NXmpes refactoring

contributed_definitions/NXmpes.nxdl.xml

@@ -314,7 +314,7 @@
                      annealing).
                 </doc>
             </field>
-            <group name="preparation_description" type="NXnote">
+            <group name="preparation_description" type="NXnote" optional="true">
                 <doc>
                      Description of the surface preparation technique for the XPS experiment, i.e.
                      UHV cleaving, in-situ growth, sputtering/annealing etc. Ideally, a full report
@@ -323,23 +323,23 @@
                      other metadata file. In the case these are not available, free-text description.
                 </doc>
             </group>
-            <field name="temperature" type="NX_FLOAT" units="NX_TEMPERATURE">
+            <field name="temperature" type="NX_FLOAT" units="NX_TEMPERATURE" recommended="true">
                 <doc>
                      In the case of a fixed temperature measurement this is the scalar temperature of
                      the sample. In the case of an experiment in which the temperature is changed and
                      recoded, this is an array of length m of temperatures. This should be a link to
                      /entry/instrument/manipulator/sample_temperature.
                 </doc>
             </field>
-            <field name="situation">
+            <field name="situation" optional="true">
                 <enumeration>
                     <item value="vacuum"/>
                     <item value="inert atmosphere"/>
                     <item value="oxidising atmosphere"/>
                     <item value="reducing atmosphere"/>
                 </enumeration>
             </field>
-            <field name="gas_pressure" type="NX_FLOAT" units="NX_PRESSURE"/>
+            <field name="gas_pressure" type="NX_FLOAT" units="NX_PRESSURE" optional="true" />
             <field name="bias" type="NX_FLOAT" units="NX_VOLTAGE" optional="true">
                 <doc>
                     Voltage applied to sample and sample holder.