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AdV-DET (Commissioning)
bonnand, mours - 21:04 Tuesday 29 November 2016 (35672) Print this report
SNEB work during today's maintenance

This morning, the SNEB minitower has been vented and the following activities performed:

  • Change the splitter in front of the camera by the nominal 99.9% instead of 90%
  • Change the B7_PD2 photodiode to get an preamplifier able to stand 50 mW instead of the previous 12 mW
  • Replace the RF cable of the B7_PD1 photodiode which was not working properly
  • Restore the correct name of the RF photodiode channels (PD1 and PD2 were swaped)
  • Change the ADC channel used for the demodulation of the B7_PD1 from 3 to 1 (although the observed problem was maybe coming from the bad cable)
  • Change the timing DAQbox cabling. Now, the bottom DAQbox is receiving first the timing and then send it to the top DAQbox.
  • Replace the B7_Cam2 camera (its air box was leaking)
  • Tighten some of the LVDT supports
  • A test of the transmission of the feedtrough (test made with Eric and Gabriel). The transmission of the 633 nm feedthrough plus the four meters fiber was around 15% for a 8 mW beam.

Then the minitower was closed and pumped down (starting from 14:15 UTC).

The recovery of the local control due to the thermic transient and possible reference change, is in progress.

Comments to this report:
bonnand - 9:20 Wednesday 30 November 2016 (35675) Print this report

 

We didn't recover yet the control of the bench SNEB, venting of the mini-toweris in progress as we suspect the bench to be stuck somewhere.

bonnand, mours, van Heijningen, pasqualetti. - 18:07 Wednesday 30 November 2016 (35684) Print this report

Today, we checked the SNEB bench has we were not able to put it in the right place.

It was indeed block by some stops and unbalance (probably because I moved the counterweigth inside the tank while it was stucked on one of the stop).

So the bench has been rebalanced properly and put back in the right position by Joris with the multi-sas. Then we also add some spacing by put the stop further away from the bench.

After checking that we could see some flashes on B7 with the bench aligned in air, Antonio proceed with the pumping done of the mini-tower while the control of th bench were opened.

The vacuum is almost over now and Joris put back the bench roughly at the right altitude and position.

The bench might move down a little during the night because of the thermal transient, so it might need some small readjustement tomorrow morning.

The signals from the local control of the bench (both multi-sas and bench LVDT) look good and the bench is controlled without troubles.

mours, pillant - 20:33 Wednesday 07 December 2016 (35746) Print this report

We tested the transmission of a spare fiber identical to the one installed in the minitower. We got a 10-15 % transmission connecting the green fiber laser at one end, and a bit more than 80% connecting it at the other end. It is therefore difficult to conclude on the transmission of the feedtrough.

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