LINAC2018 - List of Authors (Bartnik, A.C.)

Paper	Title	Page
WE1A02	CBETA, a 4-turn ERL Based on SRF Linacs and Permanent Magnet Beam Transport
	G.H. Hoffstaetter, N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, F. Furuta, R.E. Gallagher, M. Ge, C.M. Gulliford, B.K. Heltsley, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg, S.J. Brooks, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte BNL, Upton, Long Island, New York, USA D. Jusic Cornell University, Ithaca, New York, USA
	A collaboration between Cornell University and Brookhaven National Laboratory has designed a novel accelerator and is constructing it at Cornell: CBETA, the Cornell-BNL ERL Test Accelerator. The ERL technology that has been prototyped at Cornell for many years is being used, including a DC electron source and an SRF injector Linac with world-record current and normalized brightness in a bunch train, a high-current linac cryomodule optimized for ERLs, a high-power beam stop, and several diagnostics tools for high-current and high-brightness beams. BNL has designed a multi-turn ERL and a recirculating linac for eRHIC; in both designs the beam is transported many times around the 4 km long RHIC tunnel. The number of transport lines is minimized by using two arcs with Fixed Field Alternating Gradient design. This technique will be tested in CBETA, which has a single return for the 4-beam energies with strongly-focusing permanent magnets of Halbach type. The high-brightness beam with 150 MeV and up to 40 mA will have applications for Electron Ion Colliders (EICs), e.g. for their electron cooling, and for applications in industry, in nuclear physics, and in X-ray science.
	Slides WE1A02 [6.367 MB]
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THPO010	Novel Straight Merger for Energy Recovery Linacs	702
	K.E. Deitrick, A. Hutton JLab, Newport News, Virginia, USA A.C. Bartnik, C.M. Gulliford Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA S.A. Overstreet ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. One of the most critical design considerations for an energy recovery linac (ERL) is how to merge the injected bunch onto the linac axis with minimal beam degradation. All merger designs in established and upcoming machines involve significant bending of the injected beam ’ even using a so-called straight merger bends the injected beam several degrees. We propose a merger which reduces the bending of the injected beam by an order of magnitude. By passing both beams through a septum magnet followed by an rf separator cavity with a superimposed dipole magnetic field, the injected beam bends minimally within the cavity, while the recirculated beam bends to align with the linac axis. Here we describe the concept in detail and present simulation results to demonstrate the advantages of such a design, particularly for magnetized beams or minimal energy separation between the injected and recirculated beams. Measurements from an experiment at CBETA evaluating the beam dynamics of the rf separator are presented and compared with simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO010
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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Paper

Title

Page

WE1A02

CBETA, a 4-turn ERL Based on SRF Linacs and Permanent Magnet Beam Transport

G.H. Hoffstaetter, N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, F. Furuta, R.E. Gallagher, M. Ge, C.M. Gulliford, B.K. Heltsley, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte
BNL, Upton, Long Island, New York, USA
D. Jusic
Cornell University, Ithaca, New York, USA

A collaboration between Cornell University and Brookhaven National Laboratory has designed a novel accelerator and is constructing it at Cornell: CBETA, the Cornell-BNL ERL Test Accelerator. The ERL technology that has been prototyped at Cornell for many years is being used, including a DC electron source and an SRF injector Linac with world-record current and normalized brightness in a bunch train, a high-current linac cryomodule optimized for ERLs, a high-power beam stop, and several diagnostics tools for high-current and high-brightness beams. BNL has designed a multi-turn ERL and a recirculating linac for eRHIC; in both designs the beam is transported many times around the 4 km long RHIC tunnel. The number of transport lines is minimized by using two arcs with Fixed Field Alternating Gradient design. This technique will be tested in CBETA, which has a single return for the 4-beam energies with strongly-focusing permanent magnets of Halbach type. The high-brightness beam with 150 MeV and up to 40 mA will have applications for Electron Ion Colliders (EICs), e.g. for their electron cooling, and for applications in industry, in nuclear physics, and in X-ray science.

Slides WE1A02 [6.367 MB]

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THPO010

Novel Straight Merger for Energy Recovery Linacs

702

K.E. Deitrick, A. Hutton
JLab, Newport News, Virginia, USA
A.C. Bartnik, C.M. Gulliford
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
S.A. Overstreet
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One of the most critical design considerations for an energy recovery linac (ERL) is how to merge the injected bunch onto the linac axis with minimal beam degradation. All merger designs in established and upcoming machines involve significant bending of the injected beam ’ even using a so-called straight merger bends the injected beam several degrees. We propose a merger which reduces the bending of the injected beam by an order of magnitude. By passing both beams through a septum magnet followed by an rf separator cavity with a superimposed dipole magnetic field, the injected beam bends minimally within the cavity, while the recirculated beam bends to align with the linac axis. Here we describe the concept in detail and present simulation results to demonstrate the advantages of such a design, particularly for magnetized beams or minimal energy separation between the injected and recirculated beams. Measurements from an experiment at CBETA evaluating the beam dynamics of the rf separator are presented and compared with simulation results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO010

About •

paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

Export •

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