LCLS-II HE Facility Overview Advanced Instrumentation for LCLS-II HE Science October 16-17, 2018

David Fritz

LCLS-II HE DOE Review, June 19-21, 2018

LCLS-II New Injector and New Superconducting Linac

Existing Bypass Line

New Transport Line

Two New Undulators And X-Ray Transport

Exploit Existing Experimental Stations

New Cryoplant

Remove SLAC Linac from Sectors 0-10

LCLS-II Key Performance Parameters

Early Finish in FY21

2

LCLS-II variable gap hybrid undulators Development with LBNL and ANL

Frame

Variable gap undulators used in LCLS-II to provide greater wavelength tuning flexibility

•  Vertical gap horizontally polarized undulator for soft x-ray branch

•  Horizontal gap vertically polarized undulator for hard x-ray branch

3

Linac Coherent Light Source II (LCLS-II)

Now HXU - Cu SXU – Cu HXU - SC SXU - SC

Photon Energy Range (keV) 0.25 -12.8 1 - 25 0.25 - 6 1 - 5 0.25 - 1.6

Repetition Rate (Hz) 120 120 120 929,000 929,000

Per Pulse Energy (mJ) ~ 4 ~ 4 ~ 8 ~ 0.2 ~ 1

Photons/Second ~ 1014 ~ 1014 ~ 1014 ~ 1016 ~ 1017

4

LCLS-II-HE Overview - Accelerator Upgrades

1.  Upgrading the LCLS-II superconducting linac to 8 GeV with nominal bunch frequency of 1 MHz to allow programmable FEL X-ray pulses up to 1 MHz repetition rate.

2.  Installing a new cryogenic distribution box and transfer line between the cryoplant and the new L4 linac.

3.  Addition of a pulsed low-energy extraction point in the superconducting linac at 3.8 GeV to allow quasi-independent operation of the soft-X-ray and hard-X-ray programs.

4.  Use of an existing transport line to bypass the midsection of the SLAC linac and the LCLS linac along with installation of a new dump the at the end of the transport line.

5.  Installation of a Hard X-ray Self Seeding capability in the hard X-ray undulator capable of operating at high repetition rate.

5

Operation Modes

Spreader and new BSY2 kicker allow flexible patterns to HXR and SXR FELs (decouple undulator rate from linac)

6

Start-2-End Simulation Results

Examples at 8 and 13 keV Fundamental Energy 8 keV 13 keV Units

Maximum Repetition Rate 929 (300) 929 (300) kHz

FW Pulse Duration 30 (105) 30 (102) fs

Total energy/pulse 235 (625) 108 (57) µJ

Source point relative to end of undulator 25 (19) 24 (21) m

First Harmonic

Photons per FEL pulse 0.18 (0.49) 0.05 (0.028) 1012

Relative FWHM Bandwidth 0.05 (0.09) 0.06(0.1) %

FWHM Source Size 36 (37) 26 (22) 𝜇m

FWHM Source Divergence 2.4 (2.0) 1.8 (1.8) 𝜇rad

Third Harmonic

Photons per FEL pulse 0.15 (0.29) 0 . 0 1 6 (0.005) 1010

Relative FWHM Bandwidth 0.05 (0.09) 0.06 (0.1) %

FWHM Source Size <36 (<37) <26 (<22) 𝜇m

FWHM Source Divergence <2.4 (<2.0) <1.8 (<1.8) 𝜇rad

20 pC, 13 keV

100 pC, 8 keV

7

Photon Energy Upgrade Options

Reduced emittance, higher peak current, and/or higher energy can enable higher photon energies (>17 keV)

8

9

The LCLS X-ray Instruments Today

10

Notional Instrumentation Plan for LCLS-II-HE

Far Hall

DXS MFX CXI1 MEC

Near Hall

N1.1 N1.2 XPP

N2.2

CXI2

~ 50 m ~ 70 m

Blue – Upgraded for LCLS-II Black – Reuse (up to 2 kHz) Red – Upgraded for LCLS-II-HE Green – New for LCLS-II-HE

NXI

Build 1 new instrument •  XCS à Dynamic X-ray Scattering (DXS) Endstation

Upgrade 2 instruments •  XPP à Upgrade optics & diagnostics and Detector •  CXI à Upgrade microfocus system

10

11

New and upgraded instruments will address the science needs and take advantage of the transformative nature of LCLS-II-HE

•  Key Performance Parameter -  3 upgraded endstations

•  Objective KPP -  5 upgraded endstations

Instr. Upgrade Plan Science Opportunities

XPP New detector Upgraded diagnostics

•  Understand coupled dynamics of molecular structure and charge & their role in energy flow

•  Characterize materials heterogeneity, fluctuations & link to function

DXS Repetition rate enhancement IXS capability

•  Map collective excitations & understand their relation to emergent phenomena in complex materials

•  Characterize materials heterogeneity, fluctuations & link to function

CXI New optics & detector, Enhanced DAQ

•  Reveal the role of structural dynamics in biological function •  Catalysis: Reveal the correlation between chemical reactivity & structural

dynamics

12

High Average Power X-ray Optics

§ Dynamically bendable mirrors ̶  Water cooled ̶  Eutectic GaIn interface o  Good thermal contact o  Weak mechanical coupling

§  Transfocators ̶  Water cooled

13

High average power femtosecond pump laser

NIR OPCPA

Spatial profile

Power stability

Pulse duration Spectrum

88.5 ± 1.47W

•  Tunable broadband spectrum centered at ~790nm

•  Pulse durations down to 17fs

•  Output power of 88.5 W at 100kHz, with efficiency of ~12% from pump

LCLS-II detector developments

High Speed Imaging ≥ 5-10 kHz

Spectroscopic ~ 0.5 eV @ 1 keV, 10 kHz

14

15

Summary and Caveats

•  LCLS-II-HE will: •  Double the electron energy of the accelerator (4 to 8 GeV) and extends X-

ray energy limit from 5 keV to 12.8 keV •  Install a second bypass line to deliver simultaneous soft X-ray and hard X-

ray beams at high rep-rate •  A credible instrumentation plan was an essential requirement for CD-1

(and CD-0), and we created a draft plan based on the science case and community input from previous workshops – but this is not cast in stone.

•  Ideas that emerge from this workshop will be essential for re-shaping and refining the instrumentation plan for LCLS-II-HE

•  Inevitably, the initial scope of LCLS-II-HE instruments will be limited and likely implemented in phases. Ideas that emerge from this workshop will help to determine the priorities.

•  Ideas that emerge from the workshop will also help motivate plans (and establish a case) for instrumentation that goes beyond the initial scope of LCLS-II-HE instruments.

Questions?

LCLS-II HE DOE Review, June 19-21, 2018 16

LCLS-II-HE Mission Need and Hard X-ray Capabilities

•  Expanding the photon energy reach of the high repetition rate LCLS-II to beyond the current limit of 5 keV to access structure and dynamics at the atomic scale (i.e., in the 1Å region).

•  Providing a ~1,000-fold increase in average spectral brightness (spatially and temporally coherent x-ray power) over any existing hard x-ray source, exploiting self-seeding developed at LCLS.

•  Delivering spatial coherence to achieve ~1,000-fold increase in average coherent x-ray power (coherent ph/s/0.1% BW) beyond any existing hard x-ray source or proposed diffraction-limited storage ring (DLSR).

•  Delivering temporal coherence to achieve >300-fold increase in average spectral flux (ph/s/meV) via self-seeding beyond any existing hard x-ray source or proposed DLSR.

•  Generating ultrafast hard x-ray pulses in a uniform (or programmable) time structure at a repetition rate of up to 1 MHz.

LCLS-II-HE Mission Need Statement,

Approved Dec 2016

https://slacspace.slac.stanford.edu/sites/reviews/lclsiihe/cdr/LCLS-II-HE CD-0 MNS.pdf. 17

LCLS-II HE Project KPPs

KPPs proposed in the LCLS-II HE Conceptual Design Report

Performance Measure Threshold Objective

Superconducting linac electron energy 7 GeV 8 GeV

Electron bunch repetition rate in linac 93 kHz 929 kHz

Charge per bunch in SC- linac 0.02 nC 0.1 nC

Photon energy range 200 – 8,000 eV 200 to ≥ 12,800 eV

High rep-rate-capable HXR end stations ≥ 3 ≥ 5

FEL photon quantity (10-3 BW) 5×108 (50× spont. @ 8 keV)> 1011 @ 8 keV (200 µJ)

or > 1010 @ 12.8 keV (20 µJ)

Proposed Changes to the KPP listed in the Federal Project Data Sheet •  ≥ 12,800 ev: Project goal is to achieve “greater than or equal to” 12.8 keV •  >1010 photons @ 12.8 keV: Pulse energy at this photon energy is limited by

emittance and FEL performance

18

HXR Self-Seeding

•  LCLS operates with Hard X-ray Self-seeding over the range of 4 ~ 10 keV at 120 Hz

•  LCLS-II will modify the system to operate over 4 ~ 12 keV at 120 Hz from the CuRF linac

•  LCLS-II-HE will implement high rate self seeding between 4 and >9 keV

19