Post on 24-Jan-2021
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Development and Operation of APPLE Undulators at BESSY
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Outline
Operation of APPLE Undulators at BESSY, Preparing for Top-Up
Plans for New Insertion Devices at the BESSY SR
Developments for FEL-Undulators
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Undulators at BESSY
device design operational λ0 / mm periods Gap / mm By / Bz / T
U49-1 Hybrid 1998 - 49,4 83 15 0,799
U49-2 Hybrid 2000 - 49,4 83 15 0,788
U125-1 Hybrid 1998 – 2005 125 31 20 1,162
U125-2 Hybrid QPU 2000 - 125 31 15 1,360
U41 Hybrid 1999 - 41,2 79 15 0,659
U139 Hybrid 2004 - 139 10 15 1,471
UE112 APPLE II 2006 - 112 32 20 0,994 / 0,765
UE56k APPLE II 2003 - 56 1 x 30 16 0,772 / 0,529
UE46 APPLE II 2001 - 46,3 70 16 0,680 / 0,435
UE52 APPLE II 2002 - 52 77 16 0,742 / 0,505
UE49 APPLE II 2003 - 49 63 16 0,709 / 0,477
UE56-1 APPLE II 1999 - 2003 56 2 x 30 16 0,771 / 0,529
UE56-2 APPLE II 1999 - 56 2 x 30 16 0,772 / 0,529
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Smooth Operation of BESSY Undulators
Feed forward correction of natural focussing
-30 -20 -10 0 10 20 301040
1045
1050
1055
1060
1065
1070
1075 UE52 gap= 17.0mm
parallel w ithout FFWDparallel w ith FFWDantiparallel w ithout FFWDantiparallel w ith FFWDho
rizon
tal t
une
/ kH
z
horizontal shift /mm15 20 25 30 35 40 45 50
895
900
905
910
915
920
925U125-2
without Feedforward with Feedforward
verti
cal T
une
/ kH
z
Gap / mm
Undulators are coupled to monochromator and are operated under user control
Feed forward correction of residual dipole errors
gap change phase change
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
UE56 APPLE II Double Undulator
Upgrade of modulator:Absolute encodersHarmonic drive gear boxesNew motor controllerPneumatic brakes
Rotatable permanent magnets pemit two operation modes:• Chicane mode for fast helicity switching• Modulator mode couples two sections for higher brightness
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Polarization Characterization
0 undulator phase π
ellipticalmode
inclinedmode
The BESSY Soft X-ray polarimeterAgreement between theory and measurement
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Dynamic Multipoles
second order kicks, no straight line integrals (Elleaume, EPAC 1992):
dzdzyx
BdzBdz
yxBdzB
By
yx
xyx ∫ ∫ ∫ ∫ ∫⎭⎬⎫
⎩⎨⎧
∂
∂⋅+
∂∂
⋅−= '/
''/
')(
12/ ρ
θ
⎪⎭
⎪⎬⎫
⎪⎩
⎪⎨⎧
∂
∂⋅+
∂∂
⋅−=yx
BB
yxBB
BL y
yx
xu
yx //)2()(2
00
00
2
2
2/ πλ
ρθ APPLE, elliptical mode
inclined modegeneric representation of second order kicks:
)(sin)()2/(sin)()2/(cos)()( 22/
220 ϕϕϕθ ππ ⋅+⋅+⋅= xfxfxfxx
-50
0
50
05
1015
2025
-0.4-0.3-0.2-0.1
00.10.20.30.4
x / mmphase / mm
∫By
dz /
Tm
m
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-50 0 50
x / mm
dyna
mic
fie
ld in
tegr
als
/ Tm
m
-50
0
50
05
1015
2025
-0.06-0.04-0.02
00.020.040.06
x / mmphase / mm
∫By
dz /
Tm
m
elliptical mode inclined mode
f0fπfπ/2
3 genericfunctions
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Shimming of Dynamic Multipoles
BESSY UE52
-0.12
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0 10 20
shift / mm
dyna
mic
fie
ld it
egra
l / T
mm
-0.12
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0 10 20
shift / mm
dyna
mic
fie
ld it
egra
l / T
mm
elliptical mode inclined mode
J. Bahrdt et. al., SRI 2006, Daegu, Korea
afterbefore
shimming J. Chavanne et al., Proceedings of the EPAC 2000, Vienna, Austria,pp 2346-2348
reduced injection efficiency for high beta devices: UE52, UE56/2, UE56kno effect for low beta devices: UE49, UE46
successful shimming of UE52, UE56-2 in siturecovered: dynamic aperture,
injection efficiencylifetime
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
APPLE II Undulator UE112
BESSY II BRILLIANCE
10 17
10 18
10 102
103
Photon energy (eV)
Bri
llia
nce
(p
hot
ons/
(sec
mm
2 mra
d2 0
.1%
BW
))
UE112 1.7 GeV
UE112 1.9 GeV
U125-1 PGM-1
U125-1 PGM-2
Full polarization control permits:Compensation of polarizing effectsof beamline components withappropriate undulator setting
Parameters at 1.7 GeV:Circular polarization : 6.5 – 660 eVLinear horizontal polarization : 5 – 660 eVLinear vertical polarization : 8 – 660 eVRotatable (linear) polarization : 12 – 660 eVPeriod length : 12 mmNumber of periods : 32 Minimum magnetic gap : 20mm
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
APPLE II Undulator UE112Need for Analytic and Symplectic Tracking
dynamic multipoles of UE112 are one order of magnitude largeras compared to UE52 tracking studies are required
symplectic tracking scheme based on generating function formalismJ. Bahrdt, M. Scheer, G. Wuestefeld, Wiggle 2005, Mini-Workshop, Frascati, 2005J. Bahrdt, G. Wuestefeld, EPAC 2006
advantages: phase space conservationvery fast (several periods in one step)uses analytic field description
application to APPLE Undulators:
representation of main field for variable gap, shift and operation mode in a closed model
representation of Fe-shims (one data set per shift, gap)
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Analytic Field Representation of APPLE II
Main fieldscalar potential of four rows
Shim field integralscalar potential of two girders
22
0
0
0
04
03
02
01
14321
)2/cos())(sin())(cos(
)/)()/((
)/)()/((
)/)()/((
)/)()/((
)(
zxiyi
xxi
zz
xixi
xixi
zzyk
xisyixicyiyiyk
i
zzyk
xisyixicyiyiyk
i
zzyk
xisyixicyiyiyk
i
zzyk
xisyixicyiyiyk
i
n
iiiii
kkk
kikzkc
xxksxxkc
cnkeBsBcBkeV
cnkeBsBcBkeV
cnkeBsBcBkeV
cnkeBsBcBkeV
VVVVV
zyi
zyi
zyi
zyi
+=
⋅=±=±=±=
⋅++⋅−=
⋅++⋅−=
⋅++⋅+=
⋅++⋅+=
+++=
±
±
±
−−
−−−
+−
++−
−+
+++
++
−−+
=∑
ψ)(VB ∇−=
r
ykxiyisxiyic
yi
ykxiyisxiyic
yii
n
ii
yi
yi
exkBxkBk
exkBxkBk
V
VV
−
=
⋅+
+⋅+=
=∑
))sin(~)cos(~(1
))sin(~)cos(~(1~
~~
22
11
1
calculation of Fourier components i=1 to 30 of - a single row (main field)- a single girder (shim field integral)
)~(~ VdxBB ∇−=⋅= ∫r
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Accuracy of APPLE Main Field Description
analytical representation (black)simulation with RADIA (red)0
0.5
1
-100 -50 0 50 100z / mm
By
/ Tes
la
y=0mm
-0.5
0
0.5
1
-100 -50 0 50 100z / mm
Bz
/ Tes
la
y=0mm
0
0.5
1
-100 -50 0 50 100z / mm
By
/ Tes
la
y=4mm
-0.5
0
0.5
1
-100 -50 0 50 100z / mm
Bz
/ Tes
la
y=4mm
0
0.5
1
-100 -50 0 50 100z / mm
By
/ Tes
la
y=8mm
-0.5
0
0.5
1
-100 -50 0 50 100z / mm
Bz
/ Tes
la
y=8mm
parametrization of 3D-fieldusing only a few coefficientsprovides a very good field description• for various gaps• various shifts• large vertical offsets
phase=0 phase=π
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Accuracy of Shim Description
-0.4
-0.2
0
0.2
0.4
-40 -20 0 20 40z / mm
∫By
/ Tm
m
y=0mm
-0.4
-0.2
0
0.2
0.4
-40 -20 0 20 40z / mm
∫Bz
/ Tm
m
y=0mm
-0.5
0
0.5
-40 -20 0 20 40z / mm
∫By
/ Tm
m y=4mm
-0.5
0
0.5
-40 -20 0 20 40z / mm
∫Bz
/ Tm
m y=4mm
-2
-1
0
1
2
-40 -20 0 20 40z / mm
∫By
/ Tm
m
y=8mm
-2
-1
0
1
2
-40 -20 0 20 40z / mm
∫Bz
/ Tm
m
y=8mm
field integrals of L-Shim
analytical representation (black)simulation with RADIA (red)
L-Shims as proposed byChavanne et al., EPAC 2000
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Shim Optimization for UE112, Elliptical Mode
10-5
10-4
10-3
10-2
10-1
1
0 2 4 6 8 10 12 14 16
shim strength
mul
tipo
le s
tren
gth
/ (T
mm
**(2
-ord
er)) phase=λ0/2
-0.04
-0.02
0
0.02
0.04
0.06
0 0.1 0.2 0.3 0.4 0.5
row phase / period length
pow
er /
a.u.
octupole
dodecapole (x3)
quadrupoleoctupoledodecapolehexadecapoleikosapole
black: Dynamic multipolered: negative shim strengthblue: combination of shims
with different lengths
two shim widths:solid: 2mmdashed: 4mm
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Tracking Studies for the UE112
1000 turnsamplitudes: 1-30mm hor.1mm vertical
phase space plot
kick in mrad versus transverse position in mm
without shimstrajectories stablefor z < 15mm
with shimstrajectories stablefor z < 30mm
horizontal kick of the electronspassing the UE112red: without L-shimsblue: with 32 L-shims
G. Wüstefeld
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Tune Shift vs. Amplitude forDifferent Shim Strengths
Horizontal tune shift vs. hor. amplitude Hor. and vert. tune shift vs. amplitude
0.7
0.8
0.9
1.1
1.2
1.3
0.7
0.8
0.9
1.1
1.2
1.3
minimum tune variation for chosen shim strength (1.0)
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
UE112 Final Shimming
Increase of horizontal aperture byshimming the UE112 with L-shims P. Kuske
Amplitude dependent detuning fordifferent shimming iterations – opensymbols indicate beam loss of morethan 2%
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Predicted and Measured Dynamic Multipoles
Black : first iterationred / blue: third iteration
prediction (dashed)
measurement(solid)
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
-10 0 10
z / mm
dyna
mic
mul
tipo
les
/ Tes
la m
m elliptical mode
-1.5
-1
-0.5
0
0.5
1
1.5
-10 0 10
z / mmdy
nam
ic m
ulti
pole
s / T
esla
mm inclined mode
first iteration
thirditeration
third iteration
Passive shimming in elliptical mode is sufficientActive shimming in inclined mode is requiredThis will be realized with rotatable permanent magnets
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Ideas for the BESSY Storage Ring
New operation modes• Top-up operation within the next year• Energy enhancement from 1.7 GeV to 1.9 GeV
New Insertion DevicesAll straight sections are filled!• Replacement of UE56-1 double undulator with
femto second slicing facility (2004)• Replacement of planar devices with variably polarizing devices
e.g. U125-1 UE112• Smaller period length devices dedicated to special user requirements:
1: elliptically polarizing in-vacuum devicesto cover LII/III edges of Fe, Co, Ni with first harmonicand rare earth MIV/V edges with third harmonic
2: planar SC-undulators for protein crystallography
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Comparison of various ID parameters:period lengths: red: 30mm, light blue: 32.5mm, blue: 35mm, green: 37.5mm, magenta: 40mm
solid: out of vacuum, 10mm gap; dashed: in-vacuum, 6mm gap
Design goal:Smallest period compatible withoverlap between 1st and 3rd harmonic
Parameters:Photon energy range : 250eV – 2500eV Polarization : hor. / vert. linear,
ellipticalPeriod length : 30mmNumber of periods : 98Minimum gap : 6mm
Challenges for an APPLE Design:linear bearing in ultra high vacuumdrive system and encoder in UHVCu coated Ni foil for image currents ANKA designflexible taper ALS design
Other options: SC variably polarizing device: NbTI, 4KSC variably polarizing device: Nb3SnSC variably polarizing device: NbTi, 1.8K
elliptical pola
0
1
2
3
4
5
6
7
8
9
10
0 1000 2000 3000
energy / eV
bri
llia
nce
gai
n v
s U
E49
p7
0
1
2
3
4
5
6
7
8
9
10
flu
x ga
in v
s U
E49
p7
UE30
UE30: In-Vacuum Elliptical Undulator
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
UE30: In-vacuum Elliptical Undulator
Performance comparable to out-of-vac. APPLE at 2.4 GeV machine
BRILLIANCE
10 18
10 19
500 1000 1500 2000 2500 3000
Photon energy (eV)
Bri
llia
nce
(p
hot
ons/
(sec
mm
2 mra
d2 0
.1%
BW
))
UE30 1.7 GeV 0.2 A
UE30 1.9 GeV 0.2 A
ESRF 6 GeV 0.2 A, ID8
SLS 2.4 GeV 0.35 A, UE44
UE49 1.9 GeV 0.2 A
FLUX
10 14
10 15
500 1000 1500 2000 2500 3000
Photon energy (eV)
Flu
x (p
hot
ons/
(sec
0.1
% B
W))
UE30 1.7 GeV 0.2 A
UE30 1.9 GeV 0.2 A
ESRF 6 GeV 0.2 A, ID8
SLS 2.4 GeV 0.35 A, UE44
UE49 1.9 GeV 0.2 A
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
SC-ID for Protein Structure Crystallography
Parameters at 1.9 GeV:SC-wire : NbTi (80%)Usable harmonics : 1, 3, 5, 7Energy range : 2 - 12,65 keVFixed polarization : hor. linearPeriod length : 11,0mmNumber of periods : 100Kmax : 1,2Fixed gap : 4,5mm
Detailed studies required on: Image current heatingThermal load of upstream dipoleReproducibilty, hysteresisScanning capabilities
0
1
2
3
4
5
6
7
8
9
12.58 12.6 12.62 12.64 12.66 12.68 12.7
energy / keVflu
x / 1
012 /
s / 0
.1A
/ 0.
1% B
W /
77µr
ad2
Se
emittance and energy spread included
Width of 7th harmonicpermits MAD-experimentsat min. f‘ and max. f‘‘without undulator scanning
7th
New materials like Nb3Sn material or 1.8K technologymay provide even higher fields in the future
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Developments for FEL-Undulatorspartly tested at BESSY SR
• Support and drive system prototypes: UE112, PETRA III APPLE
• Prototype structure for APPLE III, development of shimming strategies
• Mover for transverse alignment of APPLE devices
• Permanent magnet phase adapter
• Mashine protection: beam loss simulationcollimator, radiation monitors (Cherenkov and powermeter)
• Control system for complex facility in analogy to BESSY ID control system
• Industrial aspects of undulator fabrication:support and drive systemmagnet structure
• Software development: Wavefront propagation with PHASE
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
New Support and Drive System for the UE112
UE112: 4.2m APPLE structureonly one piece of cast ironbionic optimization
model options for cast iron structures
wooden models: many casts possible, cost effective for series productionpolystrene models: reduced costs for prototype fabricationonly core model: reduced costs for prototype fabrication (new technology)
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Al-Magnet Girder
support at four locationsfor bending minimization(realized at BESSY IDsUE49, UE46, UE112)
-100
-80
-60
-40
-20
0
0 0.5 1 1.5 2 2.5 3 3.5 4
distance / m
defl
ecti
on /
a.u.
two supports
four supports
4m single piece
-50
-40
-30
-20
-10
0
10
20
30
40
50
0 0.5 1 1.5 2 2.5 3 3.5 4
distance / m
heig
ht /
µm
upper girder
lower girder
gap variation
fabrication accuracy
residual fluctuations can becompensated with spacers
30µm
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Gap Positioning Accuracy
UE49
magnetic fieldmeasurementduring gap drive
50
51
52
53
54
0.62 0.64 0.66 0.68 0.7 0.72 0.74
field / Tesla
redu
ced
gap
/ µm
±1µm
spectra measuredfor different directions of gap drive
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Cascaded HGHG FEL
The planned BESSY HGHG FEL facilityconsists of three HGHG lines to cover theenergy range from 24eV to 1000eV
Last radiators and final amplifiers are of the APPLE III type
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
The APPLE III Design
last Radiator and final amplifier have a new designAPPLE III design: factor 1.4 higher field as compared to APPLE II
0
0.1
0.2
0.3
0.4
0.5
0.6
5 6 7 8 9 10 11 12
new design, G=3.4mm
new design, G=5.4mm
new design, G=7.4mm
APPLE design, G=10.4mm
phase / mm
fiel
d / T
esla
APPLE III
45° inclination
0° inclination
APPLE II
G
J. Bahrdt et al., Proceedings of the 26th InternationalFEL Conference, Trieste, Italy, 2004, pp610-613 22mm APPLE III prototype under construction
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Magnet Block Characterization
Today, block characterization is essential for an effective sortingimproved magnetic material will reduce production cost
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
-50 0 50
z / mm
∫ By
dx /
Tm
mx 100
A-magnet
-8-6-4-202468
-50 0 50
z / mm
∫ By
dx /
Tm
m
x 1000
B-magnetTemperature dominated
automated Helmholtz coil system formeasurement of dipole moment
stretched wire system forcharacterization of inhomogeneities
new measuremenmt setup:reproducibility: A-magnets: 2.0 x 10-4 Tmm
3.0 x 10-4 rel.B-magnets: 1.5 x 10-3 Tmm
2.1 x 10-4 rel.
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Field Optimization
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1000 1500 2000 2500 3000 3500x / mm
fiel
d in
tegr
al /
T m
m
z = -20mm
z = -10mm
z = 0mm
z = 10mm
z = 20mm
UE49
-1.5
-1
-0.5
0
0.5
1
1.5
-40 -30 -20 -10 0 10 20 30 40z / mm
∫ Bz
dx /
Tm
m
How to meet the FEL-field tolerancesA) single block characterization and initial sorting and in-situ sortingB) virtual shimming, Fe-shimming, end correctors
A) excellent agreement between predicted and measured fields integralsfor BESSY undulators UE52, UE49, UE112
efficient sorting procedure
blue: predictionfrom single block measurementsred: hall probe measurements
longitudinal distribution transverse distribution
UE52
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Good Field Region of APPLE IDs
-0.4
-0.2
0
0.2
0.4
0.6
0.8
x 10-3
0 5 10
phase / mm
dB/B
0
HE-FEL
parallel
planar
-0.4
-0.2
0
0.2
0.4
0.6
0.8
x 10-3
0 5 10
phase / mm
dB/B
0
HE-FEL
anti parallel
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
-20 -10 0 10 20x / mm
fiel
d /
Tes
la
HE-FEL-0.2
00.20.40.60.8
11.21.41.6
-20 -10 0 10 20x / mm
fiel
d /
Tes
la
ME-, LE-FEL
tight alignment tolerances in both transverse directions support structureAPPLE III (solid) slightly relaxed as compared to APPLE II (dotted)
blue: vertical fieldred: horizontal fieldsolid: APPLE IIIdashed: APPLE II
0
0.1
0.2
0.3
0.4
0.5
0.6
x 10-3
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2
z / mm
dB/B
0
horizontal directionmax phasevertical directionplanar undulator
vertical directionmax phase
vertical directionantiparallel
electronbeam
0.1mm off axis
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Transverse Alignment Accuracy
tolerance studies on the transversepositioning accuracy forAPPLE III undulator (BESSY HE-FEL)
random transverse displacement of final amplifier undulator modules
simulation of trajectory wander andpower degradation using GENESIS
40µm displacement is acceptable.
A. Meseck, J. Bahrdt, 27th, InternationalFEL Conference, Stanford, Ca, 2005, pp47-50
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Natural focussing / defocussing
0
0.025
0.05
0.075
0.1
0.125
0.15
0.175
0.2
0.225
0.25
0 2 4 6 8 10 12 14 16 18 20
distance / m
beam
siz
e / m
m
planar device
APPLE, phase = 0
APPLE, phase = π
horizontal plane
vertical plane
Dynamic quadrupole modifies the electron beam sizedependent on gap and phase position!
adaptive focussing is essential for optimumoverlap of electron beam and photon beam
Compensation with Fe shims has to be tested for APPLE III
HE-FEL
focussing is stronger for the other FELsby a factor of:9 ME-FEL45 LE-FEL
∑
∑
∞
=−
∞
=−
+
⋅+⋅=
+⋅⋅⋅
=
1 22
22222
21
2222
2
!/!/!/!/
)(()(
2
nynxn
xynynxxnxneffx
ynn xneffxx
nBnBnkBnkB
k
BBkkmc
eKγ
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Beam Loss Simulations with GEANT
0
2
4
6
8
10
-1000 0 1000
z / mm
loca
l dem
agne
t. /
%
-1.6-1.4-1.2
-1-0.8-0.6-0.4-0.2
0
-2 -1 0 1 2
z / mm
fiel
d re
duct
ion
/ %
1 mrad
0.1 mrad
Model for simulations• 70kGray (red. Dose) for 1% loss of Br• dump 300.000nC into the
vacuum pipe at one location• get doses inside magnet segments• derive local demagnetization• get spectra from modified magnets
0
500
1000
1500
2000
2500
3000
3500
x 10 12
620 640 660 680
energy / eV
brig
htne
ss 1st harmonic
0
500
1000
1500
2000
2500
3000
3500
x 10 12
3220 3240 3260 3280
energy / eV
brig
htne
ss 5th harmonic
-0.25-0.2
-0.15-0.1
-0.050
0.050.1
0.150.2
0.25
-1000 -500 0 500 1000
z / mm
traj
. dif
f. /
Tm
m**
2 1.0 mrad0.1 mrad
-10
-5
0
5
10
15
-1000 0 1000
z / mm
ph
ase
erro
r / d
egre
e
1.0 mrad0.1 mrad
1 mrad 1 mrad
Vacuum tube Magnet
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Radiation Monitoring
Cherenkov monitorsTo be used for fast triggerCollaboration with HMI, BerlinFirst experiments at BESSYTime resolution sensitivity
chamber magnetsfibres
Powermeter monitorsTo be used for
absolute dose measurementsCollaboration with Fraunhofer Institut
Euskirchen
Similar systemsare used at FLASH
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
HGHG-FEL at MAX-lab (EUROFEL)
LaserElectron beam
Modulator Radiator
Chicane
Modulatorλu = 0.048m
30 periodsλs
Radiatorλu = 0.056m
30 periodsλs/3 - λs/5
Laserλs = 266.66 nmFLAT TOP shape
peak power: 300 MW pulse duration: 300 fs fwhm
Electron beamεnx=εny= 3 mm.mrad
Ipeak= 500 A 100µm (rms) bunch length
Ebeam = 420 MeVrel. e-spread = 0.1%σx= σy = 300 µm
Chicane4x dipol magnets:
length: 0.12 m field: ~0.15 T
separation: distance: 0.4 m
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Undulators as delivered by BESSY
Modulator RadiatorBeam height: 500mmPeriod length: 48mm 56mmNumber of periods: 30 30Remanence: 1.15 T 1.15Magnetic gap: 9,5mm 12
Operating position
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Wavefront Propagation with PHASE
Self seeding option at FLASH
00.10.20.30.40.50.60.70.80.9
1
0 500 1000 1500 2000
time / fs
pow
er /
a.u. x50
x10x5
00.10.20.30.40.50.60.70.80.9
1
-0.001 0 0.001
∆E/E
pow
er /
a.u.
59 60 61
1x106
2x106
3x106
4x106
5x106
6x106
59 60 61103
104
105
106
107
P/λ
Wavelength/nm
SASE SEEDED
0 50 100 150 200 250 300 3500.0
5.0x108
1.0x109
1.5x109
2.0x109
2.5x109
3.0x109
3.5x109
4.0x109
Pow
er/G
W
s/µm
SASE SEEDED
red: seededblack: unseeded
Wavelength selection with monochromator
Monochromator
GENESIS PHASE GENESIS
Johannes Bahrdt, BESSY, New Frontiers in Insertion Devices, ELETTRA, Trieste, Italy November 20th-21st, 2006
Summary
• APPLE devices in low and medium energy ringshave to be shimmed for the dynamic multipolesto be compatible with top-up operation
• A detailed analytic representation of the main field and the shim fieldpermits an accurate and fast symplectic tracking
• Tracking studies and experiments show that the dynamic multipolesof long period APPLE devices still can be compensated: Fe-shims in elliptical modeActive compensation in inclined mode
• Upgrade plans: topping upenergy enhencement to 1.9 GeVsmall period devices, elliptical and planar
• Design studies and hardware development for HGHG FEL:Test of components at BESSY SR and MAX-lab (EUROFEL)BESSY Soft X-Ray FEL demonstrator