IPAC2013 - List of Keywords (permanent-magnet)

Paper	Title	Other Keywords	Page
MOPEA009	ESRF Operation and Upgrade Status	undulator, storage-ring, emittance, booster	82
	J.-L. Revol, J.C. Biasci, J-F. B. Bouteille, F. Ewald, L. Farvacque, A. Franchi, G. Gautier, L. Goirand, M. Hahn, L. Hardy, J. Jacob, J.M. Koch, M.L. Langlois, G. Lebec, J.M. Mercier, T.P. Perron, E. Plouviez, P. Raimondi, K.B. Scheidt, V. Serrière ESRF, Grenoble, France
	The European Synchrotron Radiation Facility (ESRF) is presently midway through the Upgrade Programme Phase I (2009-2015), which concerns its infrastructure, beamlines and X-ray source. This paper reports on the present operation performance of the source, highlighting the more recent developments. In this context, 8 insertion device straight sections have been lengthened from five to six metres; two of them operating with canted undulators. The lattice of one cell has been modified for a further increase to 7 metres allowing the test of a mini beta optics and latter the distribution of cavities. A second cryogenic permanent magnet undulator has been completed, which gives a factor of more than 2 in flux at high energy. The booster klystron-based radio frequency transmitter has been replaced by high power solid state amplifiers. Out of three prototypes of HOM damped cavities working at room temperature which have been received and tested, one has been successfully commissioned with beam. Subsequent to the upgrade of the beam position monitor system, a new orbit feedback has substantially reduced the orbit distortion induced by ID gap motions.

MOPFI035	Preliminary Results of H²⁺ Beam Generated by a 2.45 GHz Permanent Magnet ECR Ion Source at PKU	ion, ion-source, plasma, cyclotron	363
	Y. Xu, J. Chen, J.E. Chen, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z.H. Wang, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China A.L. Zhang Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	Recently, the need to build an ion source generating high current hydrogen molecular ion H²⁺ beam has been growing rapidly. For example, H²⁺ ion can be used as a pilot beam of the intense deuteron beam during the commission phase of linear accelerators to minimize the activation of components. And it is an effective way to improve the output current of cyclotrons by accelerating H²⁺ and stripping it into H⁺ at the exit of accelerator, instead of accelerating H⁺ beam directly. To obtain high-yield H²⁺ ion beam, experimental and theoretical study was carried out on the 2.45 GHz Peking University permanent magnet electron cyclotron resonance ion source (PKU PMECR). With PMECR II, studies on the size of discharge chamber and the operation pressure were carried out to increase H²⁺ ion fraction. Beam analysis results prove that the H²⁺ can reach 40.5% with suitable operation parameters. More details will be presented in this paper. Zhizhong Song, Shixiang Peng et al., Rev. Sci. Instrum. 77, 03A305 (2006) ** Author to whom correspondence should be addressed. Electronic mail: sxpeng@pku.edu.cn.

TUPWA041	Reduction of Secondary Electron (SEY) Yield Figures on Smooth Metallic Surfaces by Means of Magnetic Roughness	electron, gun, radio-frequency	1799
	M. Taborelli, F. Caspers, M. Mensi CERN, Geneva, Switzerland L.S. Aguilera, I. Montero CSIC, Madrid, Spain
	High secondary electron yield of metallic surfaces used in accelerator and also space applications is of general concern. In addition to several well known coating techniques and microscopic or macroscopic mechanical roughness (grooves) which may significantly increase microwave losses the concept of magnetic surface roughness has been proposed recently. In this concept a smooth and very well conductimg surface with low microwave losses is maintained, but underneath this surface a large number of tiny permanent magnets are located to build a rough magnetic equipotential structure. In this paper we present and discuss measurement of the SEY and the improvement in terms of SEY for different parameter ranges

WEIB205	Promoting Local Economic Development by an Integration of Industry, Teaching and Research of Compact Low Energy Accelerators	electron, radiation, high-voltage, HOM	2119
	M. Fan, D.Z. Chen, J. Huang, D. Li, K.F. Liu, B. Qin, Y.Q. Xiong, J. Yang, T. Yu HUST, Wuhan, People's Republic of China H.Q. Gao Hubei University of Science and Technology, Hubei, People's Republic of China
	Huazhong University of Science and Technology has been carrying out R&D of compact low energy accelerators by integrating industry, teaching and research to promote local economic development supported by both national and provincial government and local enterprises. Currently, the projects include: compact medical cyclotron, electron irradiation accelerators, etc. The industry of non-power nuclear energy based on low energy particle accelerator has also drawn attention from the provincial government of Hubei and municipal government of Xianning. Meanwhile, a series of lectures about nuclear science and nuclear safety were hosted to help the public better understand nuclear technology and to wipe out fears of nuclear energy. At the moment, the application of non-power nuclear energy with based on compact low energy accelerator is developing into an industry chain in the area of central China.
	Slides WEIB205 [2.311 MB]

WEPWA003	Hall-Probe Bench for Cryogenic in-Vacuum-Undulators	undulator, vacuum, laser, cryogenics	2126
	C. Kuhn, H.-J. Bäcker, J. Bahrdt, A. Gaupp, B. Schulz HZB, Berlin, Germany
	The Helmholtz-Zentrum Berlin (HZB) builds a 2m long in-vacuum-hall-probe-bench for the characterization of several cryogenic undulators currently under development. Short period lengths and small gaps require an accurate correlation between Hall probe position / orientation and the 3D-magnetic field. The geometric tolerances of an in-vacuum bench in the presence of strong temperature gradients do not permit a Hall probe movement along a straight line without corrections. The HZB-bench employs a system of laser interferometers and position sensitive detectors, which is used in a feed-back loop for the Hall probe position / orientation. First measurements on the accuracy and reproducibility of the new device are presented.

WEPWA028	Measurement and Research on Cryogenic Remanence of Chunks Permanent Magnet for Cryogenic Undulator	cryogenics, controls, undulator, factory	2190
	Y.Z. He SINAP, Shanghai, People's Republic of China
	The higher-precision cryogenic remanence measurment technology and error for chunks permanent magnet were researched in china firstly (10-300K). Magnetic measurement tooling and magnetic field calculation and measurement method of cryogenic remanence measurement system of chunks permanent magnet for cryogenic undulator were optimized. Cryogenic calibration Hall probe were pasted on surface of domestic chunks permanent magnet(Nd2Fe14B: N52, N50M, etc.) and table magnetic field B of permanent magnet were measured, and after being converted, then cryogenic remanence of domestic chunks permanent magnet were obtained and cryogenic remanence variation of domestic chunks permanent magnet were researched. Cryogenic remanence measurement data were checked by pulse B-H tester and PPMS respectively, the results show that cryogenic remanence data has higher reliability. By this experiment, initial foundation were established for development of SSRF cryogenic undulator and for cryogenic remanence measurement and study of domestic other chunks permanent magnets.

WEPWA038	Influence of Magnet Errors and Waveguide Permeability on Magnetic Field Performance in Pure Permanent Undulators	undulator, FEL, simulation, radiation	2214
	X. Liu, K.F. Liu, B. Qin, P. Tan, B. Wu, Y.Q. Xiong, J. Yang, L. Yang HUST, Wuhan, People's Republic of China
	Abstract For pure permanent magnet (PM) undulator, unavoidable divergences of remanence field and magnetization vector in PM blocks and installation error will cause magnetic field error at the central line of the undulator. This paper presents the simulation results of the magnetic field in non-ideal undulator containing these errors, with specified tolerances in Normal distribution. As well as the peak field error, increases of the harmonic components and impact on field integrals are calculated. The influence on magnetic field caused by waveguide permeability is also discussed.

WEPWA086	Characterization of PrFeB Permanent Magnet Blocks with Helmholtz Coils at NSLS-II	undulator, cryogenics, dipole, insertion	2304
	P. He, P.L. Cappadoro, T.M. Corwin, H.C. Fernandes, D.A. Harder, C.A. Kitegi, M.M. Musardo, G. Rakowsky, J. Rank, T. Tanabe BNL, Upton, Long Island, New York, USA M. Kokole KYTE, Sezana, Slovenia
	For investigatation to build the cryogenic undulator using bake-able Praseodymium-Iron-Boron(PrFeB) magnet blocks, a short period(16.8mm) and fixed gap(5mm) hybrid undulator prototype has been fabricated at BNL. For this undulator, 36 PrFeB magnet blocks(28 type A, 4 type B, 4 type C) are used. The magnetic field characteristics of the undulator heavily depend on the directional uniformity of the magnetization of block sets. The strength and direction of magnetization of the PrFeB magnet blocks are measured using a Helmholtz coil system. The data include the three vector components of the total magnetic dipole moment of the blocks and also compare with vendor measuremeant results.

WEPFI024	Anisotropic Ferrite Magnet Focusing System for Klystrons	klystron, focusing, cathode, simulation	2756
	Y. Fuwa, H. Ikeda, Y. Iwashita, R. Kitahara, Y. Nasu, H. Tongu Kyoto ICR, Uji, Kyoto, Japan S. Fukuda, T. Matsumoto, S. Michizono KEK, Ibaraki, Japan
	The permanent magnet beam focusing for klystrons can eliminate the solenoid coil with the water cooling system and the power supply that consumes electricity. Hence the failure rate and the operating cost of RF systems should decrease. This feature is suitable for a large facility that requires a lot of klystrons such as ILC. Since the required magnetic field for klystron beam is moderate, inexpensive anisotropic ferrite magnets can be applied. The test model is fabricated for a 1.3 GHz klystron whose output power is 800 kW. Each magnet block in the model is movable for magnetic field adjustment and the iron yoke in the oil tank improves magnetic field distribution around cathode area. The result of a klystron power test will be presented.

THPME001	Permanent Magnets in Accelerators can save Energy, Space, and Cost	dipole, quadrupole, synchrotron, vacuum	3511
	F. Bødker, L.O. Baandrup, A. Baurichter, N. Hauge, K.F. Laurberg, B.R. Nielsen, G. Nielsen Danfysik A/S, Taastrup, Denmark O. Balling Aarhus University, Aarhus, Denmark F.B. Bendixen, P. Kjeldsteen, P. Valler Sintex A/S, Hobro, Denmark S.P. Møller, H.D. Thomsen ISA, Aarhus, Denmark H.-A. Synal ETH, Zurich, Switzerland
	Green Magnet technology with close to zero electrical power consumption without the need for cooling water saves costs, space and hence spares natural resources. A compact dipole based on permanent magnets has been developed at Danfysik in collaboration with Sintex and Aarhus University. This first Green Magnet has been delivered to ETH Zurich for testing in a compact accelerator mass spectrometer facility. Permanent NdFeB magnets generate a fixed magnetic field of 0.43 T at a gap of 38.5 mm without using electrical power in the H-type 90° bending magnet with a bending radius of 250 mm. Thermal drift of the permanent magnets is passively compensated. Small air cooled trim coils permit fine tuning of the magnetic field. Magnetic field measurements and thermal stability tests show that the Green Magnet fully meets the magnetic requirements of the previously used electromagnet. The use of Green Magnet technology in other accelerator systems like synchrotron light sources is discussed.

THPME012	Measuring the Direction of Permanent Magnet Easy Axis by Helmholtz Coil	quadrupole, DTL, multipole, linac	3534
	X.Y. Jia, S.X. Zheng TUB, Beijing, People's Republic of China
	Permanent magnets for quadrupole focusing was used in drift-tube linac of the Compact Pulsed Hadron Sources(CPHS) in Tsinghua university. In order to ensure the accuracy of the quadrupole field can meet the design requirement, we need measure the strength and direction of remanence and choose the suit magnet. This paper proposed an easy way to get the direction of permanent magnet easy axis by Helmholtz coil without knowing the angle between magnet and the axis of the coil: the magnet rotational angle data was measured by rotary encoder and encoder would send trigger signal every turn at the same direction. First we started to record data when trigger signal was appeared. Then measured the magnet in three perpendicular directions (x,y,z). Last, caculated the remanence in three directions. We had measured some magnet by the new method and obtained satisfactory results.

THPME043	Prototype Adjustable Permanent Magnet Quadrupoles For CLIC	quadrupole, linear-collider, collider, magnet-design	3606
	B.J.A. Shepherd, J.A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A. Bartalesi, M. Modena, M. Struik CERN, Geneva, Switzerland N.A. Collomb STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	The 42km long Drive Beam Decelerator for the Compact Linear Collider (CLIC) requires over 41,000 quadrupole magnets. ASTeC and CERN are investigating the possibility of permanent magnet quadrupoles (PMQs) to reduce running costs and heat load inside the CLIC tunnel. A prototype of a high-strength adjustable PMQ has been built, based on a simple concept using two moving sections each containing a pair of large permanent magnets. The gradient can be adjusted within a range of 15-60 T/m (3-15T integrated gradient). The prototype has undergone extensive magnetic testing at Daresbury Laboratory and CERN, and performs well in line with expectations. A prototype of the low-strength version (0.9-9T) is currently under construction.

Paper

Title

Other Keywords

Page

MOPEA009

ESRF Operation and Upgrade Status

undulator, storage-ring, emittance, booster

82

J.-L. Revol, J.C. Biasci, J-F. B. Bouteille, F. Ewald, L. Farvacque, A. Franchi, G. Gautier, L. Goirand, M. Hahn, L. Hardy, J. Jacob, J.M. Koch, M.L. Langlois, G. Lebec, J.M. Mercier, T.P. Perron, E. Plouviez, P. Raimondi, K.B. Scheidt, V. Serrière
ESRF, Grenoble, France

The European Synchrotron Radiation Facility (ESRF) is presently midway through the Upgrade Programme Phase I (2009-2015), which concerns its infrastructure, beamlines and X-ray source. This paper reports on the present operation performance of the source, highlighting the more recent developments. In this context, 8 insertion device straight sections have been lengthened from five to six metres; two of them operating with canted undulators. The lattice of one cell has been modified for a further increase to 7 metres allowing the test of a mini beta optics and latter the distribution of cavities. A second cryogenic permanent magnet undulator has been completed, which gives a factor of more than 2 in flux at high energy. The booster klystron-based radio frequency transmitter has been replaced by high power solid state amplifiers. Out of three prototypes of HOM damped cavities working at room temperature which have been received and tested, one has been successfully commissioned with beam. Subsequent to the upgrade of the beam position monitor system, a new orbit feedback has substantially reduced the orbit distortion induced by ID gap motions.

MOPFI035

Preliminary Results of H²⁺ Beam Generated by a 2.45 GHz Permanent Magnet ECR Ion Source at PKU

ion, ion-source, plasma, cyclotron

363

Y. Xu, J. Chen, J.E. Chen, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z.H. Wang, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China
A.L. Zhang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

Recently, the need to build an ion source generating high current hydrogen molecular ion H²⁺ beam has been growing rapidly. For example, H²⁺ ion can be used as a pilot beam of the intense deuteron beam during the commission phase of linear accelerators to minimize the activation of components. And it is an effective way to improve the output current of cyclotrons by accelerating H²⁺ and stripping it into H⁺ at the exit of accelerator, instead of accelerating H⁺ beam directly. To obtain high-yield H²⁺ ion beam, experimental and theoretical study was carried out on the 2.45 GHz Peking University permanent magnet electron cyclotron resonance ion source (PKU PMECR). With PMECR II*, studies on the size of discharge chamber and the operation pressure were carried out to increase H²⁺ ion fraction. Beam analysis results prove that the H²⁺ can reach 40.5% with suitable operation parameters. More details will be presented in this paper.
* Zhizhong Song, Shixiang Peng et al., Rev. Sci. Instrum. 77, 03A305 (2006)
** Author to whom correspondence should be addressed. Electronic mail:
sxpeng@pku.edu.cn.

TUPWA041

Reduction of Secondary Electron (SEY) Yield Figures on Smooth Metallic Surfaces by Means of Magnetic Roughness

electron, gun, radio-frequency

1799

M. Taborelli, F. Caspers, M. Mensi
CERN, Geneva, Switzerland
L.S. Aguilera, I. Montero
CSIC, Madrid, Spain

High secondary electron yield of metallic surfaces used in accelerator and also space applications is of general concern. In addition to several well known coating techniques and microscopic or macroscopic mechanical roughness (grooves) which may significantly increase microwave losses the concept of magnetic surface roughness has been proposed recently. In this concept a smooth and very well conductimg surface with low microwave losses is maintained, but underneath this surface a large number of tiny permanent magnets are located to build a rough magnetic equipotential structure. In this paper we present and discuss measurement of the SEY and the improvement in terms of SEY for different parameter ranges

WEIB205

Promoting Local Economic Development by an Integration of Industry, Teaching and Research of Compact Low Energy Accelerators

electron, radiation, high-voltage, HOM

2119

M. Fan, D.Z. Chen, J. Huang, D. Li, K.F. Liu, B. Qin, Y.Q. Xiong, J. Yang, T. Yu
HUST, Wuhan, People's Republic of China
H.Q. Gao
Hubei University of Science and Technology, Hubei, People's Republic of China

Huazhong University of Science and Technology has been carrying out R&D of compact low energy accelerators by integrating industry, teaching and research to promote local economic development supported by both national and provincial government and local enterprises. Currently, the projects include: compact medical cyclotron, electron irradiation accelerators, etc. The industry of non-power nuclear energy based on low energy particle accelerator has also drawn attention from the provincial government of Hubei and municipal government of Xianning. Meanwhile, a series of lectures about nuclear science and nuclear safety were hosted to help the public better understand nuclear technology and to wipe out fears of nuclear energy. At the moment, the application of non-power nuclear energy with based on compact low energy accelerator is developing into an industry chain in the area of central China.

Slides WEIB205 [2.311 MB]

WEPWA003

Hall-Probe Bench for Cryogenic in-Vacuum-Undulators

undulator, vacuum, laser, cryogenics

2126

C. Kuhn, H.-J. Bäcker, J. Bahrdt, A. Gaupp, B. Schulz
HZB, Berlin, Germany

The Helmholtz-Zentrum Berlin (HZB) builds a 2m long in-vacuum-hall-probe-bench for the characterization of several cryogenic undulators currently under development. Short period lengths and small gaps require an accurate correlation between Hall probe position / orientation and the 3D-magnetic field. The geometric tolerances of an in-vacuum bench in the presence of strong temperature gradients do not permit a Hall probe movement along a straight line without corrections. The HZB-bench employs a system of laser interferometers and position sensitive detectors, which is used in a feed-back loop for the Hall probe position / orientation. First measurements on the accuracy and reproducibility of the new device are presented.

WEPWA028

Measurement and Research on Cryogenic Remanence of Chunks Permanent Magnet for Cryogenic Undulator

cryogenics, controls, undulator, factory

2190

Y.Z. He
SINAP, Shanghai, People's Republic of China

The higher-precision cryogenic remanence measurment technology and error for chunks permanent magnet were researched in china firstly (10-300K). Magnetic measurement tooling and magnetic field calculation and measurement method of cryogenic remanence measurement system of chunks permanent magnet for cryogenic undulator were optimized. Cryogenic calibration Hall probe were pasted on surface of domestic chunks permanent magnet(Nd2Fe14B: N52, N50M, etc.) and table magnetic field B of permanent magnet were measured, and after being converted, then cryogenic remanence of domestic chunks permanent magnet were obtained and cryogenic remanence variation of domestic chunks permanent magnet were researched. Cryogenic remanence measurement data were checked by pulse B-H tester and PPMS respectively, the results show that cryogenic remanence data has higher reliability. By this experiment, initial foundation were established for development of SSRF cryogenic undulator and for cryogenic remanence measurement and study of domestic other chunks permanent magnets.

WEPWA038

Influence of Magnet Errors and Waveguide Permeability on Magnetic Field Performance in Pure Permanent Undulators

undulator, FEL, simulation, radiation

2214

X. Liu, K.F. Liu, B. Qin, P. Tan, B. Wu, Y.Q. Xiong, J. Yang, L. Yang
HUST, Wuhan, People's Republic of China

Abstract For pure permanent magnet (PM) undulator, unavoidable divergences of remanence field and magnetization vector in PM blocks and installation error will cause magnetic field error at the central line of the undulator. This paper presents the simulation results of the magnetic field in non-ideal undulator containing these errors, with specified tolerances in Normal distribution. As well as the peak field error, increases of the harmonic components and impact on field integrals are calculated. The influence on magnetic field caused by waveguide permeability is also discussed.

WEPWA086

Characterization of PrFeB Permanent Magnet Blocks with Helmholtz Coils at NSLS-II

undulator, cryogenics, dipole, insertion

2304

P. He, P.L. Cappadoro, T.M. Corwin, H.C. Fernandes, D.A. Harder, C.A. Kitegi, M.M. Musardo, G. Rakowsky, J. Rank, T. Tanabe
BNL, Upton, Long Island, New York, USA
M. Kokole
KYTE, Sezana, Slovenia

For investigatation to build the cryogenic undulator using bake-able Praseodymium-Iron-Boron(PrFeB) magnet blocks, a short period(16.8mm) and fixed gap(5mm) hybrid undulator prototype has been fabricated at BNL. For this undulator, 36 PrFeB magnet blocks(28 type A, 4 type B, 4 type C) are used. The magnetic field characteristics of the undulator heavily depend on the directional uniformity of the magnetization of block sets. The strength and direction of magnetization of the PrFeB magnet blocks are measured using a Helmholtz coil system. The data include the three vector components of the total magnetic dipole moment of the blocks and also compare with vendor measuremeant results.

WEPFI024

Anisotropic Ferrite Magnet Focusing System for Klystrons

klystron, focusing, cathode, simulation

2756

Y. Fuwa, H. Ikeda, Y. Iwashita, R. Kitahara, Y. Nasu, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
S. Fukuda, T. Matsumoto, S. Michizono
KEK, Ibaraki, Japan

The permanent magnet beam focusing for klystrons can eliminate the solenoid coil with the water cooling system and the power supply that consumes electricity. Hence the failure rate and the operating cost of RF systems should decrease. This feature is suitable for a large facility that requires a lot of klystrons such as ILC. Since the required magnetic field for klystron beam is moderate, inexpensive anisotropic ferrite magnets can be applied. The test model is fabricated for a 1.3 GHz klystron whose output power is 800 kW. Each magnet block in the model is movable for magnetic field adjustment and the iron yoke in the oil tank improves magnetic field distribution around cathode area. The result of a klystron power test will be presented.

THPME001

Permanent Magnets in Accelerators can save Energy, Space, and Cost

dipole, quadrupole, synchrotron, vacuum

3511

F. Bødker, L.O. Baandrup, A. Baurichter, N. Hauge, K.F. Laurberg, B.R. Nielsen, G. Nielsen
Danfysik A/S, Taastrup, Denmark
O. Balling
Aarhus University, Aarhus, Denmark
F.B. Bendixen, P. Kjeldsteen, P. Valler
Sintex A/S, Hobro, Denmark
S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark
H.-A. Synal
ETH, Zurich, Switzerland

Green Magnet technology with close to zero electrical power consumption without the need for cooling water saves costs, space and hence spares natural resources. A compact dipole based on permanent magnets has been developed at Danfysik in collaboration with Sintex and Aarhus University. This first Green Magnet has been delivered to ETH Zurich for testing in a compact accelerator mass spectrometer facility. Permanent NdFeB magnets generate a fixed magnetic field of 0.43 T at a gap of 38.5 mm without using electrical power in the H-type 90° bending magnet with a bending radius of 250 mm. Thermal drift of the permanent magnets is passively compensated. Small air cooled trim coils permit fine tuning of the magnetic field. Magnetic field measurements and thermal stability tests show that the Green Magnet fully meets the magnetic requirements of the previously used electromagnet. The use of Green Magnet technology in other accelerator systems like synchrotron light sources is discussed.

THPME012

Measuring the Direction of Permanent Magnet Easy Axis by Helmholtz Coil

quadrupole, DTL, multipole, linac

3534

X.Y. Jia, S.X. Zheng
TUB, Beijing, People's Republic of China

Permanent magnets for quadrupole focusing was used in drift-tube linac of the Compact Pulsed Hadron Sources(CPHS) in Tsinghua university. In order to ensure the accuracy of the quadrupole field can meet the design requirement, we need measure the strength and direction of remanence and choose the suit magnet. This paper proposed an easy way to get the direction of permanent magnet easy axis by Helmholtz coil without knowing the angle between magnet and the axis of the coil: the magnet rotational angle data was measured by rotary encoder and encoder would send trigger signal every turn at the same direction. First we started to record data when trigger signal was appeared. Then measured the magnet in three perpendicular directions (x,y,z). Last, caculated the remanence in three directions. We had measured some magnet by the new method and obtained satisfactory results.

THPME043

Prototype Adjustable Permanent Magnet Quadrupoles For CLIC

quadrupole, linear-collider, collider, magnet-design

3606

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

The 42km long Drive Beam Decelerator for the Compact Linear Collider (CLIC) requires over 41,000 quadrupole magnets. ASTeC and CERN are investigating the possibility of permanent magnet quadrupoles (PMQs) to reduce running costs and heat load inside the CLIC tunnel. A prototype of a high-strength adjustable PMQ has been built, based on a simple concept using two moving sections each containing a pair of large permanent magnets. The gradient can be adjusted within a range of 15-60 T/m (3-15T integrated gradient). The prototype has undergone extensive magnetic testing at Daresbury Laboratory and CERN, and performs well in line with expectations. A prototype of the low-strength version (0.9-9T) is currently under construction.