- Increased PSL HEPA Variac from 30 to 100% to get more airflow.
- All of the TEC setpoints seem cold to me, so I increased the laser crystal temperature to 30.6 C
- Adjusted the diode TEC setpoints individually to optimize the PMC REFL power (unlocked). DTEC A = 22.09 C, DTEC B = 21.04 C
- locked PMC at 1900 PT; let's see how long it lasts.
My hunch is that the TECs are working too hard and can't offload the heat onto the heat sinks. As the diode's degrade, more of the electrical power is converted to heat in the diodes rather than 808 nm photons. So hopefully the increased airflow will help.
I tried to increase the DTEC setpoints, but that seems to detune them too far from the laser absorption band, so that's not very efficient for us. IN any case, if we end up changin the laser temperature, we'll have to adjust the ALS lasers to match, and that will be annoying.
The office area was very cold and the HVAC air flow stronger than usual. I changed the setpoint on the thermostat near Steve's desk from 71 to 73F at 1830 today. |