IPAC2022 - Classification: MC7: Accelerator Technology / T09: Room Temperature Magnets

Paper	Title	Page
THIYSP1	Development of Advanced Magnets for Modern and Future Synchrotron Light Sources
	S.K. Sharma BNL, Upton, New York, USA
	X-ray brightness is one of major figures of merit of ongoing and planned light source projects, together with beamline capacity and reliability of operations. These requirements drive more and more compact configurations of the synchrotron magnets with precise dipole fields tailored to the lattice functions, high gradients with tight field tolerances. In the past few years new configurations of Permanent Magnet element designs have emerged featuring small apertures required for high field strengths. In collaboration with the accelerator community we have been investigating new lattice designs for a future low-emittance upgrade of the NSLS-II storage ring. These new designs require small aperture magnets of demanding specifications in terms of field and gradient strengths, field quality, vacuum chamber integration and x-ray extraction. In this presentation we describe designs of the magnets for new generation of light sources and our ongoing R&D to verify the magnet performance, field quality, methods of extraction of synchrotron radiation fan, long-term radiation resistance of the PM materials, designs of vacuum chamber and specialized alignment techniques.
	Slides THIYSP1 [4.233 MB]
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THOYSP1	Construction and Measurement of a Tuneable Permanent Magnet Quadrupole for Diamond Light Source	2424
	A.R. Bainbridge, B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A.G. Hinton, N. Krumpa STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom I.P.S. Martin, W. Tizzano DLS, Oxfordshire, United Kingdom
	Permanent magnets (PMs) are becoming an attractive proposition as a green and efficient replacement for electromagnets in particle accelerators. The Zero-Power Tuneable Optics (ZEPTO) collaboration between STFC and CERN has demonstrated that traditional limitations of PM technology, such as the ability to change the flux density in the magnet aperture, can be overcome. Moving PM blocks relative to fixed steel structures that define the field, the strength may be changed while suitable field homogeneity is maintained. A new ZEPTO variant has been developed in conjunction with Diamond Light Source (DLS) to demonstrate the technology on a real accelerator. This magnet features a number of crucial design innovations over previous generations of ZEPTO magnets that improve the convenience and versatility of PM systems and demonstrate that they can be deployed in many situations. We present the construction and measurement results of this new magnet and outline the planned data collection whilst installed on DLS. We analyse its performance relative to design and discuss the new features with focus on the real-world implications of PM technology for current and future accelerators.
	Slides THOYSP1 [3.675 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOYSP1
About •	Received ※ 30 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
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THOYSP2	The New Eddy Current Type Septum Magnet for Upgrading of Fast Extraction in Main Ring of J-PARC	2428
	T. Shibata, K. Ishii, S. Iwata, H. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan K. Fan HUST, Wuhan, People’s Republic of China
	For our first goal of the beam power of Main Ring for Fast eXtraction (FX), 750 kW, we have been evaluating a new Low-Field FX Septum magnets which are induced eddy current type (Eddy-Septum) since 2014. The pending technical issues are disagreement in two current monitor systems and the long switching time of the Main-charger to Sub-charger at low charging voltage. We measured a gap field during measurement of current, and found no drift in time variation of gap field. Our conclusion was that the cause of the disagreement is electric and radiative noise which make the drift in the time variation. The long-term stability of the output pulsed current depends on the switching time and charging voltage. We investigated the correlation between the keeping time of flat-top charging voltage and long-time stability with various charging voltages. In June 2021, we have first conducted the 1 Hz operation and high-voltage test of the Eddy-Septum which is mounted in a vacuum chamber, and we found no problem. A new pure iron duct type magnetic shield for reducing the leakage field were produced in July 2021. The new LF FX-Septum will be installed in MR in early of 2022.
	Slides THOYSP2 [5.375 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOYSP2
About •	Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 21 June 2022
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THPOTK001	Variable Permanent Hybrid Magnets for the Bessy III Storage Ring	2763
	J. Völker, V. Dürr, P. Goslawski, A. Jankowiak, M. Titze HZB, Berlin, Germany
	The Helmholtz Zentrum Berlin (HZB) is working on the conceptual design of a successor source to BESSY II, an new BESSY III facility, designed for a beam energy of 2.5GeV and based on a multi-bend achromat (MBA) lattice for a low emittances of 100pm-rad. Bending and focusing magnets in the MBA cells should consist of permanent magnets (PM), to allow for a competitive and compact lattice, to increase the magnetic stability and to decrease the electric power consumption of the machine. However, using pure permanent magnet systems would result in a completely fixed lattice. Therefore, we are developing Variable Permanent Hybrid Magnets (VPHM), combining PM materials like NdFeB with a surrounding soft iron yoke and additional electric coils. This design can achieve the same field strength and field quality as conservative magnets, with only a small fraction of the electric power consumption, and a ca. 10% variability in the field amplitudes. In this paper, design and first optimization results of the magnets will be presented, which are a promising option for the new BESSY III facility, and an estimated reduction in total power consumption for the magnet lattice of up to 80%.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK001
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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THPOTK002	Magnet Design for the PETRA IV Storage Ring	2767
	R. Bartolini, I.V. Agapov, A. Aloev, H.-J. Eckoldt, D. Einfeld, B. Krause, A. Petrov, M. Thede, M. Tischer DESY, Hamburg, Germany J. Chavanne ESRF, Grenoble, France
	The proposed PETRA IV electron storage ring that will replace DESY’s flagship synchrotron light source PETRA III will feature a horizontal emittance as low as 20 pmrad. It is based on a hybrid six-bend achromat lattice. In addition to the storage ring PETRA IV, the Booster Synchrotron and the corresponding transfer line will be renewed. Overall about 4000 magnets will be manufactured. The lattice design require high-gradient quadrupoles, which are unfeasible with conventional steel, used traditionally for normal-conducting magnets. The required gradient is safely reached with the poles, made of Permendur. The bending magnets for the storage ring will be based on permanent magnets. This contribution presents the electromagnetic design of the magnets for the storage ring and booster synchrotron.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK002
About •	Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
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THPOTK003	Optimization of Mass Resolution Parameters Combined with Ion Cooler Performance	2770
	M. Cavenago, C. Baltador, L. Bellan, M. Comunian, E. Fagotti, A. Galatà, M. Maggiore, A. Pisent, C.R. Roncolato, M. Rossignoli, A. Ruzzon INFN/LNL, Legnaro (PD), Italy G. Maero, M. Romé Universita’ degli Studi di Milano e INFN, Milano, Italy V. Variale INFN-Bari, Bari, Italy
	High mass resolution spectrometers (HRMS) for separation of exotic ion species in nuclear physics experiment request a low emittance and small energy spread (with D E the peak-to-peak value, and sE the rms value) of the input beam, so that ion cooler devices, as a Radio Frequency Quadrupole Coolers (RFQC), are typically envisioned. The SPES (Selective Production of Exotic Species) project at LNL requests M/(D M) about 20000, rms normalized emittance in the order of 2 nm, and for 160 keV ions, spread sE about 1 eV. Typical limits of RFQC[] and HRMS[] performances are discussed, and relevant formulas are implemented in easy reference tools. The necessary collisional data are reviewed, in particular for Cs+ against He gas, whose pressure ranges from 2 to 9 Pa; status of Milan test bench is briefly updated. Practical consideration on gas pumping, voltage stability and magnet design are also included. [] Cavenago et al. Optimization of ion transport in a combined RFQ Cooler …, in ICIS 2021 (in press) [**] M. Comunian et al. p. 3252 in proceedings IPAC2018 doi:10.18429/JACoW-IPAC2018-THPAK021
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK003
About •	Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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THPOTK004	The Reduction of the Leakage Field of the Injection Septum Magnet in Main Ring of J-PARC	2774
	T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan
	A new injection septum magnet (InjSep) was installed in MR in 2016 for one of the upgrading of beam power of MR. We have measured the leakage field before installation, and it was found from the measurement results that the leakage field at the beam upstream region of the circulating duct was enough smaller than previous InjSep, however we tried to reduce the leakage field further by installation a new magnetic shield. First magnetic shield was produced in 2017, and we installed it in the InjSep. The leakage field was reduced, however the magnetic field of a quadrupole magnet at beam upstream of the InjSep was also reduced slightly. The decrease of the magnetic field of the one of main magnet was not permitted from the requirement of beam optics. In consequently, the first version was failed. The second one was produced in 2018, and we measured the leakage field was measured in Jan. 2019. The leakage field was reduced, while no reduction of the quadrupole magnet. We decided to use the second version for beam operation. The new additional shield was started to use in Nov. 2019.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK004
About •	Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 13 June 2022
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THPOTK005	The New High Field Septum Magnet for Upgrading of Fast Extraction in Main Ring of J-PARC	2778
	T. Shibata, K. Ishii, S. Iwata, H. Matsumoto, N. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan K. Fan HUST, Wuhan, People’s Republic of China
	Upgrading the beam-power of the J-PARC Main Ring to 750 kW is underway by reducing the cycle from 2.48 s to 1.3 s. Required upgrade of the four High Field (HF) Septa will be completed in 2022. The operation test of a new HF SM31 was conducted in 2020. First was 1 Hz operation test. The power supply had no problem in the operation, and the joule heating at the magnet coil was lower than limit. We found a good linearity between the current and the gap field which has no saturation. The field integral in the magnet gap was measured to calculate the appropriate current for beam operation, and we found it was 3,400 A. We compared the gap field of the neutrino side with that of the beam abort side. The magnitude of gap field had no significant discrepancy larger than its measurement accuracy. The end-fringe field was measured and the we found large leakage field still existed around the end-fringes. We are producing an additional magnetic shield which will be mounted in the circulating beam duct, and it will finished in Feb. 2022. In next March we will install the inner shield and measured the leakage field. After that we will install the new SM31 in MR.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK005
About •	Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 28 June 2022
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THPOTK007	Magnet Systems for Korea 4GSR Light Source	2781
	D.E. Kim, T. Ha, G. Hahn, Y.G. Jung, H.-G. Lee, J. Lee, S. Shin, H.S. Suh PAL, Pohang, Republic of Korea
	Funding: Work supported by NRF of the Republic of Korea. A 4th generation storage ring based light source is being developed in Korea since 2021. It features < 100 pm rad emittance, about 800 m circumference, 4 GeV e-beam energy, full energy booster injection, and more than 40 beamlines which includes more than 24 insertion device (ID) beamlines. This machine requires about ~1000 magnets including dipole, longitudinal gradient dipole, transverse gradient dipole, sextupoles, and correctors. The apertures are small and the lattice space requirements are very tight. In this report, a preliminary design of the each magnet is presented with detailed plan for the future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK007
About •	Received ※ 13 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 07 July 2022
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THPOTK009	Design of a Permanent Magnet Based Dipole Quadrupole Magnet	2784
	A.G. Hinton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom M. Kokole, T. Milharčič KYMA, Trieste, Italy A. Shahveh DLS, Oxfordshire, United Kingdom B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom B.J.A. Shepherd Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Permanent magnet technology can facilitate the design of accelerator magnets with much lower power consumption than traditional resistive electromagnets. By reducing the power requirements of magnets, more sustainable accelerators can be designed and built. At STFC, as part of the I.FAST collaboration, we are working to develop sustainable technologies for future accelerators. As part of this work, we have designed a permanent magnet based dipole-quadrupole magnet with parameters suited to meet the requirements of the proposed Diamond-II upgrade. We present here the magnetic design of the dipole-quadrupole magnet. The design, based on a single sided dipole-quadrupole, uses permanent magnets to generate the field in the magnet bore. The design includes the shaping of the pole tips to reduce multipole errors as well as methods of providing thermal stabilisation using thermal shunts and field tuning using resistive coils. The mechanical design of the magnet is being undertaken by colleagues at Kyma and a prototype of the magnet will soon be built and tested.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK009
About •	Received ※ 06 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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THPOTK011	Permanent Magnets for the CEBAF 24GeV Upgrade	2792
	S.J. Brooks BNL, Upton, New York, USA S.A. Bogacz JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. An upgrade of the CEBAF facility to double its present energy of 12GeV has been proposed. To provide double the number of linac passes using the existing five stacked arc beamlines, some beamlines are replaced by fixed-field accelerator (FFA) arcs, allowing multiple energies to pass through the same magnets. A solution is presented in which two of the existing electromagnetic beamlines are replaced with permanent magnet non-scaling FFA arcs, as demonstrated at CBETA. The two-stage design reduces peak magnetic field and synchrotron radiation loss compared to using a single stage. FFAs do not pulse their magnets, making permanent magnets a promising and power-efficient technology option. However, the magnetic field requirements are still at the high end of accelerator permanent magnets produced thus far (1.6T peak on beam), while the magnets must also be combined-function, having a gradient with a dipole offset. Designs using a novel oval aperture and open midplane within an adapted Halbach magnet are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK011
About •	Received ※ 31 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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THPOTK023	Ferrite Specification for the Mu2e 300 kHz and 4.4 MHz AC Dipole Magnets	2816
SUSPMF116	use link to see paper's listing under its alternate paper code
	K.P. Harrig, E. Prebys UCD, Davis, California, USA L. Elementi, C.C. Jensen, H. Pfeffer, D.A. Still, I. Terechkine, S.J. Werkema, M. Wong Fermilab, Batavia, Illinois, USA
	Funding: Work supported by by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, in addition to grant DE-SC0019254. The Mu2e experiment at Fermilab will measure the rate for neutrinoless-conversion of negative muons into electrons with never-before-seen precision. This experiment will use a pulsed 8 GeV proton beam with pulses separated by 1.7 µs. To suppress beam induced backgrounds to this process, a set of dipoles operating at 300 kHz and 4.4 MHz have been developed that will reduce the fraction of out-of-time protons at the level of 1E-10 or less. Selection of magnetic ferrite material for construction must be carefully considered given the high repetition rate and duty cycle that can lead to excess heating in conventional magnetic material. A model of the electromagnetic and thermal properties of candidate ferrite materials has been constructed. Magnetic permeability, inductance, and power loss were measured at the two operating frequencies in toroidal ferrite samples as well as in the ferrites from which prototype magnets were built. Additionally, the outgassing rates of the ferrite material was measured to determine vacuum compatibility. The outcome of this work is a detailed specification of the electrical and mechanical details of the ferrite material required for this application.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK023
About •	Received ※ 30 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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Paper

Title

Page

THIYSP1

Development of Advanced Magnets for Modern and Future Synchrotron Light Sources

S.K. Sharma
BNL, Upton, New York, USA

X-ray brightness is one of major figures of merit of ongoing and planned light source projects, together with beamline capacity and reliability of operations. These requirements drive more and more compact configurations of the synchrotron magnets with precise dipole fields tailored to the lattice functions, high gradients with tight field tolerances. In the past few years new configurations of Permanent Magnet element designs have emerged featuring small apertures required for high field strengths. In collaboration with the accelerator community we have been investigating new lattice designs for a future low-emittance upgrade of the NSLS-II storage ring. These new designs require small aperture magnets of demanding specifications in terms of field and gradient strengths, field quality, vacuum chamber integration and x-ray extraction. In this presentation we describe designs of the magnets for new generation of light sources and our ongoing R&D to verify the magnet performance, field quality, methods of extraction of synchrotron radiation fan, long-term radiation resistance of the PM materials, designs of vacuum chamber and specialized alignment techniques.

Slides THIYSP1 [4.233 MB]

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THOYSP1

Construction and Measurement of a Tuneable Permanent Magnet Quadrupole for Diamond Light Source

2424

A.R. Bainbridge, B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.G. Hinton, N. Krumpa
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
I.P.S. Martin, W. Tizzano
DLS, Oxfordshire, United Kingdom

Permanent magnets (PMs) are becoming an attractive proposition as a green and efficient replacement for electromagnets in particle accelerators. The Zero-Power Tuneable Optics (ZEPTO) collaboration between STFC and CERN has demonstrated that traditional limitations of PM technology, such as the ability to change the flux density in the magnet aperture, can be overcome. Moving PM blocks relative to fixed steel structures that define the field, the strength may be changed while suitable field homogeneity is maintained. A new ZEPTO variant has been developed in conjunction with Diamond Light Source (DLS) to demonstrate the technology on a real accelerator. This magnet features a number of crucial design innovations over previous generations of ZEPTO magnets that improve the convenience and versatility of PM systems and demonstrate that they can be deployed in many situations. We present the construction and measurement results of this new magnet and outline the planned data collection whilst installed on DLS. We analyse its performance relative to design and discuss the new features with focus on the real-world implications of PM technology for current and future accelerators.

Slides THOYSP1 [3.675 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOYSP1

About •

Received ※ 30 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022

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THOYSP2

The New Eddy Current Type Septum Magnet for Upgrading of Fast Extraction in Main Ring of J-PARC

2428

T. Shibata, K. Ishii, S. Iwata, H. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
K. Fan
HUST, Wuhan, People’s Republic of China

For our first goal of the beam power of Main Ring for Fast eXtraction (FX), 750 kW, we have been evaluating a new Low-Field FX Septum magnets which are induced eddy current type (Eddy-Septum) since 2014. The pending technical issues are disagreement in two current monitor systems and the long switching time of the Main-charger to Sub-charger at low charging voltage. We measured a gap field during measurement of current, and found no drift in time variation of gap field. Our conclusion was that the cause of the disagreement is electric and radiative noise which make the drift in the time variation. The long-term stability of the output pulsed current depends on the switching time and charging voltage. We investigated the correlation between the keeping time of flat-top charging voltage and long-time stability with various charging voltages. In June 2021, we have first conducted the 1 Hz operation and high-voltage test of the Eddy-Septum which is mounted in a vacuum chamber, and we found no problem. A new pure iron duct type magnetic shield for reducing the leakage field were produced in July 2021. The new LF FX-Septum will be installed in MR in early of 2022.

Slides THOYSP2 [5.375 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOYSP2

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Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 21 June 2022

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THPOTK001

Variable Permanent Hybrid Magnets for the Bessy III Storage Ring

2763

J. Völker, V. Dürr, P. Goslawski, A. Jankowiak, M. Titze
HZB, Berlin, Germany

The Helmholtz Zentrum Berlin (HZB) is working on the conceptual design of a successor source to BESSY II, an new BESSY III facility, designed for a beam energy of 2.5GeV and based on a multi-bend achromat (MBA) lattice for a low emittances of 100pm-rad. Bending and focusing magnets in the MBA cells should consist of permanent magnets (PM), to allow for a competitive and compact lattice, to increase the magnetic stability and to decrease the electric power consumption of the machine. However, using pure permanent magnet systems would result in a completely fixed lattice. Therefore, we are developing Variable Permanent Hybrid Magnets (VPHM), combining PM materials like NdFeB with a surrounding soft iron yoke and additional electric coils. This design can achieve the same field strength and field quality as conservative magnets, with only a small fraction of the electric power consumption, and a ca. 10% variability in the field amplitudes. In this paper, design and first optimization results of the magnets will be presented, which are a promising option for the new BESSY III facility, and an estimated reduction in total power consumption for the magnet lattice of up to 80%.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK001

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022

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THPOTK002

Magnet Design for the PETRA IV Storage Ring

2767

R. Bartolini, I.V. Agapov, A. Aloev, H.-J. Eckoldt, D. Einfeld, B. Krause, A. Petrov, M. Thede, M. Tischer
DESY, Hamburg, Germany
J. Chavanne
ESRF, Grenoble, France

The proposed PETRA IV electron storage ring that will replace DESY’s flagship synchrotron light source PETRA III will feature a horizontal emittance as low as 20 pmrad. It is based on a hybrid six-bend achromat lattice. In addition to the storage ring PETRA IV, the Booster Synchrotron and the corresponding transfer line will be renewed. Overall about 4000 magnets will be manufactured. The lattice design require high-gradient quadrupoles, which are unfeasible with conventional steel, used traditionally for normal-conducting magnets. The required gradient is safely reached with the poles, made of Permendur. The bending magnets for the storage ring will be based on permanent magnets. This contribution presents the electromagnetic design of the magnets for the storage ring and booster synchrotron.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK002

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Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022

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THPOTK003

Optimization of Mass Resolution Parameters Combined with Ion Cooler Performance

2770

M. Cavenago, C. Baltador, L. Bellan, M. Comunian, E. Fagotti, A. Galatà, M. Maggiore, A. Pisent, C.R. Roncolato, M. Rossignoli, A. Ruzzon
INFN/LNL, Legnaro (PD), Italy
G. Maero, M. Romé
Universita’ degli Studi di Milano e INFN, Milano, Italy
V. Variale
INFN-Bari, Bari, Italy

High mass resolution spectrometers (HRMS) for separation of exotic ion species in nuclear physics experiment request a low emittance and small energy spread (with D E the peak-to-peak value, and sE the rms value) of the input beam, so that ion cooler devices, as a Radio Frequency Quadrupole Coolers (RFQC), are typically envisioned. The SPES (Selective Production of Exotic Species) project at LNL requests M/(D M) about 20000, rms normalized emittance in the order of 2 nm, and for 160 keV ions, spread sE about 1 eV. Typical limits of RFQC[*] and HRMS[**] performances are discussed, and relevant formulas are implemented in easy reference tools. The necessary collisional data are reviewed, in particular for Cs+ against He gas, whose pressure ranges from 2 to 9 Pa; status of Milan test bench is briefly updated. Practical consideration on gas pumping, voltage stability and magnet design are also included.
[*] Cavenago et al. Optimization of ion transport in a combined RFQ Cooler …, in ICIS 2021 (in press)
[**] M. Comunian et al. p. 3252 in proceedings IPAC2018 doi:10.18429/JACoW-IPAC2018-THPAK021

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK003

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Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022

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THPOTK004

The Reduction of the Leakage Field of the Injection Septum Magnet in Main Ring of J-PARC

2774

T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan

A new injection septum magnet (InjSep) was installed in MR in 2016 for one of the upgrading of beam power of MR. We have measured the leakage field before installation, and it was found from the measurement results that the leakage field at the beam upstream region of the circulating duct was enough smaller than previous InjSep, however we tried to reduce the leakage field further by installation a new magnetic shield. First magnetic shield was produced in 2017, and we installed it in the InjSep. The leakage field was reduced, however the magnetic field of a quadrupole magnet at beam upstream of the InjSep was also reduced slightly. The decrease of the magnetic field of the one of main magnet was not permitted from the requirement of beam optics. In consequently, the first version was failed. The second one was produced in 2018, and we measured the leakage field was measured in Jan. 2019. The leakage field was reduced, while no reduction of the quadrupole magnet. We decided to use the second version for beam operation. The new additional shield was started to use in Nov. 2019.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK004

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Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 13 June 2022

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THPOTK005

The New High Field Septum Magnet for Upgrading of Fast Extraction in Main Ring of J-PARC

2778

T. Shibata, K. Ishii, S. Iwata, H. Matsumoto, N. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
K. Fan
HUST, Wuhan, People’s Republic of China

Upgrading the beam-power of the J-PARC Main Ring to 750 kW is underway by reducing the cycle from 2.48 s to 1.3 s. Required upgrade of the four High Field (HF) Septa will be completed in 2022. The operation test of a new HF SM31 was conducted in 2020. First was 1 Hz operation test. The power supply had no problem in the operation, and the joule heating at the magnet coil was lower than limit. We found a good linearity between the current and the gap field which has no saturation. The field integral in the magnet gap was measured to calculate the appropriate current for beam operation, and we found it was 3,400 A. We compared the gap field of the neutrino side with that of the beam abort side. The magnitude of gap field had no significant discrepancy larger than its measurement accuracy. The end-fringe field was measured and the we found large leakage field still existed around the end-fringes. We are producing an additional magnetic shield which will be mounted in the circulating beam duct, and it will finished in Feb. 2022. In next March we will install the inner shield and measured the leakage field. After that we will install the new SM31 in MR.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK005

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Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 28 June 2022

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THPOTK007

Magnet Systems for Korea 4GSR Light Source

2781

D.E. Kim, T. Ha, G. Hahn, Y.G. Jung, H.-G. Lee, J. Lee, S. Shin, H.S. Suh
PAL, Pohang, Republic of Korea

Funding: Work supported by NRF of the Republic of Korea.
A 4th generation storage ring based light source is being developed in Korea since 2021. It features < 100 pm rad emittance, about 800 m circumference, 4 GeV e-beam energy, full energy booster injection, and more than 40 beamlines which includes more than 24 insertion device (ID) beamlines. This machine requires about ~1000 magnets including dipole, longitudinal gradient dipole, transverse gradient dipole, sextupoles, and correctors. The apertures are small and the lattice space requirements are very tight. In this report, a preliminary design of the each magnet is presented with detailed plan for the future.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK007

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Received ※ 13 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 07 July 2022

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THPOTK009

Design of a Permanent Magnet Based Dipole Quadrupole Magnet

2784

A.G. Hinton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
M. Kokole, T. Milharčič
KYMA, Trieste, Italy
A. Shahveh
DLS, Oxfordshire, United Kingdom
B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
B.J.A. Shepherd
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Permanent magnet technology can facilitate the design of accelerator magnets with much lower power consumption than traditional resistive electromagnets. By reducing the power requirements of magnets, more sustainable accelerators can be designed and built. At STFC, as part of the I.FAST collaboration, we are working to develop sustainable technologies for future accelerators. As part of this work, we have designed a permanent magnet based dipole-quadrupole magnet with parameters suited to meet the requirements of the proposed Diamond-II upgrade. We present here the magnetic design of the dipole-quadrupole magnet. The design, based on a single sided dipole-quadrupole, uses permanent magnets to generate the field in the magnet bore. The design includes the shaping of the pole tips to reduce multipole errors as well as methods of providing thermal stabilisation using thermal shunts and field tuning using resistive coils. The mechanical design of the magnet is being undertaken by colleagues at Kyma and a prototype of the magnet will soon be built and tested.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK009

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Received ※ 06 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022

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THPOTK011

Permanent Magnets for the CEBAF 24GeV Upgrade

2792

S.J. Brooks
BNL, Upton, New York, USA
S.A. Bogacz
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An upgrade of the CEBAF facility to double its present energy of 12GeV has been proposed. To provide double the number of linac passes using the existing five stacked arc beamlines, some beamlines are replaced by fixed-field accelerator (FFA) arcs, allowing multiple energies to pass through the same magnets. A solution is presented in which two of the existing electromagnetic beamlines are replaced with permanent magnet non-scaling FFA arcs, as demonstrated at CBETA. The two-stage design reduces peak magnetic field and synchrotron radiation loss compared to using a single stage. FFAs do not pulse their magnets, making permanent magnets a promising and power-efficient technology option. However, the magnetic field requirements are still at the high end of accelerator permanent magnets produced thus far (1.6T peak on beam), while the magnets must also be combined-function, having a gradient with a dipole offset. Designs using a novel oval aperture and open midplane within an adapted Halbach magnet are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK011

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Received ※ 31 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022

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THPOTK023

Ferrite Specification for the Mu2e 300 kHz and 4.4 MHz AC Dipole Magnets

2816

SUSPMF116

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K.P. Harrig, E. Prebys
UCD, Davis, California, USA
L. Elementi, C.C. Jensen, H. Pfeffer, D.A. Still, I. Terechkine, S.J. Werkema, M. Wong
Fermilab, Batavia, Illinois, USA

Funding: Work supported by by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, in addition to grant DE-SC0019254.
The Mu2e experiment at Fermilab will measure the rate for neutrinoless-conversion of negative muons into electrons with never-before-seen precision. This experiment will use a pulsed 8 GeV proton beam with pulses separated by 1.7 µs. To suppress beam induced backgrounds to this process, a set of dipoles operating at 300 kHz and 4.4 MHz have been developed that will reduce the fraction of out-of-time protons at the level of 1E-10 or less. Selection of magnetic ferrite material for construction must be carefully considered given the high repetition rate and duty cycle that can lead to excess heating in conventional magnetic material. A model of the electromagnetic and thermal properties of candidate ferrite materials has been constructed. Magnetic permeability, inductance, and power loss were measured at the two operating frequencies in toroidal ferrite samples as well as in the ferrites from which prototype magnets were built. Additionally, the outgassing rates of the ferrite material was measured to determine vacuum compatibility. The outcome of this work is a detailed specification of the electrical and mechanical details of the ferrite material required for this application.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK023

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Received ※ 30 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022

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