diff --git a/src/main.py b/src/main.py
index 5a4a762..4fa542f 100644
--- a/src/main.py
+++ b/src/main.py
@@ -115,19 +115,19 @@ def deduplicate_instruments_from_layers(layers):
         chambers.append(instruments["deposition_chamber"])
         rheeds.append(instruments["rheed_system"])
         elegant_dict[f"layer_{lyr.layer_number}"] = {
-            "Laser Systems": instruments["laser_system"],
-            "Deposition Chamber": instruments["deposition_chamber"],
-            "RHEED Systems": instruments["rheed_system"],
+            "laser_system": instruments["laser_system"],
+            "deposition_chamber": instruments["deposition_chamber"],
+            "rheed_system": instruments["rheed_system"],
         }
     ded_lasers = list( set( lasers ) )
     ded_chambers = list( set( chambers ) )
     ded_rheeds = list( set( rheeds ) )
     elegant_dict["multilayer"] = {
         # Keep key names human readable since they're used in the messages of the following errors
-        "Laser Systems": ", ".join(ded_lasers),
-        "Deposition Chamber": ", ".join(ded_chambers),
-        "RHEED Systems": ", ".join(ded_rheeds)
-    } # dictionary's name's a joke
+        "laser_system": ", ".join(ded_lasers),
+        "deposition_chamber": ", ".join(ded_chambers),
+        "rheed_system": ", ".join(ded_rheeds)
+    } # dictionary's name is a joke
     # updated_dict = {} # use this for containing the final dataset
     # for ded in elegant_dict:
     #     if len(elegant_dict[ded]) == 0:
@@ -183,6 +183,7 @@ def make_nexus_schema_dictionary(substrate_object, layers):
     '''
     Main function, takes all the other functions to reconstruct the full dataset. Takes a Substrate-class object (output of the chain_entrypoint_to_batch() function) and a list of Layer-class objects (output of the chain_entrypoint_to_layers() function), returns dictionary with the same schema as the NeXus standard for PLD fabrications.
     '''
+    instruments = deduplicate_instruments_from_layers(layers)
     pld_fabrication = {
         "sample": {
             "substrate": {
@@ -205,7 +206,7 @@ def make_nexus_schema_dictionary(substrate_object, layers):
             },
             "multilayer": {},
         },
-        "instruments_used": deduplicate_instruments_from_layers(layers),
+        "instruments_used": instruments["multilayer"],
     }
     multilayer = pld_fabrication["sample"]["multilayer"]
     for layer in layers:
@@ -305,6 +306,7 @@ def make_nexus_schema_dictionary(substrate_object, layers):
                     "units": layer.post_annealing_duration_unit,
                 },
             },
+            "instruments_used": instruments[name],
         }
     return pld_fabrication
 
@@ -365,6 +367,9 @@ def build_nexus_file(pld_fabrication, output_path, rheed_osc=None):
             nx_post_annealing = nx_layer.create_group("post_annealing")
             nx_post_annealing.attrs["NX_class"] = "NXprocess"
             post_ann_dict = layer_dict["post_annealing"]
+            nx_layer_instruments = nx_layer.create_group("instruments_used")
+            nx_layer_instruments.attrs["NX_class"] = "NXinstrument"
+            layer_instruments_dict = layer_dict["instruments_used"]
 
             ## Target metadata
             try:
@@ -435,6 +440,12 @@ def build_nexus_file(pld_fabrication, output_path, rheed_osc=None):
                 nx_post_annealing["duration"].attrs["units"] = post_ann_dict["duration"]["units"]
             except TypeError as te:
                 raise TypeError(te)
+            try:
+                nx_layer_instruments.create_dataset("laser_system", data = layer_instruments_dict["laser_system"])
+                nx_layer_instruments.create_dataset("deposition_chamber", data = layer_instruments_dict["deposition_chamber"])
+                nx_layer_instruments.create_dataset("rheed_system", data = layer_instruments_dict["rheed_system"])
+            except TypeError as te:
+                raise TypeError(te)
         
         # Instruments used section
         nx_instruments = nx_pld_entry.create_group("instruments_used")