peter.king@LIGO.ORG - posted 07:19, Thursday 26 February 2015 - last comment - 08:31, Thursday 26 February 2015(16935)
H1 PSL Laser Area Enclosure Test
04:57 Turned on the HEPA fans in the H1 PSL Laser Room. I would like to run this test for at least
a couple of hours.
It is noticeable that as soon as the fans are turned on, the minimum and maximum values of the
ISS percent diffraction vary by ~1%.
06:55 Turned off HEPA fans.
In running this test, I had forgotten that running the HEPA fans generates heat, and is not a good
idea without turning on the air conditioning. I switched on the air conditioning to bring the
temperature back down and switched it off after about 40 minutes.
Attached is the output of the quadrant photodiode that is located inside the power stabilisation
photodiode box. Assuming that DY is vertical and DX is horizontal, it appears that the vertical
alignment does not recover, whilst the horizontal alignment does.
Also attached is the reference cavity transmission signal during the same period. It seems to
recover.
Images attached to this report
Comments related to this report
Attached is the temperature rise during the period concerned. Of note is that the reference cavity transmission recovered whilst the pitch alignment into the power stabilisation photodiode box did not.
Images attached to this comment
