Installation and Integration/Meeting G&S

Grounding and Shielding meeting

20 December 2016

I presented the slide on docdb http://docs.dunescience.org:8080/cgi-bin/ShowDocument?docid=2032

The goal was to inform that Grounding and Shielding group of our current options and issues. There was some discussion regarding these options, but no one had any final thoughts. Here are some point that were brought up:

- Need to shield the cables.

- Having longer cables (> 25m) causes dispersion to become a problem, No one is keen on going to longer cables. - Data cables might be shorten and linked with a connector to avoid dispersion, a concern from some people. This would effectively double the number (and weight) of data cable, impacting the number of connectors and flanges (or at least connectors on the flanges)

- PD team have a problem with longer cables. They already are at the limit of what they have tested. Longer cables will affect the pulse amplitude, which will decreases and the signal gets wider.

It was agreed that for the moment, we should continue to aim at keeping that PD cables inside the APA tubes.

It could be good to have the power cables inside the tube since it would reduce the length (and keep it identical for all cables). The frame is grounded providing self-shielding for the cables to the wires. BUT they are not shielded from the PD and the PD team is not completely happy to have these cables next to theirs.

- If we go with solution C (along floor and walls) we should consider having only three different lengths of cables so that we will have few calibration constants to correct for the different lengths.

Grounding rules: APA are wanted to be independent, but in DUNE, it might not be the case. The questions was not answered.