January 3, 2006
ALMA Prototype Antenna Evaluation Overview
Evaluation Overview
16
Surface Stability
±
Time Stability:
°
VertexRSI: < 10
m
m RMS (May/June 2003)
°
AEC: ~ 5
m
m RMS (February 2004)
±
Ambient Temperature Stability:
°
VertexRSI: ~ 0.6-0.7
m
m/K
°
AEC: ~ 0.8
m
m/K
For each measurement series the average of the series was subtracted from each map to eliminate long-term drift.
For each measurement series maps were binned into 4-5 temperature ranges and averaged.
Maps shown are temperature difference maps for each antenna scaled to a 10C temperature difference.
Odd structure on AEC map likely due to frozen-in deformation resultant from elevation-runaway accident.