots": 1024,
-"initializer_capacity": 32768,
-"secondary_stack_factor": 2,
-"physics_list": "celer_ftfp_bert",
-"field_type": "uniform",
-"field": [
-    0.0,
-    0.0,
-    1.7
-],
-"field_options": {
-    "minimum_step": 1e-06,
-    "delta_chord": 0.025,
-    "delta_intersection": 1e-05,
-    "epsilon_step": 1e-05
-},
-"use_device": false,
-"sd_type": "simple_calo",
-"step_diagnostic": false,
-"step_diagnostic_bins": 8,
-"slot_diagnostic": false,
-"slot_diagnostic_prefix": "slot-diag-cpu-"
-}
-EOF
+          # create celeritas input file from template
+          cat celeritas.json | envsubst > ${config}.json
           # run celeritas
           celer-g4 ${config}.json