Author: Bartnik, A.C.
Paper Title Page
TUPOR031 Trapped Ion Effects and Mitigation During High Current Operation in the Cornell DC Photoinjector 1735
SUPSS054   use link to see paper's listing under its alternate paper code  
 
  • S.J. Full, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: U.S. Department of Energy (Grant No. DE-SC0012493), National Science Foundation (Award No. NSF-DMR 0807731)
The Cornell high intensity photoinjector reaches a new regime of linac beam parameters where high continuous-wave electron beam currents lead to ion trapping. Above 10 mA, we have observed beam trips that limit stable machine operation to approximately 10-15 minutes. By applying known ion clearing methods, the machine lifetime increases to at least 24 hours of continuous operation, suggesting that trapped ions are the most likely cause of the trips. In this paper we share some of our observations ion trapping in the photoinjector, as well as experimental tests of three common ion mitigation methods: clearing electrodes, beam shaking and bunch gaps.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR031  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPMR018 Time Resolved Cryogenic Cooling Analysis of the Cornell Injector Cryomodule 2298
 
  • R.G. Eichhorn, A.C. Bartnik, B.M. Dunham, G.M. Ge, G.H. Hoffstaetter, H. Lee, M. Liepe, S.R. Markham, T.I. O'Connell, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  To demonstrate key parameters of a an energy recovery linac (ERL) at Cornel, an injector based on a photo gun and an SRF cryomodule was designed and built. The goal was to demonstrate high current generation while achieving low emittances. While the emittance goal has been reached, the current achieved so far is 75 mA. Even though this is a world record, it is still below the targeted 100 mA. While ramping up the current we observed excessive heating in the fundamental power coupler which we were able to track down to insufficient cooling of the 80 K intercepts. These intercepts are cooled by a stream of parallel cryogenic flows which we found to be unbalanced. In this paper we will review the finding, describe the analysis we did, modeling of the parallel flow and the modifications made to the module to overcome the heating.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR018  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOW025 Photocathode Growth and Characterization Advances at Cornell University 3990
 
  • L. Cultrera, A.C. Bartnik, I.V. Bazarov, B.M. Dunham, C.M. Gulliford, H. Lee, R.A. Lipton, T.P. Moore
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Alkali-antimonides based photocathodes have demonstrated outstanding performance in high brightness electron beam production suitable for a wide range of applications such as FELs, ERLs and UED and for use in photomultiplier devices with picosecond resolution aimed at photon counting application in medicine and High Energy Physics. The photocathode laboratory at Cornell University is dedicated to studying the growth procedures and characterizing the properties in a wide range of photocathodes materials. Different experimental arrangements and alkali metal sources have been successfully explored to date to synthesize photosensitive materials. Recent work on commissioning a new growth chamber equipped with effusion cells loaded with pure metal allowing uniform deposition over large area substrates resulted on successful growth of photocathodes with extended sensitivity in the IR part of the spectrum and high efficiency alkali antimonides containing Rb metal. This and other advances aimed at demonstrating superior photocathodes will be presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW025  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)