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Fri Sep 26 19:08:43 2008
Refcav Trans: PD + Camera + Dumps
I went out to improve the Refcav trans path.
I removed all ND filters to get rid of the fringing.
I removed the anodized Al dump that was there.
Black anodized Aluminum dumps are forbidden
for use as
dumps in any low phase noise setup (such as our frequency stabilization cavity). The scatter was going
directly back into the cavity and making noise. For now its undumped, but Steve will find the
reflections and dump them on unblemished razor blade dumps mounted stiffly.
I will post a photo of the new setup later - the new setup is sketched on the control room markerboard.
The transPD level is now 8 V, up from its previous 3-4 V. We will probably have to also put a lens
in front of it to get the beam size down.