[Suresh D, Bubba G, Jason O, Rick S., Sudarshan G]
We have seen that a non-glitchy oplev laser could be pushed into a glitchy behaviour if the ambient temperature changes. Since we presently tune the lasers for single-mode (non-glitchy) operation in the PCal lab and then transport them to their respective oplev locations, we are required to retune their power in-situ to recover glitch-free behaviour. This is often a time consuming process. We therefore wished to be able to set the PCal room to the temperature of LVEA (or XVEA or YVEA as needed) so that we may be able to increase the reliability of this process and reduce the time needed to tune them in-situ.
At this time the two end-station VEAs in LHO have glitchy lasers. We therefore wish to replace these with tuned lasers at the earliest opportunity. We measured the temperature of these VEAs.
| Location | time | temperature | remarks |
|---|---|---|---|
| Y VEA | 23Mar2017 12:10PM | 66.1 degF | 15mins wait time for T to settle [SD, BG] |
| X VEA | 23Mar2017 03:18PM | 66.5 degF | 15 mins waiting time. T oscillates between 66.3 to 66.8 degF in ~5mins [SD,RS,SG] |
Bubba reset the air-conditioning control settings in the LSB labs, so that we can set the PCal lab temperature to required value.
We have prepared three lasers for glitch free operation. [SD, JO]. One of them is presently ready for installation at Y-end (tuned at 66.1 degF room temperature). See attached pics for further details.
Two others lasers are under preparation for installation at X-end and possibly BS.
Note: The same thermocouple sensor (Fluke hand-held device) was used at all locations to avoid calibration differences between various wall mounted sensors at these locations.
