diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 713e72d7..3ce38e6b 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,7 +14,7 @@ on:
     branches: [ master ]
     paths-ignore:
             - '.github/**'
-  workflow_dispatch:   
+  workflow_dispatch:
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
@@ -27,7 +27,7 @@ jobs:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
         - name: checkout
           uses: actions/checkout@v4
-          
+
       # Check syntax of all CIF files
         - name: check_syntax
           uses: COMCIFS/cif_syntax_check_action@master
@@ -43,7 +43,7 @@ jobs:
         with:
                  path: ~/.julia
                  key: ${{ runner.os }}-julia-v2
-                 
+
       - name: Install Julia
         uses: julia-actions/setup-julia@v1
         with:
@@ -77,13 +77,13 @@ jobs:
         run: |
                julia -e 'using Pkg; Pkg.status()'
                for file in main/*.dic
-               do      
+               do
                   echo "Checking $file"
                   julia -O0 ./julia_cif_tools/linter.jl -i $PWD/cif_core $file cif_core/ddl.dic
-                  if [ $? != 0 ] 
-                  then 
+                  if [ $? != 0 ]
+                  then
                     exit 1 ;
-                  fi 
+                  fi
                done
   ddlm:
     runs-on: ubuntu-latest
diff --git a/cif_pow.dic b/cif_pow.dic
index c69bd1f5..e2d2087c 100644
--- a/cif_pow.dic
+++ b/cif_pow.dic
@@ -43,6 +43,9 @@ save_PD_GROUP
 
     _import.get
         [
+          {
+           'dupl':Ignore  'file':cif_img.dic  'mode':Full  'save':HEAD
+          }
           {
            'dupl':Ignore  'file':multi_block_core.dic  'mode':Full
            'save':MULTIBLOCK_CORE
@@ -6805,6 +6808,26 @@ save_pd_diffractogram.instr_id
 
 save_
 
+save_pd_diffractogram.scan_id
+
+    _definition.id                '_pd_diffractogram.scan_id'
+    _definition.update            2025-07-01
+    _description.text
+;
+    The identifier for the group of imgCIF images used to produce the
+    diffractogram. Each group of images is known as a scan, and the images
+    belonging to each scan are described using imgCIF data names.
+;
+    _name.category_id             pd_diffractogram
+    _name.object_id               scan_id
+    _name.linked_item_id          '_diffrn_scan.id'
+    _type.purpose                 Link
+    _type.source                  Assigned
+    _type.container               Single
+    _type.contents                Text
+
+save_
+
 save_pd_diffractogram.spec_id
 
     _definition.id                '_pd_diffractogram.spec_id'
@@ -14351,8 +14374,11 @@ save_
 
        Added _pd_meas_overall.step_count_time.
 
-       Removed _pd_calib_detected_intensity.id as data item and category key
-       of PD_CALIB_DETECTED_INTENSITY.
+       Update PD_DIFFRACTOGRAM to link to the imgCIF scan from which the
+       diffractogram was created.
+
+       Removed _pd_calib_detected_intensity.id as data item and category
+       key of PD_CALIB_DETECTED_INTENSITY.
 
        Update PD_INSTR and PD_INSTR_DETECTOR descriptions.