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2018

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Articles 331 - 338 of 338

Full-Text Articles in Engineering Physics

First Test Results Of Superconducting Twin Axis Cavity For Erl Applications, Hyekyoung Park, Subashini De Silva, Jean R. Delayen, Andrew Hutton, Frank Marhauser Jan 2018

First Test Results Of Superconducting Twin Axis Cavity For Erl Applications, Hyekyoung Park, Subashini De Silva, Jean R. Delayen, Andrew Hutton, Frank Marhauser

Physics Faculty Publications

RF superconducting (SRF) cavities with two beam pipes have been proposed in the past for energy recovery linac applications. The relatively complex geometry of those cavities presented a serious challenge for fabrication and surface processing. The main concerns have now been overcome with the fabrication and successful RF testing of a new elliptical twin-axis cavity proposed by Jefferson Lab (JLab) and optimized by the Center for Accelerator Science (CAS) at Old Dominion University (ODU) in the framework of a DoE accelerator stewardship program. The cavity design provides uniform accelerating or decelerating fields for both beams. This paper describes the cavity …

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Cryogenic Probe Station At Old Dominion University Center For Accelerator Science, Junki Makita, Jean R. Delayen, Alex Gurevich, Gianluigi Ciovati Jan 2018

Cryogenic Probe Station At Old Dominion University Center For Accelerator Science, Junki Makita, Jean R. Delayen, Alex Gurevich, Gianluigi Ciovati

Physics Faculty Publications

With a growing effort in research and development of an alternative material to bulk Nb for a superconducting radiofrequency (SRF) cavity, it is important to have a cost effective method to benchmark new materials of choice. At Old Dominion University's Center for Accelerator Science, a cryogenic probe station (CPS) will be used to measure the response of superconductor samples under RF fields. The setup consists of a closed-cycle refrigerator for cooling a sample wafer to a cryogenic temperature, a superconducting magnet providing a field parallel to the sample, and DC probes in addition to RF probes. The RF probes will …

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Determination Of The Field-Dependence Of The Surface Resistance Of Superconductors From Cavity Tests, Jean R. Delayen, Subashini De Silva, Hyekyoung Park Jan 2018

Determination Of The Field-Dependence Of The Surface Resistance Of Superconductors From Cavity Tests, Jean R. Delayen, Subashini De Silva, Hyekyoung Park

Physics Faculty Publications

Cryogenic tests of superconducting cavities yield an average surface resistance as a function of the peak surface magnetic field. An analytical formalism has been developed to extract the actual field dependence of the surface resistance from cavity tests and is applied to coaxial cavities and cavities of more complex geometries.

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Rf Tests Of Rf-Dipole Prototype Crabbing Cavities For Lhc High Luminosity Upgrade, Subashini De Silva, Hyekyoung Park, Jean R. Delayen, Zi Li Jan 2018

Rf Tests Of Rf-Dipole Prototype Crabbing Cavities For Lhc High Luminosity Upgrade, Subashini De Silva, Hyekyoung Park, Jean R. Delayen, Zi Li

Physics Faculty Publications

The superconducting rf-dipole crabbing cavity is one of the two crabbing cavity designs proposed for the LHC high luminosity upgrade. The proof-of-principle (P-o-P) rf-dipole cavity operating at 400 MHz has demonstrated performance exceeding the design specifications. The prototype cavity for SPS beam test has been designed to include the fundamental power coupler, HOM couplers, and all the ancillary components intended to meet the design requirements. The crab cavities will be installed in the SPS beam line prior to the installation in LHC; this will be the first crabbing cavity operation on a proton beam. The fabrication of two prototype rf-dipole …

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Investigation Of The Surface Resistance Of Niobium Between 325 Mhz And 1300 Mhz Using A Coaxial Half-Wave Cavity, Hyekyoung Park, Jean R. Delayen, Subashini De Silva Jan 2018

Investigation Of The Surface Resistance Of Niobium Between 325 Mhz And 1300 Mhz Using A Coaxial Half-Wave Cavity, Hyekyoung Park, Jean R. Delayen, Subashini De Silva

Physics Faculty Publications

The Center for Accelerator Science at Old Dominion University has built a half-wave coaxial cavity (*) to measure the surface resistance of niobium as a function of frequency, temperature, rf field, preparation techniques, over a wide range of frequencies of interest for particle accelerators. The characteristics of the half-wave coaxial cavity provide these information on a same surface. The preliminary results showed clearly the frequency dependence of residual surface resistance (**). After establishing baseline, we have conducted a study of low temperature baking effect on the surface resistance under controlled environment. This paper will describe the details of the test …

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Simulation Study Of The Magnetized Electron Beam, S.A.K. Wijethunga, J.F. Benesch, Jean R. Delayen, F. E. Hannon, Geoffrey A. Krafft, M. A. Poelker, R. Suleiman Jan 2018

Simulation Study Of The Magnetized Electron Beam, S.A.K. Wijethunga, J.F. Benesch, Jean R. Delayen, F. E. Hannon, Geoffrey A. Krafft, M. A. Poelker, R. Suleiman

Physics Faculty Publications

Electron cooling of the ion beam plays an important role in electron ion colliders to obtain the required high luminosity. This cooling efficiency can be enhanced by using a magnetized electron beam, where the cooling process occurs inside a solenoid field. This paper compares the predictions of ASTRA and GPT simulations to measurements made using a DC high voltage photogun producing magnetized electron beam, related to beam size and rotation angles as a function of the photogun magnetizing solenoid and other parameters.

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Magnetron Sputtering Of Nb3Sn For Srf Cavities, Md. N. Sayeed, H. Elsayed-Ali, G. V. Eremeev, M. J. Kelley, U. Pudasaini, C. E. Reece Jan 2018

Magnetron Sputtering Of Nb3Sn For Srf Cavities, Md. N. Sayeed, H. Elsayed-Ali, G. V. Eremeev, M. J. Kelley, U. Pudasaini, C. E. Reece

Electrical & Computer Engineering Faculty Publications

Nb3Sn is a potential candidate for surface material of SRF cavities since it can enable the cavity to operate at higher temperatures with high quality factor and at an increased accelerating gradient. Nb-Sn films were deposited using magnetron sputtering of individual Nb and Sn targets onto Nb and sapphire substrates. The as-deposited films were annealed at 1200 °C for 3 hours. The films were characterized for their structure by X-ray Diffraction (XRD), morphology by Field Emission Scanning Electron Microscopy (FESEM), and composition by Energy Dispersive X-ray Spectroscopy (EDS) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The …

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Real Time Spectroscopic Ellipsometry Analysis Of First Stage Cuin1-Xgaxse2 Growth: Indium-Gallium Selenide Co-Evaporation, Puja Pradhan, Puruswottam Aryal, Dinesh Attygalle, Abdel-Rahman Ibdah, Prakash Koirala, Jian Li, Khagendra P. Bhandari, Geethika K. Liyanage, Randy J. Ellingson, Michael J. Heben, Sylvain Marsillac, Robert W. Collins, Nikolas J. Podraza Jan 2018

Real Time Spectroscopic Ellipsometry Analysis Of First Stage Cuin1-Xgaxse2 Growth: Indium-Gallium Selenide Co-Evaporation, Puja Pradhan, Puruswottam Aryal, Dinesh Attygalle, Abdel-Rahman Ibdah, Prakash Koirala, Jian Li, Khagendra P. Bhandari, Geethika K. Liyanage, Randy J. Ellingson, Michael J. Heben, Sylvain Marsillac, Robert W. Collins, Nikolas J. Podraza

Electrical & Computer Engineering Faculty Publications

Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In1-xGax)₂Se₃ (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to …

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