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The PS Radial Pick-ups |
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| Fig.1: Hybrid circuit |
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| Fig.2: Head assembly schematics |
There are five radial pick-ups in the PS, in SS22, SS36, SS51, SS76
and SS96. These pick-ups provide signals to the radial
loop of the LLRF system. Usually, only three out of the five
PUs are actively used.
PU36 and PU76 are now equipped with new 50Ω cabling.
The other three will be similarly upgraded in the 2010 shutdown.
The electrode signals are passed through a Technical Research & Manufacturing Inc.
model HS172* passive hybrid to
get sum and difference signals and then carried over 75Ω coax to CB (Fig.1).
The unused electrodes are terminated into 50Ω.
There are no active electronics in the ring.
For cable numbers and locations, see the
wiring diagram.
The head assembly is quite simple (Fig. 2). The electrodes are connected through
287Ω resistors to 75Ω cables. The electrode load resistance is
thus 362Ω, which results in a 4.4MHz low cut-off frequency.
Small adjustable capacitors are provided to allow injection of a test signal,
but these are used on none of the PUs installed.
| PU22 uses 75&Omega cabling. Cable numbers are 9312 for Σ and 9311 for X. |
| PU36 uses 50&Omega cabling. Cable numbers are 2609726A for Σ and 2609727A for X. |
| PU51 uses 75&Omega cabling. Cable numbers are 11374 for Σ and 11375 for X. |
| PU76 uses 50&Omega cabling. Cable numbers are 2609730A for Σ and 2609731A for X. The plate carrying the hybrid is stuck to the magnet base on the exterior side of the ring. |
| PU96 uses 75&Omega cabling. Cable numbers are 11735 for Σ and 11736 for X. |