SUPERCONDUCTIVE DAMPING WIGGLER
DEVELOPMENT
Robert Rossmanith
for
A. Bernhard2, S. Casalbuoni1, A. Grau1, M. Hagelstein1, M. Kläser3, B . Kostka4. E. Mashkina4, A.
S. Müller1,2, R. Rossmanith1, Th. Schneider3, E. Steffens4, D. Wollmann2, T. Baumbach1,2
H. H. Braun5, F. Zimmermann5
1
Inst. for Synchrotron Radiation (ANKA), Research Center Karlsruhe
2 Lab. For Appl. of Synchrotron Radiation, Univ. Karlsruhe
3 Inst. f. Technical Physics, Research Center Karlsruhe
4 Univ. Erlangen-Nürnberg
5CERN
Numerous contributions from many colleagues and institutions
1 | V. Name | Organisationseinheit | TT.MM.JJJJ
R. Rossmanith, CLIC workshop, October 2007
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Starting point: emittance vs. wiggler period and field
Permanent magnet wiggler
Sc wiggler from BINP
Why not here?
R.2Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Both damping and excitation of emittance in wiggler
Damping:
Synchrotron
emission
bunch
electrons
Both hor. and
transv. Momentum
reduced
cavity
Naive approach: damping the better the higher wiggler field, but
Excitation in wiggler
R.3Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
What defines emittance?
Bending magnet
Electrons with
∆s = D.(∆E/E)
Dispersion orbit
D…dispersion
Nominal energy
Lower energy
Emission of photons
electrons lose
energy and oscillate around dispersion orbit
Nominal
orbit
Inside the wiggler
Trajectory for lower energy particle
Trajectory for on-energy particle
Dispersion the higher the larger period length
R.4Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
∆s
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
SUMMARY: High wiggler fields and short periods are ideal (but a
contradiction)
B[T ]  1.55exp(g /  
Example SmCo5 Wiggler
B[T]
1.2
g = gap in cm, 0.5 cm
1
 = Period length
0.8
0.6
0.4
0
2
4
6
8
10
Period length in cm
In comparison: sc wiggler 14 mm period length, 5 mm gap, 1.33 T
(A. Geisler et al., IEEE Trans. Applied Superconductivity, Vol. 13, No. 2, June 2003, p. 1217)
R.5Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Summary: superconductive wigglers are better for damping rings
Optimized in-vacuum insertion devices developed at ANKA
Wires as close as possible to the
beam:
indirectly cooled
Gap
Period
L He
R. Rossmanith, H. O. Moser, Proc. European Particle
Accelerator Conference 2000, Vienna, Austria
Nowadays established technology: ANKA, Argonne, Berkeley, MAXLAB, ACCEL Instr., Taiwan… (everybody slightly different)
Indirect cooling: no soldered joints
R.6Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
one wire
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
ANKA: storage ring 2.5 GeV, max. current 200 mA
NbTi SCU Demonstrator
Period length 14 mm, 100 periods,
gap 8, 12, 16 mm
Since March 2005 cold in ANKA
(only routine maintenance of cryocoolers)
Compatible with normal user operation
Built by ACCEL Instr. GmbH, Germany
R.7Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Next generation of superconductive insertion devices at ANKA
under design and construction
Helical undulator
Possible area for testing
CLIC damping wiggler
Gap 8 mm
Ibeam = 60 mA
IUnd = 500 A
K= 0.69
SCU switchable period length
R.8Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Short version of CLIC damping wiggler
y
.
0
50
100
150
-10
x
0
10
020
-20
z
Gap: 5 mm, period length 2.1 cm, 2.7 T,
1 kA/mm2, k = 5.26
Proposed undulator ensemble for damping rings
wiggler
cryostat
Water-cooled
absorber
R.9Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Further developments for damping wigglers
Collaboration with CERN
Wires which can tolerate
higher heat load from the
beam:
Nb3Sn or
Magnesiumdiborid MgB2
Nb3Sn mock-up
R.10
Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Field measuring Device for mock-ups
Linear positioner for
the Hall probe sledge
Current leads
Temperature shields
Liquid nitrogen chamber
Liquid helium chamber
Vacuum chamber
R.11
Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
E. Mashkina et al., Journal in Physics, in print
Supporting plate
Mock-up with Hall
probe sledge
Heating plate
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)
Summary
a.) sc wigglers with short period and high field ideal for damping
rings
b.) ANKA can build together with an industrial and/or scientific
partner (CERN and/or BINP) a test device and
c.) test it with beam in ANKA
R.12
Rossmanith,
CLIC workshop,
October 2007
| V. Name | Organisationseinheit
| TT.MM.JJJJ
KIT – die Kooperation von
Forschungszentrum Karlsruhe GmbH
und Universität Karlsruhe (TH)

Summary - Indico