diff --git a/notebooks/Gotthard2/Correction_Gotthard2_NBC.ipynb b/notebooks/Gotthard2/Correction_Gotthard2_NBC.ipynb
index a577130fb0c5d82fe3e950ff7c594f66d4789dd4..4623fea01ae03b6156d4eef51e44d712e05c9612 100644
--- a/notebooks/Gotthard2/Correction_Gotthard2_NBC.ipynb
+++ b/notebooks/Gotthard2/Correction_Gotthard2_NBC.ipynb
@@ -64,6 +64,7 @@
     "control_template = \"CONTROL\"  # control template used to read CONTROL keys.\n",
     "ctrl_source_template = \"{}/DET/{}\"  # template for control source name (filled with karabo_id_control)\n",
     "karabo_id_control = \"\"  # Control karabo ID. Set to empty string to use the karabo-id\n",
+    "corr_data_source = \"{}/DET/{}:daqOutput\"  # Correction data source. filled with karabo_id and correction receiver\n",
     "\n",
     "# Parameters for calibration database.\n",
     "cal_db_interface = \"tcp://max-exfl-cal001:8016#8025\"  # the database interface to use.\n",
@@ -398,7 +399,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "corr_data_source = f\"{karabo_id}/DET/{corr_receiver}:daqOutput\"\n",
+    "corr_data_source = corr_data_source.format(karabo_id, corr_receiver)\n",
     "\n",
     "for raw_file in seq_files:\n",
     "\n",