Author: Molodozhentsev, A.Y.
Paper Title Page
TUPRO052 Study a ‘Sum’ Linear Coupling Resonance for J-PARC Main Ring: Observations and Simulations 1147
 
  • A.Y. Molodozhentsev, S. Igarashi
    KEK, Ibaraki, Japan
  • Y. Sato, J. Takano
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
 
  J-PARC Main Ring should deliver a high-power proton beam to neutrino experiments with limited particle losses. To meet this requirement low-order machine resonances have to be compensated. The linear coupling resonance Qx+Qy=43 has been identified as the potential source for significant particle losses at the collimator. The resonance compensation scheme has been studied experimentally by using a low intensity beam. To understand this process the simulations have been performed by using the PTC-ORBIT code. The Main Ring model has been developed to reproduce the machine operation including the initial stage of the acceleration. The 6D beam model has been defined to represent the ‘pencil’ beam used for this study. In frame of this report the single and multi particle dynamics will be discussed to understand the results of measurements, performed during RUN44 (November 2012). The results of the long-term tracking for this case will be presented. The obtained results can be used to benchmark the computer modeling the ‘sum’ linear coupling resonance with the experimental results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO052  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPRO093 Numerical Study of Intrinsic Ripples in J-PARC Main-ring Magnets 1256
 
  • Y. Shirakabe, A.Y. Molodozhentsev, M. Muto
    KEK, Ibaraki, Japan
 
  Beam ripples are one of the critical problems in high power proton synchrotrons. Magnet field ripples are considered as a main origin of the beam ripples among various possible sources. Although magnet power supply ripples are generally treated as the dominating ripple source, the load circuit parameters of the magnets and their interconnections are also playing critical roles in defining the ripple amplitudes and frequencies. In this viewpoint, the magnet power supplies are treated as simplified current sources, and the ripples generated in the circuit systems are investigated both in analytical and numerical ways. One of the findings in this direction of investigation is the existence of intrinsic ripples. The intrinsic ripples occur inevitably in the synchrotron magnets, no matter how the power supplies are producing idealistic current ramp patterns. Their amplitudes are defined by the circuit parameters such as inductance and capacitance, and the ramp parameters such as ramp rates. Some of the analytical mechanisms in generating the magnet field ripples are presented as well as the studied examples.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO093  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPRO067 Modeling Slow Extraction Process For J-PARC Main Ring 3032
 
  • A.Y. Molodozhentsev
    KEK, Ibaraki, Japan
 
  J-PARC Main Ring has to deliver the proton beam to ‘hadron’ experiments by using ‘slow extraction’ technique, base on the 3rd order horizontal resonance. The spill quality during the full extraction period is one of the most important requirements as well as the beam quality. The computer modeling of the slow extraction process for J-PARC Main Ring is based on a realistic machine model, which includes measured imperfections of the machine in addition to dynamic variation of the machine elements to perform the slow extraction. In frame of this report we represent the results of the modeling the slow extraction process from J-PARC Main Ring by using the PTC-ORBIT combined code. The resonance extraction has been controlled by changing the betatron tune. Control the horizontal emittance of the extracted beam has been performed by using ‘dynamic’ bumps. Control the spill quality of the extracted beam has been performed by using dedicated quadrupole magnets and the transverse RF signal (RF knockout). In addition, the spill quality can be improved by suppressing effect of the power supply ripple. On the request, the collective effects can be introduced into the model.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO067  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)