| Paper | Title | Page |
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| MOPME043 | Modeling and Simulation of Beam-induced Plasma in Muon Cooling Devices | 466 |
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Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. We have developed numerical algorithms and parallel software for self-consistent simulation of the plasma production and its interaction with particle beams and external fields. Simulations support the experimental program on the hydrogen gas filled RF cavities in the Mucool Test Area (MTA) at Fermilab. Computational algorithms are based on the electromagnetic particle-in-cell (PIC) code SPACE combined with a probabilistic, macroparticle-based implementation of atomic physics processes such as the absorption of the incident particles, ionization of the absorber material, and the generation and evolution of secondary particles in dense, neutral gas. In particular, we have proposed a novel algorithm for dealing with repetitive incident beam, enabling simulations of long time scale processes. Benchmarks and simulations of the experiments on gas-filled RF cavities and prediction for future experiments are discussed.
* kwangmin.yu@stonybrook.edu ** rosamu@bnl.gov |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME043 | |
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| THPRI064 | Plasma Chemistry in a High Pressure Gas Filled RF Test Cell for use in a Muon Cooling Channel | 3917 |
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| Filling an RF cavity with a high pressure gas prevents breakdown when the cavity is placed in a multi-Tesla external magnetic field. A beam of particles traversing the cavity, be it muons or protons, ionizes the gas, creating an electron-ion plasma which absorbs energy from the cavity. In order to understand the nature of this plasma loading, a variety of gas species, gas pressures, dopants, and cavity electric fields were investigated. Plasma induced energy loss, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times were measured. The results for hydrogen, deuterium, helium, and nitrogen, doped with dry air will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI064 | |
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| THPRI065 | Effects of Beam Loading and Higher-order Modes in RF Cavities for Muon Ionization Cooling | 3921 |
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| Envisioned muon ionization cooling channel is based on vaccum and/or gas-filled RF cavities of frequencies of 325 and 650 MHz. In particular, to meet the luminosity requirement for a muon collider, the muon beam intensity should be on the order of 1012 muons per bunch. In this high beam intensity, transient beam loading can significantly reduce the accelerating gradients and deteriorate the beam quality. We estimate this beam loading effect using an equivalent circuit model. For gas-filled cavity case, the beam loading is compared with plasma loading. We also investigate the excitation of higher-order modes and their effects on the performance of the cavity. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI065 | |
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