Link to notebook and website

Author: jl-wynen

src/scippneutron/atoms/__init__.py

@@ -201,15 +201,23 @@ def _find_line_with_isotope(isotope: str, io: TextIO) -> str | None:
 
 
 def _load_atomic_weight(element: str) -> tuple[int, sc.Variable | None]:
+    # The CSV file was extracted from https://www.ciaaw.org/abridged-atomic-weights.htm
+    # using the notebook in tools/atomic_weights.ipynb (in the ScippNeutron repo).
     with _open_bundled_parameters_file('atomic_weights.csv') as f:
+        f.readline()  # skip copyright
+        f.readline()  # skip header
         if line_remainder := _find_line_with_isotope(element, f):
             z, weight, error = line_remainder.rstrip().split(',')
             return int(z), _assemble_scalar(weight, error, 'Da')
     raise ValueError(f"No entry for element '{element}'")
 
 
 def _load_atomic_mass(isotope: str) -> sc.Variable | None:
+    # The CSV file was extracted from https://www.ciaaw.org/atomic-masses.htm
+    # using the notebook in tools/atomic_weights.ipynb (in the ScippNeutron repo).
     with _open_bundled_parameters_file('atomic_masses.csv') as f:
+        f.readline()  # skip copyright
+        f.readline()  # skip header
         if line_remainder := _find_line_with_isotope(isotope, f):
             weight, error = line_remainder.rstrip().split(',')
             return _assemble_scalar(weight, error, 'Da')

src/scippneutron/atoms/atomic_masses.csv

@@ -1,3 +1,4 @@
+# Numbers extracted using tools/atomic_weights.ipynb from https://www.ciaaw.org/atomic-masses.htm
 Isotope,Atomic Mass [Da],Uncertainty [Da]
 100Ag,99.916115443,0.000005367
 100Cd,99.920348829,0.000001800

src/scippneutron/atoms/atomic_weights.csv

@@ -1,3 +1,4 @@
+# Numbers extracted using tools/atomic_weights.ipynb from https://www.ciaaw.org/abridged-atomic-weights.htm
 Element,Z,Atomic Weight [Da],Uncertainty [Da]
 H,1,1.008,0.0002
 He,2,4.0026,0.0001

tools/atomic_weights.ipynb

@@ -145,6 +145,7 @@
    "outputs": [],
    "source": [
     "with open('atomic_weights.csv', 'w') as f:\n",
+    "    f.write(\"# Numbers extracted using tools/atomic_weights.ipynb from https://www.ciaaw.org/abridged-atomic-weights.htm\")\n",
     "    f.write(\"Element,Z,Atomic Weight [Da],Uncertainty [Da]\\n\")\n",
     "    for (symbol, z, weight, error) in atoms:\n",
     "        if weight is None:\n",
@@ -207,10 +208,12 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "latest.to_csv('atomic_masses.csv',\n",
-    "              columns=['mass', 'uncertainty'],\n",
-    "              index_label=\"Isotope\",\n",
-    "              header=[\"Atomic Mass [Da]\", \"Uncertainty [Da]\"])"
+    "with open('atomic_masses.csv', 'w') as f:\n",
+    "    f.write(\"# Numbers extracted using tools/atomic_weights.ipynb from https://www.ciaaw.org/atomic-masses.htm\")\n",
+    "    latest.to_csv(f,\n",
+    "                  columns=['mass', 'uncertainty'],\n",
+    "                  index_label=\"Isotope\",\n",
+    "                  header=[\"Atomic Mass [Da]\", \"Uncertainty [Da]\"])"
    ]
   }
  ],