IPAC2015 - List of Authors (Rubin, D. L.)

Paper	Title	Page
MOPMA056	Measurement and Modeling of Single Bunch Wake Field Effects in CESR	681
	J.R. Calvey, M.G. Billing, W. Hartung, J.D. Perrin, D. L. Rubin, D. Sagan, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by NSF PHY-1416318 and NSF DMR 1332208. This research used the National Energy Research Scientific Computing Center, which is supported by DOE Contract No. DE-AC02-05CH11231. Short-range wake fields have been incorporated into a Bmad-based particle tracking code in order to assess their contribution to current-dependent emittance growth, tune shift, and single bunch instabilities. The wakes are computed for CESR vacuum components using the T3P modeling software. Simulation results are compared with measurements of bunch length, vertical beam size, and coherent tune shift. Additionally, we use insertable scrapers to vary the transverse wake and measure the effect on the beam. We show that a vertical emittance increase at high current may be due to a transverse monopole wake, originating in the lump pump slots throughout CESR.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA056
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MOPWI030	Low Emittance Tuning With a Witness Bunch	1223
	D. L. Rubin, R.E. Meller, J.P. Shanks Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by NSF PHY-1416318, PHY-0734867 and PHY-1002467, and DOE DE-FC02-08ER- 41538 and DE-SC0006505 Electron positron damping rings and colliders will require frequent tuning to maintain ultra-low vertical emittance. Emittance tuning begins with precision beam based measurement of lattice errors (orbit, transverse coupling, and dispersion) followed by compensation with corrector magnets. Traditional techniques for measuring lattice errors are incompatible with simultaneous operation of the storage ring as light source or damping ring. Dedicated machine time is required. The gated tune tracker (the device that drives the beam at the normal mode frequencies) and the bunch-by-bunch, turn-by-turn beam position monitor system developed at CESR are integrated to allow synchronous detection of phase. The system is capable of measuring lattice errors during routine operation. A single bunch at the end of a train of arbitrary length, is designated as the witness. The witness bunch alone is resonantly excited, and the phase and amplitude of the witness is mea- sured at each of the 100 beam position monitors. Lattice errors are extracted from the measurements. Corrections are then applied. The emittance of all of the bunches in the train is measured and the effectiveness of the correction procedure demonstrated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI030
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TUPMA022	CESR Upgrade as a High-Energy, High-Brightness X-Ray Light Source	1884
	J.P. Shanks, D. L. Rubin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Research supported by NSF grant DMR-1332208. The Cornell Electron Storage Ring (CESR) operates most of the year as the Cornell High Energy Synchrotron Source (CHESS). CESR was originally designed and operated as an electron/positron collider, circulating high-emittance beams in order to maximize luminosity. Beam lines were developed to extract x-rays from both electron and positron beams. The two beams share a common vacuum chamber, and are electrostatically separated to avoid collisions. The requirement to store counter-rotating beams significantly constrains the storage ring optics, limiting emittance and, beam current, and bunch distributions. The proposed upgrade eliminates two-beam operation in favor of a single optimized on-axis beam. Several new undulator-based beam lines are planned. The horizontal emittance is reduced in steps, first from 90nm to 20nm at 5.3 GeV, and then in a ring-wide upgrade to as low as 300 pm-rad at 6GeV. The low-emittance optics are based on multi-bend achromats with combined function bends. The details of the optics, apertures, and magnet parameters are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA022
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Paper

Title

Page

Measurement and Modeling of Single Bunch Wake Field Effects in CESR

681

J.R. Calvey, M.G. Billing, W. Hartung, J.D. Perrin, D. L. Rubin, D. Sagan, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by NSF PHY-1416318 and NSF DMR 1332208. This research used the National Energy Research Scientific Computing Center, which is supported by DOE Contract No. DE-AC02-05CH11231.
Short-range wake fields have been incorporated into a Bmad-based particle tracking code in order to assess their contribution to current-dependent emittance growth, tune shift, and single bunch instabilities. The wakes are computed for CESR vacuum components using the T3P modeling software. Simulation results are compared with measurements of bunch length, vertical beam size, and coherent tune shift. Additionally, we use insertable scrapers to vary the transverse wake and measure the effect on the beam. We show that a vertical emittance increase at high current may be due to a transverse monopole wake, originating in the lump pump slots throughout CESR.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPWI030

Low Emittance Tuning With a Witness Bunch

1223

D. L. Rubin, R.E. Meller, J.P. Shanks
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by NSF PHY-1416318, PHY-0734867 and PHY-1002467, and DOE DE-FC02-08ER- 41538 and DE-SC0006505
Electron positron damping rings and colliders will require frequent tuning to maintain ultra-low vertical emittance. Emittance tuning begins with precision beam based measurement of lattice errors (orbit, transverse coupling, and dispersion) followed by compensation with corrector magnets. Traditional techniques for measuring lattice errors are incompatible with simultaneous operation of the storage ring as light source or damping ring. Dedicated machine time is required. The gated tune tracker (the device that drives the beam at the normal mode frequencies) and the bunch-by-bunch, turn-by-turn beam position monitor system developed at CESR are integrated to allow synchronous detection of phase. The system is capable of measuring lattice errors during routine operation. A single bunch at the end of a train of arbitrary length, is designated as the witness. The witness bunch alone is resonantly excited, and the phase and amplitude of the witness is mea- sured at each of the 100 beam position monitors. Lattice errors are extracted from the measurements. Corrections are then applied. The emittance of all of the bunches in the train is measured and the effectiveness of the correction procedure demonstrated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMA022

CESR Upgrade as a High-Energy, High-Brightness X-Ray Light Source

1884

J.P. Shanks, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Research supported by NSF grant DMR-1332208.
The Cornell Electron Storage Ring (CESR) operates most of the year as the Cornell High Energy Synchrotron Source (CHESS). CESR was originally designed and operated as an electron/positron collider, circulating high-emittance beams in order to maximize luminosity. Beam lines were developed to extract x-rays from both electron and positron beams. The two beams share a common vacuum chamber, and are electrostatically separated to avoid collisions. The requirement to store counter-rotating beams significantly constrains the storage ring optics, limiting emittance and, beam current, and bunch distributions. The proposed upgrade eliminates two-beam operation in favor of a single optimized on-axis beam. Several new undulator-based beam lines are planned. The horizontal emittance is reduced in steps, first from 90nm to 20nm at 5.3 GeV, and then in a ring-wide upgrade to as low as 300 pm-rad at 6GeV. The low-emittance optics are based on multi-bend achromats with combined function bends. The details of the optics, apertures, and magnet parameters are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)