The ProductType vocabulary is a re-use of the IVOA DataLink Core vocabulary.
Terms from the vocabulary may be used in CAOM instances as values of the caom2:Artifact.productType field. Terms in the base vocabulary are to be used without the URI prefix (e.g. "this" instead of http://www.opencadc.org/caom2/productType#this). As used in CAOM, Artifact.protuctType terms describe the relationship of the artifact to the plane; this is slightly different from describing what type of file the artifact is.
The following terms from the DataLink Core vocabulary are currently allowed in CAOM:
The term "science" is currently allowed for backwards compatibility, but usage should be replaced with "this" in future.
The term "calibration" was previously used to describe calibration artifacts in observations with intent="calibration". This usage should also be replaced by "this" to indicate those artifacts that are primary within the context of the observation and plane that contains them.