Production of Coherent Synchrotron Radiation at …July 2011 Marit Klein Laboratory for Applications...
Transcript of Production of Coherent Synchrotron Radiation at …July 2011 Marit Klein Laboratory for Applications...
KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz Association
LABORATORY FOR APPLICATIONS OF COHERENT SYNCHROTRON RADIATION
www.kit.edu
Marit Klein July 2011
Production of Coherent Synchrotron Radiation at ANKA Using Low-momentum-compaction Lattices
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Karlsruhe Institute of Technology
ANKA @ Karlsruhe
Karlsruhe Institute of Technology
N. Hiller, A. Hofmann, J.C. Heip, E. Huttel, V. Judin, B. Kehrer,
S. Marsching, S. Naknaimueang, Y.-L. Mathis, A.-S. Müller,
N. Smale, M. Süpfle
Ruhr Universität Bochum E. Bründermann
Cornell UniversityK. Sonnad
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Overview
IntroductionThe ANKA storage ringLow-alpha mode and CSR productionStable vs. bursting emission
Measurements with a hot electron bolometer (HEB)
Measurements with a streak camera
Spectral measurements
Modeling the low-alpha mode with the Accelerator Toolbox
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
The ANKA storage ring
120 ns
368 ns
C = 110.4 mEnergy range: 0.5 - 2.5 GeVRF frequency 500 MHzDBA lattice
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Beamlines:13 in operation
4 in construction / commissioning
Normal operation:Energy 2.5 GeV
Current 120-200 mA Multi-bunch (3 trains with 30ish bunches each)
Natural bunch length σz,0 ≈ 13 mm
Low-alpha mode:Coherent THz radiation
Energy 1.3 GeV Current ≈ 0.1 - 70 mA
Single- or multi-bunchNatural bunch length σz,0 ≈ 0.3 - 4.5 mm
ANKA - Parameters
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Coherent synchrotron radiation (CSR)Short bunches emit usable coherent synchrotron radiationEnormous increase in power in comparison to incoherent emissionDedicated optics with negative dispersion in the long and short straight sections for flexible bunch length tuning
Low-αc optics
Coherent radiation is produced in two regimes:
low power stable emissionhigh power radiation bursts
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
The low-alpha mode
Low-alpha user operation: 12 days/year
Operation procedure:Fill at 0.5 GeVRamp energy (regular optics) to 1.3 GeVLow-αc “squeeze”
change quadrupoles & sextupolesorbit correction between steps
Observed αc range as derived from Qs measurements: from 8.5 10-3 to 2.4 10-4
and
D*1
0 [m]
s [m]
horizontal Dispersion*10 vertical
-10
0
10
20
30
40
0 5 10 15 20 25
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
CSR for Userstime resolved experiments
IR1
IR2
streak camera port
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Synchrotron (Edge) Radiation at IR1
CSR is observed as ‘regular’ synchrotron radiation but also as ‘edge’ radiationCan be an advantage for a beamline
lower frequencies observable for the same aperture
THz Port at ANKA
(src.: ANKA-Archiv)
IR1 - Diagnostic port
source: entrance edge of a bending magnet
flux > 1013photons/s/0.1%bw
5 / 33 Vitali Judin Hot Electron Bolometer at ANKA
-40mm
-20
0
20
40
y [m
m]
-40mm -20 0 20 40x [mm]
150
100
50
0
Photons/s/.1%bw
/mm
^2 x109
(spatial distribution of the radiation 3m from
the source)
(spatial distribution of the radiation 3m fromthe source)
1.5
1.0
0.5
0.0
Mag
netic
Fie
ld [T
]
1.0m 0.5 0.0 -0.5 -1.0Position on particle trajectory [m]
fringe field region
-40mm
-20
0
20
40
y [m
m]
-40mm -20 0 20 40x [mm]
2.5
2.0
1.5
Photons/s/.1%bw
/mm
^2 x109
Main bending field as sourceSource at ANKA IR: fringe field
Calculated for a frequency of 3 THz
Aperture Aperture
Courtesy Y.-L.Mathis
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
The THz Beam Profile
incoherent, Amax ≈ 0.1 mV coherent, Amax ≈ 2.9 mV
Courtesy E. Bründermann, Ruhr Universität Bochum
Setup of beam line and detector : measurement behind a Si or CaF2 vacuum windowroom temperature pneumatic (Golay) detectordetector and aperture are mounted on a x-y imaging stage and scanned vs distance and lateral position relative to the vacuum window
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
The bursting stable thresholdHight electron densities lead to microbunching instability
Measured bursting stable threshold with Si bolometer
Good agreement with theoretical prediction+:
Ithresh ∝ σ7/3s
+G. Stupakov and S. Heifets,Phys. Rev. ST Accel. Beams 5, 054402 (2002)
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
-6 -4 -2 0 2 4 6
char
ge d
ensi
tyq
0
0.1
0.2
0.3
0.4
0.5
-6 -4 -2 0 2 4 6
char
ge d
ensi
ty
q
Microbunching cycle
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
THz Signal and Beam Current
0 50 100 150 200 250 300 350
-0.2
-0.1
0
0.1
0.2
Time / ns
HEB
Sig
nal /
V
---- HEB signal---- bunch current in a.u.
The Hot Electron Bolometer (HEB) detects the THz signal of individual bunches
Relative bunch currents from pickup
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40
0.05
0.1
0.15
0.2
0.25
bunch current / mA
HEB
Sig
nal /
V = 150 kVRFV
∝ I2bunch
theor. bursting/stable threshold
V. Judin
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
THz Signal and Beam Current
0 0.05 0.1 0.15 0.2 0.25 0.3 0.350
0.05
0.1
0.15
0.2
0.25
HEB-backgroundlevel: 0.01427V
bunch current / mA
HEB
Sig
nal /
V
=150kVRFV
bunch with lower left neighbor
bunch with higher left neighbor
V. Judin
A comparison shows a dependency of CSR on the current of the leading bunch
Investigations with tailor made filling pattern
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
CSR of Adjacent BunchesCorrelated bursting?
CSR of adjacent bunches
0 500 1000 1500 2000 2500 3000 3500 4000 4500
0
0.1
0.2
0.3
0.4
0.5
Turn
HE
B S
ign
al (a
.u
.)
0 500 1000 1500 2000 2500 3000 3500 4000 4500
-0.1
0
0.1
0.2
0.3
0.4
0.5
Turn
HE
B S
ign
al (a
.u
.)
leading bunch
following bunch
Simultanous increase of the THz-signal intensity
the signals of the bunches are correlated
this effect is being investigated
9 Vitali Judin Longitudinal Diagnostics at ANKA
V. Judin
Effect is under systematic investigation
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Radiation Bursts
Bursting behavior dependent on electron density
V. Judin
decr
easi
ng c
urre
nt
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Streak Camera
s)µSlow time axis (640 pixels = 500 0 100 200 300 400 500 600Fa
st ti
me
axis
(512
pix
els
= 19
0 ps
)
0
100
200
300
400
500Entries 327680Mean x 319.8Mean y 253.8RMS x 184.8RMS y 145.7
Entries 327680Mean x 319.8Mean y 253.8RMS x 184.8RMS y 145.7
250
300
350
400
450
500
550
Single image (#45) out of sequence
one bunch over many revolutions
averaged bunch profile
-40 -30 -20 -10 0 10 20 30 400
0.005
0.01
0.015
0.02
0.025
0.03 = 1.47 mAbunchI = 1.17 mAbunchI = 0.97 mAbunchI = 0.76 mAbunchI = 0.52 mAbunchI = 0.45 mAbunchI = 0.40 mAbunchI = 0.35 mAbunchI = 0.30 mAbunchI = 0.26 mAbunchI = 0.22 mAbunchI
position in bunch / ps
prob
abilit
y de
nsity
Double-sweep synchroscan streak camera from HamamatsuOptical port at IR beamline, now new dedicated beam portRecording of sequences of 500 consecutive imagesCorrect for oscillations
N. Hiller
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Bunch length
-210×2 -110 -110×2 1 2 3 4 5 6 7 8 910
2
10
20
beam current / mA
RM
S bu
nch
leng
th /
ps = 30.8 kHzsf
= 18.6 kHzsf
= 15.1 kHzsf
= 9.3 kHzsf
= 6.6 kHzsf = 5.6 kHzsf
Low currents: Converging to the zero current bunch lengthAbove bursting stable threshold: Turbulent bunch lengthening
empirical fits
N. Hiller
σz ∝ I7/3thresh
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
frequency (THz)-210 -110 1
pow
er (a
.u.)
-510
-410
-310
-210
-110
1
FTIRstreak cam.calculationcutoff
CSR spectra are proportional to Fourier transform of the electron distributionSpectral measurements with a Michelson InterferometerExpectation from streak cam. measurement below cutoffExplanation: substructure or stronger deformation
Single shot measurement needed
Measured and Expected Spectra
FFT-40 -30 -20 -10 0 10 20 30 400
0.005
0.01
0.015
0.02
0.025
0.03 = 1.47 mAbunchI = 1.17 mAbunchI = 0.97 mAbunchI = 0.76 mAbunchI = 0.52 mAbunchI = 0.45 mAbunchI = 0.40 mAbunchI = 0.35 mAbunchI = 0.30 mAbunchI = 0.26 mAbunchI = 0.22 mAbunchI
position in bunch / ps
prob
abilit
y de
nsity
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Coherent Radiation Comparison of single and multi-bunch fillings
10-210
-110
1
10AµIbunch = 1295 AµIbunch = 1204 AµIbunch = 1135 AµIbunch = 1074 AµIbunch = 1006 AµIbunch = 953 AµIbunch = 905 AµIbunch = 853 AµIbunch = 814 AµIbunch = 778 AµIbunch = 737 AµIbunch = 704 AµIbunch = 675 AµIbunch = 646 AµIbunch = 615 AµIbunch = 592 AµIbunch = 569 AµIbunch = 542 AµIbunch = 523 AµIbunch = 506 AµIbunch = 485 AµIbunch = 470 AµIbunch = 451 AµIbunch = 439 AµIbunch = 425
-1Wavenumber / cm
inco
h/P
coh
P
10-110
1
10
AµIbunch = 743 AµIbunch = 695 AµIbunch = 680 AµIbunch = 666 AµIbunch = 652 AµIbunch = 639 AµIbunch = 626 AµIbunch = 614 AµIbunch = 602 AµIbunch = 590 AµIbunch = 579 AµIbunch = 568 AµIbunch = 558 AµIbunch = 547 AµIbunch = 537 AµIbunch = 528 AµIbunch = 518 AµIbunch = 509 AµIbunch = 500 AµIbunch = 492 AµIbunch = 484 AµIbunch = 476 AµIbunch = 468 AµIbunch = 460 AµIbunch = 453 AµIbunch = 446 AµIbunch = 439 AµIbunch = 432 AµIbunch = 425 AµIbunch = 419 AµIbunch = 413 AµIbunch = 407 AµIbunch = 401 AµIbunch = 395 AµIbunch = 389 AµIbunch = 384 AµIbunch = 379 AµIbunch = 374 AµIbunch = 369 AµIbunch = 364 AµIbunch = 359 AµIbunch = 354 AµIbunch = 350 AµIbunch = 346 AµIbunch = 343
-1Wavenumber / cm
a.u.
10-110
1
10
AµIbunch = 1352 AµIbunch = 863 AµIbunch = 803 AµIbunch = 746 AµIbunch = 700 AµIbunch = 656 AµIbunch = 615 AµIbunch = 576 AµIbunch = 541 AµIbunch = 510 AµIbunch = 480 AµIbunch = 454 AµIbunch = 431 AµIbunch = 409 AµIbunch = 386 AµIbunch = 370 AµIbunch = 353 AµIbunch = 336 AµIbunch = 322 AµIbunch = 308 AµIbunch = 296 AµIbunch = 284 AµIbunch = 275 AµIbunch = 264 AµIbunch = 255 AµIbunch = 248
-1Wavenumber / cm
a.u.
10-210
-110
1
10
210 AµIbunch = 492 AµIbunch = 467 AµIbunch = 443 AµIbunch = 422 AµIbunch = 403 AµIbunch = 384 AµIbunch = 367 AµIbunch = 351 AµIbunch = 336 AµIbunch = 321 AµIbunch = 308 AµIbunch = 295 AµIbunch = 283 AµIbunch = 272 AµIbunch = 262 AµIbunch = 252 AµIbunch = 243 AµIbunch = 234 AµIbunch = 226 AµIbunch = 218 AµIbunch = 211 AµIbunch = 204 AµIbunch = 197 AµIbunch = 191 AµIbunch = 185 AµIbunch = 179 AµIbunch = 174 AµIbunch = 169 AµIbunch = 164 AµIbunch = 159 AµIbunch = 155 AµIbunch = 151 AµIbunch = 147 AµIbunch = 145
-1Wavenumber / cm
a.u.
single bunch
multi bunch
fs = 9.6 kHz / 5.3 ps fs = 6.6 kHz / 3.8 ps
Filter #2 < 35 cm-1
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Gain CurvesComparison of single and multi-bunch fillings
101
10
210
310
410
AµIbunch = 1295 AµIbunch = 1204 AµIbunch = 1135 AµIbunch = 1074 AµIbunch = 1006 AµIbunch = 953 AµIbunch = 905 AµIbunch = 853 AµIbunch = 814 AµIbunch = 778 AµIbunch = 737 AµIbunch = 704 AµIbunch = 675 AµIbunch = 646 AµIbunch = 615 AµIbunch = 592 AµIbunch = 569 AµIbunch = 542 AµIbunch = 523 AµIbunch = 506 AµIbunch = 485 AµIbunch = 470 AµIbunch = 451 AµIbunch = 439 AµIbunch = 425
-1Wavenumber / cm
inco
h/P
coh
P
101
10
210
310
410
AµIbunch = 743 AµIbunch = 695 AµIbunch = 680 AµIbunch = 666 AµIbunch = 652 AµIbunch = 639 AµIbunch = 626 AµIbunch = 614 AµIbunch = 602 AµIbunch = 590 AµIbunch = 579 AµIbunch = 568 AµIbunch = 558 AµIbunch = 547 AµIbunch = 537 AµIbunch = 528 AµIbunch = 518 AµIbunch = 509 AµIbunch = 500 AµIbunch = 492 AµIbunch = 484 AµIbunch = 476 AµIbunch = 468 AµIbunch = 460 AµIbunch = 453 AµIbunch = 446 AµIbunch = 439 AµIbunch = 432 AµIbunch = 425 AµIbunch = 419 AµIbunch = 413 AµIbunch = 407 AµIbunch = 401 AµIbunch = 395 AµIbunch = 389 AµIbunch = 384 AµIbunch = 379 AµIbunch = 374 AµIbunch = 369 AµIbunch = 364 AµIbunch = 359 AµIbunch = 354 AµIbunch = 350 AµIbunch = 346 AµIbunch = 343
-1Wavenumber / cm
inco
h/P
coh
P
101
10
210
310
410
510
AµIbunch = 1352 AµIbunch = 863 AµIbunch = 803 AµIbunch = 746 AµIbunch = 700 AµIbunch = 656 AµIbunch = 615 AµIbunch = 576 AµIbunch = 541 AµIbunch = 510 AµIbunch = 480 AµIbunch = 454 AµIbunch = 431 AµIbunch = 409 AµIbunch = 386 AµIbunch = 370 AµIbunch = 353 AµIbunch = 336 AµIbunch = 322 AµIbunch = 308 AµIbunch = 296 AµIbunch = 284 AµIbunch = 275 AµIbunch = 264 AµIbunch = 255 AµIbunch = 248
-1Wavenumber / cm
inco
h/P
coh
P
101
10
210
310
410
AµIbunch = 492 AµIbunch = 467 AµIbunch = 443 AµIbunch = 422 AµIbunch = 403 AµIbunch = 384 AµIbunch = 367 AµIbunch = 351 AµIbunch = 336 AµIbunch = 321 AµIbunch = 308 AµIbunch = 295 AµIbunch = 283 AµIbunch = 272 AµIbunch = 262 AµIbunch = 252 AµIbunch = 243 AµIbunch = 234 AµIbunch = 226 AµIbunch = 218 AµIbunch = 211 AµIbunch = 204 AµIbunch = 197 AµIbunch = 191 AµIbunch = 185 AµIbunch = 179 AµIbunch = 174 AµIbunch = 169 AµIbunch = 164 AµIbunch = 159 AµIbunch = 155 AµIbunch = 151 AµIbunch = 147 AµIbunch = 145
-1Wavenumber / cm
inco
h/P
coh
P
fs = 9.6 kHz / 5.3 ps fs = 6.6 kHz / 3.8 ps
single bunch
multi bunch
Filter #2 < 35 cm-1
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
ObservationsMulti bunch gain curve seems to lie significantly higher than single bunch curve for similar single bunch current for longer bunchesFor shorter bunches, the curves are closer
101
10
210
310
410 A, single bunchµ = 9.6kHz, 500s- fA, multi bunchµ = 9.6kHz, 490s- f
-1Wavenumber / cm
inco
h/P
coh
P
101
10
210
310
410
510 A, single bunchµ = 6.6kHz, 420s- fA, multi bunchµ = 6.6kHz, 420s- f
-1Wavenumber / cm
inco
h/P
coh
P
fs = 9.6 kHz / 5.3 ps
fs = 6.6 kHz / 3.8 ps
preliminary
preliminaryHypothesis: effects from the ring impedance are more significant if the CSR effect is less pronounced
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Modeling the low-alpha mode with AT
measured fs model α0
A 30.7 kHz 8.5 ·10−3
B 29.2 kHz 7.8 ·10−3
C 24.2 kHz 5.7 ·10−3
D 8.5 kHz 0.74 ·10−3
E 6.7 kHz 0.46 ·10−3
Measurements for each model:Tunes: Qx, Qy, Qs
Orbit response matrixDispersionChromaticity
5 different low-alpha optics modeled
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
LOCO fits and Chroma fitsMagnet strength calculated from currents settingsCorrection of quadrupole strength:
LOCO fit of response matrices and dispersionsAdditional quadrupole components
fit of tunes and chromaticity curve shapesCorrection of sextupole strength
fit of chromaticity values 0 5 10 15 20 25 301.5
1
0.5
0
0.5
1
1.5
2
s/m
D x/m
model Amodel E
1 0.5 0 0.5 1x 104
0.02
0
0.02
fRF
Qy
ABC
1000 500 0 500 1000
0.01
0
0.01
fRF
Qy
DE
1 0.5 0 0.5 1x 104
0.01
0
0.01
0.02
fRF
Qx
ABC
1000 500 0 500 10000.01
0
0.01
fRF
Qx
DE
horizontal vertical
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Optics functions
0 5 10 15 20 25
10
0
10
20
30
s position / m
and
D*1
0 / m
model A x
yDx
0 5 10 15 20 25
10
0
10
20
30
s position / m
and
D*1
0 [m
]
model C x
yDx
0 5 10 15 20 25
10
0
10
20
30
s position / m
and
D*1
0 [m
]
model D x
yDx
0 5 10 15 20 25
10
0
10
20
30
s position / m
and
D*1
0 [m
]
model E x
yDx
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Tunes
0.75 0.8 0.85 0.9 0.950.65
0.7
0.75
0.8
Qx
Qy
ABCDE2nd3rd4th
0 0.002 0.004 0.006 0.008 0.010
0.5
1
1.5 x 10 4
alpha(model)
Qs2
A
BC
DE
meas.model
Q2s ∝ α
Synchrotron tune:approximate the measurementsno impact seen in AT of higher order terms on synchrotron tune
Betatron tunes:approximate the measurementsbest agreement for lowest αlargest difference in the horizontal betatron tune
emphasis in modeling on sychrotron tune
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Higher order alpha
-1 0 1-310×
p
5.9
6
6.1
6.2
6.3
6.4
6.5
6.6-310×
-5 0-310×
p
0
0.1
0.2
0.3
0.4
0.5
0.6-310×
model C
model E
α0 = +(6.28 ± 0.0014) · 10−3
α1 = −(99 ± 6) · 10−3
α0 = +(0.447 ± 0.004) · 10−3
α1 = −(20 ± 1) · 10−3
α2 = −(2, 710 ± 300) · 10−3
α3 = −(190, 000 ± 90, 000) · 10−3
⇒ αc = α0 + α1δ + α2δ2 + α3δ
3 + ...
αp =dL/L
dp/pαc =
∆L/L0
∆p/p0=⇒ αp =
1 + δ
1 + αcδ
d(αcδ)
d(δ)
fs(fRF ) → αp(dp/p) = αp(δ)
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Longitudinal phase space
0.4 0.2 0 0.2 0.4 0.60.03
0.02
0.01
0
0.01
0.02
0.03
p/p
s / m0 0.1 0.2 0.3
0.03
0.02
0.01
0
0.01
p/p
s / m
model A model E
fixpointsLow α0 ➞ higher order terms have to be consideredAdditional fixpoints at:
Measurement: α0
α1= −0.023± 0.001
∆p
p fix≈ α0
α1= −0.036
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Dynamic aperture
0.05 0 0.050
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
x (m)
y (m
)
2 E1 E
01 E2 E
ph. ap.
0.05 0 0.050
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
x (m)
y (m
)
2 E1 E
01 E2 E
ph. ap.
0.05 0 0.050
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
x (m)
y (m
)
2 E1 E
01 E2 E
ph. ap.
0.05 0 0.050
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
x (m)
y (m
)
2 E1 E
01 E2 E
ph. ap.
model A model C
model D model E
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
DA for different chromticities
0.05 0 0.050
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
x (m)
y (m
)
e=0
model A
ΔQx‘ ΔQy‘-2-2-2-2-2-1-1-1-1-100000+1+1+1+1+1+2+2+2+2+2
-2-10+1+2-2-10+1+2-2-10+1+2-2-10+1+2-2-10+1+2 0.05 0 0.05
0
0.005
0.01
0.015
0.02
0.025
0.03
x (m)
y (m
)
e=0
model E
-2-2-2-2-2-1-1-1-1-100000+1+1+1+1+1+2+2+2+2+2
-2-10+1+2-2-10+1+2-2-10+1+2-2-10+1+2-2-10+1+2
ΔQx‘ ΔQy‘
Small chromaticities enlarge dynamic apertureLow α0 optics are more sensitive to chromaticity changes
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Summary
Regular low-alpha user operation
Characterized the properties of the CSRcalculated and observed bursting/stable thresholdinvestigated radiation behavior with HEB
Bunch shape and length measurements with streak camera
Spectral measurements, comparison multi and single bunch
Beam based modeling of the low-alpha modehigher order momentum compactionsecond stable fixpoints in long. phase spacedynamic aperture investigation
July 2011 Marit Klein Laboratory for Applications of Synchrotron [email protected]
Outlook
Simulations of microbunching instability and bursting behavior with a Vlasov-Solver
Bunch to bunch interaction?
HEB leading bunch analysis, bursting triggering with additional wake fields
Single shot measurements of electron distribution with electrooptical sampling
yes!
0 0.05
0.1 0.15
0.2 0.25
0.3 0.35
0.4
elec
tron
dens
ity
followingleading
elec
tron
dens
itylong. pos.