A beam position detector for SSC collider rings

A short-circuited stripline position detector which would operate in flowing liquid helium has been prototyped for the Superconducting Super Collider (SSC) main rings. Each sensing device, at 968 locations in each ring, consists of four 15-cm-long, 50- Omega strip transmission lines. To maximize signal-to-noise ratio and reduce orthogonal sensitivity, each electrode subtends 70 degrees of the 37-mm aperture. Electrical to mechanical centers are proposed to be maintained within a 0.15-mm radius by accurate tooling, so individual calibration would not be required. A radiation-resistant, impedance-matched vacuum feedthrough which is integral to the output signal cable is being considered. Because of the large quantity of detectors and inherent difficulty of replacement, reliability and manufacturability received the greatest concern during the design. >