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Plasma and Beam Physics

Old Dominion University

2013

Articles 1 - 8 of 8

Full-Text Articles in Physics

Characterization Of Microwave Discharge Plasmas For Surface Processing, Milka Nikolic Jul 2013

Characterization Of Microwave Discharge Plasmas For Surface Processing, Milka Nikolic

Physics Theses & Dissertations

We have developed several diagnostic techniques to characterize two types of microwave (MW) discharge plasmas: a supersonic flowing argon MW discharge maintained in a cylindrical quartz cavity at frequency ƒ = 2.45 GHz and a pulse repetitive MW discharge in air at ƒ = 9.5 GHz. Low temperature MW discharges have been proven to posses attractive properties for plasma cleaning and etching of niobium surfaces of superconductive radio frequency (SRF) cavities. Plasma based surface modification technologies offer a promising alternative for etching and cleaning of SRF cavities. These technologies are low cost, environmentally friendly and easily controllable, and present a …

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Special Issue On Plenary And Invited Papers From Icops 2012, Felipe Iza, Carl Ekdahl, Michael G. Kong Jan 2013

Special Issue On Plenary And Invited Papers From Icops 2012, Felipe Iza, Carl Ekdahl, Michael G. Kong

Electrical & Computer Engineering Faculty Publications

The 39th International Conference on Plasma Science (ICOPS) was held in Edinburgh, Scotland in July 2012. This was the third time that the conference was organized outside North America, the previous ones being in Karlsruhe (Germany) in 2008 and Jeju (S. Korea) in 2003. The technical programme combined seven technical areas of plasma science and technology covering a wide range of topics. The conference featured a wide range of advances in innovative plasma and beam science and applications, and served as a venue for an international community to meet and discuss their ideas and research results. More than 800 abstracts …

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Mechanical Analysis Of The 400 Mhz Rf-Dipole Crabbing Cavity Prototype For Lhc High Luminosity Upgrade, S. U. De Silva, H. Park, J. R. Delayen, Z. Li Jan 2013

Mechanical Analysis Of The 400 Mhz Rf-Dipole Crabbing Cavity Prototype For Lhc High Luminosity Upgrade, S. U. De Silva, H. Park, J. R. Delayen, Z. Li

Physics Faculty Publications

The proposed LHC high luminosity upgrade requires two crabbing systems in increasing the peak luminosity, operating both vertically and horizontally at two interaction points of IP1 and IP5. The required system has tight dimensional constraints and needs to achieve higher operational gradients. A proof-of-principle 400 MHz crabbing cavity design has been successfully tested and has proven to be an ideal candidate for the crabbing system. The cylindrical proof-of-principle rf-dipole design has been adapted in to a square shaped design to further meet the dimensional requirements. The new rf-dipole design has been optimized in meeting the requirements in rf-properties, higher order …

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Geometry Effects On Multipole Components And Beam Optics In High-Velocity Multi-Spoke Cavities, C. S. Hopper, K. Deitrick, J. R. Delayen Jan 2013

Geometry Effects On Multipole Components And Beam Optics In High-Velocity Multi-Spoke Cavities, C. S. Hopper, K. Deitrick, J. R. Delayen

Physics Faculty Publications

Velocity-of-light, multi-spoke cavities are being proposed to accelerate electrons in a compact light-source [1]. There are strict requirements on the beam quality which require that the linac have only small non-uniformities in the accelerating field. Beam dynamics simulations have uncovered varying levels of focusing and defocusing in the proposed cavities, which is dependent on the geometry of the spoke in the vicinity of the beam path. Here we present results for the influence different spoke geometries have on the multipole components of the accelerating field and how these components, in turn, impact the simulated beam properties.

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Magnetic Bunch Compression For A Compact Compton Source, B.R.P. Gamage, T. Satogata Jan 2013

Magnetic Bunch Compression For A Compact Compton Source, B.R.P. Gamage, T. Satogata

Physics Faculty Publications

A compact electron accelerator suitable for Compton source applications is in design at the Center for Accelerator Science at Old Dominion University and Jefferson Lab. Here we discuss two options for transverse magnetic bunch compression and final focus, each involving a 4-dipole chicane with M56 tunable over a range of 1.5-2.0m with independent tuning of final focus to interaction point \beta*=5mm. One design has no net bending, while the other has net bending of 90 degrees and is suitable for compact corner placement.

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Multipole Field Effects For The Superconducting Parallel-Bar/Rf-Dipole Deflecting/Crabbing Cavities, S. U. De Silva, J. R. Delayen Jan 2013

Multipole Field Effects For The Superconducting Parallel-Bar/Rf-Dipole Deflecting/Crabbing Cavities, S. U. De Silva, J. R. Delayen

Physics Faculty Publications

The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.

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Study Of Cavity Imperfection Impact On Rf-Parameters And Multipole Components In A Superconducting Rf-Dipole Cavity, R. G. Olave, J. R. Delayen, S. U. De Silva, Z. Li Jan 2013

Study Of Cavity Imperfection Impact On Rf-Parameters And Multipole Components In A Superconducting Rf-Dipole Cavity, R. G. Olave, J. R. Delayen, S. U. De Silva, Z. Li

Physics Faculty Publications

The ODU/SLAC superconducting rf-dipole cavity is under consideration for the crab-crossing system in the upcoming LHC luminosity upgrade. While the proposed cavity complies well within the rf-parameters and multipolar component restrictions for the LHC system, cavity imperfections arising from cavity fabrication, welding and frequency tuning may have a significant effect in these parameters. We report on an initial study of the impact of deviation from the ideal shape on the cavity’s performance in terms of rf-parameters and multipolar components.

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Comparison Of Electromagnetic, Thermal And Mechanical Calculations With Rf Test Results In Rf Dipole Deflecting/Crabbing Cavities, H. Park, S. U. Silva, J. R. Delayen Jan 2013

Comparison Of Electromagnetic, Thermal And Mechanical Calculations With Rf Test Results In Rf Dipole Deflecting/Crabbing Cavities, H. Park, S. U. Silva, J. R. Delayen

Physics Faculty Publications

The current requirements of higher gradients and strict dimensional constraints in the emerging applications have required the designing of compact deflecting and crabbing rf structures. The superconducting rf-dipole cavity is one of the first novel compact designs with attractive properties such as higher gradients, higher shunt impedance and widely separated higher order modes. The recent tests performed on proof-of-principle designs of the rf-dipole geometry at 4.2 K and 2.0 K in a vertical test assembly have proven the designs to achieve higher gradients with higher intrinsic quality factors and easily processed multipacting conditions. The design frequency sensitivity to pressure (df/dp) …

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