Luke, Cheryl, Rodica

This morning I checked the forward rotation after the heat sink connection last night, and reoptimized slightly by adjusting the position of the single TGG holder inside the magnet. Once re-optimized, the rotation stayed within 0.2 deg from optimim (value determined by measurement uncertainties). This was verifed for powers between 27 mW and 470 mW.

I also looked for ghost beams from the 10 surfaces of the optics assembled in the Faraday so far. Four strong AR beams seem to come from TGG and QR, two being just slightly weaker probably from QR. These rest on the periscope mount and clip on the barrel of the bottom mirror and will need to be properly routed and dumped. Also strong AR from CWP2 - one beam rests on the magnet case, another on DKDP mount. Since we don't have yet the SiC hard apertures to catch all these beams, we need to make sure they are properly routed to dumps before increasing the power. Will continue the hunting tomorrow.

Cheryl and I tested the HWP and DKDP retaining rings for smooth rotation turning them back and forth under IPA flow and wiping the metal dust away every time. Once deemed acceptable we mounted the HWP. Upon initial inspection, the two 3 mm thick DKDP crystals show an elevated density of central 'dots' that did not blow away, one significantly heavier than the other. We applied First Contact on the worst looking of the two in an attempt to remove them. This is the last optic that needs to be added to the assembly.

Luke re-assembled the picomotor rotatable HWP mount so that it rotates freely.  It needs to sit on the flow bench overnight so that the IPA can evaporate out of it.  In the morning he plans to do one last test on it to make sure that it still rotates without IPA, and then we can install it to the breadboard.