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Romanov, Gennady V.

Publications and source records attributed to Romanov, Gennady V..

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

PIC Simulations of One-side Multipactor on Dielectric

Breakdown of dielectric RF windows is an important issue for particle accelerators and high-power RF sources. One of the generally considered reasons for the RF windows failure is the multipactor on dielectric surface. The multipactor may be responsible for excessive heating of dielectric and discharge of charges that accumulated in ceramic due to secondary emission. In this study the comprehensive self-consistent PIC simulations with space charge effect were performed in order to better understand the dynamic of one-side multipactor development and floating potential on dielectric induced by the emission. The important correlations between the multipactor parameters at saturation and the secondary emission properties of dielectric and the applied RF field parameters were found and are reported in the paper.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Notes on the Variety of Multipactor Patterns

The experimental results on multipactor often are not in a good agreement with theoretical predictions and numerical simulations. The experimental results can noticeably vary from test to test even in the same geometry of electrodes, depending on the material they made of and condition of their surfaces, i.e., secondary emission properties. On the other hand, an actual secondary emission yield (SEY) of electrode material is never known a priory in the experiments. In practice, the SEY data for given material used for multipactor evaluation are obtained in specialized measurements. A difference between actual and tabulated SEY of material may result in a disagreement between pre-dictions and measurements. In this work the impact of the basic SEY characteristic variations on the multipactor dynamics in a variety of coaxial and rectangular waveguides is studied. The study was performed numerically with the use of CST Particle Studio.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Improving Magnetic Materials for RCS Cavity Tuners

Within the Lab Directed R&D Program at Fermilab, and in partnership with National Magnetics, we have recently begun to study and attempt to improve the loss parameter in garnet material. This could be used for fast tuner applications such as in rapid cycling synchrotrons.

Madrak, Robyn Leigh↗
DOE OSTI2020

Multipactor in Coaxial Line Induced by DC Bias

High DC voltage applied between outer and inner electrodes of coaxial transmission lines is considered and actually is an effective remedy against multipactor in these lines. However, the high voltage bias being below certain level itself initiates multipacting. In this technical note the experimental manifestation and numerical simulations of the phenomenon are presented.

43 PARTICLE ACCELERATORS↗