KEK · 2013. 6. 2. · M. E. Couprie, International Particle Accelerator Conference, ,Shanghai,...

M. E. Couprie, International Particle Accelerator Conference, ,Shanghai, China, May 13-17, 2013

Undulator technologies for future FEL facilities / Storage ringsMarie-Emmanuelle Couprie (Synchrotron SOLEIL)

Acknowledgments : J. Chavanne (ESRF), Y. Ivanyushenkov (APS), S. Casualbuini (KIT, ANKA), O. Chubar (BNL), F. Ciocci (SPARC), my group

Tribute to P. Elleaume (✝ 2011, March 19)

jeudi 16 mai 2013


Synchrotron Radiation Light source

HU640

U20

HU52 HU65

HU80HU44

HU64HU42

U20

U20

HU80 HU256

HU80HU44

HU60 HU256

U20

HU36

HU52

HU80 HU256

WSV50

U20

U26?U24

W164

U18

PMEMMixte

Installed

to be installed

? U18

HU42

HU65

HU64

the SOLEIL example

O. Chubar, P. Elleaume, Proc. EPAC-98, 1177.O. Chubar et. al., Proc. SPIE 4143 (2000) 48; SPIE 4769 (2002) 145.

Brilliance calculated with SRW2.75 GeV, emittance 3.7 nmrad, 500 mA20-3 ps + femto-slicing project under way

A. Nadji et al., IPAC 2011, San Sebastian, Spain, 3002-3004

Medium energy storage rings : SOLEIL, DIAMOND, CLS, ALBA, TPS, Australian Synchrotron, NSLS II, MAX IV....High energy storage rings : SPring-8, ESRF, APS, PETRA III, PEP-XTowards USR

I- Introduction

jeudi 16 mai 2013


Free Electron Lasers

I- Introduction

Medium energy linacs for soft X-ray FELs : FLASH, FERMI@ELETTRA ...High energy linacs for hard X-ray FELs : LCLS, SACLA@SPring-8, E XFAL, Swiss FEL, Pohang FEL

COST, Advanced X-ray spatial and temporal metrology, Kick-off meeting, Paris, April 2013, 4-5

Overview of short wavelength FEL

LCLSLCLS-II SACLA

SCSSPohang FELFERMI

FLASHFLASH-II

Swiss FELLUNEX5

Wisconsin FEL

VUV- soft X ray

EFELMarieSPARC

project operating FEL

NLS

hard X ray

Shanghai FEL

Dialan FEL

1-Introduction

Stockholm FELMAX IV FEL

Polish FEL

Tohoku FEL

GALAXIES

jeudi 11 avril 2013

jeudi 16 mai 2013


I- Introduction

free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generationM.E. Couprie et al., IPAC 2011, Proced. 13th International Conference on X-ray Lasers, Paris, June 11-15, 2012

0.4-‐1 GeV, emi8ance 1 π nmrad, 1 ps -‐ 10 fs

G. Stupakov., PRL 102, 074801 (2009)

!

400 MeV slice energy spread CLA : 0.02 %, LWFA : 0.1 %1.5 π mm.mrad emittance : CLA : 1.5, LWFA 1peak current : CLA : 400 A, LWFA : 10 kA, 50 pCelectron bunch length : CLA : 1 ps, LWFA : 2 fs

G. Lambert et al., Nature Physics Highlight, (2008) 296-300T. Togashi et al., Optics Express, 1, 2011, 317-324

G>(+(4,)H%2+(0

G(I%0JC.#.-7%0.-7%0#(72,..-+(0

-22%.%0-+,)D#7+0C2+C0%#,)#*-2CC?#C);C.-+(07#KLM

L,D>#L-0?(),2#,)#6-7#O%%;

N%D%)%0-+,*%1?G.,J,%0

ABB#)?!"4A"#)?

!4!"#)?E#F

=2>(#=)-@.%;#L-0?(),2#6%)%0-+,()#

LL6#7%%;,)D#

6-7#2>-?@%0

?()(2>0(?-+(0

!""#$%'()*%)+,()-.#/,)%-0#122%.%0-+(0#

"3!456%/-7%0#8-9%:,%.;#122%.%0-+(0#


I-Introduction

Accelerator type issues for insertion devices

Emittance E2 1/E

Beamsize (µm) 100 (H)-10 (V) 50-10 10-3

vacuum chamber H /V aperture

flatmin gap: 5 mm

round (ex : bore 5 mm), min gap : 3 mm round

charge high 1 nC 10 pC

Pulse duration 10 ps 100 fs 10 fs

impedance very critical critical critical

field integrals very critical very critical very critical

double field integrals very critical very critical very critical

phase errorvery critical for high harmonics

operationcritical critical

multipoles for beam lifetime and injection efficiency less critical not critical

storage ring linac / ERL LWFA

jeudi 16 mai 2013


Multipolar terms for storage rings Dipolar terms: field integral

FFWD tablesFast/slow orbit feedback to keep to source

position and divergence in 10% of the beam sizeDynamic field integral compensation

Quadrupolar terms: normal quadrupoles => tune shift => feedback on

the tunes, or FFWD tablesSkew quadrupoles => coupling

Compensation : current sheet for APPLE-II devicesJ. Bahrdt, et. al., “Active shimming of the dynamic multipoles of the BESSY UE112 Apple Undulator”, Proceedings of EPAC’08, p. 2222 (2008).

Sextupolar terms=> chromaticityMagnetic field maps (RADIA; measurements) TRACY electron beam simulation (on and off

momentum) for injection efficiency and lifetime study

J. Safranek et al, Phys. Rev. Special Topics (2002), Vol. 5, 010701O. Marcoullé et al, IPAC 2011, 3236

I-Introduction

Bare machine 2nd order kick map from RADIA

2nd order kick map from RADIA+ magnetic measurement map

SOLEIL HU36 undulator located in a short straight section (betax = 17.8 m)Measured lifetime : bare machine, 19.4 h@400 mA => 14.3 h, RP configuration 7.8 h => 6.6 h

P. Brunelle, SOLEIL

jeudi 16 mai 2013


Undulator adjustment for FEL

I-Introduction

K-value tuning in SACLA, the reason for which is ex-plained in the following.

The photon flux of spontaneous UR is a function ofmany parameters related to the electron beam quality andobservation condition, namely, it is expressed as

fð@!;K; L;!X;!Y; E;!e; x; y; x0; y0;!x;!y;!x0 ;!y0Þ;where @! is the photon energy, L is the distance from theundulator to the slit located in front of the monochromator,!X and !Y are the horizontal and vertical apertures of theslit, E and !E are the average energy and energy spread ofthe injected electron beam, x, x0, !x, !x0 are the horizontalposition, angle, beam size, and angular spread of theelectron beam, and similar notations in the vertical direc-tion. In this manner, the UR spectrum depends on a hugenumber of parameters.

Recalling the fact that the electron beam property in thelinear accelerator can fluctuate shot by shot, it is importantto reduce the number of parameters affecting the alignmentprocess. In addition, the fact that the photon flux is afunction of the slit conditions L, !x, and !y is alsotroublesome when repeating the K-value tuning processfrom segment to segment, because L is a function of thesegment number. We have to adjust the slit sizes!x and!yaccording to the target segment number so that the angularacceptance is kept constant.

Now let us consider the case when the slit aperture isopened so that the angular acceptance is wider than theangular spread of spontaneous UR and thus is effectivelyequal to the whole solid angle. The photon flux thenbecomes insensitive to the slit condition, L, !X, and !Y,and to the electron beam quality in the four-dimensionalphase space, x, y, x0, y0, !x, !y, !x0 , and !y0 . The expres-sion for the photon flux is now simplified to

fð@!;K; E;!eÞ;which contains just four parameters. The K value can beaccurately determined through the spectral measurementregardless of the segment number, beam emittance, Twissparameters, and injection conditions. The resolution andaccuracy depends on the energy spread and stability of thebeam energy. The drawback of adopting the wide apertureis that the spectral bandwidth is broadened and a simplepeak-detection method does not work.

Figure 6(a) shows the variation in spectrum with hori-zontal injection angle when the slit aperture is opened to10 mm in both directions, which has been calculated withthe spontaneous synchrotron radiation calculation codeSPECTRA [11]. As expected from the above discussions,the variation is found to be negligible. This means that wewill be able to get the same measurement results regardlessof the beam condition as long as the electron energy andenergy spread are kept constant. On the other hand, thecalculation results with the aperture size of 0.5 mm shownin Fig. 6(b) suggests that the spectral shape and peak

position depend largely on the injection angle. In conclu-sion, wider aperture is more reasonable in the process ofK-value tuning. It should be noted, however, that we haveto establish a procedure to specify the K value from thestep-function-like spectral profile as shown in Fig. 6(a), butnot from a simple Gaussian-like profile as in Fig. 6(b).As mentioned in Sec. II B, the undulator should be well

aligned both in terms of the gap and height to finely tunethe K value. In the following sections, the detailed proce-dures in respective alignment steps are presented.

1. Gap distance adjustment

In order to align the undulator gap, photon flux at aspecific photon energy is measured as a function of thegap. The higher energy edge of the spectral profile (spec-tral edge) that corresponds to the undulator fundamentalenergy !1 is shifted from higher to lower energies whenthe undulator gap is closed. The resultant measurementdata is similar to the spectral profile as in Fig. 6(a). Theresult is then analyzed to determine the optimum gap thatcorresponds to some specific K value. This optimizationprocess is repeated for all the undulator segments andseveral different K values to calibrate the relation between

FIG. 6. Example of calculated spectra of spontaneous URemitted from the 1st segment for two different slit aperture sizes:(a) 10 mm and (b) 0.5 mm.

TAKASHI TANAKA et al. Phys. Rev. ST Accel. Beams 15, 110701 (2012)

110701-6

the gap and K value. An example of the measurementresult is shown in Fig. 7, in which the electron energywas fixed at 7.8 GeV and the monochromator energy wasfixed at 10 keV, and thus the K value was nearly 2.1.

The photon flux was found to drastically change aroundthe gap between 3.88 and 3.87 mm, roughly correspondingto the K value of 2.1. In order to exactly specify theoptimum gap to give the K value of 2.1, we introducedan empirical fitting function defined as

fðgÞ ¼ ða1 þ a2gÞerf!a3 % ga4

"þ a5; (1)

where erf is the Gauss error function and a1 & a5 are thefitting parameters, among which a3 gives the central posi-tion of the spectral edge and thus this can be regarded to bethe optimum gap. The red line in Fig. 7 indicates the fittingfunction and the optimum gap in this example was found tobe 3.8736 mm. Repeating this process, all the undulatorsegments can be precisely aligned to have the identical Kvalue within some tolerance. Note that the absolute accu-racy of the K value determination with this method de-pends on the calibration accuracy of the monochromatorand electron energy. Although the monochromator can becalibrated very accurately by means of, e.g., x-ray absorp-tion experiments, the electron energy measurement with anaccuracy of the order of 10%4 would be difficult and in factnot necessary. What should be done in the undulator com-missioning is to reduce the relative difference in K valuebetween the undulator segments but not to know the exactnumber of the K value.

2. Height position adjustment

In order to align the undulator height and to eliminatethe vertical offset between the electron beam and magnetic

center of the undulator, the photon flux is measured as afunction of the undulator height as in the gap distanceadjustment. The K value depends almost quadratically onthe vertical offset under realistic conditions and thus thespectral edge is shifted from higher to lower energies whenthe offset increases. The photon flux is thus maximizedwhen the offset vanishes if the gap and monochromator areset appropriately.Figure 8 shows an example of the photon flux measured

as a function of the undulator height. In this example, theundulator height was found to be misaligned by 0.1 mm,which was corrected by a remotely controlled elevationsystem attached to the undulator.

D. Phase matching

In order to satisfy the phase matching condition, spectralcharacteristics specific to spontaneous UR emitted fromtwo adjacent undulator segments have been utilized.Figure 9(a) shows the variation in spectra with the phaseslippage between the 1st and 2nd segments, which wasvaried by changing the gap of the phase shifter installed inbetween. The undulator gap values of the two segmentswere set so that both the undulators had the identical Kvalue of 2.1. The spectral edge was found to becomesteeper at the phase shifter gap of 30.4 mm than at32.4 mm, meaning that this gap was closer to the optimumcondition for the phase matching. In other words, thephoton flux at 9.988 keV, as indicated by the dashed linein Fig. 9(a), was supposed to be maximum when the phasematching condition is satisfied. We have therefore mea-sured the flux at that energy as a function of the phaseshifter gap, the result of which is shown in Fig. 9(b). Thephase slippage has been calculated from the magneticmeasurement of the phase shifter and indicated in the

FIG. 8. Photon flux of spontaneous UR from the 1st segmentmeasured at 10 keV as a function of the undulator height (blacksquare). The result of Gaussian fitting is also indicated (red line).

FIG. 7. Photon flux of spontaneous UR from the 1st segmentmeasured at 10 keV as a function of the gap (black circle). Thefitting curve is also indicated (red line).

UNDULATOR COMMISSIONING BY CHARACTERIZATION . . . Phys. Rev. ST Accel. Beams 15, 110701 (2012)

110701-7

Example of gap tuning of the different segments

T. Tanaka et al., Undualtor commissioning by characterizaiton of radiation in x-ray free electron lasers, Phys. Rev. Spe. Topics AB 15, 110701 (2012)

jeudi 16 mai 2013


I-Introduction

Impedance issue & e-beam induced heat load

s en place

agnétique

Need to avoid discontinuity in vacuum chamber=> transition for in-vacuum system

⎮Z/n⎮eff = 0.45 Ω, 5 in vacuum ID contribution : 11.6 mΩ

10 taper of middle SS contribution : 9.3 mΩ

!"#

$%#

$"#

&%#

&"#

'%#

'"#

%# "# !%# !"# $%# $"#

!"#$%&'(#)*%&+,

-.&

!"#$%&$"//(#*&+01.&

-2*/3$4&$3'$5&6/7&8&9:;&


In-vacuum undulatorsMotivation : reach a higher field by placing directly the magnets inside the vacuum

chamberHistorical steps :• First prototype at BESSYW. Gudat et al. NIMA 246, 1986 50

• First In vac. undulator Installed on TRISTAN AR, Period : 40 mmX90, NdFeB (Br=1.2 T, iHc=21kOe), min gap 10 mm, B=0.82-0.36 T, NEG and sputter ion pumps, magnet stabilization at 125°C and vacuum commissioning at 115°C, S. Yamamoto et al. Rev. Sci. Instr 63, 400 (1992)

• 30 m long in-vacuum undulator at SPring-8 (SLUS-1) : 32 mm x 780, min gap = 12 mm (betaV = 15 m) B=0.59 T5 segments without gaps, very fine adjustments of the gap segments for phase error (11°=> 3.6°)H. Kitamura et al., NIMA 467 (2001) 110; T. Tanaka et al. NIMA 467, (2001) 149

• Revolver in-vacuum undulator (INVRUM) : 6 mm x 133, 10 mmx100, 15 mmX66, 20mmx50; min gap = 3.2 mm, B=0.74, 1.07, 1.32, 1.44 TT. Bizen et al. AIP 705, (2004), 175, 18th International Conference on Synchrotron Radiation Instrumentation, San Franscisco, 2003 417, H.S. Kang et al., EPAC 2006, 2771

Then, the gap discrepancy between segments, which givesrise to a large phase error, was corrected. Finally, the wholemagnetic distribution has been obtained by combination ofthe fields in five segments and in four junctions.

Figure 10: 25-m long IVU installed in the LSS in SPring-8.

After installation in the LSS, effects on the electronbeam were investigate with the gap closed down to 12 mm,and no serious problems were found except a slight degra-dation of the beam lifetime. After that the radiation spec-trum was measured to estimate the performance of the 25-m IVU as a SR light source and it was found that the band-width was a little wider than expected. After investigationof several factors, it was concluded that the geomagneticfield would be the most probable source, because the direc-tion of the undulator, in which the field corrections werecarried out, differed by 90◦ from the direction of installa-tion in the storage ring. In order to correct it, a uniformfield was applied to cancel the geomagnetic field. As a re-sult, the bandwidth was reduced to ideal one [17]. This factshows that the field measurement and correction carried outfor the 25-m IVU were very precise.

ADVANTAGES IN THE X-RAY FEL

IVUs installed in the storage ring have been describedso far. As a matter of course, the IVU can be utilizedas a driver for the FEL. In fact, the SCSS [18] and PAL-XFEL [19] projects are going to adopt the IVU with pe-riodic length shorter than 20 mm to realize an x-ray FELwith less electron energy, smaller facility scale, and thuslower cost.

Besides the advantage of reducing the electron energy,the IVU has several advantages over the conventional out-vacuum undulator when employed in the X-ray FEL facil-ity where a very long undulator is required for saturation.

Alignment using Optical Laser

An alignment procedure using an optical laser beam isproposed for the SCSS project in order to align the BPMsinstalled in the undulator line [20]. The diffraction pattern

of the laser beam generated by an iris inserted in the BPMpositions is monitored with a CCD camera installed down-stream. For this to be applicable, it is necessary to let theoptical laser pass through the entire undulator line, mean-ing that a wide clearance for the optical path is required. Itis easy for the IVU to realize it because the vacuum gap isvariable unlike the out-vacuum undulators.

Commissioning

The variable vacuum gap is also useful for the initialcommissioning of the electron beam. The wide clearancecreated by fully opening the gap will make it easier. In ad-dition, it is also important for the “FEL commissioning”, orthe on-beam alignment of components installed in the un-dulator line such as the BPMs, undulators, phase shifters,and correction coils. It is to be carried out by monitoringthe spontaneous radiation emitted from one or two adja-cent undulator segments. If the vacuum gap is narrow, thenthe spontaneous radiation emitted near the entrance of theundulator line may be disturbed by the undulator segmentnear the exit.

R&DS UNDER PROGRESS

In SPring-8, a number of R&Ds are under progress forfuture improvement of the IVU and related technology.Two of them are introduced in the following sections.

Cryoundulator

As mentioned in the “Permanent Magnet” section, PMswith high coercivity should be chosen for the IVU toavoid irreversible demagnetization during the bakeout pro-cess and due to radiation damage, which in turn limits theachievable peak field because such PMs have relatively lowremanent field. For example, the remanent field and coer-civity of NEOMAX35EH, which is the PM material nor-mally used for the IVU, are 1.15T and 2000kA/m, respec-tively.

Now let us assume that the magnet arrays are cooleddown to be operated at a cryogenic temperature. Then,outgassing from the PM blocks are reduced considerably;rather, the magnet array may work as a cryopump, mean-ing that the bakeout process is no more necessary. In ad-dition, the PM characteristics are improved a lot becauseboth the remanent field and coercivity normally have a neg-ative temperature coefficient. For example, the remanentfield and coercivity of NEOMAX50BH at a temperature of140K, which has the highest remanent field among the PMmaterials that are commercially available, are found to be1.58T and 3000kA/m, respectively. Compared these valuesto those of NEOMAX35EH, we can expect a 40% increasein peak field and a higher resistance to radiation damage.This is the concept of the cryogenic permanent magnet un-dulator, or the cryoundulator [21].

From the experiments to investigate the temperature de-pendence of PM material, it has been found that the rema-

Proceedings of the 27th International Free Electron Laser Conference

21-26 August 2005, Stanford, California, USA 375 JACoW / eConf C0508213

ION INSTABILITY OBSERVED IN PLS REVOLVER IN-VACUUMUNDULATOR∗

H. S. Kang† , T. Y. Lee, M. G. Kim, C. D. Park, T. Y. Koo, J. ChoiPohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk, 790-784 KOREA

AbstractRevolver In-Vacuum X-ray Undulator which was de-

signed and fabricated at Spring-8 is under commissioningat PLS. This planar undulator whose permanent magnet ar-ray structure is a revolving type with 90-degree step pro-vides 4 different undulator wavelengths of 10, 15, 20, and24 mm. The minimum gap of the undulator is 5 mm. It wasobserved that the trailing part of a long bunch-train wasscraped off due to ion instability when the undulator gapwas closed down below 6.4 mm. At that time the vacuumpressure in the undulator, which is estimated to be severaltimes lower than that at the undulator gap, increased from1.4×10−10 (gap 20 mm) to 7.9×10−10 Torr (gap 6 mm) atthe stored beam current of 100 mA. This high vacuum pres-sure causes fast beam-ion instability: trailing part of a longbunch-train oscillates vertically. It was also confirmed thatadjusting the orbit along the undulator has improved thesituation appreciably. The ion instability measured with apico-second streak camera and a one-turn BPM as well asthe result of orbit adjustment will be described in this paper.

INTRODUCTIONThe in-vacuum undulator has become popular in the 3-

rd generation light sources because it provides a possibil-ity of hard x-ray experiments in a medium-scale SR facili-ties. Many SR facilities such as SLS, ESRF, KEK, SSRL,SPring-8, NSLS, ALS, and PLS are using in-vacuum un-dulators [1, 2, 3].The stray synchrotron radiation should be blocked by ap-

propriately located photon stops in the storage ring to keepthe vacuum good because the outgassing from the cham-ber surface irradiated by stray synchrotron radiation is veryhuge. But the continuous irradiation of small amount ofstray synchrotron radiation can make the chamber surfaceclean. Under the certain circumstances such as misguidedor badly set orbit, the chamber already cleaned before doesnot cast an outgassing problem.In the out-vacuum undulator the inner surface of the vac-

uum chamber is likely to be continuously cleaned by straysynchrotron radiation so that the surface is very clean andis not weak to beam wake and/or stray synchrotron radia-tion. But, the permanent magnet array of in-vacuum un-dulator which is covered with copper plate is exposed toelectron beam and stray synchrotron radiation. The clean-ing by stray synchrotron radiation is only effective whenthe gap is closed down enough to see the radiation. Thus,

∗Work supported by Korean Ministry of Science and Technology† [email protected]

the surface condition is not good because the cleaning isintermittent depending on the position of the magnet array.That is why the inner surface of the in-vacuum undulator isweak to stray synchrotron radiation.In PLS (Pohang Light Source) there are six insertion

devices in the ring: two out-vacuum undulators, two out-vacuum wigglers, and one in-vacuum undulator. Thein-vacuum undulator is a revolver undulator (RevolverIn-Vacuum X-ray UNdulator) designed and fabricated atSpring-8 [4]. The concept of a revolver undulator is tomount a number of magnet arrays with different periodlengths on a rotary beam, which enables users to select anappropriate one among them for their experiments. Thepermanent magnet array structure of the revolver undulatoris a revolving type with 90-degree step, which provides 4different undulator wavelengths of 10, 15, 20, and 24 mm.The available radiation wavelengths are four times the con-ventional in-vacuum undulator. Figure 1 shows the magnetarray structure. The magnet material is Nd2Fe14B. Theminimum gap of the revolver is 5 mm and its magnet lengthis 1.2 meter.We observed ion instability when the gap of the revolver

was closed down below 6.4 mm. The instability was causedby vacuum degradation in the revolver. It was also foundthat adjusting the orbit along the revolver has improved thesituation appreciably.

Figure 1: Permanent magnet array structure of the in-vacuum revolver (RIVXUN).

ION INSTABILITYWhen the gap size was above 7mm, there was no insta-

bility and no lifetime change at the beam current of 165mA. However, below 6.4mm, transverse ion instability ap-peared and then beam loss occurred. At that time the re-

Proceedings of EPAC 2006, Edinburgh, Scotland THOAFI02

05 Beam Dynamics and Electromagnetic FieldsD04 Instabilities - Processes, Impedances, Countermeasures

2771

Pure Permanent magnet configuration to Hybrid technology K. Halbach, Jour. Physics, 44 (1983) 211

II- From In-vacuum to cryogenic undulators and in-vacuum wigglers

jeudi 16 mai 2013



Magnet choices

Sm2Co17 : Br ≤ 1.05T; µHcj = 2.8 T; Nd2Fe14B : Br ≤ 1.4T (1.26T); µoHc = 1.4-1.6 (resp. 2.4 T)

Br manageable heat budget- easy operation on synchrotron light sources

Prototype of Cryoundulator

Undulator period 15 mm

Type halbach ppm

Legnth ~ 0.6 m

Material NdFeB 50BH

Temperature control by heaters

Cryocooler

Heaters

• Cryocooler installation with flexible Cu plate.

• Enforcement of thermal isolation at magnet beam supports.

T. Hara, T. Tanaka, H. Kitamura, T. Bizen, X. Maréchal, T. Seike, T. Kohda, Y. Matsuura, Phys. Rev. Spc. Topics 7, 050702 (2004)Cryogenic undulator with high Tc superconductors

T. Tanaka et al. PRSTAB 7, 090794 (2004)

jeudi 16 mai 2013


Magnet choices

Spin Transition ReorientationNdFeB strong Magneto-Crystalline Anisotropy (MCA) => orientation along [001] Magneto-cristalline orientation given by the energy : E(T) = K1sin2(θ)+ K2sin4(θ) , θ angle between the magnetisation and [001]at room temperature : magnetisation // cFe MCA independant of T, Nd : K1 // [001] dominant at room T and K2//[110] at low T

PrFeB

Nd2Fe14B, Br=1.40 T/ Hcj=1.39 T

Nd2Fe14B, Br=1.39 T/ Hcj=1.63 T

Nd2Fe14B, Br=1.18 T/ Hcj=2.81 T

Nd2Fe14B, Br=1.37 T/ Hcj=1.63 T

Pr2Fe14B, Br=1.35 T/ Hcj=1.65 TTemperature coefficients :∆Br= 0.11-0.13 % /°C∆Hcj = 0.58-0.7%/°C

C. Benabderrahmane et al, NIM A 669 (2012) 1-6K. Uestuener et al., Sintered (Pt,Nd)FEB permanent magnets with (BH)max of 520 kJ/m3 at 85 K for cryogenic applications, 20th Workshop on Rare Earth Permanent Magnets 2008, Crete

M. Sagawa et al. J. Magn. Magn. Mater. 70, 316 (1987)T. Hara et al. APAC2004, Gyeongju, Korea, 216D. Givord et al. Solid State Comm. 51 (1984) 857

L. M. Garcia et al. Phys. Rev. Lett. 85 (2) 429F. Bartolomé et al. Jour. Appl. Phys. 87, 9, 2000, 4762-4764

=> Variation of the susceptibility vs T


jeudi 16 mai 2013


Cryogenic undulator : cooling

undulator technology, the performance of the magneticfield can be drastically improved.

II. CRYOGENIC PERMANENT MAGNETUNDULATORS

NdFeB magnets with high coercivity or Sm2Co17 mag-nets are generally used in in-vacuum undulators becauseof their resistance against demagnetization due to elec-tron beam irradiation. In addition, when installed in astorage ring, thermal stabilization and vacuum bakeout athigh temperatures around 420 K are necessary for themagnets; high coercivity magnets are also favored tominimize thermal demagnetization during these pro-cesses [12]. However, if the undulator is operated at acryogenic temperature, the outgassing rate from the mag-nets becomes very low or the magnets are even expectedto work as cryopumps, so that it is no more necessary toexpose the magnets to high temperatures. Supposing acryogenic temperature operation, NdFeB magnets withhigh remanent fields, normally showing low coercivity atroom temperature, are expected to have sufficiently highcoercivity and resistivity against electron beam irradia-tion. This gives us an opportunity to create a new undu-lator concept called the cryogenic permanent magnetundulators (CPMUs).

Since the magnet arrays of an in-vacuum undulator areplaced under good thermal isolation with vacuum, theundulator operation at the cryogenic temperature ofliquid nitrogen or higher simply needs some additionalrefrigerant channels or cryocoolers. Figure 1 shows two

examples of the CPMU design, both of which resemblethe ordinary in-vacuum undulator design [12] excepthaving refrigerant channels 1(a) or cryocoolers 1(b) at-tached to the magnet beams.

The most important advantage of the CPMUs is toallow a very high heat load of several hundred watts,which can be covered by a compact cryocooler of aGifford McMahon type. In case of a 1.5 m CPMU, theestimated amount of heat flowing in through the shafts ofthe magnet beams is about 100 W and thermal radiationfrom the inner surface of the vacuum chamber is about15 W. The heat generated by the resistive wall effect andsynchrotron radiation from upstream bending magnets isnormally smaller, for instance about 10 W in the case ofthe 203-bunch operation in SPring-8 at a 3 mm gap. Theseheat loads can be covered by one cryocooler, for example,the Suzuki Shokan RF90S having a cooling capacityhigher than 200 W at 80 K.

The CPMUs offer further advantages over SCUs, withthe saving of electricity and a stable operation withoutany quench. In addition, all techniques of magnetic fieldcorrection developed for permanent magnet undulatorscan be applied to the CPMUs without any significantmodification.

III. CHARACTERISTICS OF NdFeB MAGNETS ATCRYOGENIC TEMPERATURES

Sintered NdFeB magnets exhibit negative dependenceof remanent fields against temperature, typically!0:1%=K around room temperature. According to this

FIG. 1. (Color) Design examples of a CPMU with refrigerant channels (a) or with cryocoolers (b).

PRST-AB 7 CRYOGENIC PERMANENT MAGNET UNDULATORS 050702 (2004)

050702-2 050702-2

Cryocoolers Cryo Cooler: Power 2000 W (


Mini Cryogenic undulators

C. Benabderrahmane, P. Berteaud, M. Valléau, C. Kitegi, K. tavakoli, N. Béchu, A. Mary, J. M. Filhol, M. E. Couprie, Nucl. Instrum. Methods A 669 (2012) 1-6

U20-NdFeB

U9-PrFeB, fixed gap : 2.5 mm20 periods, 11 K, 1.15 T

at SOLEILat NSLS-II at BESSY/ UCLA

Validation of magnetic model at low temperature

PRASEODEMIUM IRON BORON UNDULATOR

Magnet Arrays and Measurement System The first room temperature (RT) IVU was developed at KEK in 19922. Since then, RT-IVUs have become the

de-facto standard for short period devices in synchrotron light sources around the world. Various attempts to employ superconducting undulators (SCUs) have been made. However, it appears that more R&D is needed before SCUs can be reliably used at user facilities. The concept of a CPMU was proposed in 2004 to enhance the performance of a RT-IVU3. Since it is based on the fundamental characteristics of a NdFeB permanent magnet, it is considered a much more realistic option than SCUs to achieve higher performance from an ID. Unfortunately, a NdFeB magnet starts to exhibit spin reorientation below 150K, which limits the maximum enhancement of its remanent field.

The PrFeB, a “twin” of NdFeB, was originally developed for space applications. does not show such deterioration at lower temperature. Its remanence continues to increase monotonically all the way to 4°K. Test arrays having eight full periods of 14.5mm period length have been constructed with PrFeB magnets (NEOMAX Type 53CR)4 and Vanadium Permendur poles. No elaborate shimming was done except for trajectory optimization by magnet sorting. The test undulator was installed in the VTF5 at the NSLS for field measurement with either liquid nitrogen or liquid helium as cryogens. The magnetic gap was set to 4.85mm which is determined by the thickness of the aluminum guide tube in which the Hall probes move. Hall probe calibration in LHe was done in-situ with SC calibration coils. Figure 1 shows the Radia model for the SC calibration coils, photographs of the PrFeB undulator arrays and the SC calibration coils enclosure.

(a) (c) FIGURE 1. (a) PrFeB arrays installed in the VTF; (b) Radia model of the calibration coils; (c) Photograph of the coil enclosure in the VTF.

Measurement in LN2 Bath First, a number of measurements were conducted in liquid nitrogen. The Hall probe elements were calibrated

separately against an NMR probe in a conventional electromagnet dipole ,while they were immersed in a small LN2 dewar. Figure 2-(a) shows the comparisons between predicted field by Radia6 and measurement results at both room temperature and at 77K. Br in the simulation was varied to achieve the closest fit to the measured peaks. The fitted results indicate that the magnet’s Br increased from 1.37T at RT to 1.64T at 77K. The discrepancy in the extremities is mainly due to the imperfection of the magnet machining. Hall probe data show that the average period length has decreased from 14.503mm at RT to 14.489mm at 77K due to thermal contraction of the aluminum array holder. Linear expansion of 6061-T6 aluminum alloy is supposed to contract by approximately 4!10-3 from 293K to 77K which translates 0.8mm contraction for 20cm arrays. It is known that NdFeB magnet has negative thermal expansion perpendicular to the magnetized direction. More investigation is needed to understand the reason for smaller reduction of the period length. Phase error plots for both cases are shown in Fig. 2-(c) for RT and Fig. 2-(d) for 77K. No significant change in the pattern of phase errors have been observed, but the RMS phase error exhibits

(b)

T. Tanabe, et. al., AIP Conference Proceedings, Vol. 1234, p.29 (2010). 4.85 mm gap

Notice: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH1-886 with the U.S. Department of Energy. The United States Government retains, and the publisher, by accepting the article for publication, acknowledges, a world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for the United States Government purposes.

FIGURE 3. (a) Hall probe element output voltage for two adjacent positive peaks at various temperatures. The measurement started at 4.2K and data at higher temperatures were measured as the array temperature increased. (b) Phase error plot in the full period region for a LHe temperature scan. RMS phase error is 6.8 degrees.

OTHER OPTIONS The rare-earth metal dysprosium (Dy) has one of the largest magnetic moments. In the ferromagnetic ordered

state, it could exhibit the a saturation inductance of 3.8T at 4.2K. Dy orders ferromagnetically at 90K, therefore, it could be used as pole material only in CPMU designs. The peak field of U20 at a 5mm gap assuming Br=1.50T is found to increase from 1.29T with permendur to 1.36T with textured Dy poles. The comparison was done with Radia using measured µH v.s. M data for crystallized Dy9.

Low temperature SCUs have been tested at several laboratories in the world. Heat shield problems demand increased effective magnetic gap, which in turn diminishes the advantages of SCUs. SCUs with high temperature superconductor tapes is another possibility for the future R&D. However, further increase of maximum engineering current density is required to be compete with CPMU field performance.

SUMMARY The magnetic field characteristics of PrFeB undulator arrays of 14.5mm period length have been measured at LN2

and LHe temperature. The operation at 77K was found to be very promising. Not much performance gain was observed at 4.2K. A combination of PrFeB magnets and textured Dy poles may give further performance gain compared to conventional CPMU consisting of NdFeB and permendur poles.

ACKNOWLEDGMENTS The authors wish to thank Dr. Vyacheslav Solovyov of the Material Science Department at BNL for providing

measurement data for PrFeB magnet and Dy materials, Dr. Tsutomu Kohda and Dr. Yutaka Matsuura of Hitachi Metal, NEOMAX company for their support.

REFERENCES 1. T. Tanabe, et. al., " X-25 Cryo-ready In-vacuum Undulator at the NSLS" AIP Conference Proceedings, Volume 879, pp. 283-

286 (2007). 2. S. Yamamoto, et. al., Rev. Sci. Instrum. 63, pp400 (1992) 3. T. Hara, et. al., “Cryogenic permanent undulators”, Phys. Rev. ST, Acc. and Beam, Vol. 7, p.050720 (2004). 4. http://www.hitachimetals.com/product/permanentmagnets/ 5. D. Harder, et. al., “Magnetic measurement system for the NSLS superconducting undulator vertical test facility”, Proceeding

of PAC05, pp. 1730-1732 (2005). 6. O. Chubar, P. Elleaume, and J. Chavanne, J. Synchrotron Rad. 5, pp.481 - 484 (1998). 7. http://www.cryomech.com/ 8. S. G. Sankar, in private communication. 9. Vyacheslav (Slowa)Solovyov, in private communication.

(a) (b)

J. Bahrdt et al. IPAC10, 3111

F. O’Shea et al. PRSTAB 13, 070702 (2010)

F. O’Shea, HBEB workshop, Puerto Rico, 2013


U18-PrFeB

(a) (b)

test on NLCTA (43 K) bunching observation

laser off laser on

jeudi 16 mai 2013

http://www.springer.com/series/3849http://www.springer.com/series/3849


!"#$%&'()#*%"'+*,&)-()#")+.)&/"%0&*&.#1'2)+".&()#3*+)+%&3*2+)%&4+54,*%'#&*%&%0)&)$#!&!"#$%&'&(()*#+"#,)-).*#$"/)()0*#1"#2)'30*#4521*#+6)(3-0)#16&(.)#

$"#789):8*#5;,4?6#@')99)#16&(.)"

!"#$%&'$(A# .6B3:)(8.&00B# .330)C# 8(D'&.??E# ?(C?0&936# F&>#

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

"+%#'54.%"'+&#A#$6B3:)(8.#/)6E&()(9#U&:()9#V(C?0&936#W$/UVX#8>#

&(#8(D'&.??E#?(C?0&936#F%8.%#E&Y)>#?>)#3=#9%)#)(%&(.)C#E&:()98.# M63M)698)># 3=# OC1)P# E&9)68&0# &9# 03F#9)EM)6&9?6)#ZN["###9%)#)T9)(>83(#3=#%8:%#-68008&(.)# ?(C?0&936# 6&C8&983(# 93# %8:%)6# M%393(# )()6:B#9%&(# 8># ?>?&00B# &.%8)')C# F89%# .3(')(983(&0# 8(D'&.??E#?(C?0&936>"# L%)# E&T8E?E# M)6=36E&(.)# .&(# -)# 6)&.%)C###?>8(:#OC1)P#:6&C)>#%&'8(:# 9%)#%8:%)>9# 6)E&()(.)# WP6#\#N"]#LX#&9#633E#9)EM)6&9?6)#-?9#&0>3#9%)#03F)>9#.3)6.8'89B#W^._# `NJJJ# YASEX"# 5?.%# .3)6.8'89B# 8># 8(>?==8.8)(9# 93#3M)6&9)# &(# 8(D'&.??E# ?(C?0&936# >&=)0B# &9# 633E#9)EM)6&9?6)# C?)# 93# 9%)# M3>>8-0)# C)E&:()98a&983(# 3=#M)6E&()(9# E&:()9># ?(C)6# )0).963(# -)&E# )TM3>?6)# F89%#>E&00# :&M>"# L%8># F)&Y# M38(9# 8># )08E8(&9)C# F%)(# 9%)#E&:()9# E&9)68&0# 8># .330)C# &9# .6B3:)(8.# 9)EM)6&9?6)"#LBM8.&00B*# 9%)# .3)6.8'89B# 8># 8(.6)&>)C# -B# =&.936# 3=# I"Q#F%)(#9%)#OC1)P#E&9)68&0#8>#.330)C#=63E#Ibc#7#93#NQJ#7"#L%)#9)EM)6&9?6)#3=#NQJ#7#.366)>M3(C>#93#&(#3M98E?E#8(#9%)#C)M)(C)(.)#3=# 9%)#?(C?0&936#=8)0C#3(#9%)#9)EM)6&9?6)#ZI["# # 6)0&9)C# 93# >M).8=8.# E&:()98.# M63M)69B# 3=# 9%)#OC1)P# E&9)68&0# .&00)C# 5M8(# 2)368)(9&983(# L6&(>8983(#W52LX"#P)03F#NQJ#7# 9%)# ?(C?0&936# M)&Y# =8)0C#C).6)&>)>"##L%8># ?(?>?&0# E&:()98.# -)%&'83?6# %&># 6)R?86)C# >3E)#>9?C8)>#3(#OC1)P#>&EM0)>#&9#03F#9)EM)6&9?6)#ZI[*Z]["#A(#&..?6&9)# E&:()98.# E3C)0# 3=# OC1)P# E&9)68&0# &9# 03F#9)EM)6&9?6)#6)R?86)>#(3(#08()&6#6)M6)>)(9&983("#A#08()&6#E3C)0# .&(# >9800# -)# ?>)C# -?9# 6)R?86)># Y(3F0)C:)# 3=# 9%)#E&9)68&0#E&:()98.#M)6E)&-8089B#')6>?># 9)EM)6&9?6)# ZQ[# 8(#36C)6# 93# .366).90B# M6)C8.9# 9%)# =8)0C# M)6=36E&(.)># 3=# $/UV#"#A9# 9%)#4521*#&00# 8(D'&.??E#?(C?0&936># &6)#-&Y)C#&9#NIJ#C):#$#&=9)6# 9%)86# 8(>9&00&983(# 8(# 9%)# 68(:# 8(#36C)6# 93# 08E89#9%)# P6)E>96&%0?(:# >)(9# 93# 9%)# -)&E08()# "L%8># -&Y8(:# 3=#

9%)# ?(C?0&936># 8># (39# .3EM&98-0)# F89%# 9%)# ?>)# 3=# 03F#.3)6.8'89B#OC1)P#E&9)68&0"#$3(>)R?)(90B*#9%)#?>)#3=#%8:%#6)E&()(.)# OC1)P# E&9)68&0# =36# 9%)# $/UV# 6)R?86)># 9%)#>?MM6)>>83(#3=# 9%)#-&Y8(:#M%&>)d# 9%8>#&>M).9# 8>#C8>.?>>)C#=?69%)6#8(#9%8>#M&M)6"#9# $/UV# F&># -&>)C# 3(# %8:%# .3)6.8'89B# OC1)P# W#^._eI]JJ# YASEX# &(C# 9%)6)=36)# F89%# 6)C?.)C# =8)0C#M)6=36E&(.)># WP6eN"NH# LX"# # L%)# ?(C?0&936# 8># %B-68C#>96?.9?6)# F89%# M)683C# 3=# NK# EE# &(C# 939&0# E&:()98.#0)(:9%#3=#I#E"#L%)#M68E&6B#9&6:)9#3=#9%8>#M63939BM)#F&>#93#C)')03M# 9%)# 6)R?86)C# E&:()98.# E)&>?68(:# >B>9)E># &(C#.6B3:)(8.# .3308(:# E)9%3C# &># F)00# &># 93# 3-9&8(# >3E)#)TM)68)(.)# 8(# 9%)#3M)6&983(#3=#>?.%#C)'8.)# 8(#>936&:)#68(:"# L%)# 9F3# =86>9# 93M8.># %&')# &06)&CB# -))(# C8>.?>>)C#ZI[*Zc["##L%8>#M&M)6#=3.?>)>#E&8(0B#3(#9%)#3M)6&983(#3=#9%8>#=86>9# M63939BM)# 8(>9&00)C# 8(# 9%)# 96&8:%9# >).983(# 8(#!&(?&6B# IJJK# W18:"#NX"# L%)# ?(C?0&936# 8># .3(().9)C# 93# 08R?8C#(8963:)(#.6B3DM?EM#>B>9)E#03.&9)C#8(#9%)#9).%(8.&0#:&00)6B#F89%#.6B3:)(8.#08()#939&008(:#QJ#E#8(#0)(:9%"##

#

18:?6)# Nf# 186>9# $/UV# M63939BM)# 8(>9&00)C# 8(# 9%)# 4521#96&8:%9#>).983("#

0)*%&6452)%&/"%0&6)*3&!)*%&+*(,*-.*%&$/%*(L%)# ?(C?0&936# F&># .330)C# 93# 9)EM)6&9?6)# 3=# NcK# 7#

-)=36)#9%)#&..)0)6&936#6)D>9&69#8(#!&(?&6B#IJJK"#G?)#93#9%)#%8:%#9%)6E&0#.3(>9&(9#3=#9%)#?(C?0&936#WNI"Q#%3?6>X#89#F&>#(39#M3>>8-0)#93#?>)#E&.%8()#C)C8.&9)C#98E)#=36#9%)#9%)6E&0#>9?CB"# 9)&C*# 9%)# C)'8.)# F&># E3(8936)C# C?68(:# ?>)# -B#9%)## C)68')C# =63E# 9%)# E)&>?6)E)(9# 3=# 9%)#C8==)6)(98&0# M6)>>?6)# &(C# 9)EM)6&9?6)# 3=# 08R?8C# (8963:)(#-)9F))(# 9%)# 8(M?9# &(C# 3?9M?9# 3=# 9%)# .6B3:)(8.# M?EM"#

WE5RFP067 Proceedings of PAC09, Vancouver, BC, Canada

2414Light Sources and FELs

T15 - Undulators and Wigglers

ESRF (X2)

!"#$%&'()'*+$"',$%--"'!"# $% %"# '()#*%+,,-# ."# +/0+)&0)12# '()#3&)3%&%'./0#/$#

'()# 4567# 8%"# ".-.9% '/# '(%'# 1/0)# $/ %# +/0*)0'./0%9#&//-# ')-3)&%',&)# .0:*%+,,-# ,01,9%'/&;# 9?2# '()#4567#8%"#>%@)1#%'#%# ')-3)&%',&)#/$#ABC#1)=#4;#!$')'()#.0"'%99%'./02#'()#+//9.0=#/$#'()#,01,9%'/$&/-#DCC#E#'/#AFC#E#(%1#%#*.".>9)#.-3%+'#/0#'()#*%+,,-;#G()# &)".1,%9# 3&)"",&)# 8%"# &)1,+)1# >?# /0)# /&1) /$#-%=0.',1)# $&/-# %# AC:H# ->% &%0=)# '/# AC:AC# ->% &%0=)#8.'(/,'#>)%-#I)%-# 9/%1.0=2# '()# 1)*.+)# "(/8)1# ".-.9%

*%+,,-# +/01.'./0.0=# '/# '(%'# /$# .0:*%+,,-# ,01,9%'/&"#.0"'%99)1#".0+)#AHHH#MNO;##

10-10

10-9

10-8

10-7

Pres

sure

[mB

ar]

12:00 AM13/1/09

12:00 AM14/1/09

12:00 AM15/1/09

12:00 AM16/1/09

date

280

260

240

220

200

180

160

140

Temperature [K

]

p1_C6_invac p2_C6_invac p3_C6_invac Tmag

#%@)1#I>9,)#+,&*)K#(%"#%#3)&./1#/$#BC#--# IVW7BCK# %01# ,")"# '()# "%-)#-%=0)'#-%')&.%9# %"# '()#4567# >,'# ."# /3)&%')1# %'# &//-# ')-3)&%',&);# G()# '(.&1#1)*.+)# I=&))0K#8%"# .0"'%99)1# .0#6%?#BCCL;#G()#-%=0)'.+#%"")->9?#/$#3)&./1#BB#--#IVW7BBK#."#>%")1#/0#T-B4/AX#3)&-%0)0'#-%=0)'#-%')&.%9;#G(."#,01,9%'/%"#,")1#%"#%#')"'#1)*.+)#$/'()#$,',&)#.0"'%99%'./0#/$#%#4567#>%")1#/0#(.=(# &)-%0)0+)# S# 9/8#+/)&+.*.'?#Y19.-%'./0# 3,-3";# G()# V\AF#>)%-9.0)# 8%"# %>9)# '/# '%@)# '()# ]:&%?# >)%-# $&/-# '()#,01,9%'/%#$)8#1%?"#%$')'()#&):"'%&';#G()#>)%-#9.$)'.-)#8%"# >%+@# '/# JX# (/,&"# %$') %0# .0')=&%')1# 1/")# /$# AA#!#(/,&";# #G()#*%+,,-#+/01.'./0.0=#/$# '()# '(&))# .0:*%+,,-#,01,9%'/&"#"(/80#.0#%@)1#4567# "(/,91# >)# >)'') +/01.'./0)1# '(%0# '()#8/&")#+%")#')"')1#8.'(#'()#VW7BB;#Z)+%,")# /$# '()# 9%&=)# '()&-%9# +/0"'%0'2# '()# +&?/=)0.+#

9//3# +%0# >)# "'/33)1# $/ %# $)8# (/,&"# %01# "8.'+()1# /0#%=%.0# 8.'(/,'# ".=0.$.+%0'# .-3%+'# /0# '()# ,01,9%'/')-3)&%',&);##

#%&S-!#*)&","#.0')=&%')1#+,&&)0'# $/ '(&))# 1.$$)&)0'# .0:*%+,,-# ,01,9%'/&"P# 4)99# N#4567# I3.0@K2# +)99# H# VW7BC# I>9,)K# %01# +)99# AF# VW7BB#I=&))0K;#

%()%.-/!()'G()# /3)&%'./0# /$# %# +&?/=)0.+# ,01,9%'/ .0# '()# QTU)'8))0#AFA#E#%01#AXX#E##1)3)01.0=# /0# '()# =%3# %01# '()# )9)+'&/0# >)%-# $.99.0=#3%'')&0;# G()# &)",9'.0=# .0$9,)0+)# /0# '()# 3)%@# $.)91# /$# '()#,01,9%'/&)-%.0"#*)&?#9.-.')1;#))0#1)".=0)1#8.'(#(.=(#&)-%0)0+)#Y1)0)$.'"#$&/-#%#0,->)/$# .-3&/*)-)0'"#8(.+(#8)&)#.1)0'.$.)1#$&/-#'()#$.&"'#3&/'/'?3);#

$%0)(1.+23"+)&/'G()#%,'(/&"#8/,91# 9.@)# '/#%+@0/89)1=)# '()#3)&-%0)0'#

",33/&'#$&/-#'()#*%+,,-#=&/,3#P#U;#E)&")*%02#6;#^%(02#\;#4/=0.)2#6;#_%&&)+#%01#V;#5%&%';##

4+5+4+)%+/'MAO# G;# ^%&%# )'# !9;# 5(?";# U)*;# T3)+;# G/3;# !++)9)&%'/&"#

%01#>)%-2#W/9;#X#BCCJ;#MBO# #4;#E.')=.#)'#!9;2#Q5!4`CN2#a,0)#BCCN23;#DFFH#MDO# a;#4(%*%00)#)'#!92#Q5!4`CL2#bQ54ACF2_)0/%2#a,0)#

BCCL2#3;#BBJD#MJO# 4;# Z)0%>1)&&%(-%0)# )'# !92# Q5!4`CL2# bQ54CHL2#

_)0/%2#a,0)#BCCL#3;#BBBF#MFO# _;# c)>)+# )'# !92# 54`CH2# W%0+/,*)&2# 6%?# BCCH2#

6dN53+.!$ 36 31$ '+5 =+2"+3"6# "#->7$- .8 31$ 3$45$2+3>2$'2+-"$#3(

?# 62-$2 36 7622$73 31$ 51+%$ $2262/ 0$ +55!"$- 31$ "#@%"3> 7622$73"6# 4$316-( A:3$2 %46631"#' 31$ 51+%$ $2262-+3+ φ(z) .8 !33"#' 0"31 31$ B31 62-$2 56!8#64"+! :>#73"6#36 $!"4"#+3$ 31$ 2+5"-!8 6%7"!!+3"#' 3$24 ->$ 36 31$ 32+;$7@3628 $2262/ "3 0+% -"::$2$#3"+3$- 36 6.3+"# 31$ !$!- -$="+3"6#:>#73"6# η(z) +7762-"#' 36 CD( *E,( F1$ 62-$2 6: 56!8#6@4"+! 0+% 716%$# 36 .$ $D>+! 36 31$ #>4.$2 6: "#@=+7>>4%1+:3%/ "($(/ 31$ !G+3"6# 56"#3% 6: 31$ "#@=+7>>4 .$+4( &622$:$2$#7$/ 31$ !67+3"6#% 6: 31$ !G+3"6# 56"#3% +2$ "#-"7+3$-"# -633$- !"#$% "# &"'( )*.,( F1$ +5526G"4+3$ '+5 =+2"+3"6#%+3 31$%$ !67+3"6#% 0$2$ :6>#- 36 .$ −10 µ4/ H/ +30 µ4/H/ −30 µ4/ −30 µ4/ 2$%5$73"=$!8 :264 !$:3 36 2"'13/ 01"710$2$ 7622$73$- $+%"!8 .8 31$ -"::$2$#3"+! +-;>%3$2 0"31 31$%$#%"3"="38 .$33$2 31+# I µ4(

-2000

-1500

-1000

-500

0

500

1000

1500

-800 -400 0 400 800

-4

0

4

8

12

16

(b)

2nd

Fiel

d In

tegr

al (G

.cm

2 ) (a)

300 K 117K: Before Correction 117K: After Correction

Phas

e Er

ror (

degr

ee)

z(mm)

&"'>2$ )J K$>!3% 6: 4+'#$3"7 4$+%>2$4$#3 +3 -"::$2$#3 76#@-"3"6#% "# 3$24% 6: *+, 31$ $!$7326# 32+;$73628 +#- *., 31$51+%$ $2262( F1$ %6!"- +#- -633$- !"#$% "# *+, %160 31$ 162@"L6#3+! +#- =$23"7+! 32+;$73628/ 2$%5$73"=$!8(

F1$ 2$%>!3 6: 7622$73"6# "% %160# "# '2$$# !"#$% "# &"'%( )*+, +#- *.,( F1$ 2(4(%( 51+%$ $2262 0+% 2$->7$- 36 E(E -$@'2$$/ 7645+2+.!$ 36 31+3 +3 KF( M63$ 31+3 31$ 32+;$73628 -"-#63 71+#'$ .$:62$ +#- +:3$2 31$ 7622$73"6#/ 4$+#"#' 31+331$ 32+;$73628 $2262 "% #63 31$ 4+"# 2$+%6# :62 31$ 51+%$ $2@262 "#72$+%$ ->$ 36 766!"#'(

!"##$%&

N$ 1+=$ %160# 31+3 31$ 52656%$- "#@%"3> !$!- 7622$73"6#4$316- 062O$- 0$!! "# 31$ PQRS 36 2$->7$ 31$ 51+%$ $2262"#->7$- .8 31$ 3$45$2+3>2$ '2+-"$#3( ?3 %16>!- .$ %32$%%$-31+3 31"% 4$316- "% +!%6 +55!"7+.!$ 36 #624+! ?TS% 36 762@2$73 31$ 51+%$ $2262 31+3 "% +332".>3+.!$ 36 31$ %!60!8 =+28"#'!$!- -$="+3"6# .>3 #63 36 31$ !67+!"L$- !$!- $2262%( &62 $G@+45!$/ !$3 >% 76#%"-$2 306 56%%".!$ $2262 %6>27$% 36 "#72$+%$31$ 51+%$ $2262(

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

$'()*+,-./#-)0!

F1$ +>3162% 31+#O U2%( R( V+4+4636 +#- W( X"2+3+ :6231$"2 O"#- +22+#'$4$#3 6: 31$ YM2 766!"#' %8%3$4/ +#- U2(F( F+O$>71" :62 1"% 3$71#"7+! %>55623 ->2"#' 31$ 766!"#'3$%3(

%-1-%-)'-!ZE[ F( X+2+/ F( F+#+O+/ X( W"3+4>2+/ F( \"L$#/ F( ]$"O$/ F( W61-+

+#- V( R+3%>>2+/ Q18%( K$=( ]F@A\ ^ (2004) HIH^H_(

Z_[ F( F+#+.$/ A( \!$-#8O1/ U( X+2-$2/ R( Y$1$7O+/ `(K+O60%O8 +#- a( ]O+2"3O+/ Q267( QAP _HHI/ Ebcb *_HHI,(

Z)[ F( F+#+O+/ F( X+2+/ F( \"L$#/ F( ]$"O$/ K( F%>2>/ d( R+2$71+!/X( X"2+#6/ R( R62"3+/ X( F$%1"4+/ ]( M+2"O"/ M( ]+O+"/ ?(X"2+.+8+%1"/ R( R>2+O+4" +#- X( W"3+4>2+/ M$0 a( Q18%( 9(2006) 29^(

Zc[ a( P1+=+##$/ R( X+1#/ K( W$2%$=+#/ P( W"3$'"/ P( Q$#$! +#-&( K$=6!/ Q267( CQAP _HH9/ __c) *_HH9,(

ZI[ F( F+#+O+/ K( F%>2>/ F( M+O+;"4+ +#- X( W"3+4>2+/ a( ]8#@7126326# K+-( Ec (2007) cEB(

ZB[ F( F+#+O+/ F( ]$"O$/ A( W+'+4"1+3+/ F( ]714"-3/ A( A#'1$!/R( \2e>''$2/ N( \>!'1$26#"/ \( a+O6./ +#- X( W"3+4>2+/ Q18%(K$=( ]F@A\ E_ (2009) E_H^H_(

Z^[ F( F+#+O+/ F( ]$"O$ +#- X( W"3+4>2+/ Q267( &CY 2HH^, cB9*_HH^,(

Z9[ F( F+#+O+/ F( ]$"O$ +#- X( W"3+4>2+/ Q267( &CY 2HH9, )^E*_HH9,(

Proceedings of IPAC’10, Kyoto, Japan WEPD026

02 Synchrotron Light Sources and FELsT15 Undulators and Wigglers 3149

SLS

T. Tanaka et al., IPAC 2010, 3147

Tanaka, et al., . Phys. Rev. Spec.Topics 12, 120702 (2009)

n°1 : U18, Br = 1.16 T n°2 : U18, Br = 1.383 T

U14, Br = 1.33 T

Cryogenic undulators in operation (3G)II- From In-vacuum to cryogenic undulators and in-vacuum wigglers

jeudi 16 mai 2013


DIAMOND

!"#$%&'(&)**%+,-.%&/-%$0&1%*23%&"40&5*,%3&622$-47&

&

!"#$%%# !"#'()#

*+,#-../0123/#42/567!8#

-../0123/#42/567!8#

42/56#290:/+;/#

?&

)# ;9;>& :9>>?&

'%# ;9=>;& ;9@;'& :9&L9& &M%&*2I40& ,D",&

-HH%0-",%$E&"*,%3&3%"+D-47&8B>&LF&,D%&H"74%,-+&*-%$0&G"C&

;98?& #%$2G& ,D%& ."$I%& 2#,"-4%0& #%*23%& +E+$-479& & N,& G"C&

*2I40& ,D",& "*,%3& H%"CI3-47& *23& :& D2I3CF& ,D",& ,D%& *-%$0&

+24.%37%0& ,2G"30C& ,D%&J3%O+E+$-47&."$I%9& &M%& %C,-H",%0&

,D",&"JJ32P-H",%$E&'@&D2I3C&G"C&%42I7D&*23&,D%&C,3I+,I3%&

,2&,D%3H"$$E&%QI-$-#3",%99&&R2&+D"47%&-4&,D%&JD"C%&%3323&2*&

,3"S%+,23E& C,3"-7D,4%CC& G"C& C%%4F& "C& "& 3%CI$,& 2*& ,D%3H"$&

+E+$-479&

&

-+#../(012.$*2(&

5C& ,D%&H"74%,& "33"EC&G%3%&42,"K%"#$%F& ,D%&"+D-%.%0&

."+IIH& J%3*23H"4+%& G"C& 2*& I,H2C,& -HJ23,"4+%9& & 54&

I$,-H",%& J3%CCI3%& 2*& 89

8;O:

& H#"3& G"C& "+D-%.%0F& G-,D2I,&

+22$-47& ,D%& H"74%,& "33"E9& & T4+%& ,D%& H"74%,& "33"E& -C&

+22$%0F&,D%&J3%CCI3%&0%+3%"C%C&*I3,D%3F&0I%&,2&+3E2JIHJ-4&

*32H& ,D%&H"74%,& "33"E9& & N,& -C& %PJ%+,%0& ,D",& ,D%& J3%CCI3%&

G-$$&0%+3%"C%E&"4&230%3&2*&H"74-,I0%9&

&

&

>?@>ABCD?@C#&

U"4*EC-K&D"C&0%C-74%0&"40I-$,&"&'&H& $247&+3E27%4-+&

-4O."+IIH& I40I$",23F& ,2& 0%H"40-47& CJ%+-*-+",-24CF& *23&

U-"H240&V-7D,&W2I3+%9&5C& %PJ%+,%0F&G%&2#C%3.%0& "&:OA&

?& 3%H"4%4+%& -4+3%"C%F& *23& 2I3& +D2-+%& 2*& R0/%1& 73"0%9&&

UI%& ,2&"& $2G& ,%HJ%3",I3%&73"0-%4,& "$247& ,D%&7-30%3CF&G%&

G%3%&"#$%&,2&J320I+%&"&0%.-+%&G-,D&"&JD"C%&%3323&2*&=9B2

9&&

!D%& D23-X24,"$& %$%+,324& ,3"S%+,23E& G"C& *2I40& ,2&

%PJ%3-%4+%& "& K-+K& ",& %"+D& %P,3%H-,EF& "C& %PJ%+,%09& & !D%&

.%3,-+"$& %$%+,324& ,3"S%+,23E& G"C& $"37%$E& I4"**%+,%09& & !D% &

0%.-+%&D"C& CD23,& & +233%+,-24&+2-$CF& ,2&+2I4,%3& ,D-C&K-+K&",&

%"+D&%409&

M-,D&,D%&+2HJ$%,-24&2*&,D-C&0%.-+%F&U"4*EC-K&-C&42G&C,-$$&

-4& "& J2C-,-24& ,2& CIJJ$E& "$$& ,D%& H"-4& ,EJ%C& 2*& -4C%3,-24&

0%.-+%C& G-,D& ,-7D,& J%3*23H"4+%& 3%QI-3%H%4,C9& M%& D".%&

-0%4,-*-%0& C%.%3"$& "3%"C& *23& 0%C-74& -HJ32.%H%4,F& GD-+D&

G-$$%&-HJ$%H%4,%0&-4&CI#C%QI%4,&0%.-+%C9&

&

&

&

&

/-7I3%&@(&/-4-CD%0&0%.-+%&"*,%3&*"+,23E&,%C,-479&

&

# E>&@?FA-G*-H-@!C#M%&"+K42G$%07%&,D%&"CC-C,"4+%&2*&Y& 96D"."44%&"40&69&

Z%4%$& *32H& ,D%& )W[/F& ,D32I7D& 2I3& ,%+D42$27E& ,3"4C*%3&

"73%%H%4,9&

M%& G2I$0& "$C2& $-K%& ,2& ,D"4K& /9& 120K%3F& +I33%4,$E& ",&

W-%H%4CF& \%"$,D+"3%& W%+,23F& Z"3,-+$%& !D%3"JEF& *23&

."$I"#$%&D%$J&"40&0-C+ICC-24C9&&

&

I-4-I-@>-C##

&

]8^&D,,J(__GGG90"4*EC-K90K9&

]'^&/9&1`0K%3F&a9R9&Z%0%3C%4F&69M9&TC,%4*%$0F&)9&&&&&

YII$F)919&6D3-C,%4C%4F&!9V9&W.%40C%4F&\9&1"+DF&

)Z569&';;' +'

#)+&!+1!' 8$J:$!' &$)12%"&' 61>26228"1' #>#)"/' +#' :#"!' 2&'/+&>' 9"+/' /2&26*12/+)21#.' K&' 21!"1' )2' L""0' )*"'/+%&")#'+)')*"'20"1+)$&%')"/0"1+):1"'24',F-3')*"'/+%&")'%$1!"1#' +1"' 4$))"!' ($)*' #)1$0' *"+)"1#.' 5*"' )"/0"1+):1"' 24')*"'/+%&")'%$1!"1#'$#'/+$&)+$&"!'9>'+'#)+&!+1!'M:12)*"1/'62&)1288"1.'

!"#$%&'()*%+,-+."$(%)5*"' G@HI' *+#' 9""&' 20"1+)$&%' #$&6"' N:%:#)' ;O,O.'

B$%:1"'P' #*2(#' )*"'62/0+1$#2&'($)*' )*"' #0+1"':&!:8+)21'(*$6*')*"'9"+/'8$&"'(+#'01"7$2:#8>':#$&%Q;R.''

'B$%:1"'PS'G2/0+1$#2&'24'G@HI,-.-'+&!'K=I;P.'

'

/0%+"&'-$"1)230%+'%$(%)5*"'/2#)'#$%&$4$6+&)'1$#L'+##26$+)"!'($)*')*"'G@HI'$#'

)*"'82##'24'61>2%"&$6'6228$&%.'5*"'!"7$6"'$#':&9+L"!'+&!')*"'7+6::/'$#'/+$&)+$&"!'$&'0+1)'9>')*"'61>2T0:/0$&%'24')*"' 628!' #:14+6"#.' U*"&' )*"' 6228$&%' 4+$8#' +&!' )*"')"/0"1+):1"' #)+1)#' )2' 1$#"' )*"' 7+6::/' $&' )*"'G@HI'($88'!")"1$21+)"' 27"1' +' &:/9"1' 24' *2:1#' !:"' )2' )*"1/+8'!"#210)$2&' +&!' )*"' #+4")>' $&)"1826L#' ($88' #*:)' 244' )*"'#)21"!')2'01"7"&)'"V6"##$7"'W+#'C1"/##)1+*8:&%.''K&' 21!"1' )2' !"+8' ($)*' +' /+X21' 4+:8)' ("' *+7"' $)+88"!'

)(2' +!!$)$2&+8' 7+87"#' $&' )*"' *$%*' 01"##:1"' 61>28$&"#'9")(""&' )*"'G@HI' +&!' )*"' 61>26228"1.' 5*$#' +882(#' )*"'61>26228"1' )2' 9"' 1"08+6"!' (*$8"' )*"' G@HI' $#' #)$88'(+1/$&%':0'#82(8>.''

21%(&+-$)4%".)5%"&'$#)'$)&6%)7*!8)N' 4$V"!' *"+)' 82+!' YZ)2)[' $#' 1"J:$1"!' )2' /+$&)+$&' )*"'

)"/0"1+):1"' 24' )*"' G@HI'/+%&")#' 27"1' +&!' +927"' )*"')"/0"1+):1"' )*+)' (2:8!' 9"' +6*$"7"!' )*12:%*' 6228$&%'+82&".'N##:/$&%' )*+)' +88' "&7$12&/"&)+8' *"+)' #2:16"#' +1"'62)+&)' 7+1>$&%' *"+)' #2:16"#' +1"' )*"' 9"+/'*"+)"1#' YZ*)1['\UM')*"&'

Z"9*'#*2:8!'4+88'+#'#T,'(*"1"'#' $#' )*"'%+0'($)*'9:;$&%'6:11"&)'\UM.''U"' 6+&' +8#2' #):!>' )*"' "8"6)12&' 9"+/' *"+)$&%' 9>'

/"+#:1$&%' )*"' G@HI' *"+)"1' 2:)0:)' +#' 4:&6)$2&' 24' %+0.'@1"8$/$&+1>' /"+#:1"/"&)#' +8#2' #*2(' )*+)' )*"' 9"+/'*"+)$&%'$#'!2/$&+)"!'9>'\UM.'

)!*#"+$,-,.,#/&(5*"'+:)*21#'8$L"')2')*+&L'a1'A'H"E"&)#"7'421')*"'(21L'

2&' )*"'DGUb#'+&!'a1'M'G'c2&%*$'+&!'a1'G'A$6L8$&' 421')*"'/"+#:1"/"&)#'24')*"'G@HI.'

0,1,0,#!,&(Q,R'D' G+#+89:2&$' ")' +8


Cryogenic undulators : Mechanical changes at low temperature

• Gap opening due to thermal contraction of the supporting rods to be compensated

Measurement :Capacitance type displacement monitors

(Nantex Corp.) SPring-8Wire resistivity : ESRF, SOLEIL

• Period reduction due to girder contraction, ex at SOLEIL 9 mm over 2 m,

i.E. 38 µm / period)

• Phase error correction via rod shimming

9 Institute of Physics !DEUTSCHE PHYSIKALISCHE GESELLSCHAFT

0.0

0.2

0.4

0.6

0.8

1.0

50 100 150 200 250 300

–0.03

–0.02

–0.01

0.00

0.01

0.02

Cooling process, Heating process

Gap taper

Gap variation

Var

iatio

n (m

m)

Tap

er (

mm

)

Temperature (K)

Figure 6. Reproducibility of the gap variation (top panel) and tapering (bottompanel) at different temperatures.

100 150 200 250 3008500

9000

9500

10 000

10 500

11 000

11 500

Pea

k fie

ld (

Gau

ss)

Temperature (K)

Figure 7. Peak field as a function of the temperature. The blue dot shows a theo-retical value of the undulator peak field with the same periodic length (15 mm) andgap (4 mm) but the remanence of 1.15 T (NEOMAX35EH, NEOMAX Co. Ltd.)

New Journal of Physics 8 (2006) 287 (http://www.njp.org/)

T. Tanaka et al., New Journal of Physics, Development of cryogenic permanent magnet undulaotrs operating around liquid nitrogen temperature, New Jour. Physics 6, 2011, 287

13 !"##$%&'()*+,-(),(*&++#,-&.(+

!"#$"%&'(%")*&%+&'+,-)&.,-/)/+%0"%1

./01/23452/*632734789*:/4/2079/:*34*/3;7/=:*0/3?52/0/94*

./01/23452/*984*597>820*3=89@*@72:/2?

./01/23452/*632734789*79;2/3?/?*34*=8A/2*4/01/23452/?B23:7/94*327?/?*>280*C3:*;899/;4789*34*59:5=3482*/D42/0747/?

10

8

6

4

2

0

-2

Tem

pera

ture

env

elop

T

[ K ]

300280260240220200180160140120Temperature [ K ]

T utilisé dans un modèle T calculé avec la sonde de Hall

150

148

146

144

142

Tem

péra

ture

[K]

2.01.51.00.5Position longitudinale [m]

!"#$"%&'(%")*&%+&'+,-) !

.,-/+'(0+-&1)$,2+'+,-)3#4

!"#$"

%&'(%")!)35

4

!"#$"

%&'(%")6&%+&'+,

-)!)354

ESRF

SOLEIL


jeudi 16 mai 2013


- in situ magnetic measurementsex : SAFALI (Self aligned field analyzer with laser instrumentation)

T. Tanaka et al, FEL 2007, Novosibirsk, 468;T. Tanaka et al. FEL 2008, Gyeonju, 371; T. Tanaka, et al., . Phys. Rev. Spec.Topics 12, 120702 (2009)

O-ring reciprocating seal

4axis-stage(remote 2axis)

xy linearguide

Top View

Side View

θz rotarystage

θx,y stage

x,y stage

to TMP

to TMP

SUS pipe

Figure 4: Schematic illustration of the SAFALI system forthe CPMU prototype.

cating seals have been installed to insert the SUS tube to fixthe cantilever of the Hall probe, which is actuated by meansof pushing or pulling the end of the tube. The Hall probeposition feedback is performed by the multi-axis stage sup-porting the vacuum duct including the O-ring seal. Thevariation of the Hall probe position during actuation wasslightly worse than the system for IVU24 described in thepreceding section, however, the reproducibility was simi-lar. For details, refer to [3].

RESULTS OF MEASUREMENT

IVU24We measured the magnetic distribution at the gap values

of 6, 8, 10, 14, and 20 mm and compared the magnetic per-formances with those measured by a conventional methodin July 2000, just after the field correction and before in-stallation in the SLS ring. The results are shown in Fig. 5in terms of the electron trajectory (2nd field integral) andphase error distribution.

We find negligible difference between the two measure-ments in terms of the electron trajectory, while a small dis-crepancy in the phase error distribution suggests that themagnetic field distribution has changed slightly. It shouldbe emphasized, however, that the variation is very smalland less than 0.5 degree in r.m.s. So we can concludethat no significant demagnetization took place in the IVU24during operation.

CPMU PrototypeWe measured the field distribution of CPMU prototype

at different temperatures and found that the peak field be-came maximum at a temperature of 130 K. During the mea-surement, the gap was fixed at 5 mm by measuring directlythe distance between the top and bottom magnet arrays bymeans of a laser scan micrometer. From the point of viewof field correction, what is important is the phase error vari-ation due to temperature change. Figure 6 shows the mag-netic performances measured at room temperature and 130K in terms of the electron trajectory and phase error. Wefind negligible difference between the performances at two

-800 -400 0 400 800

-3

0

3

6

-3

0

3

6

-3

0

3

6

-3

0

3

6

-3

0

3

6

6mm

z (mm)

8mm

20mm

10mm

2nd

Fie

ld In

tgeg

ral (

103 G

.cm

2 )

14mm

0 10 20 30 40 50 60 70 80 90 100 110

-8

-4

0

4

8

-8

-4

0

4

8

-8

-4

0

4

8

-8

-4

0

4

8

-8

-4

0

4

8

Pole Number

Pha

se E

rror

(de

gree

)

March 2007 (SAFALI) July 2000 (Conventional)

Figure 5: Comparison of magnetic performances of IVU24between July 2000 and March 2007. Note that measure-ment in July 2000 was done by a conventional method.

different temperatures, suggesting that cooling the perma-nent magnets did not induce a large change in the errormagnetic components that could affect the undulator per-formance. This is a very encouraging result toward realiza-tion of CPMUs.

-300 -200 -100 0 100 200 300

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2nd

Fie

ld Int

egra

l (10

3 G.c

m2 )

z(mm)

300K 130K

0 10 20 30 40 50 60 70

-10

-8

-6

-4

-2

0

2

4

6

Pha

se E

rror

(de

gree

)

Pole Number

300K (3.3o)

130K (3.2o)

Figure 6: Variation of magnetic performances of CPMUprototype at room temperature and 130 K.

SUMMARY

We have described the SAFALI system as a new schemeof undulator field characterization and its practical appli-cation. It should be also stressed that the SAFALI sys-tem is portable: the magnetic performance of IVUs can bechecked at any time without moving to the laboratory or fa-cility for the field measurement. Such a portability is veryimportant especially in X-ray FEL facilities where a num-ber of undulators will be installed. The SAFALI system canbe used not only for the final check after assembly but alsoto monitor the magnetic performance as the FEL driver. Wealso note that most undulators nowadays have a C-shapedframe, but not a O-shaped frame, in order to ensure open-ings for field mapping with Hall probe scanning, whetherthey are in-vacuum or out-vacuum. This imposes a severerestriction on the undulator design, because C-shape frame

WEPPH052 Proceedings of FEL 2007, Novosibirsk, Russia

FEL Technology II

470

Light Source (SLS) as a collaboration to aim at utilizationof angstrom x rays in the medium-sized SR facility. After3-year operation, IVU24 has been replaced with anotherIVU and returned to SPring-8. It is important to measurethe magnetic field of IVU24 and compare with the initialstate, and to check the variation of magnetic performancesfrom the point of view of demagnetization due to electronirradiation during operation.

Top View

Side View

steppermotor

laser diode

undulator magnet Hall probeiris

2-axis stagecarriage

corner cube

rail

laser scale

PSD

Figure 1: Schematic illustration of the SAFALI system forthe CPMU prototype.

Figure 1 shows a schematic illustration of the SAFALIsystem for IVU24. We have installed a rail and carriage toactuate the Hall probe by means of a tensioned loop wiredriven by a stepper motor. The Hall probe cantilever wasattached to the carriage together with the cubic mirror toreflect the laser beam of the laser scale to measure the lon-gitudinal position of the Hall probe. In addition, two irisesare attached at the both ends of the Hall probe cantileverwith a diameter of 2 mm. In order to measure the transverseHall probe position during actuation, two laser beams wereintroduced to irradiate the irises and create laser spots atthe opposite side. The positions of the laser spot were mea-sured with position sensitive detectors (PSDs), the averageof which defines the position of the Hall probe.

-1000 -800 -600 -400 -200 0 200 400 600 800 1000

-0.1

0.0

0.1

0.2

0.3

with feedbackσ

x=4.9µm,σ

y=3.9µm

Tra

nsv

ers

Posi

tion (m

m)

z (mm)

Horizontal Vertical

without feedbackσ

x=51µm,σ

y=79µm

Figure 2: Variation of the Hall probe position with andwithout feedback.

The feedback of the Hall probe position is done by mov-ing the rail with the three sets of 2-axis stages supporting

the rail. Figure 2 shows the variation of the Hall probe po-sition measured with and without the feedback procedure.We can clearly find the effects due to the feedback. Themagnetic error due to the positional deviation of 5 µ is just5×10−6 for an undulator with a magnetic period of 10 mm,and smaller for a longer period.

As a field measurement system for undulators, the re-producibility is the most important. We measured the mag-netic field distribution of IVU24 four times under the samecondition to examine the reproducibility. The results areshown in Fig. 3 in terms of the phase error as a functionof the pole number, where we find quite a good agreementbetween the measurement results.

0 10 20 30 40 50 60 70 80 90 100 110

-10

-8

-6

-4

-2

0

2

4

6

1st 2nd 3rd 4th

Phase

Err

or (d

egre

e)

Pole Numbere

Figure 3: Reproducibility of the field measurement in termsof the phase error distribution.

As described above, the developed SAFALI system hasbeen found to have a performance good and reliable enoughto measure the magnetic field of IVU24.

SAFALI FOR CPMU PROTOTYPE

The CPMU is a novel undulator proposed at SPring-8in 2004 [1]. The permanent magnets in the IVU is cooleddown to improve the magnetic property in terms of the re-manence and coercivity. The operation temperature will bearound 100∼150K where the remanence becomes maxi-mum, and much higher than liquid helium, so the operationwill be much more feasible than superconducting undula-tors composed of NbTi wires. We have constructed a pro-totype of CPMU with a magnetic length of 600 mm and amagnetic period of 15 mm and made experiments to inves-tigate the feasibility of CPMUs such as the cooling capa-bility, variation of the magnetic gap and tapering during thecooling process [2]. Although promising results have beenobtained in these experiments, we have to establish a fieldmeasurement technique to be adapted to the CPMUs. So,we have developed a system based on the SAFALI methodto measure accurately the magnetic performance at a cryo-genic temperature [3].

Figure 4 shows a schematic illustration of the SAFALIsystem for the CPMU prototype. A pair of O-ring recipro-

Proceedings of FEL 2007, Novosibirsk, Russia WEPPH052

FEL Technology II

469

SACLA undulators

T. Tanabe, et al., . Design concept for a modular in vacuum probe mapper for use with CPMU convertible in vacuum undulators of varying magnetic length, PAC 2011, 2534

Cryogenic undulators : Magnetic measurements


jeudi 16 mai 2013


SOLEIL

12 !"##$%&'()*+,-(),(*&++#,-&.(+

!"#$%&''(#(%)"*+,(*%-'.*(*"+#/*"&0

+/01/2314*560176184*69/1:0;8*01

M. E. Couprie, International Particle Accelerator Conference, ,Shanghai, China, May 13-17, 2013 !

Test RP : 13 décembre 2011

SOLEIL

Cryogenic undulators Radiation : radiation

!


jeudi 16 mai 2013


Cryogenic undulators Radiation : measured spectraExample of measured spectra at ESRF

Photon flux in 0.6 mm x 0.6 mm @ 30 m in ID11 (G. Vaughan, J. Wright)

Courtesy J. Chavanne

Robust consistency between magnetic design - field measurements - observation in beamline


jeudi 16 mai 2013


Cryogenic undulators Radiation : comparison with in-vacuum undulator

Check CPMU performance wrt conventional Sm2Co17 hybrid IVU22 in ID11

Gain in photon flux ~ 2 @ 60 keV, ~3 above 90 keV as expected

Photon flux in 0.6 mmx 0.6 mm @ 30 m, gap 6.4 mm

ID11 CPMU expected to be operated with minimum gap 5 mm in 2014



jeudi 16 mai 2013


Cryogenic undulators Radiation : measured spectra

- gap ~ 4 mm

- period ~ 14

- Peak field ~ 1.3 T

- K ≥ 1.7

CPMUs for new Ultra Low Emittance (150 pm) Storage Ring

1 very short period CPMU to be constructed in 2014



jeudi 16 mai 2013


Cryogenic undulators with high Tc superconductors

T. Tanaka et al. PRSTAB 7, 090794 (2004)

remarkable enhancement of the achievable Bp as thecritical current density (Jc, the maximum current densitywhich can flow in the superconductor) increases. If thesuperconductor has a Jc value higher than 1:1 kA=mm2,Bp of CU plus is expected to exceed that of the recentSCU [22] at the same gap.

It should be noted that the minimum gap of CU pluscan probably be made narrower than that of the SCUoperating around liquid helium temperature, becausethe operating temperature, 40–80 K, of CU plus ismuch higher than that of liquid helium, which ensuresa high cooling capacity of the state-of-the-art cryo-coolers. In such a case, the performance of CU plus isfurther improved as indicated by a chain curve forgap ! 3 mm.

IV. EXPERIMENTS

We performed experiments to verify the principle ofCU plus with superconductor rings made from a commer-cially available material, Gd-Ba-Cu-O.

First we investigated the performance of the supercon-ductor ring itself by applying an external field using aseparated magnetic flux generator. The illustration anddimensions of the superconductor ring are shown inFig. 3(a) and the results are in Fig. 3(b). The abscissashows the strength of the external field, while the ordinateshows the field measured by a Hall probe at the center ofthe superconductor ring. The measurement was per-formed at the temperature of liquid nitrogen (77 K). Wecan find a typical hysteresis curve brought by the diamag-netism of the superconductor ring. From the experimentalresults, Jc was roughly estimated at "200 A=mm2 bycomparison with a calculation of the magnetic field by acurrent loop with the same shape and dimensions as the

superconductor ring. This value is indeed typical for acopper-oxide SC material [15].

Then we performed experiments using the test magnetassembly comprised of PMs and the superconductors, asshown in Fig. 4(a). The PMs were made from NEOMAX

15mm

2mm

7.5mm60mm

a

-0.50 -0.25 0.00 0.25 0.50

-0.50

-0.25

0.00

0.25

0.50

Fie

ld a

t the

cen

ter of

supe

rcon

duct

or r

ing

(T)

External field (T)

b

Gd-Ba-Cu-Osuperconductor

Hall probe

FIG. 3. (Color) Determination of the critical current density(Jc) of the superconductor ring used for the test magnetassembly. (a) Illustration and dimensions of the superconductorring and (b) result of the field measurement for the supercon-ductor ring at the temperature of 77 K.

period=14mm

15mm

25mm

Pole piece (Permendur)

Permanent magnet (PrFeB)

Bulk HTSC

Electron beam

a

c

b

12mm

Lp

Ts

Gap

Electron beam

Pole piece

Permanent magnet

Bulk HTSC

10 2 10 3 10 4 10 5

0.8

1.2

1.6

2.0

2.4

2.8

currently achieved by SCU

Gap = 5mm

Gap = 3mm

Ach

ieva

ble

Pea

k Fie

ld (T)

Critical Current Density (A/mm2)

FIG. 2. (Color) Example of a magnetic structure model for cryoundulator (CU) plus (a),(b) and its magnetic performance (c).Detailed dimensions for each component are indicated in (a) and a longitudinal cross-sectional view of the CU plus model is givenin (b). Achievable peak fields calculated as a function of Jc are shown in (c) for two different values of the gap width, 5 mm (solidcurve) and 3 mm (chain curve), respectively.

PRST-AB 7 TAKASHI TANAKA et al. 090704 (2004)

090704-3 090704-3

!"#

$"!%&'

()*&

+,-,).*

!""#$%&'(()*+,#-&,.#/01*#2"

33#$%&'(()*+,#-&,.#45#/01*#2"

33#$%&'()*+,#6&71&809.#45#/01*#2:;


Choice of an in vacuum wiggler rather than a superconducting wigglerIn vacuum wiggler

performance magnet (remanent field 1.17T, coer-cive force 12 kOe) compatible with the hightemperature bake-out process required for ultra-high vacuum operation.

The wiggler has just been delivered to theSPring-8 insertion device magnetic measurementlaboratory, and is now being characterized (field,field integrals). Fig. 2 shows the variation of thevertical peak magnetic field measured as a functionof the gap. At 7mm, the vertical peak magneticfield is 1.95 T (corresponding to a critical energyec=83 keV for the 8GeV SPring-8 electron beam).At 5mm, the minimum gap set for the operation ofin-vacuum undulators, the peak field increases upto 2.3 T (ec=98 keV). The uniformity of thevertical magnetic field in the orbit plane has alsobeen measured (Fig. 3). In a ! 5mm rangearound the wiggler axis (i.e., around the main axisof the electron trajectory), the vertical field variesby less than 0.2% for gaps between 5 and 20mm.In a ! 2mm range around the wiggler axis, theroll-off is below 0.06% (0.03% at gap 7mm).

Field integrals and their transverse distributions,which characterize the transparency of an inser-tion device to the electron beam (i.e. the ID mustnot generate any beam losses or any significantmodification of the ring optic), are now beingmeasured and corrected. The results of the fieldcorrections will be presented in a future paper.

3. Effective parameters and performances

The well-know formulas (see Ref. [3] forexample) using the value of the peak field tocalculate the deflection parameter, the total powerPT and the power density Pd are not validanymore: they assume a pure sinusoidal field,while high field wigglers, such as the in-vacuum

Fig. 1. The in-vacuum wiggler during magnetic field measure-ments and correction.

Table 1In-vacuum wiggler main parameters

Period length 90mmNumber of period 10Peak field @ 7mm 1.95TTransverse roll-off ! 5mm @ 7mm 0.17%Magnet H"W"L 30" 80" 19mm3

Pole H"W"L 25" 60" 7mm3

Fig. 3. Transversal homogeneity of the magnetic field at gaps 5,7, 15, 20 and 40mm.

Fig. 2. Peak magnetic field as a function of the gap.

X.-M. Maréchal et al. / Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 138–140 139

SPring-8 : 1.95T, gap=7 mm, 10x90 mm

SOLEIL : 2.1T, gap=5.5 mm, 10x150 mm

X.M. Marechal et al, NIMA 4676-468 (2001) 138-140

O. Marcouillé et al., SRI 09O. Marcouillé et al., to appear in PRSTAB 2013


jeudi 16 mai 2013


Spectral Flux per Unit Horizontal Angle (Far-Field Estimation)

In vacuum wiggler

O. Chubar


jeudi 16 mai 2013


Historical steps

III- Superconducting undulator

C. Bazin, Y. Farge, M. Lemonnier, J. Perot, Y. Petroff Design of an undulator for ACO and its possible use as FEL, NIM 172 (1980) 61-65 C. Bazin, M. Billardon, D. Deacon, Y. Farge, J. M. Ortéga, J. Pérot, Y. Petroff, Y. Farge, M. Velghe, First results of a superconucting undualtor on the ACO storage ring, J Physique-LETTERS 41 (1980) L-547-L-550

L. M. Barkov, V. B. Baryshev, G. N. Kulipanov, N. A. Mezentsev, V. E. Pindyurin, A. N. Skrinsky, V. M. Khorev, A proposal to install a superconducting wiggler magnet on the storage ring VEPP3 for generation of the synchrotron radiation, NIM 152 (1978) 23-29 A. S. Artamonov et al., First reuslts of the work with a superconducting «snake» at the VEPP-3 storage ring, NIM 177 (1980) 239-246

240 A.S. Artamonov et al. / A superconducting "snake"

Fig. 1. A general view of the snake for the storage ring VEPP- 3; 1 - liquid helium supply pipe, 2 - current leads, 3 - dewar, 4 - liquid nitrogen, 5 - liquid helium, 6 - superconducting magnets, 7 - vacuum container, 8 - storage ring vacuum chamber.

The number of quenches required in order to reach the plateau was approximately proportional to the general number of SCMs connected in series and was equal to 3 - 4 quenches per magnet.

The threshold showed that during tile training process each of the SCMs is quenched occasionally, approximately the same number of times, except for the edge magnets where the number of quenches was 1.5 times higher.

In the complete block the number of windings in the edge magnets was decreased by 30%, that enabled us to partly compensate for the horizontal angle acquired by the beam at the snake exit and also to

increase the SCM stability. Apparently, the training process can be explained by reference to the mechanical seal of the SCM winding in the direction of the forces acting on the current carrying windings. In this case, the interwinding filter (fiberglass tissue impreg- nated with epoxide compound) is a sufficiently dense, inelastic medium which is capable of "remem- bering" the training result. The training results are also conserved after the uniform heating of the SCM up to room temperature with subsequent cooling. As a rule, additional training with far fewer cycles is needed after the disassembly and reassembly of the magnetic system.

For preliminary tests the snake was assembled on the "bench". The maximum current supplied to the SCMs on the bench was 220 A, which corresponds to a field of 36 kG on the snake axis. Helium consump- tion in the field-off regime was 3.6 1/h. The measured shift of the SCMs with respect to the horizontal plane during cooling from room temperature to 4.2 K did not exceed 0.3 mm.

After the bench tests the snake was installed in the straight section of the VEPP-3 storage ring. The snake design made it possible to mount it around the VEPP- 3 vacuum chamber without deterioration of the vacuum in the storage ring.

During the first switching-on of the snake, the SCM training was conducted once more. After five cycles the cntical current in the SCM increased from 146 up to 190 A. The last figure corresponds to a field ofBo = 31 kG on the snake axis. A further training of the SCM will be carried out during the forth- coming work on the snake. The measured helium con- sumption with the field on was ~4 1/h.

3. Insertion of the electron beam into the snake with superconducting field off

Insertion of the "damped" electron beam into the snake vacuum chamber is performed by four special correction magnets of rectangular shape placed in the experimental straight section. In addition, a special magnetic straight-section structure was chosen to facilitate orbit distortion, arrangement of the snake and correction magnets. The structual alterations were such that, on the one hand, a straight section could be supplied with a unit transport matrix in both directions and, on the other hand, to make effective use of the lens magnetic fields in the case of orbit distortion.

244 A.S. Artamonov et al. / A superconducting "snake"

AI, then the radiation spectrum differs slightly from the usual spectrum of synchrotron radiation.

In another limiting case, the length of the usual synchrotron radiation formation p /7 a is much larger than the snake period. For a weak magnetic field in the snake (a0 ~ 1/7) the radiation field value is sinusoidal with a period Al of length NAl . Due to the finite length of the snake, the amplitude of the spectral constituent of the radiation with the wave number K is described by an apparatus function of the form:

K sin(Ng AI/2) EK ~ (2rr/A/.)2 _ K2 •

For the main maximum we can write down the following relation:

(+ X = 2b + . The latter gives a representation of the dependence between the correlation X-O and the energy. The form of the apparatus function makes it possible to determine the dependence of subsidiary maxima at a given K on the angle 0 and on the energy as well. At the angle 0 = 0 in case of a weak field in the snake the radiation maximum is attained at the wavelength X = b/72. For the VEPP-3 snake this corresponds to a 920 A vacuum ultraviolet region at an energy of 350 MeV.

The transverse motion becomes relativistic on increasing the snake field, and the shape of radiation field amplitude differs from the sinusoidal one, this leads to the appearance of harmonics in the radiation. The condition for the maximum of the nth harmonic can be written as follows:

nX = 2b + 4 + m

An increase in ao results in increasing the wavelength of the first harmonic at zero angle. So, for example, the radiation of red light at this angle and for an energy of 350 MeV corresponds to a field of about 4 kG. For a snake with a finite number of periods N the above relation holds in a certain range of wavelengths ~xX/X = 1]nN at a fixed 0.

In fig. 5 there are the pictures of the intensity dis- tr ibution of the 1st, 2nd, 3rd and 4th harmonics of radiation from the snake on a screen placed behind the red-light-filter at a fixed energy of 350 MeV and different values of the snake magnetic field.

The light from the snake passes through a special Fig. 5. Intensity distribution of the 1st, 2nd, 3rd and 4th harmonics of radiation from the snake.

M. Bazin e t al. / A n undulator for A. C.O. 6 3

SAFETY VALVE

e,- o ¢,/) z LI.I

h i . . I

ff

YOKE

WINDINGS

POLE PIECES

ALIGNMENT BARS

HELIUM JACKET

SUPPORTS

BEAM CHAMBER

SUPPO

Date post:	04-Feb-2021
Category:	Documents
Upload:	others
View:	2 times
Download:	0 times

KEK · 2013. 6. 2. · M. E. Couprie, International Particle Accelerator Conference, ,Shanghai,...

Documents