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Full-Text Articles in Physics
Cryogenic Test Results Of The Sps Prototype Rf-Dipole Crabbing Cavity With Higher Order Mode Couplers, Subashini De Silva, H. Park, Jean R. Delayen, Z. Li
Cryogenic Test Results Of The Sps Prototype Rf-Dipole Crabbing Cavity With Higher Order Mode Couplers, Subashini De Silva, H. Park, Jean R. Delayen, Z. Li
Physics Faculty Publications
The rf-dipole crabbing cavity planned for the LHC High Luminosity Upgrade is designed to deliver a transverse kick of 3.34 MV; crabbing the proton beam in the horizontal plane. The proton beams of the LHC machine operating at 7 TeV each sets high impedance thresholds on the crabbing cavity systems. The rf-dipole crabbing cavity is designed with a two higher order mode couplers to suppress those HOMs. The first prototype of the HOM couplers are fabricated at Jefferson Lab. This paper reports the cryogenic test results of the HOM couplers with the SPS prototype rf-dipole cavity.
Cryogenic Probe Station At Old Dominion University Center For Accelerator Science, Junki Makita, Jean R. Delayen, Alex Gurevich, Gianluigi Ciovati
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 …
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
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 …
Room Temperature Measurements Of Higher Order Modes For The Sps Prototype Rf Dipole Crabbing Cavity, Subashini De Silva, P. Berrutti, Jean R. Delayen, N. A. Huque, Hyekyoung Park
Room Temperature Measurements Of Higher Order Modes For The Sps Prototype Rf Dipole Crabbing Cavity, Subashini De Silva, P. Berrutti, Jean R. Delayen, N. A. Huque, Hyekyoung Park
Physics Faculty Publications
LHC High Luminosity Upgrade will be developing two local crabbing systems to increase the luminosity of the colliding bunches at the ATLAS and CMS experiments. One of the crabbing systems uses the rf-dipole cavity design that will be crabbing the beam in the horizontal plane. The fully integrated crabbing cavity has two higher order mode couplers in damping those excited modes. Currently two sets of HOM couplers have been fabricated at Jefferson Lab for prototyping and testing with the LARP crabbing cavities. This paper presents the measurements of the higher order modes with the prototype HOM couplers carried out at …
Determination Of The Field-Dependence Of The Surface Resistance Of Superconductors From Cavity Tests, Jean R. Delayen, Subashini De Silva, Hyekyoung Park
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.
Coupled Bunch Instability From Jleic Crab Cavity Higher Order Modules, S. I. Sosa, R. Li, H. Park, S. De Silva, V. S. Morozov, J. R. Delayen
Coupled Bunch Instability From Jleic Crab Cavity Higher Order Modules, S. I. Sosa, R. Li, H. Park, S. De Silva, V. S. Morozov, J. R. Delayen
Physics Faculty Publications
Particle bunches traveling in a ring can excite wakefields inside any radio-frequency element present. These electromagnetic modes can resonate long enough and interact with subsequent passing bunches. A coherent oscillation between bunches can quickly become an instability and needs to be addressed. The Jefferson Lab electron ion collider has a large 50 mrad crossing angle and thus relies on bunch crabbing to achieve high luminosity. Bunch crabbing is done with compact superconducting rf dipole cavities. We study coupled bunch oscillations driven by the higher order modes of multicell RFD crab cavities under study for JLEIC, we calculate the instability growth …
Measurements Of Frequency, Temperature, Rf Field Dependent Surface Resistance Using Superconducting Half-Wave Cavity, Hyekyoung Park, Subashini De Silva, Jean R. Delayen
Measurements Of Frequency, Temperature, Rf Field Dependent Surface Resistance Using Superconducting Half-Wave Cavity, Hyekyoung Park, Subashini De Silva, Jean R. Delayen
Physics Faculty Publications
A theory of surface resistance of superconductor was rigorously formulated by Bardeen, Cooper, Schrieffer more than 50 years ago. Since then the accelerator community has been used the theory as a guideline to improve the surface resistance of the superconducting cavity. It has been observed that the surface resistance is dependent on frequency, temperature and rf field strength, and surface preparation. To verify these dependences, a well-controlled study is required. Although many different types of cavities have been tested, the typical superconducting cavities are built for specific frequencies of their application. They do not provide data other than at its …
Rf Tests Of Rf-Dipole Prototype Crabbing Cavities For Lhc High Luminosity Upgrade, Subashini De Silva, Hyekyoung Park, Jean R. Delayen, Zi Li
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 …
Lessons Learned From Rf-Dipole Prototype Cavities For Lhc High Luminosity Upgrade, Subashini De Silva, Jean R. Delayen, Z. Li, H. Park
Lessons Learned From Rf-Dipole Prototype Cavities For Lhc High Luminosity Upgrade, Subashini De Silva, Jean R. Delayen, Z. Li, H. Park
Physics Faculty Publications
The RF-Dipole Crabbing Cavity designed for the LHC High Luminosity Upgrade includes two higher order mode (HOM) couplers. One of the HOM couplers is an rf filter, which is a high pass filter designed to couple to the horizontal dipole modes and accelerating modes up to 2 GHz, while rejecting the fundamental operating mode at 400 MHz. The coupler consists of a high pass filter circuit where the rejection of the operating mode and transmission of HOMs are sensitive to dimensional deviations. An rf test box has been designed to measure the transmission of the rf filter in order to …