Single board op-amp beam position monitors electronics

A new approach has been developed for beam position monitors (BPM) in the new 600 keV beamline. A single four layer printed circuit board, attached with short (0.3 m) cables to the electrodes, processes the raw signals and outputs voltages proportional to the beam intensity, horizontal and vertical position, and quadrapole moment. Newly-available high-speed operational amplifiers are used exclusively instead of more conventional RF components. The RF input frequency can be as high as 36 MHz, and the IF frequency is 100 kHz. The output signals from each monitor will be digitized by the VME-based control system which will provide operator displays and use the information as feedback in automatic loops controlling the beam position, envelope, and dispersion. The signal processing at each BPM location eliminates the need for expensive multiplexing and routing of signals to a central processing location. The cylindrical electrode is split into four equal segments allowing both horizontal and vertical information to be obtained at each location thus minimizing the required beamline insertion length.<
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