Gerardo, Sheila

Gerardo did a Helium leak check on the the fiber feedthroughs, after each leak check we took it to the optics lab for a transmission measurement. 

In our previous transmission checks, (40681) we used the fiber coupled 1064 nm beam from the Prometheus in the optics lab, but this path has been taken apart already (for cleaning out the optics lab for HVAC work).  The 532 nm path is still available, so we used that instead. 

For SN9 we measured 88.7% transmission after the leak testing.  For SN8 we measured 98% transmission.  We will plan to use SN8 for 532 nm light, since we have had the higher transmission for that feedthrough for both tests.