Cavities - Design
SRF gun cavities
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THP080 Status of the All Superconducting Gun Cavity at DESY 1087
 
  • E. Vogel, S. Barbanotti, A. Brinkmann, Th. Buettner, J.I. Iversen, K. Jensch, D. Klinke, D. Kostin, W.-D. Möller, A. Muhs, J. Schaffran, M. Schmökel, J.K. Sekutowicz, S. Sievers, L. Steder, N. Steinhau-Kühl, A. Sulimov, J.H. Thie, H. Weise, M. Wenskat, M. Wiencek, L. Winkelmann, B. van der Horst
    DESY, Hamburg, Germany
 
  At DESY, the development of a 1.6-cell, 1.3 GHz all superconducting gun cavity with a lead cathode attached to its back wall is ongoing. The special features of the structure like the back wall of the half-cell and cathode hole require adaptations of the procedures used for the treatment of nine-cell TESLA cavities. Unsatisfactory test results of two prototype cavities motivated us to re-consider the back-wall design and production steps. In this contribution we present the status of the modified cavity design including accessories causing accelerating field asymmetries, like a pick up antenna located at the back wall and fundamental power- and HOM couplers. Additionally, we discuss preliminary considerations for the compensation of kicks caused by these components.  
poster icon Poster THP080 [7.365 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP080  
About • paper received ※ 20 June 2019       paper accepted ※ 02 July 2019       issue date ※ 14 August 2019  
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THP081 A Cryocooled Normal Conducting and Superconducting Hybrid CW RF Gun 1091
 
  • H.J. Qian, G. Shu, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • S. Barbanotti, B. Petersen, E. Vogel
    DESY, Hamburg, Germany
  • A.A. Gorchakov, M. Gusarova
    MEPhI, Moscow, Russia
 
  Continuous wave (CW) photoinjectors have seen great progress in the last decades, such as DC gun, superconducting RF (SRF) gun and normal conducting (NC) gun. Developments of Free electron lasers and electron microscopy in the CW mode are pushing for further improvements of CW guns towards higher acceleration gradient, higher beam energy and compatibility with high QE cathodes for better beam brightness. Current SC gun gradient is limited by the cathode cell due to the complication of a cathode back plane and a normal conducting cathode plug, and R&D on SC gun improvement is ongoing. A high gradient cryocooled CW NC gun was proposed to house the high QE cathode, and a SC cavity immediately nearby gives further energy acceleration. In this paper, further RF optimization of the NC gun and ASTRA simulations of such a hybrid photoinjector are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP081  
About • paper received ※ 25 June 2019       paper accepted ※ 03 July 2019       issue date ※ 14 August 2019  
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THP082 Geometry Dependent Beam Dynamics of a 3.5-cell SRF Gun Cavity at ELBE 1095
 
  • K. Zhou
    CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
  • A. Arnold, S. Ma, J. Schaber, J. Teichert, R. Xiang
    HZDR, Dresden, Germany
 
  In order to optimize the next generation SRF gun at HZDR ELBE radiation source, the impact on beam dynamics from the SRF cavity geometry needs to be investigated. This paper presents an analysis on the electromagnetic fields and output electron beam qualities, by changing the geometry parameters of a 3.5-cell SRF gun cavity. The simulation results show the higher electric field ratio in the first half cell to the TESLA like cell, the better beam parameters we can obtain, which, however, will also lead to a higher Emax/E0 and Bmax/E0.  
poster icon Poster THP082 [1.935 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP082  
About • paper received ※ 22 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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THP083 Quadrupole Scan Transverse Emittance Measurements at HZDR ELBE 1100
SUSP028   use link to see paper's listing under its alternate paper code  
 
  • S. Ma, A. Arnold, A.A. Ryzhov, J. Schaber, J. Teichert, R. Xiang, K. Zhou
    HZDR, Dresden, Germany
 
  Two quadrupoles and one screen are used for beam transverse emittance measurements at HZDR ELBE. In this paper, the emittance calculated with two different methods, one with thin-lens approximation and the other one without this approximation, are compared and analized. To analyze the measurement error, quadrupole calibration is need. Two aspects about quadrupole analysis are made. The first one is quadrupole’s effective length and strength and the second one is quadrupole’s converged or diverged ability in reality.  
poster icon Poster THP083 [1.726 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP083  
About • paper received ※ 25 June 2019       paper accepted ※ 03 July 2019       issue date ※ 14 August 2019  
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FRCAB4 Development of High Intensity, High Brightness, CW SRF Gun with Bi-Alkali Photocathode 1219
 
  • T. Konomi, Y. Honda, E. Kako, Y. Kobayashi, S. Michizono, T. Miyajima, H. Sakai, K. Umemori, S. Yamaguchi
    KEK, Ibaraki, Japan
 
  Superconducting conduction electron guns can realize high acceleration voltage and high beam repetition. KEK has been developing the 1.3 GHz elliptical type 1.5 cell superconducting RF gun to investigate fundamental performance. The surface cleaning methods and tools were developed by using KEK SRF gun cavity #1 and surface peak electric field reached to 75 MV/m without field emission. We will apply this technique to the SRF gun cavity #2 for beam operation. The gun cavity #2 equips the helium jacket, frequency tuner cathode position adjuster to operate the electron beam. The RF structure was designed based on the gun cavity #1. The cathode rod is made of Nb. The photocathode deposited on the cathode rod will be cool down to 2K to minimize thermal emittance. The fabrication of the gun cavity #2 and helium jacket were completed. 4 times vertical tests were carried out. We will report the vertical test results and preparation of the horizontal test.  
slides icon Slides FRCAB4 [10.826 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAB4  
About • paper received ※ 23 June 2019       paper accepted ※ 03 July 2019       issue date ※ 14 August 2019  
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FRCAB5 Performance of 112 MHz SRF Gun at BNL 1223
 
  • T. Xin, I. Ben-Zvi, J.C. Brutus, C. Folz, T. Hayes, P. Inacker, Y.C. Jing, D. Kayran, V. Litvinenko, J. Ma, G.J. Mahler, M. Mapes, K. Mernick, T.A. Miller, G. Narayan, P. Orfin, I. Pinayev, S. Polizzo, T. Rao, F. Severino, J. Skaritka, K.S. Smith, R. Than, J.E. Tuozzolo, E. Wang, G. Wang, Q. Wu, B.P. Xiao, W. Xu, A. Zaltsman
    BNL, Upton, New York, USA
  • S.A. Belomestnykh
    Fermilab, Batavia, Illinois, USA
  • C.H. Boulware, T.L. Grimm
    Niowave, Inc., Lansing, Michigan, USA
  • K. Mihara
    Stony Brook University, Stony Brook, USA
  • I. Petrushina
    SUNY SB, Stony Brook, New York, USA
  • K. Shih
    SBU, Stony Brook, New York, USA
 
  Funding: This work is funded by the DOE FOA (No. DE-FOA-0000632) and National Science Foundation (Award No. PHY-1415252).
A 112 MHz SRF electron photoinjector (gun) was developed at Brookhaven National Laboratory to produce high-brightness and high-bunch-charge bunches for the coherent electron cooling proof-of-principle experiment. The gun is designed to deliver electrons with a kinetic energy of up to 2 MeV. Electrons are generated by illuminating a high quantum efficiency (QE) K2CsSb photoemission layer with a green laser operating at a wavelength of 532 nm. The gun was able to generating 3 nC bunches at 1.7 MeV. The design goals, fabrication, performance and operational experience are reported here.
 
slides icon Slides FRCAB5 [3.984 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAB5  
About • paper received ※ 22 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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