diff --git a/notebooks/Jungfrau/Jungfrau_Create_Fit_Spectra_Histos_NBC.ipynb b/notebooks/Jungfrau/Jungfrau_Create_Fit_Spectra_Histos_NBC.ipynb
index 3e9b18eee8e1ad703baa84400257b0854dfa9a9a..0f24946fe5395448ea4cdfea16f0086057d8de8f 100644
--- a/notebooks/Jungfrau/Jungfrau_Create_Fit_Spectra_Histos_NBC.ipynb
+++ b/notebooks/Jungfrau/Jungfrau_Create_Fit_Spectra_Histos_NBC.ipynb
@@ -45,7 +45,7 @@
     "extra_dims = ['cell', 'row', 'col']  # labels for the DataArray dims after the first\n",
     "fit_func = 'CHARGE_SHARING'  # function used to fit the single photon peak\n",
     "fit_h_range = (150, 350.)  # range of the histogram in x-axis units used in fitting\n",
-    "\n",
+    "chunk_size = 10\n",
     "# parameters for the peak finder\n",
     "n_sigma = 5.  # n of sigma above pedestal threshold\n",
     "ratio = 0.99  # ratio of the next peak amplitude in the peak_finder\n",