IPAC2017 - Classification: 07 Accelerator Technology / T09 Room-temperature Magnets

Paper	Title	Page
TUPIK130	A Permanent Magnet Quadrupole Magnet for CBETA	2016
	H. Witte, J.S. Berg, J. Cintorino, G.J. Mahler, N. Tsoupas, P. Wanderer BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Recently a collaboration between Brookhaven National Laboratory and Cornell University was established, aiming to build the CBETA accelerator. CBETA is a 150 MeV electron test accelerator, which prototypes essential technologies of eRHIC, which is a proposed upgrade to the existing Relativistic Heavy Ion Collider (RHIC) hadron facility at Brookhaven National Laboratory. Similar to eRHIC, CBETA employs an FFAG lattice for the arcs. The arcs require short, large aperture quadrupole magnets, which are located close together. BNL has been working on a design employing permanent magnets; we show the concept and the engineering design of these magnets. Prototype magnets have been constructed recently; we report on magnetic field quality measurements and their agreement with computer simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK130
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THYB1	Review of Permanent Magnet Technology for Accelerators
	C. Benabderrahmane, J. Chavanne ESRF, Grenoble, France
	Permanent magnets can provide many opportunities for accelerators in terms of energy and cost savings, and could significantly simplify their infrastructure. The recent developments in tunability could considerably widen their range of applications. I will review the recent advancements in materials and designs, and will give a perspective on future areas of applications.
	Slides THYB1 [26.489 MB]
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THPIK007	Production of Low Cost, High Field Quality Halbach Magnets	4118
	S.J. Brooks, J. Cintorino, A.K. Jain, G.J. Mahler BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. A shimming method has been developed at BNL that can improve the integrated field linearity of Halbach magnets to roughly 1 unit (1 part in 10⁴) at r=10mm. Two sets of magnets have been produced: six quadrupoles of strength 23.62T/m and six combined-function (asymmetrical) Halbach magnets of 19.12T/m with a central field of 0.377T. These were assembled using a 3D printed plastic mould inside an aluminium tube for strength. A shim holder, which is also 3D printed, is fitted within the magnet bore and holds iron wires of particular masses that cancel the multipole errors measured using a rotating coil on the unshimmed magnet. A single iteration of shimming reduces error multipoles by a factor of 4 on average. This assembly and shimming method results in a high field quality magnet at low cost, without stringent tolerance requirements or machining work. Applications of these magnets include compact FFAG beamlines such as FFAG proton therapy gantries, or any bending channel requiring a ~4x momentum acceptance. The design and shimming method can also be generalised to produce custom nonlinear fields, such as those for scaling FFAGs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK007
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THPIK012	The Magnets of BERLinPro: Specification, Design, Measurement and Quality Analysis	4124
	A.N. Matveenko, M. Abo-Bakr, K.B. Bürkmann-Gehrlein HZB, Berlin, Germany I.V. Davidyuk, O.A. Shevchenko, A.V. Utkin, N.A. Vinokurov BINP SB RAS, Novosibirsk, Russia
	Funding: Work supported by grants of Helmholtz Association VH-NG-636 and HRJRG-214 A total of 77 magnets form the magnetic lattice of the BERLinPro energy recovery linac prototype: 1+8+8 dipole magnets of three different types, 12+40 quadrupole magnets of two different types and 8 sextupole magnets have been produced by BINP. After the design phase, magnets production started in 2015, measurements and delivery took place in 2016, first assembly stage was finished in 03/2017. The motivation for the magnet specification and a summary of the basic design is given in this paper. Select-ed measurement data from the final acceptance tests are presented and analysed to ensure the magnet quality.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK012
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THPIK022	Measurements of High-Order Magnetic Field Components of Permanent Quadrupole Magnets for a Laser-Plasma-Driven Undulator X-Ray Source	4145
	P. Winkler University of Hamburg, Hamburg, Germany D. Kocon, A.Y. Molodozhentsev ELI-BEAMS, Prague, Czech Republic A.R. Maier CFEL, Hamburg, Germany L. Pribyl Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic M. Trunk University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Laser wakefield acceleration as a novel source of high-energy electron beam is a prominent candidate to drive a next generation of compact light sources. For applications, the electron beam needs to be captured using quadrupole magnets with extremely high field gradient. It allows to preserve properties of the laser-plasma driven electron beam. We designed and manufactured compact permanent quadrupole magnets providing magnetic field gradient up to 510 T/m at an aperture radius of only of a few mm. The Halbach-type quadrupole magents use 12 NdFeB wedges with a remanent magnetic field of 1.2 Tesla. We measured the magnetic field of the permanent magnet quadrupoles using the pulsed-wire and rotating-coil methods. Here, we present an analysis of the magnetic field quality and, in particular, the integrated field gradient and high-order field components. We further discuss the influence of the field imperfections on the electron beam quality and its consequences for application in the transport line of a laser-plasma-driven undulator X-ray source.
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THPIK027	Dynamic Behaviour of Fast-Pulsed Quadrupole Magnets for LINAC4 Transfer Line	4150
	S. Kasaei IPM, Tehran, Iran M.C.L. Buzio, L. Fiscarelli CERN, Geneva, Switzerland
	Linac4, recently built at CERN, is a linear normal conducting accelerator for negative hydrogen ions (H⁻). A new transfer line will link Linac4 to the Proton Synchrotron Booster. This transfer line includes 21 quadrupole magnets characterized by fast excitation cycles, which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on rotating and fixed search coils. We show how these instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour of these quadrupoles, such as the impact of hysteresis and dynamic eddy current effects.
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THPIK042	The Magnetic Measurement of Conventional Magnets for Electron Beam Accelerator of Northwest Institute of Nuclear Technology	4190
	Z. Zhang, L. Yang IHEP, Beijing, People's Republic of China
	The project of electron beam accelerator is worked together completed by NINT (Northwest Institute of Nuclear Technology) and IHEP (Institute of High Energy Physics, China). Conventional magnet of the project includes a total of three dipole magnets, four quadrupole magnets, six solenoid magnets, and four correction magnets. All of magnets to complete the measurement by IHEP hall measuring equipment. The integrated magnetic field measurement of the arc-shaped dipole magnet requires simultaneous movement by the X-axis and the Z-axis, using Labview software written a new measurement procedure, the new measurement procedure has been completed by setting the measuring angle and the measuring radius. All measurement results of conventional magnets have reached the physical design requirements, and each magnet were carried out more than twice the measurement, the reproducibility of the measurement results are better than one-thousandth, fully meet the design claim of NINT.
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THPIK079	Developments and Measurements Done at ALBA Magnetic Measurements Laboratory Along 2016	4266
	J. Campmany, L.G.O. Garcia-Orta, J. Marcos, V. Massana ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	Along 2016, ALBA magnetic measurements laboratory has measured magnets for a number of facilities that are being built over the world. Their measurement has been a challenge in terms of improving the methodologies of fiducialization and data analysis, since we have to accommodate to the different set of magnets characteristics and specifications. Especially relevant has been the measurement of closed structures using a conventional Hall probe bench, making the measurement in two steps and relying on alignment accuracy to merge both measurements. In this paper we enumerate the different projects in which ALBA has collaborated, and we remark the method for aligning the quadrupoles to the rotating coil, as well the methodology used to measure closed magnets in two steps with the conventional Hall probe bench.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK079
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THPIK082	Quadrupole Magnet Design for the ESS MEBT	4276
	D. Fernandez-Cañoto, I. Bustinduy, G. Harper, J.L. Muñoz, I. Rueda, S. Varnasseri ESS Bilbao, Zamudio, Spain
	Funding: Consortium ESS Bilbao ESS Bilbao is responsible for the design and fabrication of the ESS MEBT as an In-Kind contribution. The MEBT includes a focusing lattice with 11 quadrupole magnets with different operational gradients, but fabricated from the same model to simplify manufacturing and save costs. The magnet is designed with a 20.5 mm aperture radius to generate focusing fields of up to 2.74 T and also includes two additional steering coil systems assembled around yoke return arms to produce vertical and horizontal dipole fields up to 20 G·m. The magnet model, which fabrication starts in 2017, is here introduced. Magnetic, thermoelectric and dimensional studies are performed and results compared to specifications. Suitable transfer functions for magnet operation and magnetic fields for a doublet system with a BCM magnetically shielded placed between the two magnets are presented.
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THPIK092	Considerations on the Effect of Magnet Yoke Dilution on Remanent Field at ELENA	4299
	C. Carli, L. Fiscarelli, D. Schoerling CERN, Geneva, Switzerland
	The Extra Low Energy Antiproton ring (ELENA) is a small synchrotron constructed at CERN to decelerate antiprotons down to 100 keV and, thus, operated at very low magnetic fields. The CERN magnet group has carried out extensive investigations on accelerator magnets for very low fields, comprising theoretical studies and the construction of several prototype magnets, to ensure that the required field quality can be reached at these very low fields. In the course of this work, experimental investigations [1] led to the initially unexpected observation that dilution of the yoke, i.e. alternating laminations made of electric steel with thicker non-magnetic stainless steel laminations, increases the remnant field. An explanation for this behaviour has already been anticipated in a previous paper [2]. Here, we treat this specific topic in analytical detail. We come to the conclusion that magnet yoke thinning in most practical situations does not improve the field quality at very low field levels, but rather enhances the impact from hysteresis and remanence effects. [1] L.Fiscarelli, Magnetic measurements on the quadrupoles prototypes for ELENA (PXMQNLGNAP), CERN internal report. [2] D. Schoerling, Case Study of a Magnetic System for low-Energy Machines, PRAB 19, 082401 (2016).
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THPIK098	Bz Calculation of TPS Linac Focusing Coils and a Toolkit for Bz Optimization	4321
	H.H. Chen, H.-P. Chang, C.L. Chen, C.-S. Fann, K.-K. Lin, Y.K. Lin, K.L. Tsai NSRRC, Hsinchu, Taiwan
	A set of focusing coils is installed along TPS linac beam centerline at low energy region (< 10 MeV) in order to confine the beam radius within 5 mm. The longitudinal magnetic field calculation along the beam centerline has been carried out in this study. The estimated Bz is obtained based on Biot-Savart law calculation. Then, it is verified by field measurement using Gauss meter at specific centerline locations. Calibration process is performed by comparing the calculated and measured Bz fields at selected operation settings. The comparison result is presented in this report. The linac operation experience indicates that tuning of the coil settings is critical concerning beam property optimization. Consequently, a Bz calculation toolkit is developed to cope with the multi-knobs optimization process while tuning of numerous focusing coils installed in the system at various locations. The applications of the Bz calculation toolkit is briefly described.
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THPIK104	Transient Simulation of the ISIS Synchrotron Singlet Quadrupoles Using OPERA 3D	4334
	I. Rodríguez STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	Type QX10⁶ singlet magnets are AC defocusing quadrupoles used in the ISIS main synchrotron ring. They have an aperture of 202 mm and a yoke length of 303 mm, so the end effects are significant. The iron poles and the yoke are asymmetric and the coils are driven by a 50Hz, 400 A AC current, biased with a DC current of 665 A. Therefore the yoke has to be laminated, and the laminations are slitted up to a depth of 90 mm on each side to further reduce the eddy current losses. Two 3D models (DC and transient) have been developed using OPERA 3D for different purposes. Both models require the use of an anisotropic BH curve for the yoke, and the transient model also requires an anisotropic conductivity and a prismatic/hexahedral mesh to overcome the limitations of the linear tetrahedral edge elements in OPERA's vector potential formulation. The quadrupole field quality was originally measured in 1982 with a DC excitation at the biased peak current (1065 A) and those measurements are now compared to both models. The iron losses due to the eddy currents are also presented and compared to the original specifications defined in 1980, as well as an estimation of the eddy currents in the coils.
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THPIK105	The ZEPTO Dipole: Zero Power Tuneable Optics for CLIC	4338
	A.R. Bainbridge, J.A. Clarke, B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom N.A. Collomb STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom M. Modena CERN, Geneva, Switzerland
	Permanent magnet (PM) based systems create a significantly reduced power consumption compared to conventional room temperature electromagnets. STFC and CERN are investigating the feasibility of using tuneable PM systems to reduce high electricity and water-cooling costs; plus the associated large scale infrastructure burden in the proposed CLIC accelerator. This collaboration has previously resulted in the development of two tuneable PM Quadrupole systems. We present here a continuation of this work in the development of a pure PM C-Dipole with a tuning range of over 50%. A prototype has been simulated and constructed using a single 50x40x20 cm block of NdFeB which slides horizontally to provide tuning. We outline the design, construction and measurement of a prototype dipole and discuss its suitability as a replacement for electromagnetic systems. Issues including field homogeneity over a large tuning range and the management of high magnetic forces are addressed.
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THPIK107	Design and Characterisation of the Focusing Solenoidal System for the CLARA High Repetition Rate Electron Source	4346
	D.J. Scott, A.R. Bainbridge, K.B. Marinov, B.L. Militsyn, B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R.J. Cash, T.J. Jones STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom C.S. Edmonds The University of Liverpool, Liverpool, United Kingdom
	One of the critical components of electron injectors based on RF photoelectron sources is the focusing system. The system typically consists of a Main Focusing Solenoid and a Bucking Coil. Combination of these two solenoids should provide proper focusing of the beam at the exit of the RF cavity and zero longitudinal magnetic field in the photocathode plane to minimise the beam emittance. Imperfection of the solenoid design, manufacturing and alignment frequently leads to asymmetry of the focusing field which has to be compensated with additional coils. In order to eliminate mechanical and magnetic misalignment the CLARA photoinjector solenoids are mounted on one integrated bench and before installation into the beamline have been aligned in the magnet laboratory with simultaneous measurement of the magnetic field. In order to define multipole field components, dedicated measurements of the transverse magnetic field have been done. The amplitudes of the multipoles have been obtained from analysis of the transverse field map. We present here the results of field characterisation.
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THPIK128	Switching Magnet for Heavy-Ion Beam Separation	4403
	J.J. Hartzell, R.B. Agustsson, S.V. Kutsaev, A. Laurich, A.Y. Murokh, F.H. O'Shea, T.J. Villabona RadiaBeam, Santa Monica, California, USA G. Leyh LOD, Brisbane, USA E.A. Savin RadiaBeam Systems, Santa Monica, California, USA
	Funding: This work was supported by the United States Department of Energy SBIR Grant No. DE-SC0015124. We present a design for a complete switching magnet system capable of deflecting 8-25 MeV/u heavy-ion beams by 10 degrees. The system can produce flat-top pulses from 1 to 30 ms with rise and fall times of less than 0.5 ms at a duty cycle of 3-91% into a heavily inductive load. As determined by physics needs, the operational parameters of this magnet place it between fast rising kicker magnets with short duration and slow rising (or DC) resistive magnets which are optimized for efficiency and current-based power loss. This magnet must operate efficiently with over 91% duty factor and have a modestly fast rise time. The resulting design uses a resistive magnet scheme, to optimize the current-based losses, that is pulsed using a new circuit to control the applied voltage. The magnet has a laminated, iron dominated, H-shaped core. Directly-cooled copper pancake coils energize the magnet. The modulator employs a novel, proprietary, over-voltage topology to overcome the inherent inductance and achieve the fast rise and fall times, switching to a precision DC supply to efficiently maintain the flattop without requiring voltage in excess of ±3 kV.
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THPIK129	Non-Linear Inserts for the IOTA Ring	4407
	F.H. O'Shea, R.B. Agustsson, P.S. Chang, Y.C. Chen RadiaBeam, Santa Monica, California, USA D.W. Martin, J.D. McNevin RadiaBeam Systems, Santa Monica, California, USA
	Funding: Work supported by DOE under contract DE-SC0009531. We present here the complete non-linear insert for the IOTA ring at Fermilab. In particular, we will show the results for the magnetic measurements and a discussion of leak correction in the unusually shaped vacuum chamber. A test assembly of the insert has been successfully completed and the insert functions mechanically as designed.
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THPVA151	Halbach Magnets for CBETA and eRHIC	4814
	H. Witte, J.S. Berg, B. Parker BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. At Brookhaven National Laboratory two design efforts are underway: eRHIC and CBETA. eRHIC is a proposed upgrade to the existing Relativistic Heavy Ion Collider (RHIC), which would allow collisions of up to 21 GeV polarized electrons with protons or heavy ions. CBETA is a 150 MeV electron accelerator, aiming to demonstrate essential technology necessary for eRHIC. Both machines employ FFAG arcs and are designated to use permanent magnet material for the required quadrupole magnets. One proposed design is a Halbach magnet; this paper investigates the feasibility of this approach.
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Paper

Title

Page

A Permanent Magnet Quadrupole Magnet for CBETA

2016

H. Witte, J.S. Berg, J. Cintorino, G.J. Mahler, N. Tsoupas, P. Wanderer
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Recently a collaboration between Brookhaven National Laboratory and Cornell University was established, aiming to build the CBETA accelerator. CBETA is a 150 MeV electron test accelerator, which prototypes essential technologies of eRHIC, which is a proposed upgrade to the existing Relativistic Heavy Ion Collider (RHIC) hadron facility at Brookhaven National Laboratory. Similar to eRHIC, CBETA employs an FFAG lattice for the arcs. The arcs require short, large aperture quadrupole magnets, which are located close together. BNL has been working on a design employing permanent magnets; we show the concept and the engineering design of these magnets. Prototype magnets have been constructed recently; we report on magnetic field quality measurements and their agreement with computer simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK130

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THYB1

Review of Permanent Magnet Technology for Accelerators

C. Benabderrahmane, J. Chavanne
ESRF, Grenoble, France

Permanent magnets can provide many opportunities for accelerators in terms of energy and cost savings, and could significantly simplify their infrastructure. The recent developments in tunability could considerably widen their range of applications. I will review the recent advancements in materials and designs, and will give a perspective on future areas of applications.

Slides THYB1 [26.489 MB]

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THPIK007

Production of Low Cost, High Field Quality Halbach Magnets

4118

S.J. Brooks, J. Cintorino, A.K. Jain, G.J. Mahler
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A shimming method has been developed at BNL that can improve the integrated field linearity of Halbach magnets to roughly 1 unit (1 part in 10⁴) at r=10mm. Two sets of magnets have been produced: six quadrupoles of strength 23.62T/m and six combined-function (asymmetrical) Halbach magnets of 19.12T/m with a central field of 0.377T. These were assembled using a 3D printed plastic mould inside an aluminium tube for strength. A shim holder, which is also 3D printed, is fitted within the magnet bore and holds iron wires of particular masses that cancel the multipole errors measured using a rotating coil on the unshimmed magnet. A single iteration of shimming reduces error multipoles by a factor of 4 on average. This assembly and shimming method results in a high field quality magnet at low cost, without stringent tolerance requirements or machining work. Applications of these magnets include compact FFAG beamlines such as FFAG proton therapy gantries, or any bending channel requiring a ~4x momentum acceptance. The design and shimming method can also be generalised to produce custom nonlinear fields, such as those for scaling FFAGs.

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THPIK012

The Magnets of BERLinPro: Specification, Design, Measurement and Quality Analysis

4124

A.N. Matveenko, M. Abo-Bakr, K.B. Bürkmann-Gehrlein
HZB, Berlin, Germany
I.V. Davidyuk, O.A. Shevchenko, A.V. Utkin, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia

Funding: Work supported by grants of Helmholtz Association VH-NG-636 and HRJRG-214
A total of 77 magnets form the magnetic lattice of the BERLinPro energy recovery linac prototype: 1+8+8 dipole magnets of three different types, 12+40 quadrupole magnets of two different types and 8 sextupole magnets have been produced by BINP. After the design phase, magnets production started in 2015, measurements and delivery took place in 2016, first assembly stage was finished in 03/2017. The motivation for the magnet specification and a summary of the basic design is given in this paper. Select-ed measurement data from the final acceptance tests are presented and analysed to ensure the magnet quality.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK012

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THPIK022

Measurements of High-Order Magnetic Field Components of Permanent Quadrupole Magnets for a Laser-Plasma-Driven Undulator X-Ray Source

4145

P. Winkler
University of Hamburg, Hamburg, Germany
D. Kocon, A.Y. Molodozhentsev
ELI-BEAMS, Prague, Czech Republic
A.R. Maier
CFEL, Hamburg, Germany
L. Pribyl
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
M. Trunk
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Laser wakefield acceleration as a novel source of high-energy electron beam is a prominent candidate to drive a next generation of compact light sources. For applications, the electron beam needs to be captured using quadrupole magnets with extremely high field gradient. It allows to preserve properties of the laser-plasma driven electron beam. We designed and manufactured compact permanent quadrupole magnets providing magnetic field gradient up to 510 T/m at an aperture radius of only of a few mm. The Halbach-type quadrupole magents use 12 NdFeB wedges with a remanent magnetic field of 1.2 Tesla. We measured the magnetic field of the permanent magnet quadrupoles using the pulsed-wire and rotating-coil methods. Here, we present an analysis of the magnetic field quality and, in particular, the integrated field gradient and high-order field components. We further discuss the influence of the field imperfections on the electron beam quality and its consequences for application in the transport line of a laser-plasma-driven undulator X-ray source.

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THPIK027

Dynamic Behaviour of Fast-Pulsed Quadrupole Magnets for LINAC4 Transfer Line

4150

S. Kasaei
IPM, Tehran, Iran
M.C.L. Buzio, L. Fiscarelli
CERN, Geneva, Switzerland

Linac4, recently built at CERN, is a linear normal conducting accelerator for negative hydrogen ions (H⁻). A new transfer line will link Linac4 to the Proton Synchrotron Booster. This transfer line includes 21 quadrupole magnets characterized by fast excitation cycles, which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on rotating and fixed search coils. We show how these instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour of these quadrupoles, such as the impact of hysteresis and dynamic eddy current effects.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK027

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THPIK042

The Magnetic Measurement of Conventional Magnets for Electron Beam Accelerator of Northwest Institute of Nuclear Technology

4190

Z. Zhang, L. Yang
IHEP, Beijing, People's Republic of China

The project of electron beam accelerator is worked together completed by NINT (Northwest Institute of Nuclear Technology) and IHEP (Institute of High Energy Physics, China). Conventional magnet of the project includes a total of three dipole magnets, four quadrupole magnets, six solenoid magnets, and four correction magnets. All of magnets to complete the measurement by IHEP hall measuring equipment. The integrated magnetic field measurement of the arc-shaped dipole magnet requires simultaneous movement by the X-axis and the Z-axis, using Labview software written a new measurement procedure, the new measurement procedure has been completed by setting the measuring angle and the measuring radius. All measurement results of conventional magnets have reached the physical design requirements, and each magnet were carried out more than twice the measurement, the reproducibility of the measurement results are better than one-thousandth, fully meet the design claim of NINT.

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THPIK079

Developments and Measurements Done at ALBA Magnetic Measurements Laboratory Along 2016

4266

J. Campmany, L.G.O. Garcia-Orta, J. Marcos, V. Massana
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

Along 2016, ALBA magnetic measurements laboratory has measured magnets for a number of facilities that are being built over the world. Their measurement has been a challenge in terms of improving the methodologies of fiducialization and data analysis, since we have to accommodate to the different set of magnets characteristics and specifications. Especially relevant has been the measurement of closed structures using a conventional Hall probe bench, making the measurement in two steps and relying on alignment accuracy to merge both measurements. In this paper we enumerate the different projects in which ALBA has collaborated, and we remark the method for aligning the quadrupoles to the rotating coil, as well the methodology used to measure closed magnets in two steps with the conventional Hall probe bench.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK079

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THPIK082

Quadrupole Magnet Design for the ESS MEBT

4276

D. Fernandez-Cañoto, I. Bustinduy, G. Harper, J.L. Muñoz, I. Rueda, S. Varnasseri
ESS Bilbao, Zamudio, Spain

Funding: Consortium ESS Bilbao
ESS Bilbao is responsible for the design and fabrication of the ESS MEBT as an In-Kind contribution. The MEBT includes a focusing lattice with 11 quadrupole magnets with different operational gradients, but fabricated from the same model to simplify manufacturing and save costs. The magnet is designed with a 20.5 mm aperture radius to generate focusing fields of up to 2.74 T and also includes two additional steering coil systems assembled around yoke return arms to produce vertical and horizontal dipole fields up to 20 G·m. The magnet model, which fabrication starts in 2017, is here introduced. Magnetic, thermoelectric and dimensional studies are performed and results compared to specifications. Suitable transfer functions for magnet operation and magnetic fields for a doublet system with a BCM magnetically shielded placed between the two magnets are presented.

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THPIK092

Considerations on the Effect of Magnet Yoke Dilution on Remanent Field at ELENA

4299

C. Carli, L. Fiscarelli, D. Schoerling
CERN, Geneva, Switzerland

The Extra Low Energy Antiproton ring (ELENA) is a small synchrotron constructed at CERN to decelerate antiprotons down to 100 keV and, thus, operated at very low magnetic fields. The CERN magnet group has carried out extensive investigations on accelerator magnets for very low fields, comprising theoretical studies and the construction of several prototype magnets, to ensure that the required field quality can be reached at these very low fields. In the course of this work, experimental investigations [1] led to the initially unexpected observation that dilution of the yoke, i.e. alternating laminations made of electric steel with thicker non-magnetic stainless steel laminations, increases the remnant field. An explanation for this behaviour has already been anticipated in a previous paper [2]. Here, we treat this specific topic in analytical detail. We come to the conclusion that magnet yoke thinning in most practical situations does not improve the field quality at very low field levels, but rather enhances the impact from hysteresis and remanence effects.
[1] L.Fiscarelli, Magnetic measurements on the quadrupoles prototypes for ELENA (PXMQNLGNAP), CERN internal report.
[2] D. Schoerling, Case Study of a Magnetic System for low-Energy Machines, PRAB 19, 082401 (2016).

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THPIK098

Bz Calculation of TPS Linac Focusing Coils and a Toolkit for Bz Optimization

4321

H.H. Chen, H.-P. Chang, C.L. Chen, C.-S. Fann, K.-K. Lin, Y.K. Lin, K.L. Tsai
NSRRC, Hsinchu, Taiwan

A set of focusing coils is installed along TPS linac beam centerline at low energy region (< 10 MeV) in order to confine the beam radius within 5 mm. The longitudinal magnetic field calculation along the beam centerline has been carried out in this study. The estimated Bz is obtained based on Biot-Savart law calculation. Then, it is verified by field measurement using Gauss meter at specific centerline locations. Calibration process is performed by comparing the calculated and measured Bz fields at selected operation settings. The comparison result is presented in this report. The linac operation experience indicates that tuning of the coil settings is critical concerning beam property optimization. Consequently, a Bz calculation toolkit is developed to cope with the multi-knobs optimization process while tuning of numerous focusing coils installed in the system at various locations. The applications of the Bz calculation toolkit is briefly described.

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THPIK104

Transient Simulation of the ISIS Synchrotron Singlet Quadrupoles Using OPERA 3D

4334

I. Rodríguez
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

Type QX10⁶ singlet magnets are AC defocusing quadrupoles used in the ISIS main synchrotron ring. They have an aperture of 202 mm and a yoke length of 303 mm, so the end effects are significant. The iron poles and the yoke are asymmetric and the coils are driven by a 50Hz, 400 A AC current, biased with a DC current of 665 A. Therefore the yoke has to be laminated, and the laminations are slitted up to a depth of 90 mm on each side to further reduce the eddy current losses. Two 3D models (DC and transient) have been developed using OPERA 3D for different purposes. Both models require the use of an anisotropic BH curve for the yoke, and the transient model also requires an anisotropic conductivity and a prismatic/hexahedral mesh to overcome the limitations of the linear tetrahedral edge elements in OPERA's vector potential formulation. The quadrupole field quality was originally measured in 1982 with a DC excitation at the biased peak current (1065 A) and those measurements are now compared to both models. The iron losses due to the eddy currents are also presented and compared to the original specifications defined in 1980, as well as an estimation of the eddy currents in the coils.

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THPIK105

The ZEPTO Dipole: Zero Power Tuneable Optics for CLIC

4338

A.R. Bainbridge, J.A. Clarke, B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
M. Modena
CERN, Geneva, Switzerland

Permanent magnet (PM) based systems create a significantly reduced power consumption compared to conventional room temperature electromagnets. STFC and CERN are investigating the feasibility of using tuneable PM systems to reduce high electricity and water-cooling costs; plus the associated large scale infrastructure burden in the proposed CLIC accelerator. This collaboration has previously resulted in the development of two tuneable PM Quadrupole systems. We present here a continuation of this work in the development of a pure PM C-Dipole with a tuning range of over 50%. A prototype has been simulated and constructed using a single 50x40x20 cm block of NdFeB which slides horizontally to provide tuning. We outline the design, construction and measurement of a prototype dipole and discuss its suitability as a replacement for electromagnetic systems. Issues including field homogeneity over a large tuning range and the management of high magnetic forces are addressed.

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THPIK107

Design and Characterisation of the Focusing Solenoidal System for the CLARA High Repetition Rate Electron Source

4346

D.J. Scott, A.R. Bainbridge, K.B. Marinov, B.L. Militsyn, B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R.J. Cash, T.J. Jones
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
C.S. Edmonds
The University of Liverpool, Liverpool, United Kingdom

One of the critical components of electron injectors based on RF photoelectron sources is the focusing system. The system typically consists of a Main Focusing Solenoid and a Bucking Coil. Combination of these two solenoids should provide proper focusing of the beam at the exit of the RF cavity and zero longitudinal magnetic field in the photocathode plane to minimise the beam emittance. Imperfection of the solenoid design, manufacturing and alignment frequently leads to asymmetry of the focusing field which has to be compensated with additional coils. In order to eliminate mechanical and magnetic misalignment the CLARA photoinjector solenoids are mounted on one integrated bench and before installation into the beamline have been aligned in the magnet laboratory with simultaneous measurement of the magnetic field. In order to define multipole field components, dedicated measurements of the transverse magnetic field have been done. The amplitudes of the multipoles have been obtained from analysis of the transverse field map. We present here the results of field characterisation.

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THPIK128

Switching Magnet for Heavy-Ion Beam Separation

4403

J.J. Hartzell, R.B. Agustsson, S.V. Kutsaev, A. Laurich, A.Y. Murokh, F.H. O'Shea, T.J. Villabona
RadiaBeam, Santa Monica, California, USA
G. Leyh
LOD, Brisbane, USA
E.A. Savin
RadiaBeam Systems, Santa Monica, California, USA

Funding: This work was supported by the United States Department of Energy SBIR Grant No. DE-SC0015124.
We present a design for a complete switching magnet system capable of deflecting 8-25 MeV/u heavy-ion beams by 10 degrees. The system can produce flat-top pulses from 1 to 30 ms with rise and fall times of less than 0.5 ms at a duty cycle of 3-91% into a heavily inductive load. As determined by physics needs, the operational parameters of this magnet place it between fast rising kicker magnets with short duration and slow rising (or DC) resistive magnets which are optimized for efficiency and current-based power loss. This magnet must operate efficiently with over 91% duty factor and have a modestly fast rise time. The resulting design uses a resistive magnet scheme, to optimize the current-based losses, that is pulsed using a new circuit to control the applied voltage. The magnet has a laminated, iron dominated, H-shaped core. Directly-cooled copper pancake coils energize the magnet. The modulator employs a novel, proprietary, over-voltage topology to overcome the inherent inductance and achieve the fast rise and fall times, switching to a precision DC supply to efficiently maintain the flattop without requiring voltage in excess of ±3 kV.

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THPIK129

Non-Linear Inserts for the IOTA Ring

4407

F.H. O'Shea, R.B. Agustsson, P.S. Chang, Y.C. Chen
RadiaBeam, Santa Monica, California, USA
D.W. Martin, J.D. McNevin
RadiaBeam Systems, Santa Monica, California, USA

Funding: Work supported by DOE under contract DE-SC0009531.
We present here the complete non-linear insert for the IOTA ring at Fermilab. In particular, we will show the results for the magnetic measurements and a discussion of leak correction in the unusually shaped vacuum chamber. A test assembly of the insert has been successfully completed and the insert functions mechanically as designed.

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THPVA151

Halbach Magnets for CBETA and eRHIC

4814

H. Witte, J.S. Berg, B. Parker
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
At Brookhaven National Laboratory two design efforts are underway: eRHIC and CBETA. eRHIC is a proposed upgrade to the existing Relativistic Heavy Ion Collider (RHIC), which would allow collisions of up to 21 GeV polarized electrons with protons or heavy ions. CBETA is a 150 MeV electron accelerator, aiming to demonstrate essential technology necessary for eRHIC. Both machines employ FFAG arcs and are designated to use permanent magnet material for the required quadrupole magnets. One proposed design is a Halbach magnet; this paper investigates the feasibility of this approach.

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