Abstracts Brochure - CERN

THPLS — Poster Session 29-Jun-06 16:00 - 18:00
Development of a Cryogenic Permanent In-vacuum Undulator at the ESRF
Lowering the temperature of NdFeB materials
increases their field remanence and intrinsic
coercivity*. This property is potentially
interesting for the construction of cryogenic
C.A. Kitegi, J. Chavanne, P. Elleaume, C. Penel, B. Plan, F. Revol,
M. Rossat (ESRF)
permanent in-vacuum undulators (CPMU)**. Around 150K, the coercivity is increased to such an extent that the Nd-
FeB material is comparable to the Sm2Co17 as far as resistance to radiation damages is concerned. The improvement
in field remanence is less remarkable (15% at 150K) and is dominated by a reversible Spin Reorientation Transition
(SRT) occurring around 135K. Below this temperature, the remanence decreases. The complete magnetization
curves of NdFeB material measured at different cryogenic temperatures are presented. Non-linear models have been
constructed and used in the RADIA code in order to compute the field performance of a hybrid NdFeB in-vacuum
undulator. A prototype CPMU is presently under construction at the ESRF. It has a period of 18mm and a magnetic
length of 2m. The field integral and local field measurements of the cryogenic device require new systems operated
in vacuum. A stretched wire bench and a hall probe bench are under construction; their main characteristics will be
presented.
*D. Givord et al. Analysis of hysteresis loops in NdFeB sintered magnets, J. Appl. Phys. 60(9) (3263-3265).**T. Hara
et al. Cryogenic permanent undulator, Phys.rev. ST AB volume 7 050702 (2004).
Tracking Simulation of Helical Undulators
Symplectic and fast tracking simulations of
an APPLE type undulator for the BESSY II G. Wuestefeld, J. Bahrdt, M. Scheer (BESSY GmbH)
storage ring are presented. The simulation is
based on a multiple harmonic decomposition of the magnetic field and on a generating function approach. Because of
the relatively large undulator period length of 112 mm, corrections of the dynamic multipoles are required to achieve
a good dynamical aperture.
Status of the PETRA III Damping Wigglers
After mid-2007, the present PETRA storage
ring at DESY will be reconstructed towards a
dedicated third generation light source operating
at 6 GeV. An emittance reduction down
to 1 nm can be achieved by means of damp-
M. Tischer, K. Balewski, W. Decking, M. Seidel, L. Yongjun (DESY)
A.A. Krasnov, V. Kuzminykh, E. Levichev, P. Vobly, K. Zolotarev
(BINP SB RAS)
ing wigglers. 20 permanent magnet wigglers will be installed in two of the long straights of the machine. The wiggler
segments are compact fixed gap devices surrounded by iron enclosures to reduce the leakage flux. Each device will
provide a damping integral of 4 T2m per segment and generate a synchrotron radiation power of 42 kW. Every wiggler
segment will be followed by an SR-absorber to protect all downstream components, the accumulated on-axis power
of about 200 kW will be taken up by a final absorber at the damping section end. The wiggler’s magnetic design, field
properties and correction schemes have previously been proven by a one period long prototype. At present, the first
full length (4m) prototype wiggler has been assembled and characterized magnetically.
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THPLS121