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Articles 1 - 30 of 30
Full-Text Articles in Physical Sciences and Mathematics
Analyzing Major Challenges Of Wind And Solar Variability In Power Systems, Falko Ueckerdt, Robert Brecha, Gunnar Luderer
Analyzing Major Challenges Of Wind And Solar Variability In Power Systems, Falko Ueckerdt, Robert Brecha, Gunnar Luderer
Physics Faculty Publications
Ambitious policy targets together with current and projected high growth rates indicate that future power systems will likely show substantially increased generation from renewable energy sources. A large share will come from the variable renewable energy (VRE) sources wind and solar photovoltaics (PV); however, integrating wind and solar causes challenges for existing power systems. In this paper we analyze three major integration challenges related to the structural matching of demand with the supply of wind and solar power: low capacity credit, reduced utilization of dispatchable plants, and over-produced generation. Based on residual load duration curves we define corresponding challenge variables …
Infographics And Mathematics: A Mechanism For Effective Learning In The Classroom, Ivan Sudakov, Thomas Bellsky, Svetlana Usenyuk, Victoria V. Polyakova
Infographics And Mathematics: A Mechanism For Effective Learning In The Classroom, Ivan Sudakov, Thomas Bellsky, Svetlana Usenyuk, Victoria V. Polyakova
Physics Faculty Publications
This work discusses the creation and use of infographies in an undergraduate mathematics course. Infographies are a visualization of information combining data, formulas, and images. This article discusses how to form an infographic and uses infographics on topics within mathematics and climate as examples. It concludes with survey data from undergraduate students on both the general use of infographics and on the specific infographics designed by the authors.
Cost-Availability Curves For Hierarchical Implementation Of Residential Energy-Efficiency Measures, Roman Villoria-Siegert, Philip Brodrick, Kevin P. Hallinan, Robert J. Brecha
Cost-Availability Curves For Hierarchical Implementation Of Residential Energy-Efficiency Measures, Roman Villoria-Siegert, Philip Brodrick, Kevin P. Hallinan, Robert J. Brecha
Physics Faculty Publications
Historical residential electricity data and natural gas consumption data were collected for, respectively, 1,200 and 178 residences in a small town in the USA. These data were merged with local building and weather databases, and energy consumption models were developed for each residence, revealing substantial variation in heating and cooling intensity. After estimating approximate physical building characteristics, energy profiles for each residence were calculated, and savings from adoption of the most cost-effective energy-efficiency measures for each residence were estimated. Effectively, we wish to leverage commonly available data sets to infer characteristics of building envelopes and equipment, without the need for …
Secondary Electron Yield Of Electron Beam Welded Areas Of Srf Cavities, M. Basovic, S. Popovic, M. Tomovic, L. Vuskovic, A. Samolov, F. Cuckov
Secondary Electron Yield Of Electron Beam Welded Areas Of Srf Cavities, M. Basovic, S. Popovic, M. Tomovic, L. Vuskovic, A. Samolov, F. Cuckov
Physics Faculty Publications
Secondary Electron Emission (SEE) is a phenomenon that contributes to the total electron activity inside the Superconducting Radiofrequency (SRF) cavities during the accelerator operation. SEE is highly dependent on the state of the surface. During electron beam welding process, significant amount of heat is introduced into the material causing the microstructure change of Niobium (Nb). Currently, all simulation codes for field emission and multipacting are treating the inside of the cavity as a uniform, homogeneous surface. Due to its complex shape and fabricating procedure, and the sensitivity of the SEE on the surface state, it would be interesting to see …
Design And Prototyping Of A 400 Mhz Rf-Dipole Crabbing Cavity For The Lhc High-Luminosity Upgrade, S. U. De Silva, J. R. Delayen, H. Park, Z. Li, T. H. Nicol
Design And Prototyping Of A 400 Mhz Rf-Dipole Crabbing Cavity For The Lhc High-Luminosity Upgrade, S. U. De Silva, J. R. Delayen, H. Park, Z. Li, T. H. Nicol
Physics Faculty Publications
LHC High Luminosity Upgrade is in need of two crabbing systems that deflects the beam in both horizontal and vertical planes. The 400 MHz rf-dipole crabbing cavity system is capable of crabbing the proton beam in both planes. At present we are focusing our efforts on a complete crabbing system in the horizontal plane. Prior to LHC installation the crabbing system will be installed for beam test at SPS. The crabbing system consists of two rf-dipole cavities in the cryomodule. This paper discusses the electromagnetic design and mechanical properties of the rf-dipole crabbing system for SPS beam test.
Imperfection And Tolerance Analysis Of Hom Couplers For Odu/Slac 400 Mhz Crabbing Cavity, S. U. De Silva, R. G. Olave, H. Park, J. R. Delayen, Z. Li
Imperfection And Tolerance Analysis Of Hom Couplers For Odu/Slac 400 Mhz Crabbing Cavity, S. U. De Silva, R. G. Olave, H. Park, J. R. Delayen, Z. Li
Physics Faculty Publications
In preparation for the LHC High Luminosity upgrade, a 400 MHz crab cavity has been developed jointly at ODU/SLAC, including two higher order mode couplers designed to dampen the wakefields in order to comply with the impedance budget specified for the LHC system. During fabrication, assembly, and processing of the couplers, a number of imperfections may arise that could modify the higher order mode spectrum and the associated impedance for each mode. We present here a detailed study of the imperfections of the horizontal- and vertical- HOM couplers, and the associated allowed tolerances for manufacture, assembly and processing.
Fpc And Hi-Pass Filter Hom Coupler Design For The Rf Dipole Crab Cavity For The Lhc Hilumi Upgrade, Zenghai Li, S. U. De Silva, J. R. Delayen, Hyekyoung Park, R. G. Olave
Fpc And Hi-Pass Filter Hom Coupler Design For The Rf Dipole Crab Cavity For The Lhc Hilumi Upgrade, Zenghai Li, S. U. De Silva, J. R. Delayen, Hyekyoung Park, R. G. Olave
Physics Faculty Publications
A 400-MHz compact RF dipole (RFD) crab cavity design was jointly developed by Old Dominion University and SLAC under the support of US LARP program for the LHC HiLumi upgrade. The RFD cavity design is consisted of a rounded-square tank and two ridged deflecting poles, operating with a TE11-like dipole mode, which is the lowest mode of the cavity. A prototype RFD cavity is being manufactured and will be tested on the SPS beam line at CERN. The coaxial fundamental Power Coupler (FPC) of the prototype cavity was re-optimized to minimizing the power heating on the coupler internal antenna. A …
Development And Testing Of A 325 Mhz Β0= 0.82 Single-Spoke Cavity, C. S. Hopper, Hyekyoung Park, J. R. Delayen
Development And Testing Of A 325 Mhz Β0= 0.82 Single-Spoke Cavity, C. S. Hopper, Hyekyoung Park, J. R. Delayen
Physics Faculty Publications
A single-spoke cavity operating at 325 MHz with geometric beta of 0.82 has been developed and tested. Initial results* showed high levels of field emission which limited the achievable gradient. Several rounds of helium processing significantly improved the cavity performance. Here we discuss the development process and report on the improved results.
Electromagnetic Design Of 400 Mhz Rf-Dipole Crabbing Cavity For Lhc High Luminosity Upgrade, S.U. De Silva, H. Park, J. R. Delayen, Z. Li
Electromagnetic Design Of 400 Mhz Rf-Dipole Crabbing Cavity For Lhc High Luminosity Upgrade, S.U. De Silva, H. Park, J. R. Delayen, Z. Li
Physics Faculty Publications
The beam crabbing proposed for the LHC High Luminosity Upgrade requires two crabbing systems operating in both horizontal and vertical planes. In addition, the crabbing cavity design needs to meet strict dimensional constraints and functional specifications of the cavities. This paper presents the detailed electromagnetic design including em properties, multipole analysis, multipacting levels of the 400 MHz rf-dipole crabbing cavity.
Beam Dynamics Studies Of 499 Mhz Superconducting Rf-Dipole Deflecting Cavity System, S. U. De Silva, K. E. Deitrick, H. Park, J. R. Delayen
Beam Dynamics Studies Of 499 Mhz Superconducting Rf-Dipole Deflecting Cavity System, S. U. De Silva, K. E. Deitrick, H. Park, J. R. Delayen
Physics Faculty Publications
A 499 MHz deflecting cavity has been designed as a three-way beam spreader to separate an electron beam into 3 beams. The rf tests carried out on the superconducting rf-dipole cavity have demonstrated that a transverse voltage of 4.2 MV can be achieved with a single cavity. This paper discusses the beam dynamics on a deflecting structure operating in continuous-wave mode with a relativistic beam. The study includes the analysis on emittance growth, energy spread, and change in bunch size including effects due to field non-uniformities.
High-Velocity Spoke Cavities, C. S. Hopper, Hyekyoung Park
High-Velocity Spoke Cavities, C. S. Hopper, Hyekyoung Park
Physics Faculty Publications
There are several current and recent projects which explore the feasibility of spoke-loaded cavities operating in the high-velocity region. Spoke cavities have a large number of geometric parameters which often influence multiple rf properties. Fabricating, handling, and processing these cavities presents some unique challenges, not unlike other TEM-class structures. This paper will summarize the current efforts toward the design, fabrication, and testing of spoke cavities with optimum beta greater than 0.8.
Measurements Of Rf Properties Of Thin Film Nb3Sn Superconducting Multilayers Using A Calorimetric Technique, S. Sosa-Guitron, A. Gurevich, J. Delayen, E. Chang Beom, C. Sundahl, G. V. Eremeev
Measurements Of Rf Properties Of Thin Film Nb3Sn Superconducting Multilayers Using A Calorimetric Technique, S. Sosa-Guitron, A. Gurevich, J. Delayen, E. Chang Beom, C. Sundahl, G. V. Eremeev
Physics Faculty Publications
Results of RF tests of NB3SN thin film samples related to the superconducting multilayer coating development are presented. We have investigated thin film samples of Nb3Sn/Al2O3/Nb with Nb3Sn layer thicknesses of 50 nm and 100 nm using a Surface Impedance Characterization system. These samples were measured in the temperature range 4 K-19 K, where significant screening by Nb3Sn layers was observed below 16-17 K, consistent with the bulk critical temperature of Nb3Sn.
Crab Cavity And Cryomodule Development For Hl-Lhc, F. Carra, A. A. Carvalho, K. Artoos, S. Atieh, I. A. Santillana, S. Belomestnykh, A. Boucherie, J. P. Brachet, K. Brodzinski, G. Burt, S. U. De Silva, J. R. Delayen, R. Olave, H. Park
Crab Cavity And Cryomodule Development For Hl-Lhc, F. Carra, A. A. Carvalho, K. Artoos, S. Atieh, I. A. Santillana, S. Belomestnykh, A. Boucherie, J. P. Brachet, K. Brodzinski, G. Burt, S. U. De Silva, J. R. Delayen, R. Olave, H. Park
Physics Faculty Publications
The HL-LHC project aims at increasing the LHC luminosity by a factor 10 beyond the design value. The installation of a set of RF Crab Cavities to increase bunch crossing angle is one of the key upgrades of the program. Two concepts, Double Quarter Wave (DQW) and RF Dipole (RFD) have been proposed and are being produced in parallel for test in the SPS beam before the next long shutdown of CERN accelerator’s complex. In the retained concept, two cavities are hosted in one single cryomodule, providing thermal insulation and interfacing with RF coupling, tuning, cryogenics and beam vacuum. This …
A Facility For Magnetic Field Penetration Measurements On Multilayer S-I-S Structures, Oleg B. Malyshev, Lewis Gurran, Shrikant Pattalwar, Ninad Pattalwar, Keith D. Dumbell, Reza Valizadeh, Alex Gurevich
A Facility For Magnetic Field Penetration Measurements On Multilayer S-I-S Structures, Oleg B. Malyshev, Lewis Gurran, Shrikant Pattalwar, Ninad Pattalwar, Keith D. Dumbell, Reza Valizadeh, Alex Gurevich
Physics Faculty Publications
Superconducting RF cavities made of bulk Nb has reached a breakdown field of about 200 mT which is close to the superheating field for Nb. As it was theoretically shown a multilayer coating can be used to enhance the breakdown field of SRF cavities. The simple example is a superconductor-insulator-superconductor (S-I-S), for example bulk niobium (S) coated with a thin film of insulator (I) followed by a thin layer of a superconductor (S) which could be a dirty niobium. To verify such an enhancement in a presence of a DC magnetic field at 4.2 K a simple experimental facility was …
Analysis Of A 750 Mhz Srf Dipole Cavity, Alejandro Castilla, J. R. Delayen
Analysis Of A 750 Mhz Srf Dipole Cavity, Alejandro Castilla, J. R. Delayen
Physics Faculty Publications
There is a growing interest in using rf transverse deflecting structures for a plethora of applications in the current and future high performance colliders. In this paper, we present the results of a proof of principle superconducting rf dipole, designed as a prototype for a 750 MHz crabbing corrector for the Medium Energy Electron-Ion Collider (MEIC), which has been successfully tested at 4.2 K and 2 K at the Jefferson Lab’s Vertical Testing Area (VTA). The analysis of its rf performance during cryogenic testing, along with Helium pressure sensitivity, Lorentz detuning, surface resistance, and multipacting processing analysis are presented in …
Anisotropy Reversal Of The Upper Critical Field At Low Temperatures And Spin-Locked Superconductivity In K₂Cr₃As₃, F. F. Balakirev, T. Kong, M. Jaime, R. D. Mcdonald, C. H. Mielke, A. Gurevich, P. C. Canfield, S. L. Bud'ko
Anisotropy Reversal Of The Upper Critical Field At Low Temperatures And Spin-Locked Superconductivity In K₂Cr₃As₃, F. F. Balakirev, T. Kong, M. Jaime, R. D. Mcdonald, C. H. Mielke, A. Gurevich, P. C. Canfield, S. L. Bud'ko
Physics Faculty Publications
We report measurements of the anisotropic upper critical field Hc2(T) for K2Cr3As3 single crystals up to 60 T and T > 0.6K. Our results show that the upper critical field parallel to the Cr chains, H∥c2(T), exhibits a paramagnetically limited behavior, whereas the shape of the H⊥c2(T) curve (perpendicular to the Cr chains) has no evidence of paramagnetic effects. As a result, the curves H⊥c2(T) and H∥c2(T) cross at T ≈ 4K, so that the anisotropy parameter H(T)=H …
Recent Developments In Superconducting Deflecting-Mode Cavities, J. R. Delayen
Recent Developments In Superconducting Deflecting-Mode Cavities, J. R. Delayen
Physics Faculty Publications
In the last few years there has been a growing interest in compact superconducting cavities operating in a deflecting mode to be used either in rf separators or crabbing systems. This talk will give an overview of recent progress in global activities towards SRF deflecting mode cavities.
Design Of Dressed Crab Cavities For The Hl-Lhc Upgrade, C. Zanoni, K. Artoos, S. Atieh, I. Aviles-Santillana, S. Belomestnykh, I. Ben-Zvi, J.P. Brachet, G. Burt, R. Calaga, O. Captina, S. U. De Silva, J. R. Delayen, A. May, K. Marinov, R. Olave, H. Park, N. Templeton
Design Of Dressed Crab Cavities For The Hl-Lhc Upgrade, C. Zanoni, K. Artoos, S. Atieh, I. Aviles-Santillana, S. Belomestnykh, I. Ben-Zvi, J.P. Brachet, G. Burt, R. Calaga, O. Captina, S. U. De Silva, J. R. Delayen, A. May, K. Marinov, R. Olave, H. Park, N. Templeton
Physics Faculty Publications
The HL-LHC upgrade relies on a set of RF crab cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final geometry is provided along with an insight in the mechanical and thermal analyses performed to validate the …
Engineering Design And Prototype Fabrication Of Hom Couplers For Hl-Lhc Crab Cavities, C. Zanoni, S. Atieh, I. Aviles Santillana, S. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, R. Olave, H. Park
Engineering Design And Prototype Fabrication Of Hom Couplers For Hl-Lhc Crab Cavities, C. Zanoni, S. Atieh, I. Aviles Santillana, S. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, R. Olave, H. Park
Physics Faculty Publications
The High-Luminosity upgrade for the LHC relies on a set of RF Crab Cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final shape is provided along with an insight in the mechanical and thermal analyses performed …
Performance Evaluation Of Hl-Lhc Crab Cavity Prototypes In A Cern Vertical Test Cryostat, K. G. Hernández-Chahín, A. Macpherson, C. Jarrige, M. Navarro-Tapia, R. Torres Sánchez, G. Burt, A. Tutte, S. U. De Silva
Performance Evaluation Of Hl-Lhc Crab Cavity Prototypes In A Cern Vertical Test Cryostat, K. G. Hernández-Chahín, A. Macpherson, C. Jarrige, M. Navarro-Tapia, R. Torres Sánchez, G. Burt, A. Tutte, S. U. De Silva
Physics Faculty Publications
Three proof-of-principle compact crab cavity designs have been fabricated in bulk niobium and cold tested at their home labs, as a first validation step towards the High Luminosity LHC project. As a cross check, all three bare cavities have been retested at CERN, in order to cross check their performance, and cross-calibrate the CERN SRF cold test facilities. While achievable transverse deflecting voltage is the key performance indicator, secondary performance aspects derived from multiple cavity monitoring systems are also discussed. Temperature mapping profiles, quench detection, material properties, and trapped magnetic flux effects have been assessed, and the influence on performance …
Superconducting Cavity For The Measurements Of Frequency, Temperature, Rf Field Dependence Of The Surface Resistance, Hyekyoung Park, S.U. De Silva, J. R. Delayen
Superconducting Cavity For The Measurements Of Frequency, Temperature, Rf Field Dependence Of The Surface Resistance, Hyekyoung Park, S.U. De Silva, J. R. Delayen
Physics Faculty Publications
In order to better understand the contributions of the various physical processes to the surface resistance of superconductors the ODU Center for Accelerator Science is developing a half-wave resonator capable of operating between 325 MHz and 1.3 GHz. This will allow the measurement of the temperature and rf field dependence of the surface resistance on the same surface over the range of frequency of interest for particle accelerators and identify the various sources of power dissipation.
Experiment And Results On Plasma Etching Of Srf Cavities, J. Upadhyay, Do Im, J. Peshl, S. Popovic, L. Vuskovic, A. -M. Valente-Feliciano, L. Phillips
Experiment And Results On Plasma Etching Of Srf Cavities, J. Upadhyay, Do Im, J. Peshl, S. Popovic, L. Vuskovic, A. -M. Valente-Feliciano, L. Phillips
Physics Faculty Publications
The inner surfaces of SRF cavities are currently chemically treated (etched or electro polished) to achieve the state of the art RF performance. We designed an apparatus and developed a method for plasma etching of the inner surface for SRF cavities. The process parameters (pressure, power, gas concentration, diameter and shape of the inner electrode, temperature and positive dc bias at inner electrode) are optimized for cylindrical geometry. The etch rate non-uniformity has been overcome by simultaneous translation of the gas point-of-entry and the inner electrode during the processing. A single cell SRF cavity has been centrifugally barrel polished, chemically …
Progress On A Compact Accelerator Design For A Compton Light Source, K. Deitrick, J. R. Delayen, B.R.P. Gamage, Geoffrey A. Krafft, T. Satogata
Progress On A Compact Accelerator Design For A Compton Light Source, K. Deitrick, J. R. Delayen, B.R.P. Gamage, Geoffrey A. Krafft, T. Satogata
Physics Faculty Publications
A compact Compton light source using an electron linear accelerator is in design at the Center for Accelerator Science at Old Dominion University and Jefferson Lab. We report on the current design, including beam properties through the entire system based on a full end-to-end simulation, compare current specifications to design goals, and target areas for improvement.
Progress On The Design Of The Polarized Medium Energy Electron Ion Collider At Jlab, F. Lin, S. A. Bogacz, P. D. Brindza, A Camsonne, E. Daly, Y. S. Derbenev, D. Douglas, R. Ent, D. Gaskell, R. L. Geng, A. Castilla, J. R. Delayen, C. E. Hyde, K. Park
Progress On The Design Of The Polarized Medium Energy Electron Ion Collider At Jlab, F. Lin, S. A. Bogacz, P. D. Brindza, A Camsonne, E. Daly, Y. S. Derbenev, D. Douglas, R. Ent, D. Gaskell, R. L. Geng, A. Castilla, J. R. Delayen, C. E. Hyde, K. Park
Physics Faculty Publications
The Medium-energy Electron Ion Collider (MEIC) at JLab is designed to provide high luminosity and high polarization needed to reach new frontiers in the exploration of nuclear structure. The luminosity, exceeding 1033 cm-2s−1 in a broad range of the center-of-mass (CM) energy and maximum luminosity above 1034 cm-2s−1, is achieved by high-rate collisions of short small-emittance low-charge bunches made possible by high-energy electron cooling of the ion beam and synchrotron radiation damping of the electron beam. The polarization of light ion species (p, d, 3He) can be easily preserved and …
Effects Of Crab Cavities Multipole Content In An Electron-Ion Collider, A. Castilla, V. S. Morozov, T. Satogata, J. R. Delayen
Effects Of Crab Cavities Multipole Content In An Electron-Ion Collider, A. Castilla, V. S. Morozov, T. Satogata, J. R. Delayen
Physics Faculty Publications
The impact on the beam dynamics of the Medium Energy Electron-Ion Colider (MEIC) due to the multipole content of the 750 MHz crab cavity was studied using thin multipole elements for 6D phase space particle tracking in ELEGANT. Target values of the sextupole component for the cavity’s field expansion were used to perform preliminary studies on the proton beam stability when compared to the case of pure dipole content of the rf kicks. Finally, important effects on the beam sizes due to non-linear components of the crab cavities’ fields were identified and some criteria for their future study were proposed.
Peppo: Using A Polarized Electron Beam To Produce Polarized Positrons, A. Adeyemi, G.L Gueye, P.A. Adderly, M. L. Stutzman, M. M. Ali, H. Areti, J. F. Benesch, L. S. Cardman, J. Clark, S. Covert, S. Golge, C. Hyde
Peppo: Using A Polarized Electron Beam To Produce Polarized Positrons, A. Adeyemi, G.L Gueye, P.A. Adderly, M. L. Stutzman, M. M. Ali, H. Areti, J. F. Benesch, L. S. Cardman, J. Clark, S. Covert, S. Golge, C. Hyde
Physics Faculty Publications
An experiment demonstrating a new method for producing polarized positrons has been performed at the CEBAF accelerator at Jefferson Laboratory. The PEPPo (Polarized Electrons for Polarized Positrons) concept relies on the production of polarized e+/e− pairs originating from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a 1.0 mm tungsten pair-production target. This paper describes preliminary results of measurements using an 8.2 MeV/c electron beam with polarization 84% to generate positrons in the range of 3.1 to 6.2 MeV/c with polarization as high as ∼80%.
Temperature Mapping Of Nitrogen-Doped Niobium Superconducting Radiofrequency Cavities, Junki Makita, Gianluigi Ciovati, Pashupati Dhakal
Temperature Mapping Of Nitrogen-Doped Niobium Superconducting Radiofrequency Cavities, Junki Makita, Gianluigi Ciovati, Pashupati Dhakal
Physics Faculty Publications
It was recently shown that diffusing nitrogen on the inner surface of superconducting radiofrequency (SRF) cavities at high temperature can improve the quality factor of the niobium cavity. However, a reduction of the quench field is also typically found. To better understand the location of rf losses and quench, we used a thermometry system to map the temperature of the outer surface of ingot Nb cavities after nitrogen doping and electropolishing. Surface temperature of the cavities was recorded while increasing the rf power and also during the quenching. The results of thermal mapping showed no precursor heating on the cavities …
Nitrogen Doping Study In Ingot Niobium Cavities, Pashupati Dhakal, Gianluigi Ciovati, Peter Kneisel, Ganapati Rao Myneni, Junki Makita
Nitrogen Doping Study In Ingot Niobium Cavities, Pashupati Dhakal, Gianluigi Ciovati, Peter Kneisel, Ganapati Rao Myneni, Junki Makita
Physics Faculty Publications
Thermal diffusion of nitrogen in superconducting radio frequency cavities at temperatures around 800C has resulted in the increase in quality factor with a low-field Q-rise. However, the maximum accelerating gradients of these doped cavities often reduces below the values achieved by standard treatments. In this contribution, we present the results of the nitrogen diffusion into ingot niobium cavities subjected to successive material removal from the inner cavity surface by electropolishing in an effort to explore the underlying cause for the gradient degradation.
Development Of Srf Cavity Tuners For Cern, K. Artoos, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, N. Kuder, R. Leuxe, P. Minginette, W. Venturini Delsolaro, G. Villiger, C. Zanoni, P. Zhang, S. Verdu-Andrés, B. Xiao, G. Burt, J. Delayen, Hyekyoung Park, T. Jones, N. Templeton
Development Of Srf Cavity Tuners For Cern, K. Artoos, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, N. Kuder, R. Leuxe, P. Minginette, W. Venturini Delsolaro, G. Villiger, C. Zanoni, P. Zhang, S. Verdu-Andrés, B. Xiao, G. Burt, J. Delayen, Hyekyoung Park, T. Jones, N. Templeton
Physics Faculty Publications
Superconducting RF cavity developments are currently on-going for new accelerator projects at CERN such as HIE ISOLDE and HL-LHC. Mechanical RF tuning systems are required to compensate cavity frequency shifts of the cavities due to temperature, mechanical, pressure and RF effects on the cavity geometry. A rich history and experience is available for such mechanical tuners developed for existing RF cavities. Design constraints in the context of HIE ISOLDE and HL-LHC such as required resolution, space limitation, reliability and maintainability have led to new concepts in the tuning mechanisms. This paper will discuss such new approaches, their performances and planned …
Control Of Synchrotron Radiation Effects During Recirculation With Bunch Compression, D. R. Douglas, S. V. Benson, R. Li, Y. Roblin, C. D. Tennant, Geoffrey A. Krafft, Balŝa Terzić, C. -Y. Tsai
Control Of Synchrotron Radiation Effects During Recirculation With Bunch Compression, D. R. Douglas, S. V. Benson, R. Li, Y. Roblin, C. D. Tennant, Geoffrey A. Krafft, Balŝa Terzić, C. -Y. Tsai
Physics Faculty Publications
Studies of beam quality preservation during recirculation * have been extended to generate a design of a compact arc providing bunch compression with positive momentum compaction ** and control of both incoherent and coherent synchrotron radiation (ISR and CSR) effects using the optics balance methods of diMitri et al.***. In addition, the arc/compressor generates very little micro-bunching gain. We detail the beam dynamical basis for the design, discuss the design process, give an example solution, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of micro-bunching effects ****.