LCLS-IISC Parameters

LCLS-IISC ParametersTor Raubenheimer10/1/2013

LCLS-II - Linac and Compressor Layout for 4 GeV

CM01 CM2,3 CM04 CM15 CM16 CM35

BC1270 MeV

R56 = -65 mmIpk = 60 A

Lb = 0.40 mmsd = 1.4 %

BC21550 MeV

R56 = -65 mmIpk = 1000 A

Lb = 0.024 mmsd = 0.50 %

GUN0.75 MeV

LH98 MeV

R56 = -5 mmIpk = 12 A

Lb = 2.0 mmsd = 0.006 %

L0j 0

V0 97 MV

L1j =-26°

V0 =235 MV

HLj =-170°

V0 =40 MV

L2j = -28°

V0 = 1448 MV

L3j = 0

V0 = 2460 MV

LTU4.0 GeVR56 = 0

Ipk = 1000 ALb = 0.024 mmsd 0.02 %

100 pC; Machine layout 26SEP2013; Bunch length Lb is FWHM

3.9GHz

Linac

V(MV)

j(deg)

Acc. Grad.

(MV/m)

No. Cryo

Mod’s

No. Cav’s

Spare Cav’s

Cavities per

Amplifier

L0 97 * 14.6 1 8 1 1

L1 235 -26 15.1 2 16 1 1

HL -40 -170 - 3 (3.9GHz) 12 0 12?

L2 1448 -28 15.5 12 96 6 32?

L3 2460 0 15.7 20 160 10 32?

* L0 phases: (-40, -52, 0, 0, 0, 13, 33), with cav-2 at 20% of other L0 cav’s.

Start from 10A APEX beamIncludes 2-km RW wake

Paul Emma

LCLS-II Overview 3

Operating modes

1.0 - 18 keV (120 Hz)1.0 - 5 keV (100 kHz)

0.2-1.2 keV (100kHz)4 GeV SC Linac

•Two sources: high rate SCRF linac and 120 Hz NCu LCLS-I linac

•North and south undulators always operate simultaneously in any modeUndulator

SC Linac (up to 100kHz) Cu Linac (up to 120Hz)

North 0.25-1.2 keV

South 1.0-5.0 keV up to 18 keVhigher peak power pulses

Cu Linac

• Concurrent operation of 1-5 keV and 5-18 keV is not possible

4

Preliminary Operating Parameters

LCLS-II Overview

Preliminary LCLS-II Summary Parameters v0.7 8/30/13

North Side Source South Side Source

Running mode SC Linac SC Linac Cu Linac

Repetition rate up to 1 MHz* up to 1 MHz* 120 Hz

Electron Energy 4 GeV 4 GeV 14 GeV

Photon energy 0.25-1.2 keV 1-5 keV 1-20 keV

Max Photon pulse energy (mJ) (full charge, long pulse)

up to 2 mJ* up to 2 mJ* up to10 mJ

Peak Spectral Brightness (10 fs pulse) (low charge, 10pC)

3.9x1030 ** 12x1030 ** 247x1030 **

Peak Spectral Brightness(100fs pulse) (full charge, 100pC)

3.0x1030 ** 6.9x1030 ** 121x1030 **

* Limited by beam power on optics **N_photons/(s*mm^2*mrad^2*0.1% bandwidth)

5Insert Presentation Title in Slide Master

High Level Schedule


More Immediate Schedule

1. Mid-October Workshop to review design, cost and

schedule with collaborators

2. Late November FAC review of the draft CDR

3. Mid-December Director’s Review for CD1 Review

4. Early-February CD1 Lehman Review


Assumed Beam Parameters

The assumed emittance of 0.43 at 100 pC is roughly 25% larger than

the LCLS-II baseline. It is more conservative than the NLS or the

scaled NGLS values (the latter are consistent with the LCLS-II baseline)

however a gun has not yet been demonstrated that achieves the

desired emittances. Reduced emittances will decrease gain lengths.

Peak current is consistent with higher energy beams and BC’s

NLS NGLS LCLS-IISC

Beam energy [GeV] 2.25 2.4 4

Bunch charge [pC] 200 300 100

Emittance [mm-mrad] 0.3 0.6 0.43

Energy spread [keV] 150 150 keV 300 keV

Peak current [kA] 0.97 0.5 1

Useful bunch fraction [%] 40 50 50


Example of Injector: APEX

9

Example of Litrack fromAPEX Simulation

100pC20A peak currentSlice emittance 0.2-0.25 umProjected emittance ~ 0.35 um

better current/energy profile

Charge =100pCR56@BC1=-38.5mmR56@BC2=-54.7mmL1 phase =-21.7 degreeL2 phase =-29.2 degreeL3 phase =-2 degree3rd HC phase =-158 degreeL1voltage =211 MVL2 voltage =1.54GV3rd HC Voltage=47MV

Lanfa Wang


SCRF Linac

Roughly 400 meters long including laser heater at ~100

MeV, BC1 at ~300 MeV and BC2 at 1000-2000 GeV. Long

bypass line starting at Sector 10 BSY.

Based on 1.3 GHz TESLA

9-cell cavity with minor

mods for cw operation

11

1.3 GHz 8-cavity cryomodule (CM)

• It is proposed to use an existing cryomodule design for the 4-GeV

LCLS-II SRF linac.

• CM is roughly 13 meters for 8 cavities plus a quadrupole package

• The best-fit is the EU-XFEL cryomodule

• Modifications are required for LCLS-II• (The CEBAF 12 GeV upgrade module must also be considered)• (The ILC CM is similar but has several important differences and is

not as well suited for CW application)

• 100 cryomodules of this design will be built and tested by the

XFEL by 2016 Global industrial support for this task

• One XFEL ~prototype CM was assembled and tested at Fermilab• (Fermilab assembled an ILC cryomodule and has parts for another)\

12

Linac Parameters

v0.9 2013-08-30

Linac parameters

Energy 4 GeV

Cavity Gradient 16 MV/m

Cavity Q_0 2E+10

Operational temperature 1.8 deg_K

rate 1E+06 Hz

Average current 0.3 mA

Beam power 1.2 MW

Cryogenics power 3.0 MW

Total SC RF AC Power 3.4 MW

SC Layout

1.3 GHz Cryomodules 34 (+1 spare) count

1.3 GHz Voltage 4.2 GV

1.3 GHz Cavities 264 count

1.3 GHz Rf power/cavity 7 kW

1.3 GHz Cavities/klystron 32 count

1.3 GHz SSA 24 count

1.3 GHz Cryomodules/klystron 4 count

1.3 GHz Dist. Between klystrons 57 m

1.3 GHz Klystron avg. power 3.0E+05 W

1.3 GHz Klystron (10% margin) 8

1.3 GHz Mod V 50 kV

1.3 GHz Mod A 10 A

1.3 GHz Sector-pair RF AC power 1.32E+06 W

1.3 GHz Cryomodule spacing 13 m

3.9 GHz cryomodules 3 count

3.9 GHz Voltage 60 MV

3.9 GHz Cavities 12 count

3.9 GHz Cavities/klystron 4 count

L0 length 8 m

L1 RF length 16 m

LC length (3.9 GHz) 4 m

L2 RF length 96 m

L3 RF length 144 mTotal Linac length; not incl BC1 BC2 405 m

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Linac View in SLAC Tunnel

SLAC Linac

(11 wide x 10 feet high)

(3.35 x 3.05 m)

x

14

First 800 m of SLAC linac (1964):

Cryoplant placement and construction

350 m

Injector Length

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Geometry downstream of SC linac

LCLS2SC bypass

Plan view

Elevation view

old LCLS2 linac

LCLS2SC bypass

120 Hz

100 kHz

old LCLS2 linacdump

fast kicker

100 kHz

9/26/2013 -- Y. Nosochkov

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LCLS2SC bypass (from sec-21) to dump

9/26/2013 -- Y. Nosochkov

bypass

LTU dogleg + V-bend diagnostic undulator

dump

extension


Assumed FEL Configuration

• High rep rate beam could be directed to either of two undulators

HXR or SXR bunch-by-bunch

• 120 Hz beam could be directed to the HXR at separate times

• The SC linac would be located in Sectors 0-10 and would be

transported to BSY in the 2km long Bypass Line. It would use a

dual stage bunch compressor.

• A dechirper might be used to further cancel energy spread for

greater flexibility in beam parameters

• The high rep rate beam energy would be 4 GeV and the HXR

would fill the LCLS hall with ~144 m while the SXR would be <75

m so that it could be fit into ESA

• Both undulators would need to support self-seeding as well as

other seeding upgrades


Undulator Requirements

Requirements:

1. SXR self-seeding operation between 0.2 and 1.3 keV

in ESA tunnel (<75 meters) with 2.5 to 4 GeV beam

2. HXR self-seeding operation between 1.3 and 4 keV in

LCLS tunnel (~144 meters) with 4 GeV beam

3. HXR SASE operation up to 5 keV with 4 GeV beam

4. Primary operation of SXR and TXR at constant beam

energy large K variation

5. HXR operation comparable to present LCLS with 2 to

15 GeV beam

Baseline Tuning Range

With overhead

LCLS-IISC Undulator Options

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X-ray pulse energy at High Rate

Results assume full beam and are somewhat optimistic


21

Comparison of HXR with LCLS performance at 120 Hz (1)

26 mm HXR covers 0.5 keV at ~2.5 GeV to ~30 keV at 15 GeV


22

Comparison of HXR with LCLS performance at 120 Hz (2)

26 mm HXR provides lower pulse energy than 30 mm LCLS but much shorter l


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Options for HXR: SCU or 30 mm period (2)

Example of a 30 mm period hybrid undulator below. Nearly recovers LCLS

performance (reduction due to slightly larger gap with VG undulator) however the

maximum photon energy at high rate, i.e., 4 GeV is now 4.3 keV not 5 keV as

with 26 mm period and 5 keV would require 4.4 GeV beams.



SuperrConducting Undulator options

An SCU has a number of benefits:

1. Would attain comparable performance as LCLS even

while achieving 5 keV at 4 GeV at high rate by operating

with high K

2. Would allow shorter SXR period to reduce SXR beam

energy and gain length to ensure space in ESA while still

covering full wavelength range at constant energy.

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Potential Areas of Collaboration with Partner Labs

SLAC LBNL FNAL JLAB ANL Cornell Wisconsin

Injector X X X

Undulator X X

SC linac prototype X X X

SC Linac X X

SC cryo line X X

Cryo plant X X

LLRF X X X X

RF systems X

Beam Physics X X

Instruments/Detectors

X X

PM/Integration X

Installation X X X

Commissioning X

LCLS-II Overview


Points of Contact


CDR Writing

• Must keep the document concise – it is a conceptual design

1. Executive Summary (Galayda)

2. Scientific Objectives (TBD)

3. Machine Performance and Parameters (Raubenheimer)

4. Project Overview (Galayda)

5. Electron Injector (Schmerge)

6. Superconducting Linac Technologies (Ross,Corlett)

7. Electron Bunch Compression and Transport (Raubenheimer, Emma)

8. FEL Systems (Nuhn)

9. Electron Beam Diagnostics (Frisch, Smith)

10. Start-to-End Tracking Simulations (Emma)

11. Photon Transport and Diagnostics (Rowen)

12. Experimental End-Stations (Schlotter)

13. Timing and Synchronization (Frisch)

14. Controls and Machine Protection (Shoaee, Welch)

15. Conventional Facilities (Law)

16. Environment, Safety and Health (Healy)

17. Radiological Issues (Rokni)

18. Future Upgrade Options (Galayda)

LCLS-IISC Parameters

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