Author: Barrett, S.T.
Paper Title Page
TUPAB018 Initial Data From an Electron Cloud Detector in a Quadrupole Magnet at CesrTA 1352
 
  • J.P. Sikora, S.T. Barrett, M.G. Billing, J.A. Crittenden, K.A. Jones, Y. Li, T.I. O'Connell
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467 and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505
In September 2016, we installed a detector in a quadrupole magnet that measures the electron cloud density using two independent techniques. Stripline electrodes collect cloud electrons which pass through holes in the beam-pipe wall. The array of small holes shields the striplines from the beam-induced electromagnetic pulse. The beam-pipe chamber has also been designed so that microwave measurements of the electron cloud density can be performed. The resonant microwaves are confined to be within the 56 cm length of the quadrupole. The detector is placed in a newly installed quadrupole that is adjacent to an existing lattice quadrupole of the same polarity. Since they are powered independently, their relative strengths can be varied with stored beam – allowing electron cloud measurements to be made as a function of gradient. This paper presents the first data obtained with this detector with trains of positron bunches at 5.3 GeV. The detector is installed in the Cornell Electron Storage Ring and is part of the test accelerator program for the study of electron cloud build-up using electron and positron beams from 2 to 5 GeV.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB018  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPVA146 Vacuum System Design and Simulation for CHESS-U 3612
 
  • Y. Li, S.T. Barrett, D.C. Burke, J.V. Conway, X. Liu, A. Lyndaker
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work is supported by National Science Foundation Reward #DMR-1332208
A major upgrade project (dubbed CHESS-U) is planned to elevate performance of Cornell High Energy Synchrotron Source (CHESS) to the state-of-art 3rd generation light sources. In the project, about 80-m of Cornell Electron Storage Ring (CESR) will be replaced with double-bend achromat (DBA) lattice to reduce electron beam emittance. In this presentation, we will describe designs of the CHESS-U vacuum system, including new beam pipe extrusions and chambers, sliding joints, and crotch absorbers. Vacuum pumping system consists of distributed pumps (in the form of NEG strips) in the dipole chambers, and compact discrete NEG/Ion pumps in the quad straight and undulator beampipes. MolFlow+ is used to evaluate pumping performances of the CHESS-U vacuum system. First, we demonstrate that the planned vacuum pumping system can achieve and sustain required ultra-high vacuum level in CHESS-U operations, after an initial beam conditioning. Second, we will explore beam commissioning processes of the new vacuum chambers, and simulate the saturation of the NEG strips during the commissioning. These simulations will aid continuing design optimization for the CHESS-U vacuum pumping system.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA146  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)