diff --git a/notebooks/LPD/LPD_Correct_Fast.ipynb b/notebooks/LPD/LPD_Correct_Fast.ipynb
index 733627b88aafc985a98b7182416f4485f57a30e1..e8b2956c1cf0703e4b23b0ef5ac7f1b6fcd36e2a 100644
--- a/notebooks/LPD/LPD_Correct_Fast.ipynb
+++ b/notebooks/LPD/LPD_Correct_Fast.ipynb
@@ -399,10 +399,13 @@
     "        \n",
     "    ccv_gains[aggregator] = np.ones(ccv_shape, dtype=np.float32)\n",
     "\n",
-    "    if parallel_gain and 'Noise' in consts:\n",
-    "        ccv_noise[aggregator] = _prepare_data('Noise', np.float32)\n",
+    "    if parallel_gain and combine_parallel_gain:\n",
+    "        if 'Noise' in consts:\n",
+    "            ccv_noise[aggregator] = _prepare_data('Noise', np.float32)\n",
+    "        else:\n",
+    "            raise RuntimeError('parallel gain combination requires available noise constant')\n",
     "    else:\n",
-    "        ccv_noise[aggregator] = np.zeros(ccv_shape, dtype=np.float32)\n",
+    "        ccv_noise[aggregator] = None\n",
     "    \n",
     "    if 'BadPixelsDark' in consts:\n",
     "        ccv_masks[aggregator] = _prepare_data('BadPixelsDark', np.uint32)\n",