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Title: Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude

A beam current limiter is disclosed 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 linearmore » response region. The system thus provides a large dynamic range in combination with good linearity. 6 figs.« less
Inventors:
; ;
Issue Date:
OSTI Identifier:
101001
Assignee:
Univ. of Chicago, IL (United States) PTO; SCA: 430300; PA: EDB-95:131502; SN: 95001445744
Patent Number(s):
US 5,440,210/A/
Application Number:
PAN: 8-048,652
Contract Number:
W-31109-ENG-38
Resource Relation:
Other Information: PBD: 8 Aug 1995
Research Org:
Univ. of Chicago, IL (United States)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BEAM CURRENTS; MONITORING; CONTROL; CYCLOTRONS; CONTROL SYSTEMS; LINEAR ACCELERATORS; DESIGN; LIMITING VALUES; BEAM MONITORS

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