Yesterday we noticed a low level (20% nominal) of the CO2 laser output power on the NI bench. The following investigation showed that the problem was in the signal fed by the RF square wave generator (at 40.7 MHz, in TCS room) to the laser RF driver; the signal was splitted by a BNC T and sent to both the NI and WI lasers from the output of the RF generator, and that introduced some distortion effect (also, the cables from TCS room to lasers are pretty long). In order to have both lasers operating at full power we need to solve the problem. According to Nocera and Paoletti, a solution could be an active splitter feeding the two signals. For the next week tests on CH, however, we decided to bring an additional RF square wave generator from Tor Vergata, in order to separately drive the two lasers.

Notice that It will be not possible to lock the two RF generators to a 10 MHz signal (or similar), so for the moment they will be freely running. In parallel, we will work to put in place a better solution to replace the added RF generator.

Also, few tests on the system would be needed to asses the best solution scheme, that is, investigate the effects on power of changing the cable length and/or changing the square wave amplitude. These test will be performed during the next shifts on TCS CO2 benches.