NAPAC2016 - List of Authors (Bergan, W.F.)

Paper	Title	Page
TUPOA57	Using High Precision Beam Position Monitors at the Cornell Electron Storage Ring (CESR) to Measure the One Way Speed of Light Anisotropy	399
	W.F. Bergan, M.J. Forster, N.T. Rider, D. L. Rubin, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA B.A. Schmookler MIT, Cambridge, Massachusetts, USA B. Wojtsekhowski CMU, Pittsburgh, Pennsylvania, USA
	Funding: NSF PHY-1416318 NSF DGE-1144153 The Cornell Electron Storage Ring (CESR) has been equipped with a number of high-precision beam position monitors which are capable of measuring the orbit of a circulating beam with a precision of a few microns. This technology will enable a precision measurement of deviations in the one-way speed of light. An anisotropic speed of light will alter the beam momentum as it travels around the ring, resulting in a change of orbit over the course of a sidereal day. Using counter-circulating electron and positron beams, we will be able to suppress many of the systematics such as those relating to variations in RF voltage or magnet strength. We show here initial feasibility studies to measure the stability of our beam position monitors and the various systematic effects which may hide our signal and discuss ways in which we can minimize their impact.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA57
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TUPOA58	Minimization of Emittance at the Cornell Electron Storage Ring With Sloppy Models	402
SUPO03	use link to see paper's listing under its alternate paper code
	W.F. Bergan, A.C. Bartnik, I.V. Bazarov, H. He, D. L. Rubin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.P. Sethna Cornell University, Ithaca, New York, USA
	Funding: DOE DE-SC0013571 NSF DGE-1144153 Our current method to minimize the vertical emittance of the beam at the Cornell Electron Storage Ring (CESR) involves measurement and correction of the dispersion, coupling, and orbit of the beam and lets us reach emittances of 10 pm, but is limited by finite dispersion measurement resolution.* For further improvement in the vertical emittance, we propose using a method based on the theory of sloppy models.** The storage ring lattice permits us to identify the dependence of the dispersion and emittance on our corrector magnets, and taking the singular value decomposition of the dispersion/corrector Jacobian gives us the combinations of these magnets which will be effective knobs for emittance tuning, ordered by singular value. These knobs will permit us to empirically tune the emittance based on direct measurements of the vertical beam size. Simulations show that when starting from a lattice with realistic alignment errors which has been corrected by our existing method to have an emittance of a few pm, this new method will enable us to reduce the emittance to nearly the quantum limit, assuming that vertical dispersion is the primary source of our residual emittance. * J. Shanks, D.L. Rubin, and D. Sagan, Phys. Rev. ST Accel. Beams 17, 044003 (2014). ** K.S. Brown and J.P. Sethna, Phys. Rev. E 68, 021904 (2003).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA58
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Paper

Title

Page

Using High Precision Beam Position Monitors at the Cornell Electron Storage Ring (CESR) to Measure the One Way Speed of Light Anisotropy

399

W.F. Bergan, M.J. Forster, N.T. Rider, D. L. Rubin, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
B.A. Schmookler
MIT, Cambridge, Massachusetts, USA
B. Wojtsekhowski
CMU, Pittsburgh, Pennsylvania, USA

Funding: NSF PHY-1416318 NSF DGE-1144153
The Cornell Electron Storage Ring (CESR) has been equipped with a number of high-precision beam position monitors which are capable of measuring the orbit of a circulating beam with a precision of a few microns. This technology will enable a precision measurement of deviations in the one-way speed of light. An anisotropic speed of light will alter the beam momentum as it travels around the ring, resulting in a change of orbit over the course of a sidereal day. Using counter-circulating electron and positron beams, we will be able to suppress many of the systematics such as those relating to variations in RF voltage or magnet strength. We show here initial feasibility studies to measure the stability of our beam position monitors and the various systematic effects which may hide our signal and discuss ways in which we can minimize their impact.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA57

Export •

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

TUPOA58

Minimization of Emittance at the Cornell Electron Storage Ring With Sloppy Models

402

SUPO03

use link to see paper's listing under its alternate paper code

W.F. Bergan, A.C. Bartnik, I.V. Bazarov, H. He, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.P. Sethna
Cornell University, Ithaca, New York, USA

Funding: DOE DE-SC0013571 NSF DGE-1144153
Our current method to minimize the vertical emittance of the beam at the Cornell Electron Storage Ring (CESR) involves measurement and correction of the dispersion, coupling, and orbit of the beam and lets us reach emittances of 10 pm, but is limited by finite dispersion measurement resolution.* For further improvement in the vertical emittance, we propose using a method based on the theory of sloppy models.** The storage ring lattice permits us to identify the dependence of the dispersion and emittance on our corrector magnets, and taking the singular value decomposition of the dispersion/corrector Jacobian gives us the combinations of these magnets which will be effective knobs for emittance tuning, ordered by singular value. These knobs will permit us to empirically tune the emittance based on direct measurements of the vertical beam size. Simulations show that when starting from a lattice with realistic alignment errors which has been corrected by our existing method to have an emittance of a few pm, this new method will enable us to reduce the emittance to nearly the quantum limit, assuming that vertical dispersion is the primary source of our residual emittance.
* J. Shanks, D.L. Rubin, and D. Sagan, Phys. Rev. ST Accel. Beams 17, 044003 (2014).
** K.S. Brown and J.P. Sethna, Phys. Rev. E 68, 021904 (2003).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA58

Export •

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