IPAC2019 - List of Authors (Gulliford, C.M.)

Paper	Title	Page
MOPGW124	Coherent Synchrotron Radiation Simulation for CBETA	406
	W. Lou, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes SLAC, Menlo Park, California, USA N. Tsoupas BNL, Upton, Long Island, New York, USA
	CBETA is an energy recovery linac accelerating from 6 MeV to 150 MeV in four linac passes, using a single return beamline accepting all energies from 42 to 150 MeV. While CBETA gives promise to deliver unprecedentedly high beam current with simultaneously small emittance, Coherent Synchrotron Radiation (CSR) can pose detrimental effect on the beam at high bunch charges and short bunch lengths. To investigate the CSR effects on CBETA, we used the established simulation code Bmad to track a bunch with different parameters. We found that CSR causes phase space dilution, and the effect becomes more significant as the bunch charge and recirculation pass increase. Potential ways to mitigate the effect involving vacuum chamber shielding and increasing bunch length are being investigated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW124
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB074	Using an Energy Scan to Determine the Tunes and Orbit in the First FFA Girder of CBETA	742
	C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg BNL, Upton, Long Island, New York, USA
	This work reports the results of performing a scan of the beam energy performed during the Fractional Arc Test of the CBETA machine, a multi-pass SRF ERL featuring a non-scaling FFA return loop. The FFA arc consists of identical doublets that are designed to have an energy acceptance from 42 to 150 MeV, with a betatron phase advance (i.e., tune) per cell and periodic orbit position that depends on energy. In the CBETA fractional arc test, we transport the beam through 4 such cells (the first girder), and are capable of injecting beam in to the arc with energies as high as 59 MeV. By creating betatron oscillations in the arc, we can compute the phase advance per cell and periodic orbit position as a function of energy within that range. In addition, because the phase advance varies as a function of energy, the computation also provides an estimate of the offsets of the BPMs in that arc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB074
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB075	Radiation Limits on Permanent Magnets in CBETA	745
	V.O. Kostroun, C.M. Gulliford Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The Cornell Brookhaven Energy Recovery Linac Test Accelerator (CBETA), under construction at Cornell, uses Fixed Field Alternating Gradient (FFAG) Halbach magnets made from grade N35EH NdFeB. To reduce the 1% level magnetization errors in fabricated blocks to magnets with better than 0.001 field accuracy, iron wire shimming is necessary. This also limits magnetization changes by external influences to the ~1% level. The ambient radiation field present during CBETA operation can induce permanent magnet demagnetization. The radiation field arises from electrons in the beam halo hitting the vacuum chamber and from residual gas, Touschek and Intra-Beam scattering. The radiation dose rate due to electrons striking the vacuum chamber of a 4 cell straight section of CBETA FFAG magnets was calculated using the many particle Monte Carlo radiation code MCNP6.2. MCNP6.2 has a track-length heating tally for different particles and a collision heating tally that gives energy deposition/mass from all particles in the problem. Calculations show that electron loss has to be a fraction of a watt/m to keep the dose rate at an acceptable level during the accelerator lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB075
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB076	CBETA Beam Commissioning Results	748
	C.M. Gulliford, N. Banerjee, A.C. Bartnik, I.V. Bazarov, J.A. Crittenden, K.E. Deitrick, A. Galdi, G.H. Hoffstaetter, P. Quigley, K.W. Smolenski Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg, S.J. Brooks, R.J. Michnoff, D. Trbojevic BNL, Upton, Long Island, New York, USA
	We report on the first results of commissioning CBETAwith a fully closed return loop. We repeat much of our early commissioning from the fractional arc test, namely setting up the injection system, calibrating the main linac, and steering the beam through the first splitter line. Most importantly, first results from sending the beam all the way through the FixedField Alternating gradient permanent magnet return arc are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB076
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB077	Results From the CBETA Fractional Arc Test	751
	C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg BNL, Upton, Long Island, New York, USA
	We report on commissioning experiments of the Cornell Brookhaven Energy Recovery Test Accelerator Fractional Arc Test. The beam from the injector is accelerated by a linac with a 36 MeV design energy gain, is transported through a splitter line that uses conventional magnets, and finally into a four cell permanent magnet based fixed field alternating (FFA) gradient arc. We measure beam properties in the injector, calibrate the energy gain and phase of the linac cavities using time of flight to a BPM at the end of the linac. We scan individual cavity phases and pass beam through the cavities to determine the transverse offset of the individual cavities. We scan the beam position in the splitter BPMs to estimate and correct the nonlinearity in the BPM response. We tested our path length adjustment mechanism. We measure the dispersion and R56 in the FFA arc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB077
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB078	Beam Based Measurements of the CBeta Main Linac Cavity Alignment	755
	C.M. Gulliford, A.C. Bartnik, J.A. Crittenden, P. Quigley Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg BNL, Upton, Long Island, New York, USA
	Funding: This work was funded by NYSERDA, the New York State Energy Research and Development Agency. Initial attempts at steering the beam through the CBETA main linac indicated the cavities were vertically offset with respect to the BPMs on either side of the linac. In particular, manual alignment of the beam in the first and last cavities suggested a vertical offset of roughly 5 mm. This work presents the results of beam based measurements of the individual cavity offsets taken during the CBETA Fractional Arc Test. With only a single cavity powered at a time, beam was injected at several different vertical offsets, the RF phase was scanned over 360 degrees, and the beam position was measured at the end of the cryomodule. We analyzed the data in two ways. We first compute the RMS spread in the measurements at a given position, and considered the offset with the minimum RMS spread to be the cavity offset. We also fit the measurements at a given phase to a line as a function of initial displacement, and use a model for the transfer matrix of the cavity and downstream drift to compute the offset. The two methods agree well, resulting in an average vertical offset of the main linac cavities of 4.0 plus/minus 1 mm.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB078
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPGW086	Energy and RF Cavity Phase Symmetry Enforcement in Multi-Turn ERL Models	1606
	R.M. Koscica, N. Banerjee, C.M. Gulliford, G.H. Hoffstaetter, W. Lou Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	In a multi-pass Energy Recovery Linac (ERL), each cavity must regain all energy expended from beam acceleration during beam deceleration, and the beam should achieve specific energy targets during each loop that returns it to the linac. For full energy recovery, and for every returning beam to meet loop energy requirements, we must optimize the phase and voltage of cavity fields in addition to selecting adequate flight times. If we impose symmetry in time and energy during acceleration and deceleration, fewer parameters are needed, simplifying the optimization. As an example, we present symmetric models of the Cornell BNL ERL Test Accelerator (CBETA) with solutions that satisfy the optimization targets of loop energy and zero cavity loading.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW086
About •	paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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TUPGW102	CBETA - Novel Superconducting ERL	1651
	R.J. Michnoff, J.S. Berg, S.J. Brooks, J. Cintorino, Y. Hao, C. Liu, G.J. Mahler, F. Méot, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, S. Trabocchi, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte BNL, Upton, Long Island, New York, USA N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, C.M. Gulliford, B.K. Heltsley, G.H. Hoffstaetter, D. Jusic, 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 D. Douglas Douglas Consulting, York, Virginia, USA M. Dunham, C.E. Mayes SLAC, Menlo Park, California, USA
	Funding: New York State Research&Development Authority - NYSERDA agreement number 102192 We are successfully commissioning a unique Cornell University and Brookhaven National Laboratory Electron Recovery Linac (ERL) Test Accelerator ’CBETA’ [1]. The ERL has four accelerating passes through the supercon-ducting linac with a single Fixed Field Alternating Linear Gradient (FFA-LG) return beam line built of the Halbach type permanent magnets. CBETA ERL accelerates elec-trons from 42 MeV to 150 MeV, with the 6 MeV injec-tor. The novelties are that four electron beams, with ener-gies of 42, 78, 114, and 150 MeV, are merged by spreader beam lines into a single arc FFA-LG beam line. The elec-tron beams from the Main Linac Cryomodule (MLC) pass through the FFA-LG arc and are adiabatically merged into a single straight line. From the straight section the beams are brought back to the MLC the same way. This is the first 4 pass superconducting ERL and the first single permanent magnet return line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW102
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPTS093	Magnetized Gridded Thermionic Electron Source	2140
SUSPFO122	use link to see paper's listing under its alternate paper code
	M.S. Stefani ODU, Norfolk, Virginia, USA C.M. Gulliford, V.O. Kostroun, C.E. Mayes, K.W. Smolenski Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA F.E. Hannon, M. Poelker, R. Suleiman JLab, Newport News, Virginia, USA
	Funding: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy. The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of Electron Ion Colliders and the potential of easily forming flat beams for various applications. The demand for high average current for effective ion beam cooling has caused consideration of using bunched magnetized electron beam produced by a gridded thermionic electron gun. This paper presents the design of a potential electron source for JCIEC first measurements characterizing the beam properties of a magnetized thermionic gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS093
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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THPRB100	A Generic Software Platform for Rapid Prototyping of Online Control Algorithms	4063
SUSPFO123	use link to see paper's listing under its alternate paper code
	C.J.R. Duncan, M.B. Andorf, I.V. Bazarov, I.V. Bazarov, C.M. Gulliford, V. Khachatryan, J.M. Maxson, D.L. Rubin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA I.V. Bazarov Cornell University, Ithaca, New York, USA
	Funding: US Department of Energy DE-SC 0013571 Algorithmic control of accelerators is an active area of research that promises significant improvements in machine performance. To facilitate rapid algorithm prototyping, we have developed a generic interface between accelerator controls, beam physics modelling software and modern scripting languages. The work-flow of a project using this interface begins with testing algorithms of choice offline in simulation. After off-line testing, the same code can be deployed on real machines via the Experimental Physics and Industrial Control System (EPICS) API. We include noise in our simulations in order to mimic realistic accelerator behaviour and to evaluate robustness of algorithms to experimental uncertainties and long-term drifts. The results of test cases of using this framework are presented, including emittance tuning of the Cornell Electron Storage Ring (CESR), correction of diurnal drift in CESR steering and orbit correction on CESR and the Cornell-BNL ERL Test Accelerator (CBETA).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB100
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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Paper

Title

Page

Coherent Synchrotron Radiation Simulation for CBETA

406

W. Lou, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes
SLAC, Menlo Park, California, USA
N. Tsoupas
BNL, Upton, Long Island, New York, USA

CBETA is an energy recovery linac accelerating from 6 MeV to 150 MeV in four linac passes, using a single return beamline accepting all energies from 42 to 150 MeV. While CBETA gives promise to deliver unprecedentedly high beam current with simultaneously small emittance, Coherent Synchrotron Radiation (CSR) can pose detrimental effect on the beam at high bunch charges and short bunch lengths. To investigate the CSR effects on CBETA, we used the established simulation code Bmad to track a bunch with different parameters. We found that CSR causes phase space dilution, and the effect becomes more significant as the bunch charge and recirculation pass increase. Potential ways to mitigate the effect involving vacuum chamber shielding and increasing bunch length are being investigated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW124

About •

paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB074

Using an Energy Scan to Determine the Tunes and Orbit in the First FFA Girder of CBETA

742

C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg
BNL, Upton, Long Island, New York, USA

This work reports the results of performing a scan of the beam energy performed during the Fractional Arc Test of the CBETA machine, a multi-pass SRF ERL featuring a non-scaling FFA return loop. The FFA arc consists of identical doublets that are designed to have an energy acceptance from 42 to 150 MeV, with a betatron phase advance (i.e., tune) per cell and periodic orbit position that depends on energy. In the CBETA fractional arc test, we transport the beam through 4 such cells (the first girder), and are capable of injecting beam in to the arc with energies as high as 59 MeV. By creating betatron oscillations in the arc, we can compute the phase advance per cell and periodic orbit position as a function of energy within that range. In addition, because the phase advance varies as a function of energy, the computation also provides an estimate of the offsets of the BPMs in that arc.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB074

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB075

Radiation Limits on Permanent Magnets in CBETA

745

V.O. Kostroun, C.M. Gulliford
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The Cornell Brookhaven Energy Recovery Linac Test Accelerator (CBETA), under construction at Cornell, uses Fixed Field Alternating Gradient (FFAG) Halbach magnets made from grade N35EH NdFeB. To reduce the 1% level magnetization errors in fabricated blocks to magnets with better than 0.001 field accuracy, iron wire shimming is necessary. This also limits magnetization changes by external influences to the ~1% level. The ambient radiation field present during CBETA operation can induce permanent magnet demagnetization. The radiation field arises from electrons in the beam halo hitting the vacuum chamber and from residual gas, Touschek and Intra-Beam scattering. The radiation dose rate due to electrons striking the vacuum chamber of a 4 cell straight section of CBETA FFAG magnets was calculated using the many particle Monte Carlo radiation code MCNP6.2. MCNP6.2 has a track-length heating tally for different particles and a collision heating tally that gives energy deposition/mass from all particles in the problem. Calculations show that electron loss has to be a fraction of a watt/m to keep the dose rate at an acceptable level during the accelerator lifetime.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB075

About •

paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB076

CBETA Beam Commissioning Results

748

C.M. Gulliford, N. Banerjee, A.C. Bartnik, I.V. Bazarov, J.A. Crittenden, K.E. Deitrick, A. Galdi, G.H. Hoffstaetter, P. Quigley, K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, R.J. Michnoff, D. Trbojevic
BNL, Upton, Long Island, New York, USA

We report on the first results of commissioning CBETAwith a fully closed return loop. We repeat much of our early commissioning from the fractional arc test, namely setting up the injection system, calibrating the main linac, and steering the beam through the first splitter line. Most importantly, first results from sending the beam all the way through the FixedField Alternating gradient permanent magnet return arc are described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB076

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB077

Results From the CBETA Fractional Arc Test

751

C.M. Gulliford, N. Banerjee, A.C. Bartnik, J.A. Crittenden, P. Quigley
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg
BNL, Upton, Long Island, New York, USA

We report on commissioning experiments of the Cornell Brookhaven Energy Recovery Test Accelerator Fractional Arc Test. The beam from the injector is accelerated by a linac with a 36 MeV design energy gain, is transported through a splitter line that uses conventional magnets, and finally into a four cell permanent magnet based fixed field alternating (FFA) gradient arc. We measure beam properties in the injector, calibrate the energy gain and phase of the linac cavities using time of flight to a BPM at the end of the linac. We scan individual cavity phases and pass beam through the cavities to determine the transverse offset of the individual cavities. We scan the beam position in the splitter BPMs to estimate and correct the nonlinearity in the BPM response. We tested our path length adjustment mechanism. We measure the dispersion and R56 in the FFA arc.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB077

About •

paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB078

Beam Based Measurements of the CBeta Main Linac Cavity Alignment

755

C.M. Gulliford, A.C. Bartnik, J.A. Crittenden, P. Quigley
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg
BNL, Upton, Long Island, New York, USA

Funding: This work was funded by NYSERDA, the New York State Energy Research and Development Agency.
Initial attempts at steering the beam through the CBETA main linac indicated the cavities were vertically offset with respect to the BPMs on either side of the linac. In particular, manual alignment of the beam in the first and last cavities suggested a vertical offset of roughly 5 mm. This work presents the results of beam based measurements of the individual cavity offsets taken during the CBETA Fractional Arc Test. With only a single cavity powered at a time, beam was injected at several different vertical offsets, the RF phase was scanned over 360 degrees, and the beam position was measured at the end of the cryomodule. We analyzed the data in two ways. We first compute the RMS spread in the measurements at a given position, and considered the offset with the minimum RMS spread to be the cavity offset. We also fit the measurements at a given phase to a line as a function of initial displacement, and use a model for the transfer matrix of the cavity and downstream drift to compute the offset. The two methods agree well, resulting in an average vertical offset of the main linac cavities of 4.0 plus/minus 1 mm.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB078

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPGW086

Energy and RF Cavity Phase Symmetry Enforcement in Multi-Turn ERL Models

1606

R.M. Koscica, N. Banerjee, C.M. Gulliford, G.H. Hoffstaetter, W. Lou
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

In a multi-pass Energy Recovery Linac (ERL), each cavity must regain all energy expended from beam acceleration during beam deceleration, and the beam should achieve specific energy targets during each loop that returns it to the linac. For full energy recovery, and for every returning beam to meet loop energy requirements, we must optimize the phase and voltage of cavity fields in addition to selecting adequate flight times. If we impose symmetry in time and energy during acceleration and deceleration, fewer parameters are needed, simplifying the optimization. As an example, we present symmetric models of the Cornell BNL ERL Test Accelerator (CBETA) with solutions that satisfy the optimization targets of loop energy and zero cavity loading.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW086

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paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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TUPGW102

CBETA - Novel Superconducting ERL

1651

R.J. Michnoff, J.S. Berg, S.J. Brooks, J. Cintorino, Y. Hao, C. Liu, G.J. Mahler, F. Méot, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, S. Trabocchi, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte
BNL, Upton, Long Island, New York, USA
N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, C.M. Gulliford, B.K. Heltsley, G.H. Hoffstaetter, D. Jusic, 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
D. Douglas
Douglas Consulting, York, Virginia, USA
M. Dunham, C.E. Mayes
SLAC, Menlo Park, California, USA

Funding: New York State Research&Development Authority - NYSERDA agreement number 102192
We are successfully commissioning a unique Cornell University and Brookhaven National Laboratory Electron Recovery Linac (ERL) Test Accelerator ’CBETA’ [1]. The ERL has four accelerating passes through the supercon-ducting linac with a single Fixed Field Alternating Linear Gradient (FFA-LG) return beam line built of the Halbach type permanent magnets. CBETA ERL accelerates elec-trons from 42 MeV to 150 MeV, with the 6 MeV injec-tor. The novelties are that four electron beams, with ener-gies of 42, 78, 114, and 150 MeV, are merged by spreader beam lines into a single arc FFA-LG beam line. The elec-tron beams from the Main Linac Cryomodule (MLC) pass through the FFA-LG arc and are adiabatically merged into a single straight line. From the straight section the beams are brought back to the MLC the same way. This is the first 4 pass superconducting ERL and the first single permanent magnet return line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW102

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS093

Magnetized Gridded Thermionic Electron Source

2140

SUSPFO122

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

M.S. Stefani
ODU, Norfolk, Virginia, USA
C.M. Gulliford, V.O. Kostroun, C.E. Mayes, K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
F.E. Hannon, M. Poelker, R. Suleiman
JLab, Newport News, Virginia, USA

Funding: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy.
The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of Electron Ion Colliders and the potential of easily forming flat beams for various applications. The demand for high average current for effective ion beam cooling has caused consideration of using bunched magnetized electron beam produced by a gridded thermionic electron gun. This paper presents the design of a potential electron source for JCIEC first measurements characterizing the beam properties of a magnetized thermionic gun.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS093

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPRB100

A Generic Software Platform for Rapid Prototyping of Online Control Algorithms

4063

SUSPFO123

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C.J.R. Duncan, M.B. Andorf, I.V. Bazarov, I.V. Bazarov, C.M. Gulliford, V. Khachatryan, J.M. Maxson, D.L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
I.V. Bazarov
Cornell University, Ithaca, New York, USA

Funding: US Department of Energy DE-SC 0013571
Algorithmic control of accelerators is an active area of research that promises significant improvements in machine performance. To facilitate rapid algorithm prototyping, we have developed a generic interface between accelerator controls, beam physics modelling software and modern scripting languages. The work-flow of a project using this interface begins with testing algorithms of choice offline in simulation. After off-line testing, the same code can be deployed on real machines via the Experimental Physics and Industrial Control System (EPICS) API. We include noise in our simulations in order to mimic realistic accelerator behaviour and to evaluate robustness of algorithms to experimental uncertainties and long-term drifts. The results of test cases of using this framework are presented, including emittance tuning of the Cornell Electron Storage Ring (CESR), correction of diurnal drift in CESR steering and orbit correction on CESR and the Cornell-BNL ERL Test Accelerator (CBETA).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB100

About •

paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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