diff --git a/src/dials/algorithms/scaling/SConscript b/src/dials/algorithms/scaling/SConscript
index 1ba5e56b10..da2769b009 100644
--- a/src/dials/algorithms/scaling/SConscript
+++ b/src/dials/algorithms/scaling/SConscript
@@ -8,6 +8,6 @@ env.SharedLibrary(
 
 env.SharedLibrary(
     target="#/lib/dials_tof_scaling_ext",
-    source=["tof/boost_python/tof_scaling_ext.cc"],
+    source=["tof/boost_python/tof_scaling.cc"],
     LIBS=env["LIBS"],
 )