Near term opportunities for LCLS 'upgrades'

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Near term opportunities for LCLS 'upgrades'

• J. Hastings for the LCLS
• Experimental Facilities DivisionJune 25, 2009

gex,y 0.4 mm (slice) Ipk 3.0 kA sE/E 0.01
(slice)
Recent Results! (25 of 33 undulators installed)
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Goals

• Increase user access
• Multiplex options
• Soft x-rays (800-2000eV) - AMO, SXR
• Hard x-rays (up to 25 keV) XPP, XCS, CXI, MEC
• Performance enhancements
• Energy range
• Long wavelength
• Short wavelength
• Polarization
• Pulse duration
• Laser-electron beam interactions

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Polarization
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CXI
X-ray transport tunnel
XCS
XPP
MEC
SXR
XCS Offset Monochromator
AMO
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Instrument layout
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Soft X-ray experiments at LCLS
(500) 800 eV 2 keV
Beam sharing in place on a 12 hour basis
(mirror deflection between AMO and SXR)
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XCS Large Offset Monochromator
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XCS Large Offset Monochromator
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Increased Energy Reach
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Long wavelength limit
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2nd Harmonic Afterburner
Increase hard x-ray energy reach
1.5-Å LCLS Undulator
afterburner
130 m
43 m
0.75-Å radiation using spent LCLS beam, and
completely parasitic to LCLS operation at 1.5
Å. Add 40-m, 2nd-harmonic tapered
undulator SLAC-PUB-10694.
0.75-Å
Parameters
Z. Huang, S. Reiche
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Pulse Duration
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Polarization Control by Crossed Undulator

• Horizontal vertical undulators or two helical
  undulators
• Polarization controlled by phase shifter, fast
  switch possible with pulsed dipoles at 100 Hz

-p/2
p/4
-p/4
0
Ex
Ey
Phase shifter ?
p
5p/4
p/2
p/2

• Studies show that equal power in x y requires
  L2 1.3LG
• Over 80 polarization is expected at SASE
  saturation
• Second undulator can be adjusted as a
  second-harmonic afterburner if needed

K.-J. Kim, NIMA 2000 Y. Ding Z. Huang, PRST-AB
2008
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Multiplex options
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Thin slotted foil in center of chicane
PRL 92, 074801 (2004).
y
P. Emma, M. Cornacchia, K. Bane, Z. Huang, H.
Schlarb, G. Stupakov, D. Walz (SLAC)
2Dx
x ? DE/E ? t
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z ? 60 m
Genesis 1.3 FEL code
1010 photons
x-ray Power
(lt1 fs possible)
Power (GW)
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Measurements and Simulations20-pC Bunch, 14 GeV
MEASURED SLICE EMITTANCE
135 MeV
20 pC
gex 0.14 µm
accepted in PRL
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Power profile at 25 m
Average photon number 2.4x1011 Estimated
time-bandwidth product 3 times
Fourier-transform limit.
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Two-Stage SASE FEL
Self-seeding
Short pulse, or narrow bandwidth, wavelength
is more stable Moderate new undulator line or
upgrade SLAC-PUB-9370, TESLA-FEL
-97-06E, SLAC-PUB-9633, SLAC-PUB-10310
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Parameters
C. Pellegrini
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Laser electron beam interaction
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Measuring Bunch Arrival Time Jitter with an RF
Deflector
e-
S-band (2856 MHz)
y-BPM
slope -2.34 mm/deg
Now measure BPM jitter with deflector OFF, and
then ON (at constant phase)
Timing Jitter (110 mm)/(2.34 mm/deg) 0.047
deg ? 46 fsec rms
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SASE FEL
4 GeV
14 GeV
Allows synchronization between laser pulse and
x-ray pulse
E-SASE (applied to LCLS)
A. Zholents PRL
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ESASE in the LCLS
4.54 GeV ?z ? 0.02 mm
rf gun
rf gun
Linac-1 L ? 9 m ?rf ?-25
Linac-2 L ? 330 m ?rf ? -41
Linac-3 L ? 550 m ?rf ? -10
13.6 GeV

new
Linac-0 L ?6 m
Linac-1
Linac-2
Linac-3
BC1
BC2
Linac-0
undulator L ?130 m
undulator L ?130 m
X
X
existing linac
existing linac
BC1 R56?39 mm
BC2 R56?25 mm
DL2
Laser Heater
Laser Heater
DL2 R56?0
DL1 R56?-6 mm
SLAC linac tunnel
undulator hall
New elements
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ESASE single spike selection

• Two ten-cycle lasers (second laser tunable
  wavelength with OPA)
• Tapered undulator to compensate LSC and enhance
  contrast

?E (MeV)
P (GW)
Ding, Huang, Ratner, Bucksbaum, Merdji, FEL2008
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Special Thanks to
Y. Ding, P. Emma, J. Frisch, Z. Huang, H. Loos,
A. Zholents, J. Wu
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End of Presentation