Measurement Status, potential optics for replacement of H1 core optics.
4ITM05 is the best candidate replacement due to good radius of curvature match with the existing Y-arm ITM
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billingsley_g  "AT"  ligo.caltech.edu
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ALL LIGO 1 OPTICS	4ITM05	Notes
Scatter (small integrating sphere) Scatter (arb. units, 45 °)	31 ppm 231
Transmission (%)	2.8
AR coating (ppm)	1000	good job Liyuan and Helena!
Bulk Absorption (ppm/cm)	3 prelim Data at center only
Coating Absorption ppm (Stanford, witness samples) HR side absorption (CIT - ppm) AR side absorption (CIT - ppm)	~0.35 ~.5 ~.5
Radius of Curv. (Km) measured over 150mm diameter	13.91 See note 1 below  Image-TPA
Surface error, central 80mm (nm rms)	0 .4406
Notes	note2

p - preliminary measurement

Note1:  The range of radii of curvature measured for 4ITM05 were from 13.77K to 14.02K with the Average being 13.91K. The change in the measured saggita over this range is 3.3nm 
The preliminary measurement for this optic 13.58 was measured with a different insrument calibration (the instrument has since been rebuilt)  The new calibration (4-2005) is ... new, and will be refined with ongoing measurement.  The old measurement may be a better indicator of ROC match with other optics measured under the same instrument calibration.

Note 2:  The same streaks as seen on 4ITM01 (uncoated), 4ITM08, BS06 and one of the (now repolished) SPETMs can be seen on 4ITM05.  The streaks do not change the surface enough to put it beyond the specification that the surface error (with power and astigmatism subtracted) be less than 0.8nm rms