@article{PATENT,
      recid = {8531},
      title = {Indirectly sensing accelerator beam currents for limiting  maximum beam current magnitude},
      number = {PATENT},
      month = {Aug},
      year = {1995},
      abstract = {A beam current limiter for sensing and limiting the beam  current in a particle accelerator, such as a cyclotron or  linear accelerator, used in scientific research and medical  treatment. A pair of independently operable capacitive  electrodes sense the passage of charged particle bunches to  develop an RF signal indicative of the beam current  magnitude produced at the output of a bunched beam  accelerator. The RF signal produced by each sensing  electrode is converted to a variable DC voltage indicative  of the beam current magnitude. The variable DC voltages  thus developed are compared to each other to verify proper  system function and are further compared to known  references to detect beam currents in excess of  pre-established limits. In the event of a system  malfunction, or if the detected beam current exceeds  pre-established limits, the beam current limiter  automatically inhibits further accelerator operation. A  high Q tank circuit associated with each sensing electrode  provides a narrow system bandwidth to reduce noise and  enhance dynamic range. System linearity is provided by  injecting, into each sensing electrode, an RF signal that  is offset from the bunching frequency by a pre-determined  beat frequency to ensure that subsequent rectifying diodes  operate in a linear response region. The system thus  provides a large dynamic range in combination with good  linearity.},
      url = {http://knowledge.uchicago.edu/record/8531},
}