I went to re-align the beam into the PMC just now. I also tapped all the components between the laser and the PMC; nothing seems suspicious or loose.

The only problem was that someone (probably Steve or Valera) had closed down the iris just downstream of the AOM to ~1-2 mm diameter. This is much too tight! Don't leave irises closed down after aligning. An iris is not to b used as a beam dump. Getting it within a factor of 5-10 of the beam size will certainly make extra noise from clipping/scattering. After opening the iris, the reflected beam onto the PMC REFL camera is notably changed.

Not sure if this will have any effect on our worsening transmission drift, but let's see over the weekend.

I took pictures of this clipping as well as the beam position on Steve's new Retro Position Sensor, but I can't find the cable for the Olympus 570UZ. Steve, please buy a couple more USB data cables of this particular kind so that we don't have to hunt so much if one of the cryo (?) people borrows a cable.

Attachment shows PMC power levels before and after alignment. After alignment, you can see spikes from where I was tapping the mounts in the beamline. We ought to replace the U-100 mount ahead of the AOM with a Polanski

EDIT: Cryo team returns cable - receives punishments. Picture added.