MEDSI2018 - Classification: Accelerators / Insertion Devices

Paper	Title	Page
TUOPMA03	Development of the new UE38 Undulator for the Athos Beamline in SwissFEL	1
	H. Jöhri, M. Calvi, M. Hindermann, L. Huber, A. Keller, M. Locher, T. Schmidt, X. Wang PSI, Villigen PSI, Switzerland
	For the next beamline, we will profit from the experience of the U15 undulator development, but there are new requirements, because it will be a polarized undulator with a period of 38mm. We are developing a new arrangement of the drives, a further development of the magnet keepers and a vacuumpipe with only 0.2mm of wall thickness. A rough overview was given at Medsi 2016, together with the talk of the U15 Undulator. Meentime, the UE38 is in production and the talk will present the actual status and the lessons we learned during development and the fabrication: - Realization of vacuumchamber with 0.2mm wall thickness - Supportstructure for the vacuumchamber - Precision of manufacturing - Precision of assembling - Design of Magnetkeeper: Differential screw, forces, stiffness
	Slides TUOPMA03 [7.765 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUOPMA03
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TUOPMA04	Apple II Insertion Devices Made at MAXIV	6
	A. Thiel, M. Ebbeni, H. Tarawneh MAX IV Laboratory, Lund University, Lund, Sweden
	At present five Apple II insertion devices were made and installed at MAX IV, three of them in the 1.5GeV-ring, and two in the 3GeV-ring. The assembly of the last one of a total number of six Apple II undulators made at MAX IV is currently going on. The undulators have period lengths of 48mm (two devices), 53mm, 58mm, 84mm and 95.2mm. The operational gap range of the 3GeV devices is between 11mm and 150mm, the range of the 1.5GeV devices is 14mm to 150mm. Structural analysis was applied to assure a minimum deflection of the main frame and the magnet array girders. The main frame is made of nodular cast iron, while the girders are made of aluminium alloy. In order to optimize the magnetic tuning the position of the magnet keepers can be adjusted by wedges. The undulators were fiducialized before the installation in the ring tunnel and were aligned in the straight section using their magnetic centre as reference. All MAX IV made undulators have three feet with vertical adjustment and separate horizontal adjusters. This paper describes the design, assembly, shimming and installation of the MAX IV Apple II devices in more detail.
	Slides TUOPMA04 [12.328 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUOPMA04
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TUPH03	U15 Design and Construction Progress	26
	F. Briquez, C.A. Arrachart, N.B. Baron, P. Berteaud, F. Blache, C.B. Bourgoin, N. Béchu, M.-E. Couprie, J. Da Silva Castro, J.M. Dubuisson, J.P. Duval, C. Herbeaux, F. Lepage, A. Lestrade, F. Marteau, A. Mary, F.M. Michel, S.M. Morand, M.-H. Nguyen, A.R. Rouquié, M. Sebdaoui, G. Sharma, K.T. Tavakoli, M. Tilmont, M. Valléau, M.V. Vandenberghe, J. Vétéran, C. de Oliveira SOLEIL, Gif-sur-Yvette, France
	A 15 mm period PrFeB Cryogenic Permanent Magnet Undulator (CPMU) is under construction at SOLEIL in the frame of a collaboration with MAXIV, relying on the experience gained from the two PrFeB CPMU already installed at SOLEIL. The improved design includes a magnetic length of 3 m and a minimum gap of 3 mm, leading to a polyvalent device of interest for both synchrotron radiation sources and free electron lasers. A dedicated magnetic measurement bench is also under development to perform measurements at cryogenic temperature, based on the SAFALI system. The designs of both undulator and measurement bench will be explained, the construction progress will be detailed and first results will be given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH03
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TUPH05	Design of a Radiation Tolerant, Indexing Profile Monitor for the LCLS Electron Beam	33
	A.G. Cedillos, R.C. Field SLAC, Menlo Park, California, USA
	Funding: Work was performed in support of the U.S. DOE, Office of Sci-ence, LCLS project, under contract DE-AC02-76SF00515. The Linac Coherent Light Source (LCLS) electron beam can damage YAG:Ce scintillation screens. After one year of use, the existing profile monitor has diminished fluorescence of the screen. The decrease in performance has resulted in distorted beam images which can com-promise the acquired data. Scheduling a YAG screen replacement is difficult, resulting in weeks of diminished performance. We have developed a unique profile moni-tor that incorporates multiple YAG screens (Ø40 mm, 50 um thick) and methods to reduce device downtime. This device uses unique geometry to direct coherent optical transition radiation (COTR) away from the optical path, which preserves the high resolution beam image. We are presenting the operational requirements, device design and installed device operational results.
	Poster TUPH05 [2.024 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH05
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TUPH06	Construction of a Twin-Helix Undulator Prototype
	C.-H. Chang, C.H. Chang, T.Y. Chung, C.-S. Hwang, C.Y. Kuo NSRRC, Hsinchu, Taiwan C.-S. Hwang NCTU, Hsinchu, Taiwan
	Funding: This work was supported in part by the Ministry of Science and Technology of Taiwan under contract MOST106-2221-E-213-001-MY2. A Twin-Helix Undulator (THU) with a period length of 24 mm was designed to produce strong and homogeneous helical fields within a 5 mm diameter aperture. A 10-period prototype was constructed to test mechanical and magnetic performance characteristics. The prototype is composed of four helically shaped magnet arrays, which are designed to produce helical and linear fields by shifting its diagonal magnet arrays. A quadrant and half of the magnetic arrays are evaluated to verify the magnetic field performance. Helical array girders were assembled in a rectangular box-like frame with a cross-roller guideway. Mechanical considerations and field analysis of the THU are discussed in this note. [1] C.Y. Kuo et al., IEEE Transactions on Applied Superconductivity, 28, 4100805 (2018). [2] T.Y. Chung et al., Synchrotron Radiat. News Vol.31, No. 3 (2018).
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TUPH11	Retractable Absorber (Mask) and White Beam Imager Diagnostic for Canted Straight Section	45
	J. Da Silva Castro, N. Béchu, C. Herbeaux, N. Hubert, N. Jobert, M. Labat, F. Lepage, A. Mary, K.T. Tavakoli SOLEIL, Gif-sur-Yvette, France
	At the SOLEIL synchrotron, as in other accelerators, two canted sources can coexist on the same straight section for space and economic reasons. For its two long beamlines (ANATOMIX source upstream and NANOSCOPIUM source downstream) SOLEIL has made the choice to equip one of his long straight section with two canted insertion devices capable to operate simultaneously. That implies to take into account the degradation risk management of equipment, due to radiation. As the beam power deposition from the upstream undulator can seriously degrade the downstream one, or even other equipment. To handle these risks, Soleil first designed and installed in 2016 a retractable vertical absorber between both insertions to protect the downstream source from the upstream one. In 2017, Soleil then designed and installed a white beam imager, redundant an existing photon beam monitor (XBPM), to verify the correct positioning / alignment of equipment and beams relative to each other. For the vertical absorber as for the white beam imager Soleil had to meet some interesting technological and manufacturing aspects that we propose to present in a poster.
	Poster TUPH11 [3.744 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH11
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TUPH19	A Mechanical Undulator Frame to Minimize Intrinsic Phase Errors	69
	J.C. Huang, C.H. Chang, C.-S. Hwang, C.S. Yang, C.K. Yang NSRRC, Hsinchu, Taiwan H. Kitamura RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan S. M. Mizumoto NEOMAX Co., Ltd., Mishima-gun, Osaka, Japan
	A PrFeB-based cryogenic permanent magnet undu-lator (CPMU) is under construction at the Taiwan Photon Source (TPS) to generate brilliant X-rays. When magnets are cooled to 77 K, a CPMU with a period length of 15 mm can generate an effective magnetic field of 1.32 T in a gap of 4 mm. A main feature of the TPS CPMU is its low-intrinsic-phase errors by the installation of force-compensation modules on the out-of-vacuum girders in a four-support-points configuration. Moreover, adjusting the spring settings one can obtain very low undulator phase errors. In this paper, a mechanical frame design for the TPS-CPMU with force-compensating spring modules will be discussed. Observations of deformation effects of the out-of-vacuum girders on the CPMU will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH19
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TUPH22	Study on Cooling Technology of the Superconducting Undulator at SSRF	75
	Y. Liu, S. Sun, J. Wang, L. Wang, S.H. Wang SINAP, Shanghai, People's Republic of China
	A superconducting undulator (SCU) prototpye with the period of 16 mm and the magnetic gap of 9.5 mm has been designed and fabricated at the Shanghai Institute of Applied Physics(SINAP) since late 2013. A set of cooling system is designed to cool down cold masses. This paper presents the details of their design, calculation and test: 4 small cryogenic refrigerators are used as cold sources, and the superconducting coil and beam pipe are independently cooled down; The 4.2 K superconducting coil is mainly cooled by the liquid helium tube of the thermosyphon loop with evaporation and recondensation; The 10~20 K ultra-high vacuum beam tube is cooled by heat conduction. The main sources and mechanism of thermal loads for SCU were analyzed. And experimental test of cooling technology for SCU prototype had been performed, the feasibility of cooling scheme and the rationality of the cooling structure for the SINAP SCU prototype were verified. The cryogenic test and operation of the SCU doesn't require the input of liquid helium from the outside, and is not limited by the liquid helium source. This is the characteristic of SINAP's SCU cooling technology.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH22
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TUPH26	A Quasi-Periodic Elliptically Polarized Undulator at the National Synchrotron Light Source II	88
	M. Musardo, P.L. Cappadoro, O.V. Chubar, T.M. Corwin, D.A. Harder, Y. Hidaka, J. Rank, T. Tanabe BNL, Upton, New York, USA C.A. Kitegi SOLEIL, Gif-sur-Yvette, France
	Funding: Work supported by DOE under contract DE-SC0012704 A 2.8 m long quasi-periodic APPLE II type undulator has been commissioned at the National Synchrotron Light Source II (NSLS-II) for the Electron Spectro-Microscopy (ESM) beamline in the framework of the NEXT (NSLS-II Experimental Tools) project. It provides high brilliance photon beams in circularly and linearly polarized radiation from VUV to soft X-Rays. The mechanical structure implemented to achieve the quasi-periodicity in the magnetic field profile is described together with the optimization techniques utilized to correct the undesirable phase-dependent errors. The final magnetic results are presented as well as the spectral performance of the device. Although this EPU (Elliptically Polarizing Undulator) was procured as a turn-key device, the vendor was only responsible for the mechanical frame and the control system. Sorting and assembly of the magnet modules and the magnetic field tuning - Virtual Shimming and Magic Finger - were performed at the NSLS-II Magnetic Measurement Lab.
	Poster TUPH26 [2.507 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH26
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TUPH31	Development of a Revolver Type Undulator	105
	T. Ramm, M. Tischer DESY, Hamburg, Germany
	A revolver type undulator is developed for the SASE section of the FLASH Free-Electron Laser (FEL) at DESY. Currently, a 1,2GeV linear accelerator injects electrons into two undulator lines to provide fully coherent VUV light to different experimental stations in two experimental halls. The more recently built FLASH2 branch consists of 12 planar undulators with a fixed magnet structure of ~32mm period length. Within plans for refurbishment of the original FLASH1 undulator section and also to open up new operation schemes with an extended photon energy range, an undulator development was started that allows for a change of different magnet structures. Once installed, it will be possible to change the wavelength range or the FEL operation scheme within a short period of time. Magnet structures can then be switched at any time without any observable effect on the electron beam orbit or the photon beam position. The single design steps are described in the following article: profile of requirements, choice of an applicable changing mechanism, development of a new magnet structure, the position of the bearing points, a new floor assembly and improvement of the cantilever arm.
	Poster TUPH31 [1.534 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH31
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TUPH42	A Novel Attempt to Develop a Linear Polarization Adjustable Undulator Based on Magnetic Force Compensation Technology	140
	W. Zhang, Y. Zhu SINAP, Shanghai, People's Republic of China
	A linear polarization adjustable undulator is proposed in this paper. This undulator can reach 1.5T magnetic peak field with a period length 68mm and magnet length 4m. By adding two repulsive magnet arrays beside center array the magnetic force between girders can be reduced from 70kN to near zero. Such an approach can result in a significant reduction of the undulator volume, simplification of the strong back design and fabrication. By means of rotating through the center of undulator we can achieve magnetic field from vertical orientation to horizontal orientation. The linear polarization of radiation can be adjusted between zero and 90 degree
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH42
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Development of the new UE38 Undulator for the Athos Beamline in SwissFEL

1

H. Jöhri, M. Calvi, M. Hindermann, L. Huber, A. Keller, M. Locher, T. Schmidt, X. Wang
PSI, Villigen PSI, Switzerland

For the next beamline, we will profit from the experience of the U15 undulator development, but there are new requirements, because it will be a polarized undulator with a period of 38mm. We are developing a new arrangement of the drives, a further development of the magnet keepers and a vacuumpipe with only 0.2mm of wall thickness. A rough overview was given at Medsi 2016, together with the talk of the U15 Undulator. Meentime, the UE38 is in production and the talk will present the actual status and the lessons we learned during development and the fabrication: - Realization of vacuumchamber with 0.2mm wall thickness - Supportstructure for the vacuumchamber - Precision of manufacturing - Precision of assembling - Design of Magnetkeeper: Differential screw, forces, stiffness

Slides TUOPMA03 [7.765 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUOPMA03

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TUOPMA04

Apple II Insertion Devices Made at MAXIV

6

A. Thiel, M. Ebbeni, H. Tarawneh
MAX IV Laboratory, Lund University, Lund, Sweden

At present five Apple II insertion devices were made and installed at MAX IV, three of them in the 1.5GeV-ring, and two in the 3GeV-ring. The assembly of the last one of a total number of six Apple II undulators made at MAX IV is currently going on. The undulators have period lengths of 48mm (two devices), 53mm, 58mm, 84mm and 95.2mm. The operational gap range of the 3GeV devices is between 11mm and 150mm, the range of the 1.5GeV devices is 14mm to 150mm. Structural analysis was applied to assure a minimum deflection of the main frame and the magnet array girders. The main frame is made of nodular cast iron, while the girders are made of aluminium alloy. In order to optimize the magnetic tuning the position of the magnet keepers can be adjusted by wedges. The undulators were fiducialized before the installation in the ring tunnel and were aligned in the straight section using their magnetic centre as reference. All MAX IV made undulators have three feet with vertical adjustment and separate horizontal adjusters. This paper describes the design, assembly, shimming and installation of the MAX IV Apple II devices in more detail.

Slides TUOPMA04 [12.328 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUOPMA04

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TUPH03

U15 Design and Construction Progress

26

F. Briquez, C.A. Arrachart, N.B. Baron, P. Berteaud, F. Blache, C.B. Bourgoin, N. Béchu, M.-E. Couprie, J. Da Silva Castro, J.M. Dubuisson, J.P. Duval, C. Herbeaux, F. Lepage, A. Lestrade, F. Marteau, A. Mary, F.M. Michel, S.M. Morand, M.-H. Nguyen, A.R. Rouquié, M. Sebdaoui, G. Sharma, K.T. Tavakoli, M. Tilmont, M. Valléau, M.V. Vandenberghe, J. Vétéran, C. de Oliveira
SOLEIL, Gif-sur-Yvette, France

A 15 mm period PrFeB Cryogenic Permanent Magnet Undulator (CPMU) is under construction at SOLEIL in the frame of a collaboration with MAXIV, relying on the experience gained from the two PrFeB CPMU already installed at SOLEIL. The improved design includes a magnetic length of 3 m and a minimum gap of 3 mm, leading to a polyvalent device of interest for both synchrotron radiation sources and free electron lasers. A dedicated magnetic measurement bench is also under development to perform measurements at cryogenic temperature, based on the SAFALI system. The designs of both undulator and measurement bench will be explained, the construction progress will be detailed and first results will be given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH03

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TUPH05

Design of a Radiation Tolerant, Indexing Profile Monitor for the LCLS Electron Beam

33

A.G. Cedillos, R.C. Field
SLAC, Menlo Park, California, USA

Funding: Work was performed in support of the U.S. DOE, Office of Sci-ence, LCLS project, under contract DE-AC02-76SF00515.
The Linac Coherent Light Source (LCLS) electron beam can damage YAG:Ce scintillation screens. After one year of use, the existing profile monitor has diminished fluorescence of the screen. The decrease in performance has resulted in distorted beam images which can com-promise the acquired data. Scheduling a YAG screen replacement is difficult, resulting in weeks of diminished performance. We have developed a unique profile moni-tor that incorporates multiple YAG screens (Ø40 mm, 50 um thick) and methods to reduce device downtime. This device uses unique geometry to direct coherent optical transition radiation (COTR) away from the optical path, which preserves the high resolution beam image. We are presenting the operational requirements, device design and installed device operational results.

Poster TUPH05 [2.024 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH05

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TUPH06

Construction of a Twin-Helix Undulator Prototype

C.-H. Chang, C.H. Chang, T.Y. Chung, C.-S. Hwang, C.Y. Kuo
NSRRC, Hsinchu, Taiwan
C.-S. Hwang
NCTU, Hsinchu, Taiwan

Funding: This work was supported in part by the Ministry of Science and Technology of Taiwan under contract MOST106-2221-E-213-001-MY2.
A Twin-Helix Undulator (THU) with a period length of 24 mm was designed to produce strong and homogeneous helical fields within a 5 mm diameter aperture. A 10-period prototype was constructed to test mechanical and magnetic performance characteristics. The prototype is composed of four helically shaped magnet arrays, which are designed to produce helical and linear fields by shifting its diagonal magnet arrays. A quadrant and half of the magnetic arrays are evaluated to verify the magnetic field performance. Helical array girders were assembled in a rectangular box-like frame with a cross-roller guideway. Mechanical considerations and field analysis of the THU are discussed in this note.
[1] C.Y. Kuo et al., IEEE Transactions on Applied Superconductivity, 28, 4100805 (2018).
[2] T.Y. Chung et al., Synchrotron Radiat. News Vol.31, No. 3 (2018).

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TUPH11

Retractable Absorber (Mask) and White Beam Imager Diagnostic for Canted Straight Section

45

J. Da Silva Castro, N. Béchu, C. Herbeaux, N. Hubert, N. Jobert, M. Labat, F. Lepage, A. Mary, K.T. Tavakoli
SOLEIL, Gif-sur-Yvette, France

At the SOLEIL synchrotron, as in other accelerators, two canted sources can coexist on the same straight section for space and economic reasons. For its two long beamlines (ANATOMIX source upstream and NANOSCOPIUM source downstream) SOLEIL has made the choice to equip one of his long straight section with two canted insertion devices capable to operate simultaneously. That implies to take into account the degradation risk management of equipment, due to radiation. As the beam power deposition from the upstream undulator can seriously degrade the downstream one, or even other equipment. To handle these risks, Soleil first designed and installed in 2016 a retractable vertical absorber between both insertions to protect the downstream source from the upstream one. In 2017, Soleil then designed and installed a white beam imager, redundant an existing photon beam monitor (XBPM), to verify the correct positioning / alignment of equipment and beams relative to each other. For the vertical absorber as for the white beam imager Soleil had to meet some interesting technological and manufacturing aspects that we propose to present in a poster.

Poster TUPH11 [3.744 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH11

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

TUPH19

A Mechanical Undulator Frame to Minimize Intrinsic Phase Errors

69

J.C. Huang, C.H. Chang, C.-S. Hwang, C.S. Yang, C.K. Yang
NSRRC, Hsinchu, Taiwan
H. Kitamura
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. M. Mizumoto
NEOMAX Co., Ltd., Mishima-gun, Osaka, Japan

A PrFeB-based cryogenic permanent magnet undu-lator (CPMU) is under construction at the Taiwan Photon Source (TPS) to generate brilliant X-rays. When magnets are cooled to 77 K, a CPMU with a period length of 15 mm can generate an effective magnetic field of 1.32 T in a gap of 4 mm. A main feature of the TPS CPMU is its low-intrinsic-phase errors by the installation of force-compensation modules on the out-of-vacuum girders in a four-support-points configuration. Moreover, adjusting the spring settings one can obtain very low undulator phase errors. In this paper, a mechanical frame design for the TPS-CPMU with force-compensating spring modules will be discussed. Observations of deformation effects of the out-of-vacuum girders on the CPMU will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH19

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TUPH22

Study on Cooling Technology of the Superconducting Undulator at SSRF

75

Y. Liu, S. Sun, J. Wang, L. Wang, S.H. Wang
SINAP, Shanghai, People's Republic of China

A superconducting undulator (SCU) prototpye with the period of 16 mm and the magnetic gap of 9.5 mm has been designed and fabricated at the Shanghai Institute of Applied Physics(SINAP) since late 2013. A set of cooling system is designed to cool down cold masses. This paper presents the details of their design, calculation and test: 4 small cryogenic refrigerators are used as cold sources, and the superconducting coil and beam pipe are independently cooled down; The 4.2 K superconducting coil is mainly cooled by the liquid helium tube of the thermosyphon loop with evaporation and recondensation; The 10~20 K ultra-high vacuum beam tube is cooled by heat conduction. The main sources and mechanism of thermal loads for SCU were analyzed. And experimental test of cooling technology for SCU prototype had been performed, the feasibility of cooling scheme and the rationality of the cooling structure for the SINAP SCU prototype were verified. The cryogenic test and operation of the SCU doesn't require the input of liquid helium from the outside, and is not limited by the liquid helium source. This is the characteristic of SINAP's SCU cooling technology.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH22

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TUPH26

A Quasi-Periodic Elliptically Polarized Undulator at the National Synchrotron Light Source II

88

M. Musardo, P.L. Cappadoro, O.V. Chubar, T.M. Corwin, D.A. Harder, Y. Hidaka, J. Rank, T. Tanabe
BNL, Upton, New York, USA
C.A. Kitegi
SOLEIL, Gif-sur-Yvette, France

Funding: Work supported by DOE under contract DE-SC0012704
A 2.8 m long quasi-periodic APPLE II type undulator has been commissioned at the National Synchrotron Light Source II (NSLS-II) for the Electron Spectro-Microscopy (ESM) beamline in the framework of the NEXT (NSLS-II Experimental Tools) project. It provides high brilliance photon beams in circularly and linearly polarized radiation from VUV to soft X-Rays. The mechanical structure implemented to achieve the quasi-periodicity in the magnetic field profile is described together with the optimization techniques utilized to correct the undesirable phase-dependent errors. The final magnetic results are presented as well as the spectral performance of the device. Although this EPU (Elliptically Polarizing Undulator) was procured as a turn-key device, the vendor was only responsible for the mechanical frame and the control system. Sorting and assembly of the magnet modules and the magnetic field tuning - Virtual Shimming and Magic Finger - were performed at the NSLS-II Magnetic Measurement Lab.

Poster TUPH26 [2.507 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH26

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TUPH31

Development of a Revolver Type Undulator

105

T. Ramm, M. Tischer
DESY, Hamburg, Germany

A revolver type undulator is developed for the SASE section of the FLASH Free-Electron Laser (FEL) at DESY. Currently, a 1,2GeV linear accelerator injects electrons into two undulator lines to provide fully coherent VUV light to different experimental stations in two experimental halls. The more recently built FLASH2 branch consists of 12 planar undulators with a fixed magnet structure of ~32mm period length. Within plans for refurbishment of the original FLASH1 undulator section and also to open up new operation schemes with an extended photon energy range, an undulator development was started that allows for a change of different magnet structures. Once installed, it will be possible to change the wavelength range or the FEL operation scheme within a short period of time. Magnet structures can then be switched at any time without any observable effect on the electron beam orbit or the photon beam position. The single design steps are described in the following article: profile of requirements, choice of an applicable changing mechanism, development of a new magnet structure, the position of the bearing points, a new floor assembly and improvement of the cantilever arm.

Poster TUPH31 [1.534 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH31

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

TUPH42

A Novel Attempt to Develop a Linear Polarization Adjustable Undulator Based on Magnetic Force Compensation Technology

140

W. Zhang, Y. Zhu
SINAP, Shanghai, People's Republic of China

A linear polarization adjustable undulator is proposed in this paper. This undulator can reach 1.5T magnetic peak field with a period length 68mm and magnet length 4m. By adding two repulsive magnet arrays beside center array the magnetic force between girders can be reduced from 70kN to near zero. Such an approach can result in a significant reduction of the undulator volume, simplification of the strong back design and fabrication. By means of rotating through the center of undulator we can achieve magnetic field from vertical orientation to horizontal orientation. The linear polarization of radiation can be adjusted between zero and 90 degree

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2018-TUPH42

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