Jason, Camilla, and myself went out to the two CO2 tables to measure the output directly out of the CO2 lasers themselves, not just from the power meters we have on table. We used the Thorlabs S314C sensor head since our beefier unit we couldn't get the fan to work. Since this unit can only handle up to 40W, we first checked that the power agreed with one on table downstream so we wouldn't burn the head. Unfortunately, it was the same story and the powers are far below nominal. (pictures for proof)
CO2X - 37.72W
CO2Y - 31.74W
More unfortunate news, Jason spotted a lens on CO2X with what looks to be plastic burn marks on the plastic retainer ring and splattering on the lens itself (lens labeled LX-1060-Z-ET3.0 PL/CX 6.00” FL).
These numbers are within 3W of the medm values (alog 64618): CO2Y is 28.7W. CO2X is 34.4W.
Updated measurement of output power. Looks like CO2 lasers have been off for the last month.
Thanks Aidan, we've had the CO2's off during our vent. Next week we plan to swap CO2Y (currently SN 20306-20419D, installed 2016 alog29174) for our spare (20510-20816D). We'll then need to make a decision about what do do for CO2x.
Jason and I checked the spares located in the CO2 storage cupboard on the concrete slab through the egress door at the start of September:
- One complete laser and RF driver set (20510-20816D). Notes say it was refurbished by access laser in 2016, I expect during the upgrade in alog 29174.
- One laser only, no RF driver (S/N 20710-21002D). There is a note on laser saying “tested 2014”, purchase/production date on laser is 2012.
From alogs I think current CO2X laser is SN 20706-21015D, CO2Y laser is SN 20306-20419D.
Not sure this is related, but this is the readback of the TCS RF distribution chassis. It started degrading about 4 years ago.
I check on the floor and the output of the RF distribution amp was showing -2.2dBm (nominal ~13dBm). I then proceeded to measure the N-output of the SG382 RF source, and it showed -2.7dBm. I noticed that it also has a BNC output that showed 9.5dBm, so I switched the cable. This resulted in the distribution amplifier to show +9.8dBm and the EPICS readback +18.2dBm.
Not sure what the nominal RF power should be, but this is still 3dB shy of the initial value 5-6 years ago. The SG382 output amplitude is set to 9.49dBm, meaning it is all consistent now. To recover the old values we would have to set the RF source to ~12.5dBm.
