NAPAC2022 - List of Authors (Hoffstaetter, G.H.)

Paper	Title	Page
MOYD6	Chromatic Correction of the EIC Electron Ring Lattice
	Y. Cai, Y.M. Nosochkov SLAC, Menlo Park, California, USA J.S. Berg, J. Kewisch, Y. Li, D. Marx, C. Montag, S. Tepikian, F.J. Willeke BNL, Upton, New York, USA G.H. Hoffstaetter, J.E. Unger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	We have developed a new chromatic compensation scheme for the electron storage ring with two low-beta interaction regions in the electron-ion collider. The hybrid scheme consists of modular chromatic matching of periodic systems and beamlines. The first-order chromatically matched solutions are linearly parameterized with the local linear chromaticities that control the higher order chromatic beatings. The parameterization enables an efficient optimization of dynamic aperture. As a result, we successfully achieve the 1% design criterion for the momentum aperture in the ring.
	Slides MOYD6 [1.667 MB]
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MOZD6	Accelerator Physics Lessons from CBETA, the First Multi-Turn SRF ERL	41
	K.E. Deitrick JLab, Newport News, Virginia, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The Cornell-BNL ERL Test Accelerator (CBETA) has been designed, constructed, and commissioned in a collaboration between Cornell and BNL. It focuses on energy-saving measures in accelerators, including permanent magnets, energy recovery, and superconductors; it has thus been referred to as a green accelerator. CBETA has become the world’s first Energy Recovery Linac (ERL) that accelerates through multiple turns and then recovers the energy in SRF cavities though multiple decelerating turns. The energy is then available to accelerate more beam. It has also become the first accelerator that operates 7 beams in the same large-energy aperture Fixed Field Alternating-gradient (FFA) lattice. The FFA is constructed of permanent combined function magnets and transports energies of 42, 78, 114, and 150 MeV simultaneously. Accelerator physics lessons from the commissioning period will be described and applications of such an accelerator from hadron cooling to EUV lithography and from nuclear physics to a compact Compton source will be discussed.
	Slides MOZD6 [3.207 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOZD6
About •	Received ※ 23 July 2022 — Revised ※ 27 July 2022 — Accepted ※ 03 August 2022 — Issue date ※ 06 August 2022
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TUPA14	Fast First-Order Spin Propagation for Spin Matching and Polarization Optimization with Bmad	369
	J.M. Asimow, G.H. Hoffstaetter, D. Sagan, M.G. Signorelli Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Accurate spin tracking is essential for the simulation and propagation of polarized beams, in which a majority of the particles’ spin point in the same direction. Bmad, an open-sourced library for the simulation of charged particle dynamics, traditionally tracks spin via integrating through each element of a lattice. While exceptionally accurate, this method has the drawback of being slow; at best, the runtime is proportional to the length of the element. By solving the spin transport equation for simple magnet elements, Bmad can reduce this algorithm to constant runtime while maintaining high accuracy. This method, known as "Sprint," enables quicker spin matching and prototyping of lattice designs via Bmad.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA14
About •	Received ※ 30 July 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 24 August 2022
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TUPA17	Beam-Based Alignment of Sextupole Families in the EIC	378
	J.C. Wang, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C. Montag BNL, Upton, New York, USA
	To steer the closed orbit in a storage ring through the center of its quadrupoles, it is important to accurately know the quadrupole centers relative to nearby beam position monitors. Usually this is achieved by beam-based alignment (BBA). Assuming the quadrupole strength can be changed individually, one finds the BPM reading where changing a quadrupole’s strength does not alter the closed orbit. Since most quadrupoles are powered in series, they can only be varied independently if costly power supplies are added. For the EIC electron storage ring (ESR), we investigate whether sextupole BBA can be used instead. Individually powered sextupole BBA techniques already exist, but most sextupoles are powered in families and cannot be individually changed. We therefore developed a method where a localized bump changes the beam excursion in a single sextupole of a family, turning off all families that also have sextupoles in the bump. The bump amplitude at which the sextupole does not cause a closed orbit kick determines the sextupole’s alignment. This study was made to investigate the precision to which this method can be utilized.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA17
About •	Received ※ 04 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 29 August 2022
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WEXD3	Map Tracking Including the Effect of Stochastic Radiation	548
	D. Sagan, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA E. Forest KEK, Ibaraki, Japan
	Funding: Department of Energy Using transfer maps to simulate charged particle motion in accelerators is advantageous since it is much faster than tracking step-by-step. One challenge to using transfer maps is to properly include radiation effects. The effect of radiation can be divided into deterministic and stochastic parts. While computation of the deterministic effect has been previously reported, handling of the stochastic part has not. In this paper, an algorithm for including the stochastic effect is presented including taking into account the finite opening angle of the emitted photons. A comparison demonstrates the utility of this approach. Generating maps which include radiation has been implemented in the PTC software library which is interfaced to the Bmad toolkit.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD3
About •	Received ※ 06 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 24 August 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOYD6

Chromatic Correction of the EIC Electron Ring Lattice

Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, USA
J.S. Berg, J. Kewisch, Y. Li, D. Marx, C. Montag, S. Tepikian, F.J. Willeke
BNL, Upton, New York, USA
G.H. Hoffstaetter, J.E. Unger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We have developed a new chromatic compensation scheme for the electron storage ring with two low-beta interaction regions in the electron-ion collider. The hybrid scheme consists of modular chromatic matching of periodic systems and beamlines. The first-order chromatically matched solutions are linearly parameterized with the local linear chromaticities that control the higher order chromatic beatings. The parameterization enables an efficient optimization of dynamic aperture. As a result, we successfully achieve the 1% design criterion for the momentum aperture in the ring.

Slides MOYD6 [1.667 MB]

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

MOZD6

Accelerator Physics Lessons from CBETA, the First Multi-Turn SRF ERL

41

K.E. Deitrick
JLab, Newport News, Virginia, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The Cornell-BNL ERL Test Accelerator (CBETA) has been designed, constructed, and commissioned in a collaboration between Cornell and BNL. It focuses on energy-saving measures in accelerators, including permanent magnets, energy recovery, and superconductors; it has thus been referred to as a green accelerator. CBETA has become the world’s first Energy Recovery Linac (ERL) that accelerates through multiple turns and then recovers the energy in SRF cavities though multiple decelerating turns. The energy is then available to accelerate more beam. It has also become the first accelerator that operates 7 beams in the same large-energy aperture Fixed Field Alternating-gradient (FFA) lattice. The FFA is constructed of permanent combined function magnets and transports energies of 42, 78, 114, and 150 MeV simultaneously. Accelerator physics lessons from the commissioning period will be described and applications of such an accelerator from hadron cooling to EUV lithography and from nuclear physics to a compact Compton source will be discussed.

Slides MOZD6 [3.207 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOZD6

About •

Received ※ 23 July 2022 — Revised ※ 27 July 2022 — Accepted ※ 03 August 2022 — Issue date ※ 06 August 2022

Cite •

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

TUPA14

Fast First-Order Spin Propagation for Spin Matching and Polarization Optimization with Bmad

369

J.M. Asimow, G.H. Hoffstaetter, D. Sagan, M.G. Signorelli
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Accurate spin tracking is essential for the simulation and propagation of polarized beams, in which a majority of the particles’ spin point in the same direction. Bmad, an open-sourced library for the simulation of charged particle dynamics, traditionally tracks spin via integrating through each element of a lattice. While exceptionally accurate, this method has the drawback of being slow; at best, the runtime is proportional to the length of the element. By solving the spin transport equation for simple magnet elements, Bmad can reduce this algorithm to constant runtime while maintaining high accuracy. This method, known as "Sprint," enables quicker spin matching and prototyping of lattice designs via Bmad.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA14

About •

Received ※ 30 July 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 24 August 2022

Cite •

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

TUPA17

Beam-Based Alignment of Sextupole Families in the EIC

378

J.C. Wang, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C. Montag
BNL, Upton, New York, USA

To steer the closed orbit in a storage ring through the center of its quadrupoles, it is important to accurately know the quadrupole centers relative to nearby beam position monitors. Usually this is achieved by beam-based alignment (BBA). Assuming the quadrupole strength can be changed individually, one finds the BPM reading where changing a quadrupole’s strength does not alter the closed orbit. Since most quadrupoles are powered in series, they can only be varied independently if costly power supplies are added. For the EIC electron storage ring (ESR), we investigate whether sextupole BBA can be used instead. Individually powered sextupole BBA techniques already exist, but most sextupoles are powered in families and cannot be individually changed. We therefore developed a method where a localized bump changes the beam excursion in a single sextupole of a family, turning off all families that also have sextupoles in the bump. The bump amplitude at which the sextupole does not cause a closed orbit kick determines the sextupole’s alignment. This study was made to investigate the precision to which this method can be utilized.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA17

About •

Received ※ 04 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 29 August 2022

Cite •

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

WEXD3

Map Tracking Including the Effect of Stochastic Radiation

548

D. Sagan, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
E. Forest
KEK, Ibaraki, Japan

Funding: Department of Energy
Using transfer maps to simulate charged particle motion in accelerators is advantageous since it is much faster than tracking step-by-step. One challenge to using transfer maps is to properly include radiation effects. The effect of radiation can be divided into deterministic and stochastic parts. While computation of the deterministic effect has been previously reported, handling of the stochastic part has not. In this paper, an algorithm for including the stochastic effect is presented including taking into account the finite opening angle of the emitted photons. A comparison demonstrates the utility of this approach. Generating maps which include radiation has been implemented in the PTC software library which is interfaced to the Bmad toolkit.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD3

About •

Received ※ 06 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 24 August 2022

Cite •

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