The official document describing the focal plane layout is https://docushare.lsst.org/docushare/dsweb/Get/Version-65557/LCA-13381-B-APPROVED-(DetectorPlaneLayout).pdf
The amp names in this document are Segment00 -> Segment17. However, within the DM stack, amp.getName() returns C00 -> C17. This has caused confusion. Can I assume that C12 is the same as Segment12? The EXTNAME values in the fits headers are also SegmentXX. We either need to edit the approved focal plane layout and change the EXTNAME in the headers, or we need to change the amp names in DM to be SegmentXX so that they agree with the focal plane document and the headers. I propose the latter, but we can discuss.