Tor O. Raubenheimerfor the LCLS and LCLS-II teams

LCLS-II Design

and FELR&D

2High Brightness Electron Beams Workshop, 2013

LCLS Concept: Fourth Generation Workshop20 Years Ago

C. Pellegrini, A 4 to 0.1 nm FEL Based on the SLAC Linac,Workshop on Fourth Generation Light Sources, February, 1992

Herman Winick’s Study GroupClaudio Pellegrini Herman Winick

Engaged Bjorn Wiik andGerd Materlik duringsabbaticals at SLAC

Slide 3

High Brightness Electron Beams Workshop, 2013

Linac Coherent Light Source FacilityInjector at 2-km point

Existing Linac (1 km)(with modifications)

First Light April 2009, CD-4 June 2010

New e- Transfer Line (340 m)

X-ray Transport Line (200 m)

UCLA

Undulator (130 m)

Near Experiment Hall

Far Experiment Hall

High Brightness Electron Beams Workshop, 2013

SLAC linac tunnel research yard

Linac-0L =6 m

Linac-1L 9 mrf -25°

Linac-2L 330 mrf -41°

Linac-3L 550 mrf 0°

BC1L 6 m

R56 -39 mm

BC2L 22 m

R56 -25 mm DL2 L =275 m

DL1L 12 mR56 0

undulatorL =130 m

6 MeVz 0.83 mm 0.05 %

135 MeVz 0.83 mm 0.10 %

250 MeVz 0.19 mm 1.6 %

4.50 GeVz 0.022 mm 0.71 %

13.6 GeVz 0.022 mm 0.01 %

Linac-XL =0.6 mrf= -160

21-1b,c,d

...existinglinac

L0-a,b

rfgun

21-3b24-6dX 25-1a

30-8c

undulator

Commission Mar-Aug 2007 Commission Jan-Aug 2008

beam parked here

Generation of low emittance beam Preservation of 6D brightness in accelerator and compressors Undulators meeting tolerance and trajectory control

LCLS commissioning ended Oct. 2009

Nov 2008…

4

5High Brightness Electron Beams Workshop, 2013

LCLS Operational Performance(480 eV – 10 keV) (280 eV – 10 keV)

High Brightness Electron Beams Workshop, 2013

• Exceptional e- beam quality from RF gun (gex,y 0.4 mm)

• Pulse length easily adjustable for users (60 - 500 fs FWHM)

with <<10 fs pulses at low charge (20 pC)

• Wider photon energy range: 280 - 10000 eV (design was:

830 - 8300 eV)

• Peak FEL power >70 GW (10 GW in CDR)

• Pulse energy up to 6 mJ (2 mJ in CDR)

• 96.7% accelerator availability, 94.8% photon availability

• Total of 133 publications, 35 in high impact journals

6

LCLS Achievements

Slide 7

High Brightness Electron Beams Workshop, 2013

Linac Coherent Light Source IIInjector @1-km point

Sectors 10-20 ofLinac (1 km)(with modifications)

X-ray Transport Optics/Diagnostics

New Underground Experiment Hall

Bypass LCLS LinacIn PEP Line(extended)

New Beam TransportHall

SXR, HXR Undulators

2010: April- Critical Decision 0 approved2011: October- Critical Decision 1 approved2012: March- Critical Decision 3a approved2012: August- Critical Decision 22013: June- Critical Decision 3b ??2018: Sept. First FEL Light2019: Sept. Critical Decision 4

LCLS-II Accelerator for 250 pC, 120 Hz

Injector, linac, and compression parameters are all very similar to LCLS-I, but not exactHigh Brightness Electron Beams Workshop, 2013 8

LCLC-II Parameter Space Photon Energy vs Beam Energy

Calculation by H-D Nuhn

High Brightness Electron Beams Workshop, 2013 9

10High Brightness Electron Beams Workshop, 2013

LCLS-II Greater Capacity

• Dedicated new injector at Sector 10• Two new SASE undulator x-ray sources, both variable gap• High Field Physics Soft X-Ray Experiment Station• Immediately:

- 4X increase in operations hours for soft x-rays- Generally, soft x-ray experiments run one-at-a-time

• Immediate 20% increase in operations hours for hard x-rays- Since hard x-ray instruments will someday run simultaneously, perhaps

2 or even 3 at a time, this can mean nearly 20% more time per station

• Future: Room in new experiment hall for at least 3 more new instruments with new scientific capabilities

• Future: 4th undulator in existing tunnel, 2 more instruments

High Brightness Electron Beams Workshop, 2013

LCLS-II Enhanced Capability

LCLS-II will provide expanded spectral range using two beamlines and variable gap undulators

- Up to 13 keV (above Selenium K-edge) @ 10.5-13.5 GeV- Down to 250 eV (Carbon K-edge) @ 7-10 GeV

• 300 meter undulator tunnel - Adequate space to accommodate future enhancements:

- Options for BW control: SS, iSASE, pSASE, …- Two-color generation- Polarization control- TW peak power

- Details will be determined by ongoing LCLS R&D program11

LCLS-I R&D Studies Improving LCLS-II Design

• Many beam physics studies on LCLS and NLCTA that are helping clarify LCLS-II design Injector studies to optimize and verify performance:

rf gun, laser heater, BC1, and BC2 CSR and bunch shaping studies for longitudinal phase space Jitter studies to understand performance limits Component studies – LCLS-II designs are similar in many cases Gain length, angular divergence, operational stability

measurements to help specify x-ray characteristics

• Other R&D studies enhancing the LCLS-II design Polarization control, self-seeding, & improved diagnostics Improved-SASE (iSASE) and Purified SASE (pSASE) Two-color generation, …

High Brightness Electron Beams Workshop, 2013 12

13

LCLS-I FEL R&D ProjectsLCLS-I R&D will clarify LCLS-II upgrades

TW

CTF (Cathode Test Facility)

High Brightness Electron Beams Workshop, 2013

14

Hard X-ray Self-Seeding

High Brightness Electron Beams Workshop, 2013

15

Hard X-Ray Self-SeedingNew Capability in LCLS Operation

Nature Photonics (2012)

Improve longitudinal coherence by increasing the longitudinal slippage

Narrow SASE bandwidth without fixing the central photon energy. Pulse Intensity is less sensitive to energy jitters

LCLS proof-of-principle experiment:Use detuned undulator as phase shifts Detune every other undulator after U5

Improved SASE (iSASE)

J. Wu, A. Marinelli, Pellegrini, FEL2012

iSASE experiment

SASE: (red) 1.21 mJ; average spectrum (FWHM 17 eV)iSASE: (blue) 0.21 mJ; average spectrum (FWHM 5 eV)

SASE iSASE

Single shot spectrum (13.8 GeV,150 pC)

High Brightness Electron Beams Workshop, 2013 18

TW FEL: LCLS Strong Tapering Studies

Envelope of measured power similar to on-energy simulations

• Large sensitivity to energy jitter as previously observed

• 1% taper demonstrated

blue (on-energy), black (+0.1 %), red ( -0.1 % ), magenta (-0.2 %)

simulation

experiment

J. Wu, et al

19High Brightness Electron Beams Workshop, 2013

TW FEL: LCLS Divergence StudiesSpecifying LCLS-II Apertures

Measurements of LCLS Angular Divergence

Y. Feng, J. Krzywinski, J. Turner, J. Welch

• X-ray stay clear (mirrors, diagnostics, energy attenuator) all depend on x-ray beam sizes

20

XTCAV: LCLS X-Band Transverse Cavity

Commissioning to start soon! P. KrejcikY. Ding

• A deflecting cavity has been installed after the undulator to measure the longitudinal phase space (t, DE/E) of the e- and g beams

High Brightness Electron Beams Workshop, 2013

21

XTCAV: e- and g Longitudinal Phase Space

SoftX-Rays

HardX-Rays

Y. DingReconstructed e- profile Reconstructed g profile

FEL off FEL on

High Brightness Electron Beams Workshop, 2013

22

HXR Beam Splitting at LCLSIt works!!

High Brightness Electron Beams Workshop, 2013

Two-color FELSingle slotted foil to control pulse durationChicane to control delay

Magnetic Chicane1st undulator section

K1

e-

x-ray1st Color

2nd undulator section

x-ray2nd Color

Controlled Delay

K2

A. Lutman, R. Coffee, Y. Ding, et al.

Eb = 5800 MeV and Eg = 1.5 keVColor separation 19 eV

24

DELTA Undulator for Polarization Control

Cornell 0.3-m Delta undulator (A. Temnykh)

• Polarization control• Flexible post-saturation taper• Second-harmonic afterburner• Simple upgrade to LCLS undulator

H.-D. Nuhn, E. KraftLCLS 1-m prototype

High Brightness Electron Beams Workshop, 2013

High Brightness Electron Beams Workshop, 2013

Soft X-Ray Self Seeding

SLAC, LBNL, PSI collaboration

• Photon energy 500-1000 eV (expandable to 300-1200 eV)• Resolving power ~ 5000• Fit in one undulator section (U9), < 4m in length

2011-12 2015-162013-14 2017-18 2019-20

LCLS-II injector LCLS-II completion

HXRSS

Injector R&DITF-FACET2: advanced beam generation,

high-energy compression and seeding

Temporal diagnostics & timing

Attosecond & mode-locking x-rays

X-ray seeding & brightness

E-beam brightness & manipulation

Technologydevelopment

Ultrafast techniques

ECHO-7

Soft X-Ray Self-SeedingECHO-75, laser phase error

error

THz & Polarization

THz

Polarization control

Multi bunches, detectors, novel undulators, high-rep. rate

ASTA (Cathode R&D)

X-ray spectrometer, beam sharing

TWFEL

HHG efficiency and control

Completed Ongoing Under development

iSASE

26

SLAC X-ray FEL R&D roadmap

Zhirong Huang

THz Facility Options

27High Brightness Electron Beams Workshop, 2013

Summary

• LCLS has been a great success- Very flexible beam operations allows for wide range of

photon science studies- R&D program is defining new capability

• Short fs-scale bunches• Wide photon energy range; photon beam splitting• Self-seeding with >0.01% BW; iSASE• Two color operation• Polarized x-rays• Strongly tapered operation

• LCLS-II will be the next addition to the SLAC photon science portfolio expands LCLS capability and capacity greatly