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Title: RF low-level control for the Linac4 H{sup −} source

The H{sup −} source for the Linac4 accelerator at CERN uses an RF driven plasma for the production of H{sup −}. The RF is supplied by a 2 MHz RF tube amplifier with a maximum power output of 100 kW and a pulse duration of up to 2 ms. The low-level RF signal generation and measurement system has been developed using standard CERN controls electronics in the VME form factor. The RF frequency and amplitude reference signals are generated using separate arbitrary waveform generator channels. The frequency and amplitude are both freely programmable over the duration of the RF pulse, which allows fine-tuning of the excitation. Measurements of the forward and reverse RF power signals are performed via directional couplers using high-speed digitizers, and permit the estimation of the plasma impedance and deposited power via an equivalent circuit model. The low-level RF hardware and software implementations are described, and experimental results obtained with the Linac4 ion sources in the test stand are presented.
Authors:
; ; ; ;  [1] ;  [2]
  1. CERN, Geneva (Switzerland)
  2. Graduate School of Science and Technology, Keio University, Yokohama (Japan)
Publication Date:
OSTI Identifier:
22391415
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1655; Journal Issue: 1; Conference: NIBS 2014: 4. International Symposium on Negative Ions, Beams and Sources, Garching (Germany), 6-10 Oct 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; AMPLIFIERS; BEAM PRODUCTION; CERN; DIGITIZERS; EQUIVALENT CIRCUITS; EXCITATION; FORM FACTORS; HYDROGEN IONS 1 MINUS; IMPEDANCE; ION SOURCES; LINEAR ACCELERATORS; MHZ RANGE; MODE CONTROL; PLASMA; RF SYSTEMS; WAVE FORMS