Speaker
Dr
Fumihiko Tamura
(JAREI)
Description
The J-PARC Rapid cycling synchrotron (RCS) requires a very
stable and precise low level RF (LLRF) control system to handle the
ultra-high proton beam currents. The MA-loaded low-Q cavities for the
RCS are driven by the superposition of the dual-harmonic RF signal for
both the acceleration and the longitudinal bunch shaping. We employ a
full-digital system based on direct digital synthesis (DDS). The
multi-harmonic RF signals generated by the DDS are easily synchronized
without PLLs. We describe the design and the structure of the LLRF
blocks. The common feedback loops are used for the stabilizing the
beam orbit and phase as well as the RF voltages of the cavity. The
heavy beam loading effect is compensated by using the beam feedforward
method. We also present the test results of the recently manufactured
modules.
Author
Dr
Fumihiko Tamura
(JAREI)
Co-authors
Dr
Akira Takagi
(KEK)
Dr
Alexander Schnase
(JAERI)
Dr
Chihiro Ohmori
(KEK)
Dr
Eizi Ezura
(KEK)
Dr
Keigo Hara
(KEK)
Dr
Masahiro Nomura
(JAERI)
Dr
Masahito Yoshii
(KEK)
Dr
Masanobu Yamamoto
(JAERI)
Dr
Shozo Anami
(KEK)
