Reports until 18:27, Friday 04 October 2013
H1 ISC
rich.abbott@LIGO.ORG - posted 18:27, Friday 04 October 2013 (8006)
HAM1&6 ISC Electronics Installation Work (V2)
A rare day indeed...

Alexa, Stefan, Sheila, Kiwamu, Rich

HAM1 Status:
1.  All RF connections from air to vacuum have been fixed.  After much head scratching, we found an idiosyncrasy (=design flaw) with the air-side 2-row 5-way coaxial connector.  Each coaxial element in the 5-way connector is supposed to free float somewhat in order to mate properly when inserted into the flange.  Moreover, each coaxial element is spring loaded such that there is a restoring force to maintain proper insertion.  The air side connector has large coaxial cables to minimize the RF loss on the trip back to the racks, and it is here that the trouble begins.  This large coaxial cable - being quite stiff - has enough friction inside the connector body that when you try and plug the 5-way connector into the flange, some of the individual coaxial elements simply compress the spring, and don't insert into the socket.  With the strain relief screws loosened, it is actually possible to push an individual cable and feel it snap into the flange.  Of course, there's a down side to this.  If you pull an individual cable, it is possible to pop it out of its socket causing a loss of connection.  We secured the cable bundles to the conflat protector ring cross bolt such that all the cables are reasonably immobile.  This will likely be quite sufficient.

A small consolation prize is that the in-vacuum version of this connector doesn't seem to be anywhere near as susceptible to this phenomenon.  Still, any plugging and unplugging (which is highly discouraged) should be done by watching with a time domain reflectometer (TDR) to ensure no harm has been done before and after the evolution.

2.  Beam diverters have been tested and are all OK
3.  Tip/tilt electronics chain is showing good signs of life in that the sensors are sensing and the pushers are pushing. 

Next Steps:
1.  Remaining parts for the RFPDs are to be delivered in town tomorrow.  Assembly will be completed and the detectors will be installed in HAM1
2.  Finish checkout of tip/tilt chain
3.  Take transfer functions for all RFPDs in HAM1
4.  Clean up in-vacuum cable installation