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Articles 1 - 30 of 90
Full-Text Articles in Physics
Eic 197 Mhz Crab Cavity Hom Damping And Tolerence Analysis, Z. Li, B. Xiao, S. U. De Silva, Q. Wu, J. R. Delayen, R. Rimmer
Eic 197 Mhz Crab Cavity Hom Damping And Tolerence Analysis, Z. Li, B. Xiao, S. U. De Silva, Q. Wu, J. R. Delayen, R. Rimmer
Physics Faculty Publications
Crab cavities, operating at 197 MHz and 394 MHz respectively, will be used to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point in the Electron Ion Collider (EIC). Both cavities are of the RF Dipole (RFD) type. To meet the stringent impedance requirements for beam stability and quality, the cavity design must incorporate strong Higher Order Mode (HOM) damping. A special type of HOM coupler has been developed (for both horizontal and vertical HOMs), which consisting of a waveguide stub that couples to the cavity and a waveguide-to-coaxial transition that extracts the …
Sensitivity Analysis Of The 197 Mhz Prototype Crab Cavity For Eic, Subashini De Silva, Jean R. Delayen, B. Xiao, E. Drachuk, I. H. Senevirathne, A. Castilla, N. Huque, Z. Li
Sensitivity Analysis Of The 197 Mhz Prototype Crab Cavity For Eic, Subashini De Silva, Jean R. Delayen, B. Xiao, E. Drachuk, I. H. Senevirathne, A. Castilla, N. Huque, Z. Li
Physics Faculty Publications
The Electron-Ion Collider at BNL requires several crabbing systems that will be operating at 197 MHz and 394 MHz to compensate for the loss of luminosity due to the large crossing angle of the colliding beams. Two 197 MHz crab cavity cryomodules containing two cavities each will be installed in the Hadron Storage Ring (HSR) at the IP6 interaction region. Due to its large size compared to previously developed crabbing cavities, the 197 MHz crabbing cavity system was identified as one of the critical rf systems in the EIC. Therefore, a cavity has been designed including the ancillaries, and is …
Design Of A Shipping Fixture For A Compact Cryomodule Hermetic Assembly, J. Lewis, G. Ciovati, N. Huque, J. Armstrong, K. Harding
Design Of A Shipping Fixture For A Compact Cryomodule Hermetic Assembly, J. Lewis, G. Ciovati, N. Huque, J. Armstrong, K. Harding
Physics Faculty Publications
Two conduction-cooled 915 MHz superconducting radio frequency hermetic assemblies must be safely transported from the Jefferson Lab in Newport News, VA to General Atomics in San Diego, CA for performance testing in a custom horizontal test cryostat. One hermetic assembly consists of a 2-cell 915 MHz cavity, a coaxial fundamental power coupler, and the warm-to-cold transition beam tubes. The second hermetic assembly consists of a 2-cell 915 MHz cavity only. The assemblies will be transported on a flatbed air-ride trailer over the approximate 4000 km distance. Design requirements included adequate attenuation of 4g vertical axis, 5g beamline axis, and 1.5g …
Optical Investigation Of A Low-Pressure Plasma In A Superconducting Radio-Frequency Cavity, Zachary A. Caudell
Optical Investigation Of A Low-Pressure Plasma In A Superconducting Radio-Frequency Cavity, Zachary A. Caudell
Electrical & Computer Engineering Theses & Dissertations
The state-of-the-art cryomodules for particle accelerators use superconducting radio-frequency (SRF) cavities. It is known that accumulation of hydrocarbon impurities reduces the cavity surface work function, decreasing cryomodule performance metrics such as field emission, thermal stability, and accelerating gradients. An in-situ method of plasma processing has recently been developed to clean the cavities and restore cryomodule performance [1]. This study is to understand the properties of the low-pressure plasmas generated in a C100 SRF cavity and ultimately to improve the performance of plasma surface cleaning using optical emission spectroscopy. Using a 500 mm focal length Czerny-Turner monochromator coupled with a photomultiplier …
Weak-Strong Beam-Beam Simulation With Crab Cavity Noises For The Hadron Storage Ring Of The Electron-Ion Collider, Y. Luo, B. Gamage, C. Montag, D. Marx, D. Xu, F. Willeke, H. Huang, H. Lovelace Iii, J. Berg, M. Blaskiewicz, S. Peggs, T. Satogata, V. Ptitsyn, V. Morozov, Y. Hao
Weak-Strong Beam-Beam Simulation With Crab Cavity Noises For The Hadron Storage Ring Of The Electron-Ion Collider, Y. Luo, B. Gamage, C. Montag, D. Marx, D. Xu, F. Willeke, H. Huang, H. Lovelace Iii, J. Berg, M. Blaskiewicz, S. Peggs, T. Satogata, V. Ptitsyn, V. Morozov, Y. Hao
Mathematics & Statistics Faculty Publications
The Electron Ion Collider (EIC), to be constructed at Brookhaven National Laboratory, will collide polarized high-energy electron beams with hadron beams, achieving luminosities of up to 1 X 1034cm−2s−1 in the center-mass energy range of 20-140 GeV. Crab cavities are employed to compensate for the geometric luminosity loss caused by a large crossing angle of 25 mrad in the interaction region. The phase noise in crab cavities will induce a significant emittance growth for the hadron beams in the Hadron Storage Ring (HSR). Various models have been utilized to study the effects of crab cavity …
Crabbing Cavity System Development For International Linear Collider, Subashini De Silva
Crabbing Cavity System Development For International Linear Collider, Subashini De Silva
Physics Faculty Publications
The International Liner Collider requires a crabbing system to increase the luminosity of the colliding electron bunches. The ILC has a large crossing angle that requires compensation in order to meet the luminosity requirements. There are several frequency options proposed for the crabbing cavity design. Two crab cavity designs were selected to be prototyped in the pre-lab phase, following the Down Selection Review on Crab Cavity Design held in April 2023. The two rf designs selected are the 1.3 GHz rf-dipole cavity and the 2.6 GHz QMiR cavity. We will be presenting the electromagnetic and mechanical design details of the …
Investigation Of Hot-Spots Due To Trapped Flux In Niobium Superconducting Radiofrequency Cavities, B. Khanal, P. Dhakal
Investigation Of Hot-Spots Due To Trapped Flux In Niobium Superconducting Radiofrequency Cavities, B. Khanal, P. Dhakal
Physics Faculty Publications
One of the significant sources of residual losses in superconducting radio-frequency cavities is magnetic flux trapped during the cool-down due to the incomplete Messier effect. If the trapped vortices are non-uniformly distributed on the cavity surface, the temperature mapping revealed the “hot-spots” at the location of high density of pinned vortices. Here, we performed a rf test on 1.3 GHz single cell cavity with the combination of the temperature mapping system. The temperature mapping reveled the development of the hot spots with the increase in rf field inside the cavity. When magnetic field is trapped locally on the surface of …
Rf And Mechanical Design Of A 915 Mhz Srf Cavity For Conduction-Cooled Cryomodules, G. Ciovati, A. Castilla-Loeza, G. Cheng, J. Henry, J. Rathke, J. Vennekate, K. Harding, T. Schultheiss, J. Lewis
Rf And Mechanical Design Of A 915 Mhz Srf Cavity For Conduction-Cooled Cryomodules, G. Ciovati, A. Castilla-Loeza, G. Cheng, J. Henry, J. Rathke, J. Vennekate, K. Harding, T. Schultheiss, J. Lewis
Physics Faculty Publications
Conduction-cooled SRF niobium cavities are being developed for use in compact, continuous-wave electron linear accelerators for a variety of industrial applications. A 915 MHz two-cell cavity has been designed to achieve an energy gain of 3.5 MeV. The design of the cell shape aims at minimizing the peak surface magnetic field. Field flatness is achieved by adjusting the length of the outer end half-cells. The higher-order mode analysis shows that absorbers are not required for a moderate beam current of 5 mA. One of the beam tubes has two side-ports for insertion of coaxial fundamental power couplers. The mechanical design …
Thermal Diffusivity And Acoustic Properties Of Nb Thin Films Studied By Time-Domain Thermoreflectance, Md. Obidul Islam, Hani Elsayed-Ali
Thermal Diffusivity And Acoustic Properties Of Nb Thin Films Studied By Time-Domain Thermoreflectance, Md. Obidul Islam, Hani Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
The thermal diffusion and acoustic properties of Nb impacts the thermal management of devices incorporating Nb thin films such as superconducting radiofrequency (SRF) cavities and superconducting high-speed electronic devices. The diffusion and acoustic properties of 200-800 nm thick Nb films deposited on Cu substrates were investigated using time-domain thermoreflectance (TDTR). The films were examined by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The grain size and thermal diffusivity increase with film thickness. The thermal diffusivity increased from 0.100± 0.002 cm2s-1 to 0.237± 0.002 cm2s-1 with the increase in film thickness from 200 …
Transfer Learning For Field Emission Mitigation In Cebaf Srf Cavities, K. Ahammed, J. Li, A. Carpenter, C. Tennant, R. Suleiman
Transfer Learning For Field Emission Mitigation In Cebaf Srf Cavities, K. Ahammed, J. Li, A. Carpenter, C. Tennant, R. Suleiman
Electrical & Computer Engineering Faculty Publications
The Continuous Electron Beam Accelerator Facility (CEBAF) operates hundreds of superconducting radio frequency (SRF) cavities in its two linear accelerators (linacs). Field emission (FE) is an ongoing operational challenge in higher gradient SRF cavities. FE generates high levels of neutron and gamma radiation leading to damaged accelerator hardware and a radiation hazard environment. During machine development periods, we performed invasive gradient scans to record data capturing the relationship between cavity gradients and radiation levels measured throughout the linacs. However, the field emission environment at CEBAF varies considerably over time as the configuration of the radio-frequency (RF) gradients changes or due …
Design Of A Resonant Optical Cavity For Imaging Magneto-Optically Active Thin Film Samples, Cody Robert Brelage
Design Of A Resonant Optical Cavity For Imaging Magneto-Optically Active Thin Film Samples, Cody Robert Brelage
Graduate Theses - Physics and Optical Engineering
This document describes the design and fabrication of an optical resonator system to investigate magneto-optic properties of thin film samples. This system uses an open-air optical resonator to enable photons to make multiple passes through each thin film and thus increase the magnitude of the Faraday rotation that each sample imposes onto the light that exits the system. This system promises many future experiments to study the magneto-optic properties of thin film and nano-particle samples. Using an optical resonator to enhance Faraday rotation should enable an improved signal-to-noise ratio in taking measurements and images with a photodetector.
Temperature, Rf Field, And Frequency Dependence Performance Evaluation Of Superconducting Niobium Half-Wave Coaxial Cavity, N. K. Raut, G. Ciovati, S. U. De Silva, J. R. Delayen, P. Dhakal, B. D. Khanal, J. K. Tiskumara
Temperature, Rf Field, And Frequency Dependence Performance Evaluation Of Superconducting Niobium Half-Wave Coaxial Cavity, N. K. Raut, G. Ciovati, S. U. De Silva, J. R. Delayen, P. Dhakal, B. D. Khanal, J. K. Tiskumara
Physics Faculty Publications
Recent advancement in superconducting radio frequency cavity processing techniques, with diffusion of impurities within the RF penetration depth, resulted in high quality factor with increase in quality factor with increasing accelerating gradient. The increase in quality factor is the result of a decrease in the surface resistance as a result of nonmagnetic impurities doping and change in electronic density of states. The fundamental understanding of the dependence of surface resistance on frequency and surface preparation is still an active area of research. Here, we present the result of RF measurements of the TEM modes in a coaxial half-wave niobium cavity …
Numerical Calculations Of Superheating Field In Superconductors With Nanostructured Surfaces, M.R.P. Walive Pathiranage, A. Gurevich
Numerical Calculations Of Superheating Field In Superconductors With Nanostructured Surfaces, M.R.P. Walive Pathiranage, A. Gurevich
Physics Faculty Publications
We report calculations of a dc superheating field Hs in superconductors with nanostructured surfaces. Particularly, we performed numerical simulations of the Ginzburg-Landau (GL) equations for a superconductor with an inhomogeneous profile of impurity concentration, a thin superconducting layer on top of another superconductor, and S-I-S multilayers. The superheating field was calculated taking into account the instability of the Meissner state at a finite wavelength along the surface depending on the value of the GL parameter. Simulations were done for the materials parameters of Nb and Nb₃Sn at different values of the GL parameter and the mean free paths. We show …
Eic 197 Mhz Crab Cavity Rf Optimization, Zenghai Li, Subashini U. De Silva, Jean R. Delayen, Robert A. Rimmer, Qiong Wu, Binping Xiao, Wencan Xu
Eic 197 Mhz Crab Cavity Rf Optimization, Zenghai Li, Subashini U. De Silva, Jean R. Delayen, Robert A. Rimmer, Qiong Wu, Binping Xiao, Wencan Xu
Physics Faculty Publications
Crab cavities, operating at 197 MHz and 394 MHz respectively, will be used to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point in the Electron Ion Collider (EIC). Both crab cavities are of the RF Dipole (RFD) shape. To meet the machine design requirements, there are a few important cavity design considerations that need to be addressed. First, to achieve stable cavity operation at the design voltages, cavity geometry details must be optimized to suppress potential multipacting. Incorporating strong HOM damping in the cavity design is required for the beam stability and …
Cavity And Cryomodule Developments For Eic, R. A. Rimmer, E. Daly, J. Guo, J. Henry, J. Matalevich, H. Wang, S. Wang, D. Holmes, K. Smith, W. Xu, A. Zaltsman, B. Xiao, Subashini De Silva, Jean R. Delayen
Cavity And Cryomodule Developments For Eic, R. A. Rimmer, E. Daly, J. Guo, J. Henry, J. Matalevich, H. Wang, S. Wang, D. Holmes, K. Smith, W. Xu, A. Zaltsman, B. Xiao, Subashini De Silva, Jean R. Delayen
Physics Faculty Publications
The EIC is a major new project under construction at BNL in partnership with JLab. It relies upon a number of new SRF cavities at 197 MHz, 394 MHz, 591 MHz and 1773 MHz to pre-bunch, accelerate, cool and crab the stored beams. R&D is focusing on the 591 MHz elliptical cavity and 197 MHz crab cavity first as these are the most challenging. Preliminary designs of these cavities are presented along with an R&D status report. To avoid developing multiple different cryostats a modular approach is adopted using a high degree of commonality of parts and systems. This approach …
Crab Cavities For Ilc, P. A. Mcintosh, S. A. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, I. V. Gonin, T. N. Khabiboulline, A. Lunin, T. Okugi, Y. M. Orlov, S. Verdú-Andrés, B. P. Xiao, V. P. Yakovlev, A. Yamamoto
Crab Cavities For Ilc, P. A. Mcintosh, S. A. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, I. V. Gonin, T. N. Khabiboulline, A. Lunin, T. Okugi, Y. M. Orlov, S. Verdú-Andrés, B. P. Xiao, V. P. Yakovlev, A. Yamamoto
Physics Faculty Publications
For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of …
197 Mhz Waveguide Loaded Crabbing Cavity Design For The Electron-Ion Collider, Subashini De Silva, Jean Delayen, J. Guo, R. A. Rimmer, Z. Li, B. P. Xiao
197 Mhz Waveguide Loaded Crabbing Cavity Design For The Electron-Ion Collider, Subashini De Silva, Jean Delayen, J. Guo, R. A. Rimmer, Z. Li, B. P. Xiao
Physics Faculty Publications
The Electron-Ion Collider will require crabbing systems at both hadron and electron storage rings in order to reach the desired luminosity goal. The 197 MHz crab cavity system is one of the critical rf systems of the collider. The crab cavity, based on the rf-dipole design, explores the option of waveguide load damping to suppress the higher order modes and meet the tight impedance specifications. The cavity is designed with compact dog-bone waveguides with transitions to rectangular wave-guides and waveguide loads. This paper presents the compact 197 MHz crab cavity design with waveguide damping and other ancillaries.
Bunch Length Measurements At The Cebaf Injector At 130 Kv, Sunil Pokharel, M. W. Bruker, J. M. Grames, A. S. Hofler, R. Kazimi, Geoffrey A. Krafft, S. Zhang
Bunch Length Measurements At The Cebaf Injector At 130 Kv, Sunil Pokharel, M. W. Bruker, J. M. Grames, A. S. Hofler, R. Kazimi, Geoffrey A. Krafft, S. Zhang
Physics Faculty Publications
In this work, we investigated the evolution in bunch length of beams through the CEBAF injector for low to high charge per bunch. Using the General Particle Tracer (GPT), we have simulated the beams through the beamline of the CEBAF injector and analyzed the beam to get the bunch lengths at the location of chopper. We performed these simulations with the existing injector using a 130 kV gun voltage. Finally, we describe measurements to validate these simulations. The measurements have been done using chopper scanning technique for two injector laser drive frequency modes: one with 500 MHz, and another with …
Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang
Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang
Physics Faculty Publications
The longitudinal and transverse emittance growth in hadron beams due to intra-beam scattering (IBS) and other heating sources deteriorate the luminosity in a collider. Hence, a strong hadron beam cooling is required to reduce and preserve the emittance. The cooling of high energy hadron beam is challenging. We propose a dual energy storage ring-based electron cooler that uses an electron beam to extract heat away from hadron beam in the cooler ring while the electron beam is cooled by synchrotron radiation damping in the high energy damping ring. In this paper, we present a design of a dual energy storage …
Modeling A Nb3Sn Cryounit In Gpt In Uitf, Sunil Pokharel, Geoffey A. Krafft, A. S. Hofler
Modeling A Nb3Sn Cryounit In Gpt In Uitf, Sunil Pokharel, Geoffey A. Krafft, A. S. Hofler
Physics Faculty Publications
Nb₃Sn is a prospective material for future superconducting RF (SRF) accelerator cavities. The material can achieve higher quality factors, higher temperature operation and potentially higher accelerating gradients (E_{acc} 96 MV/m) compared to conventional niobium. In this work, we performed modeling of the Upgraded Injector Test Facility (UITF) at Jefferson Lab utilizing newly constructed Nb₃Sn cavities. We studied the effects of the buncher cavity and varied the gun voltages from 200-500 keV. We have calibrated and optimized the SRF cavity gradients and phases for the Nb₃Sn five-cell cavities energy gains with the framework of General Particle Tracer (GPT). Our calculations show …
Evaluation Of Single-Cell Cavities Made Of Forged Ingot Niobium At Jefferson Lab, P. Dhakal, Bashu D. Khanal, Gianluigi Ciovati, G. R. Myneni
Evaluation Of Single-Cell Cavities Made Of Forged Ingot Niobium At Jefferson Lab, P. Dhakal, Bashu D. Khanal, Gianluigi Ciovati, G. R. Myneni
Physics Faculty Publications
Currently, fine grain niobium (Nb) (grain size ∼ 50 µm) and large grain Nb (grain size of a few cm) are being used for the fabrication of superconducting radio frequency (SRF) cavities. Medium grain forged ingot with grain size of a few hundred µm may be beneficial for cost-effectiveness as well as providing better performance for future SRF-based accelerators. Forged ingot Nb with medium grain size is a novel production method to obtain Nb discs used for the fabrication of superconducting radio frequency cavities. We have fabricated two 1.5 GHz single cell cavities made from forged Nb ingot with a …
Magnetic Flux Expulsion In Superconducting Radio-Frequency Niobium Cavities Made From Cold Worked Niobium, Bashu D. Khanal, S. Balachandran, S. Chetri, P. J. Lee, P. Dhakal
Magnetic Flux Expulsion In Superconducting Radio-Frequency Niobium Cavities Made From Cold Worked Niobium, Bashu D. Khanal, S. Balachandran, S. Chetri, P. J. Lee, P. Dhakal
Physics Faculty Publications
Trapped residual magnetic field during the cooldown of superconducting radio frequency (SRF) cavities is one of the primary source of RF residual losses leading to lower quality factor. Historically, SRF cavities have been fabricated from high purity fine grain niobium with grain size ~50 - 100 μm as well as large grain with grain size of the order of few centimeters. Non-uniform recrystallization of fine-grain Nb cavities after the post fabrication heat treatment leads to higher flux trapping during cooldown, hence the lower quality factor. We fabricated two 1.3 GHz single cell cavities from cold-worked niobium from different vendors and …
Lower Temperature Annealing Of Vapor Diffused Nb3Sn For Accelerator Cavities, Jayendrika K. Tiskumara, Jean R. Delayen, G. V. Eremeev, U. Pudasaini
Lower Temperature Annealing Of Vapor Diffused Nb3Sn For Accelerator Cavities, Jayendrika K. Tiskumara, Jean R. Delayen, G. V. Eremeev, U. Pudasaini
Physics Faculty Publications
Nb3Sn is a next-generation superconducting material for the accelerator cavities with higher critical temperature and superheating field, both twice compared to Nb. It promises superior performance and higher operating temperature than Nb, resulting in significant cost reduction. So far, the Sn vapor diffusion method is the most preferred and successful technique to coat niobium cavities with Nb3Sn. Although several post-coating techniques (chemical, electrochemical, mechanical) have been explored to improve the surface quality of the coated surface, an effective process has yet to be found. Since there are only a few studies on the post-coating heat treatment …
Magnetic Field Mapping Of 1.3 Ghz Superconducting Radio Frequency Niobium Cavities, Ishwari P. Parajuli, Gianluigi Ciovati, Jean R. Delayen, Alex V. Gurevich
Magnetic Field Mapping Of 1.3 Ghz Superconducting Radio Frequency Niobium Cavities, Ishwari P. Parajuli, Gianluigi Ciovati, Jean R. Delayen, Alex V. Gurevich
Physics Faculty Publications
Niobium is the material of choice to build superconducting radio frequency (SRF) cavities, which are fundamental building blocks of modern particle accelerators. These cavities require a cryogenic cool-down to ~2 - 4 K for optimum performance minimizing RF losses on the inner cavity surface. However, temperature-independent residual losses in SRF cavities cannot be prevented entirely. One of the significant contributor to residual losses is trapped magnetic flux. The flux trapping mechanism depends on different factors, such as surface preparations and cool-down conditions. We have developed a diagnostic magnetic field scanning system (MFSS) using Hall probes and anisotropic magneto-resistance sensors to …
Preliminary Results Of Magnetic And Temperature Map System For 3 Ghz Superconducting Radio Frequency Cavities, Ishwari Parajuli, Bashu Khanal, Gianluigi Ciovati, Jean Delayen, Alex Gurevich
Preliminary Results Of Magnetic And Temperature Map System For 3 Ghz Superconducting Radio Frequency Cavities, Ishwari Parajuli, Bashu Khanal, Gianluigi Ciovati, Jean Delayen, Alex Gurevich
Physics Faculty Publications
Superconducting radio frequency (SRF) cavities are fundamental building blocks of modern particle accelerators. When we cool these cavities at cryogenic temperature ~2 – 4 K, we can get optimum performance by minimizing RF losses on the inner cavity surface. However, temperature-independent residual losses in SRF cavities cannot be prevented entirely. One of the leading sources of residual losses in SRF cavities is trapped magnetic flux. The flux trapping mechanism depends on different surface preparations and cool-down conditions. We have designed, developed, and commissioned a combined magnetic (B) and temperature (T) mapping system using anisotropic magneto-resistance (AMR) sensors and carbon resistors …
Samples For 3rd Harmonic Magnetometry Assessment Of Nbtin-Based Sis Structures, D.R. Beverstock, C.Z. Antoine, Jean R. Delayen, D. Manos, Iresha Harshani Senevirathne, J. K. Spradlin, A-M. Valente-Feliciano
Samples For 3rd Harmonic Magnetometry Assessment Of Nbtin-Based Sis Structures, D.R. Beverstock, C.Z. Antoine, Jean R. Delayen, D. Manos, Iresha Harshani Senevirathne, J. K. Spradlin, A-M. Valente-Feliciano
Physics Faculty Publications
In the quest for alternative superconducting materials to bring accelerator cavity performance beyond the bulk niobium (Nb) intrinsic limits, a promising concept uses superconductor-insulator-superconductor (SIS) thin film structures that allows magnetic flux shielding in accelerator cavities to higher fields [1]. Candidate materials for such structures are NbTiN as the superconductor and AlN as the insulator. We have demonstrated high quality NbTiN and AlN deposited by reactive DC magnetron sputtering (DCMS), both for individual layers and multilayers. Interface quality has been assessed for bilayer stacks with 250 nm NbTiN layers and AlN thicknesses from 30 nm down to1 nm. These SIS …
Preliminary Results From Magnetic Field Scanning System For A Single-Cell Niobium Cavity, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen, Alex V. Gurevich
Preliminary Results From Magnetic Field Scanning System For A Single-Cell Niobium Cavity, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen, Alex V. Gurevich
Physics Faculty Publications
One of the building blocks of modern particle accelerators is superconducting radiofrequency (SRF) cavities. Niobium is the material of choice to build such cavities, which operate at liquid helium temperature (2 - 4 K) and have some of the highest quality factors found in Nature. There are several sources of residual losses, one of them is trapped magnetic flux, which limits the quality factor in SRF cavities. The flux trapping mechanism depends on different niobium surface preparations and cool-down conditions. Suitable diagnostic tools are not yet available to study the effects of such conditions on magnetic flux trapping. A magnetic …
Field Shielding Of NBT��N Based Multilayer Structure For Accelerating Cavities, Iresha Harshani Senevirathne, Jean R. Delayen, Alex Gurevich, D. R. Beverstock, A.-M. Valente-Feliciano
Field Shielding Of NBT��N Based Multilayer Structure For Accelerating Cavities, Iresha Harshani Senevirathne, Jean R. Delayen, Alex Gurevich, D. R. Beverstock, A.-M. Valente-Feliciano
Physics Faculty Publications
Over the past few decades, bulk niobium (Nb) has been the material of choice for superconducting radio frequency (SRF) cavities used in particle accelerators to achieve higher accelerating gradients and lower RF losses. Multi-layer (SIS) structures consisting of alternating thin layers of superconductor(S) and insulator(I) deposited on a bulk Nb have been proposed to enhance the peak surface magnetic field and sustain a higher accelerating gradient. In this study, multilayers based NbTiN and AlN deposited on bulk Nb are used to test the proposed enhancement using the DC magnetic Hall probe technique. The technique detects a penetrating magnetic field through …
Effect Of Duration Of 120 °C Baking On The Performance On Superconducting Radio Frequency Niobium Cavities, B. D. Khanal, P. Dhakal
Effect Of Duration Of 120 °C Baking On The Performance On Superconducting Radio Frequency Niobium Cavities, B. D. Khanal, P. Dhakal
Physics Faculty Publications
Over the last decade much attention was given in increasing the quality factor of superconducting radio frequency (SRF) cavities by impurity doping. Prior to the era of doping, the final cavity processing technique to achieve the high accelerating gradient includes the "in situ" low temperature baking of SRF cavities at temperature ~ 120 °C for several hours. Here, we present the results of a series of measurements on 1.3 GHz TESLA shape single-cell cavities with successive low temperature baking at 120 °C up to 96 hours. The experimental data were analyzed with available theory of superconductivity to elucidate the effect …
Real-Time Cavity Fault Prediction In Cebaf Using Deep Learning, Md. M. Rahman, K. Iftekharuddin, A. Carptenter, T. Mcguckin, C. Tennant, L. Vidyaratne, Sandra Biedron (Ed.), Evgenya Simakov (Ed.), Stephen Milton (Ed.), Petr M. Anisimov (Ed.), Volker R.W. Schaa (Ed.)
Real-Time Cavity Fault Prediction In Cebaf Using Deep Learning, Md. M. Rahman, K. Iftekharuddin, A. Carptenter, T. Mcguckin, C. Tennant, L. Vidyaratne, Sandra Biedron (Ed.), Evgenya Simakov (Ed.), Stephen Milton (Ed.), Petr M. Anisimov (Ed.), Volker R.W. Schaa (Ed.)
Electrical & Computer Engineering Faculty Publications
Data-driven prediction of future faults is a major research area for many industrial applications. In this work, we present a new procedure of real-time fault prediction for superconducting radio-frequency (SRF) cavities at the Continuous Electron Beam Accelerator Facility (CEBAF) using deep learning. CEBAF has been afflicted by frequent downtime caused by SRF cavity faults. We perform fault prediction using pre-fault RF signals from C100-type cryomodules. Using the pre-fault signal information, the new algorithm predicts the type of cavity fault before the actual onset. The early prediction may enable potential mitigation strategies to prevent the fault. In our work, we apply …