Author: Hartung, W.
Paper Title Page
MOPPC019 Secondary Electron Yield Measurements of Fermilab’s Main Injector Vacuum Vessel 166
 
  • D.J. Scott, D. Capista, K.L. Duel, R.M. Zwaska
    Fermilab, Batavia, USA
  • S. Greenwald, W. Hartung, Y. Li, T.P. Moore, M.A. Palmer
    CLASSE, Ithaca, New York, USA
  • R.E. Kirby, M.T.F. Pivi, L. Wang
    SLAC, Menlo Park, California, USA
 
  We discuss the progress made on a new installation in Fermilab’s Main Injector that will help investigate the electron cloud phenomenon by making direct measurements of the secondary electron yield (SEY) of samples irradiated in the accelerator. In the Project X upgrade the Main Injector will have its beam intensity increased by a factor of three compared to current operations. This may result in the beam being subject to instabilities from the electron cloud. Measured SEY values can be used to further constrain simulations and aid our extrapolation to Project X intensities. The SEY test-stand, developed in conjunction with Cornell and SLAC, is capable of measuring the SEY from samples using an incident electron beam when the samples are biased at different voltages. We present the design and manufacture of the test-stand and the results of initial laboratory tests on samples prior to installation.  
 
WEPPR015 Intrabeam Scattering Studies at CesrTA 2970
 
  • M. P. Ehrlichman
    Cornell University, Ithaca, New York, USA
  • F. Antoniou, Y. Papaphilippou
    CERN, Geneva, Switzerland
  • W. Hartung, M.A. Palmer, D.P. Peterson, N.T. Rider, D. L. Rubin, J.P. Shanks, C.R. Strohman, S. Wang
    CLASSE, Ithaca, New York, USA
  • R. Holtzapple
    CalPoly, San Luis Obispo, California, USA
 
  Funding: NSF Award (PHY-0734867) NSF Award (PHY-1002467) Japan/US Cooperation Program Education and lifelong learning, co-financed by Greece and the European Union
Intrabeam scattering dilutes the emittance of low energy, low emittance rings. Because CesrTA can be operated at low energies with low transverse emittances and high bunch intensity, it is an ideal laboratory for the study of IBS effects. Furthermore, CesrTA is instrumented for accurate beam size measurements in all three dimensions, providing the possibility of a complete determination of the intensity dependence of emittances. Models based on classical IBS theories and multi-particle simulations are used to estimate the effect of IBS at CesrTA at different beam emittances, intensities and energies. The first measurements from machine studies at CesrTA are presented.
 
 
WEPPR088 Modeling and Simulation of Retarding Field Analyzers at CESRTA 3138
 
  • J.R. Calvey, J.A. Crittenden, G. Dugan, W. Hartung, J. Makita, M.A. Palmer
    CLASSE, Ithaca, New York, USA
  • M.A. Furman, M. Venturini
    LBNL, Berkeley, California, USA
 
  Funding: Work supported by the US National Science Foundation (PHY-0734867 and PHY-1002467), and Department of Energy (DE-FC02-08ER41538).
Over the course of the CESRTA program at Cornell, Retarding Field Analyzers (RFAs) have been installed in drift, dipole, quadrupole, and wiggler field regions of the CESR storage ring. RFAs are used to measure the local electron cloud flux on the vacuum chamber wall. Through the use of a retarding grid and segmented collectors, they also provide information on the energy and transverse distribution of the cloud. Understanding these measurements on a quantitative level requires the use of cloud buildup simulation codes, adapted to include a detailed model of the structure of the RFA and its interaction with the cloud. The nature of this interaction depends strongly on the strength of the local magnetic field. We have developed models for RFAs in drift and dipole regions. The drift model has been cross-checked with bench measurements, and we have compared the RFA-adapted cloud buildup simulations with data. These comparisons have then been used to obtain best fit values for the photo-emission and secondary electron emission characteristics of some of the vacuum chamber materials and cloud mitigating coatings employed at CESRTA.