Author: Fang, Z.
Paper Title Page
WEPAB297 A Recent Upgrade on Phase Drift Compensation System for a Stable Beam Injection at J-PARC Linac 3357
 
  • E. Cicek, Z. Fang, Y. Fukui, K. Futatsukawa
    KEK, Ibaraki, Japan
  • T. Hirane, S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
  • Y. Sato
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
  
  J-PARC linac, con­sist­ing of 324 MHz and 972 MHz ac­cel­er­a­tion sec­tions, de­liv­ers H− beam to the rapid cy­cling syn­chro­tron (RCS). The drift in the beam in­jec­tion mo­men­tum from linac to RCS was mea­sured to be highly de­pen­dent on the hu­mid­ity at the kly­stron gallery. Also, changes in both tem­per­a­ture and hu­mid­ity strongly af­fect the rf field phase con­trolled within the dig­i­tal feed­back (DFB) sys­tem. To cope with this, a unique phase drift com­pen­sa­tion sys­tem, namely the phase drift mon­i­tor (PDM) sys­tem, is im­ple­mented in the MEBT2B1 sta­tion as the first step at the linac. How­ever, the com­pen­sa­tion of the drift cor­rec­tion could not be achieved di­rectly since two dif­fer­ent fre­quen­cies were used. The new PDM, which adapts the di­rect sam­pling method using the Radio Fre­quency Sys­tem-on-Chip (RFSoC), will pave the way to en­sure rf phase sta­bil­ity at all sta­tions si­mul­ta­ne­ously. Here we pre­sent the ef­fects of tem­per­a­ture and hu­mid­ity on the rf field phase, along with per­for­mance and pre­lim­i­nary test re­sults con­cern­ing the phase drift com­pen­sa­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB297  
About • paper received ※ 19 May 2021       paper accepted ※ 01 July 2021       issue date ※ 18 August 2021  
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