Reports until 10:24, Friday 27 April 2012
H2 COC
garilynn.billingsley@LIGO.ORG - posted 10:24, Friday 27 April 2012 (2714)
Dark Field microscope inspection of H2 ITMy SN: ETM02
April 11, 2012 - Gari Billingsley and Betsy Bland 

First contact was pulled with ion gun blow. 

Laser pointer inspection (green diode)… there appeared to be more stuff reflecting at the top. FC was down ~2", more stuff there, least in the bottom half. 

Dark Field Microscope - Area Examined: ~1cm wide strip, various elevations covering the center ~200mm diameter top to bottom. 
The optic is clean in the examined areas. 

In the 5x field we observe dots, 5-15 per field on average. There are some scratches, never exceeding field length, and some chatter marks (linearly correlated dots.) 

One odd feature, a concentric circle. Three rings, outer asymmetric, two inner symmetric but non concentric. all tagged at the edge with a small boulder visible at 50x. 

20x all over. faint, short sleek marks. Uncorrelated direction. Some scratches. 

50x most dots still not resolvable, this limits their size to ~<2 micrometers. 

Early suspicions 
Dots and high magnification sleeks may be native to the optic from polish and coating - Gari to check on some other LMA coating. 
Small scratches are horizontal and consistent with the "dab" cleaning method used on the first fiber break. 
Chatter marks are a mystery. 

Large features seen: The absorption measurement burn. The twins: two bright defects (with flashlight) upper center right.