diff --git a/dap/algos/addmask.py b/dap/algos/addmask.py
index cdfaf3c..ffb187c 100644
--- a/dap/algos/addmask.py
+++ b/dap/algos/addmask.py
@@ -1,11 +1,15 @@
 #TODO: find a better way to handle this
 
-def calc_apply_additional_mask(results, detector, pixel_mask_pf):
+def calc_apply_additional_mask(results, pixel_mask_pf):
     apply_additional_mask = results.get("apply_additional_mask", False)
     if not apply_additional_mask:
         return
 
-    if detector == "JF06T08V04":
+    detector_name = results.get("detector_name", None)
+    if not detector_name:
+        return
+
+    if detector_name == "JF06T08V04":
         # edge pixels
         pixel_mask_pf[0:1030, 1100] = 0
         pixel_mask_pf[0:1030, 1613] = 0
@@ -52,7 +56,7 @@ def calc_apply_additional_mask(results, detector, pixel_mask_pf):
         pixel_mask_pf[1794, 1503:1550] = 0
 
 
-    if detector == "JF17T16V01":
+    elif detector_name == "JF17T16V01":
         # mask module 11
         pixel_mask_pf[2619:3333,1577:2607] = 0
 
diff --git a/dap/worker.py b/dap/worker.py
index 0a9a820..558a817 100644
--- a/dap/worker.py
+++ b/dap/worker.py
@@ -105,8 +105,6 @@ def work(backend_address, accumulator_host, accumulator_port, visualisation_host
         pulse_id = results.get("pulse_id", 0)
         results.update(peakfinder_parameters)
 
-        detector_name = results.get("detector_name", "")
-
         results["number_of_spots"] = 0
         results["is_hit_frame"] = False
 
@@ -157,7 +155,7 @@ def work(backend_address, accumulator_host, accumulator_port, visualisation_host
                 pixel_mask_pf = None
 
 
-        calc_apply_additional_mask(results, detector_name, pixel_mask_pf) # changes pixel_mask_pf in place
+        calc_apply_additional_mask(results, pixel_mask_pf) # changes pixel_mask_pf in place
 
 
         if pixel_mask_corrected is not None: