M10.6.9: Design and fabrication of AMC modules for controlling step motors, piezo and waveguide tuners

Abstract

FLASH accelerator is using superconducting RF cavities to accelerate electron beam. These cavities must be precisely tuned to RF frequency due to very high Q factor (~109 unloaded Q and ~106 loaded Q). They are tuned by slight dimension change (particularly length) induced by tuners driven by step motors. For high gradients (~20MV/m and more) the cavities are dynamically detuned during RF pulse due to Lorentz Force Detuning (LFD). To keep them in resonance the fast tuners with piezos are used. Both slow and fast tuners need the control integrated with the LLRF system