diff --git a/js/sources/model/SourcesModel.ts b/js/sources/model/SourcesModel.ts
index 3c584a25..926b1bee 100644
--- a/js/sources/model/SourcesModel.ts
+++ b/js/sources/model/SourcesModel.ts
@@ -36,7 +36,7 @@ export default class SourcesModel extends VSMModel<VSMField> {
         SPRING,
         PDLConstants.CUSTOM_LAUNCHER_DEFAULT_STANDARD_DEVIATION_ANGLE,
         1, {
-          tandem: fieldTandem.createTandem( `customLauncher` )
+          tandem: fieldTandem.createTandem( 'customLauncher' )
         } );
 
       return new VSMField( [ customLauncher ], identifier, {