Keyword: low-level-rf
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PO04 The Darmstadt Multi-Frequency Digital Low Level RF System in Pulsed Application controls, linac, cavity, electron 58
  • R. Eichhorn, U. Bonnes, C. Burandt, M. Konrad, P.N. Nonn
    TU Darmstadt, Darmstadt, Germany
  • G. Schreiber, W. Vinzenz
    GSI, Darmstadt, Germany
  Funding: Work supported by DFG through CRC 634 and by the BMBF under 06 DA 9024 I
Triggered by the need to control the superconducting cavities of the S-DALINAC, the development of a digital low level RF control system was started several years ago. The chosen design proved to be very flexible since other frequencies than the original 3 GHz may be adapted easily: The system converts the RF signal coming from the cavity (e. g. 3 GHz) down to the base band using a hardware I/Q demodulator. The base band signals are digitized by ADCs and fed into a FPGA where the control algorithm is implemented. The resulting signals are I/Q modulated before they are sent back to the cavity. Meanwhile, this system has been successfully operated on 3 GHz, 6 GHz and 325 MHz cavities, on normal and superconducting cavities as well as in cw or pulsed mode. This contribution will focus on the 325 MHz version built to control a pulsed prototype test stand for the p-LINAC at FAIR and possible extensions to even lower frequencies. We will present the architecture of the RF control system as well as results obtained during operation.