CODD reference data

Electrodes

Pick-up electrodes

The CODD pick-up electrodes consist of four plates, shaped to obtain a linear characteristic w.r.t. displacement, and equal inter-electrode capacitances. The four plates are mounted inside a shield that is insulated with respect to the vacuum chamber. They come in two versions: One dubbed 'standard', with a 166 mm horizontal aperture, and an enlarged model, with a 212 mm aperture for use in injection or ejection regions.

Some pick-up properties Standard Large Aperture 166x80mm 212x80mm Length 62mm 62mm Cel 70pF 70pF Single plate to shield Cline 30pF 30pF (Up to feedthrough) Csc 1nF ? Shield to chamber Cecx 0.5pF ? X electrode to chamber Cecy 0.3pF ? Y electrode to chamber Rt 0.52Ω 0.52Ω (At PU electrodes, high Z) Sx 174.3mm 227.8mm (Using CODD hybrid) Sy 82.3mm 83.5mm (Using CODD hybrid)

Schematic of head assembly

References

• J. Durand, J. Gonzalez, E. Schulte, M. Thivent, "New electrostatic pick-ups for the PS", CERN/PS 88-42 (PA)
• J. Belleman, "On the linearity of the PS closed orbit display pick-up electrodes", PS/BD/Note93-01(Tech)