From: Steve Raftopoulos
Sent: Monday, July 17, 2006 2:04 PM
To: mviola; tbrown; Arthur W. Brooks; mcole
Cc: mduco
Subject: VVSA1 scan data

Attachments: PPL SCAN_VVSA1 RO_FIX _WITH BEST FIT SHIFTED POINTS (1).xls

Folks,

This is the data from the full scan that we performed here at PPPL.  Our 
scan did not match the MTM data, even though we aligned using their 
fiducial points and this initially perplexed us, but we are now confident 
that we now understand why.  The cylinders that MTM  provided for holding 
the reflectors mounts were shallower than the 1/4" pin of our reflector 
mount.  We assumed that MTM had a mount with a shorter pin which would 
allow the holder to bottom out properly, so we cut our pin down.  It's now 
fairly obvious that MTM didn't bother to bottom out their mount, and by 
modifying our pin we essentially introduced an alignment offset.  While 
this introduced alignment error, the shape of the point cluster is valid 
with respect to shape of the VVSA1.  Once the pppl data had been run 
through a best fit it matched MTM's data to a high degree (as we see it on 
verisurf).

If we've interpreted the data correctly, we've validated their scan and 
best fit, but we still have the opportunity to come up with improved best 
fit(s).  We do need to decide quickly and "fix" our coordinate system so 
that we can start installing the loops, studs and tubes.

Steve



Steve Raftopoulos
Senior Staff Engineer
Princeton Plasma Physics Laboratory
P.O. Box 451, Princeton, NJ 08543
(609) 243-3626 Voice
(609) 243-3248 Fax