diff --git a/csst_common/file.py b/csst_common/file.py
index 5210ed242f8438a553ee03d2e67f6a5042772850..0fd1aec5f5d595cdc70da9d57743141eec3f8b7c 100644
--- a/csst_common/file.py
+++ b/csst_common/file.py
@@ -120,5 +120,6 @@ class File:
     def __repr__(self):
         return f"<File {self.file_path}>"
 
-    def level_id(self):
+    @property
+    def level0_id(self):
         return self.obs_id + self.detector