[Halld-tracking-hw] FDC cables

[Lubomir Pentchev]

Hi Fernando,

I have several questions and concerns regarding the cables.
Sorry for the late feedback, it turned out I did not subscribe the general 
gluex list.

1.HV cables

It is very good that we will have spare HV modules and extra slots in 
case we need more. Based on my experience with the BigCal calorimeter in Hall C, 
it is very important also to have spare HV cables, that run together with 
the used HV cables. Replacing installed already cable is much more 
difficult. In Hall C we had also spare channels within the cables, which is 
also very useful.
We can discuss how exactly to organize this which may affect the HV 
translator board, but for the cable procurement I think we should have 
12 instead of 8 cables.

2.Signal cables

Same arguments are valid here, but because of the big numbers we should be 
more precise. 528 signal cables (24+1 channels) corresponds exactly to the 
total number of the FDC channels. I think it is  good to have at least 6 
spare cables per package (24 in total) that run at different azimuthal 
angles (every 10 min.). Let's have also 6 extra cables not installed. In 
total we will have 558 signal (Amphenol 50 conductors) cables.

3.Cables source

For the FDC your source is at "12:00 downstream". Just wanted to make 
sure that it is taken into account that the signal cables will run at all 
azimuthal angles, and that "downstream" means the FDC position taken out 
downstream for servicing.

Thanks,
  Lubomir