This log goes into more detail from yesterday's work (alog75754) and what Jason and I did today.

After we checked the chiller lines had no leaks without the table in loop, we added the tables in next. The Y table was free of leaks, but the X table had a slow drip from a few od the push to connect fittings on the RF driver (attachment 1). We swapped all of these fittings for new ones and cut the 1/4" diameter tubes ~0.5", with a cutter that we borrowed from PSL, for fresh connections. This worked great and there were no more leaks.

To fire up the laser to wanted to avoid the fried opamps that we've had in the past, so we turned on the CO2X electronics in this order:

1. TCSX HV power supply - CER mezz
2. X & Y RF source - mech room mezz
3. X & Y power supplies - mech room mezz
4. X & Y AA chassis - CER
5. X & Y control box - rack by tables

No fried opamps this way. When we turned the newly refurbished laser on, it output 53W according to our Thorlabs S322C power head placed just after M1. The alignment was far off in yaw, not even hitting POL1. Jason and I first yawed the laser itself within its mounting bolt holes, which didn't move much, then started to align downstream. We eventually got the beam to the irises before the periscope, but had moved a large majority of the optics along the way - M1, ISSPO, PM1, PM2, M4, M5, M6 (table drawing). Using the FLIR One camera we got the beam to hit the irises in a similar way to before the laser swap (before, iris1 now, iris2 now). We then checked on the table FLIR for mask alignment. Here we noticed that the annular mask was a little off horizontally, so we translated the mask to better match the previous position (before, annular now). Once we inject into vacuum we might need to make some more minor changes on table, but this looks good for now.

The last steps today were to recalibrate the thermopile at the laser head and verify that the power meter is still centered on the beam. The power meter need a small translation to center the beam. The gain in the laser head WATTS filter was previously 8.58755 and we eventually ended up at 13.904. Jason used new_gain=old_gain*P_m /P_E , where P_m is power measured with the Thorlabs S322C just after M1 and P_E is the power reported in Epics with the old calibration. We iterated this a few times to make sure it was as close as we could feasibly get.

Next steps are to inject the beam into vacuum and check centering with the HWS. The plan is for this to be done just before commissioning starts in a few weeks.

We left the CO2X laser keyed off and ready for the upcoming laser safe work.