diff --git a/src/scgenerator/physics/simulate.py b/src/scgenerator/physics/simulate.py
index cd62985..7488609 100644
--- a/src/scgenerator/physics/simulate.py
+++ b/src/scgenerator/physics/simulate.py
@@ -689,8 +689,8 @@ class RaySimulations(Simulations, priority=2):
 
     @property
     def sim_jobs_total(self):
-        if self.configuration.config.worker_num is not None:
-            return self.configuration.config.worker_num
+        if self.configuration.worker_num is not None:
+            return self.configuration.worker_num
         tot_cpus = ray.cluster_resources().get("CPU", 1)
         return int(min(self.configuration.num_sim, tot_cpus))