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TUPO042 RF Results of Nb Coated SRF Accelerator Cavities via HiPIMS cavity, SRF, superconductivity, niobium 427
 
  • M.C. Burton, A.D. Palczewski, H.L. Phillips, C.E. Reece, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • R.A. Lukaszew
    The College of William and Mary, Williamsburg, Virginia, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Bulk Niobium (Nb) SRF (superconducting radio frequency) cavities are currently the preferred method for acceleration of charged particles at accelerator facilities around the world. Since the SRF phenomena occurs within a shallow depth of 40 nm (for Nb), a proposed option has been to deposit a superconducting Nb thin film on the interior of a cavity made of a suitable alternative material such as copper or aluminum. While this approach has been attempted in the past using DC magnetron sputtering (DCMS), such cavities have never performed at the bulk Nb level. However, new energetic condensation techniques for film deposition offer the opportunity to create suitably thick Nb films with improved density, microstructure and adhesion compared to traditional DCMS. One such technique that has been developed somewhat recently is ’High Power Impulse Magnetron Sputtering’ (HiPIMS). Here we report early results from various thin film coatings carried out on 1.3 GHz Cu Cavities, a 1.5 GHz Nb cavity and small Cu coupon samples coated at Jefferson Lab using HiPIMS.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO042  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO050 Construction of Thin-film Coating System Toward the Realization of Superconducting Multilayered Structure cathode, cavity, experiment, SRF 445
 
  • R. Ito, T. Nagata
    ULVAC, Inc, Chiba, Japan
  • H. Hayano, T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • H. Ito
    Sokendai, Ibaraki, Japan
  • Y. Iwashita, R. Katayama
    Kyoto ICR, Uji, Kyoto, Japan
  • H. Oikawa
    Utsunomiya University, Utsunomiya, Japan
 
  Although S-I-S (superconductor-insulator-superconductor) multilayered structure is expected to increase the maximum acceleration gradient of SRF cavities, in order for it to function in reality, it is necessary to develop a coating processing that can realize high purity and quality superconducting thin-films. We launched the co-sputtering system to create superconducting alloy thin-films such as Nb3Sn and to research how the characteristics of them change depending on the coating conditions. The deposition rate of two elements was optimized by adjusting each input power, so we successfully obtained an alloy thin-film having appropriate composition ratio. In addition, we developed another experimental equipment for coating on the inner surface of the 3GHz TESLA type small cavities. A cylindrical shape Nb in which some permanent magnets are inserted was adopted as the sputtering target. Glow discharge of the target was confirmed, and the inner-sputtering test was conducted. This presentation reports the specifications of the two sputtering apparatuses and the results of the coating test.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO050  
About • paper received ※ 18 September 2018      issue date ※ 18 January 2019  
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TUPO055 Next Generation Nb3Sn SRF Cavities for Linear Accelerators cavity, SRF, operation, linac 462
 
  • R.D. Porter, D.L. Hall, M. Liepe, J.T. Maniscalco
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • T. Arias, P. Cueva, D.A. Muller, N. Sitaraman
    Cornell University, Ithaca, New York, USA
 
  Niobium-3 Tin (Nb3Sn) is a very promising alternative material for SRF accelerator cavities. The material can achieve higher quality factors, higher temperature operation and potentially higher accelerating gradients (~ 96 MV/m) compared to conventional niobium. This material is formed by vaporizing Sn in a high temperature vacuum furnace and letting the Sn absorb into a Nb substrate to form a 2-3 um Nb3Sn layer. Current Nb3Sn cavities produced at Cornell achieve Q ~ 1010 at 4.2 K and 17 MV/m. Here we present a summary of the current performance of Nb3Sn cavities at Cornell and recent progress in improving the accelerating gradient.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO055  
About • paper received ※ 20 September 2018      issue date ※ 18 January 2019  
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TUPO076 An Innovative Nb3Sn Film Approach and Its Potential for SRF Applications cavity, SRF, cathode, accelerating-gradient 513
 
  • E.Z. Barzi, D. Turrioni, C. Ciaccia
    Fermilab, Batavia, Illinois, USA
  • G.V. Eremeev, R.L. Geng, R.A. Rimmer, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • S. Falletta
    Politecnico di Torino, Torino, Italy
  • H. Hayano, T. Saeki
    KEK, Ibaraki, Japan
  • H. Ito
    Sokendai, Ibaraki, Japan
  • A. Kikuchi
    NIMS, Tsukuba, Ibaraki, Japan
 
  Funding: Work supported by U.S. DOE contract No. DE-AC02-07CH11359
A novel electro-chemical technique to produce Nb3Sn films on Nb substrates was developed and optimized at Fermilab. The Nb3Sn phase is obtained in a two-electrode cell, by electrodeposition from aqueous solutions of Sn layers and Cu intermediate layers onto Nb substrates. Subsequent thermal treatments in inert atmosphere are realized at a maximum temperature of 700°C to obtain the Nb3Sn superconducting phase. Several superconduct-ing Nb3Sn films were obtained on Nb substrates by study-ing and optimizing most parameters of the electro-plating process. Samples were characterized at Fermilab, NIMS, KEK and JLAB, including EPMA analyses, DC and in-ductive tests of critical temperature Tc0, and lower critical field Hc1(4.2 K) by SQUID. In parallel to sample devel-opment and fabrication at FNAL, at JLAB and KEK effort was put into etching and electro-polishing techniques adequate to remove the Cu and bronze phases from the samples’ outer surface. This is necessary prior to meas-urements at JLAB of the surface impedance of flat sam-ples in a setup that make use of an RF host cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO076  
About • paper received ※ 21 September 2018      issue date ※ 18 January 2019  
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THPO017 Progress of the Novel Three-dimensional Spiral Injection Scheme Test Experiment kicker, injection, electron, experiment 717
 
  • M.R. Rehman
    Sokendai, Ibaraki, Japan
  • K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa
    KEK, Ibaraki, Japan
  • H. Iinuma
    Ibaraki University, Hitachi, Ibaraki, Japan
 
  Funding: This work was supported by JSPS KAKENHI Grant Number JP26287055 and JP 23740216.
A new muon g-2/EDM experiment at J-PARC (E34) is under preparation in order to resolve a 3𝜎 discrepancy of muon anomalous magnetic dipole moment between the measurement and the standard model prediction. The E34 experiment will employ a unique three-dimensional spiral injection scheme in order to store the muon beam into a small storage orbit. In order to demonstrate the feasibility of this novel injection scheme, the Spiral Injection Test Experiment (SITE) with the electron beam is under construction at KEK Tsukuba campus. The goals of the SITE are divided into two phases. In the first phase of the SITE, 80 keV DC electron beam was injected and detected as a fluorescent light due to the de- excitation of the nitrogen gas into solenoidal storage magnet. In the second phase of the SITE, the pulsed electron beam, and a pulsed magnetic kicker are developed in order to keep the pulsed beam on the very midplane of the solenoidal storage magnet. This paper describes the achievements of the first phase of SITE and progress towards the second phase.
*H. Iinuma et al., Nuclear Instruments and Methos in Physics Research A, 832, 51-62 (2016).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO017  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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