LCLS-IISC Parameters Tor Raubenheimer

2 Operating modes keV (120 Hz) keV (100 kHz) 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 mode UndulatorSC Linac (up to 100kHz)Cu Linac (up to 120Hz) North keV South keVup to 18 keV higher peak power pulses Cu Linac Concurrent operation of 1-5 keV and 5-18 keV is not possible LCLS-II Overview

3 Preliminary Operating Parameters LCLS-II Overview Preliminary LCLS-II Summary Parameters v0.78/30/13 North Side SourceSouth Side Source Running modeSC Linac Cu Linac Repetition rateup to 1 MHz* 120 Hz Electron Energy4 GeV 14 GeV Photon energy keV1-5 keV1-20 keV Max Photon pulse energy (mJ) (full charge, long pulse) up to 2 mJ* up to10 mJ Peak Spectral Brightness (10 fs pulse) (low charge, 10pC) 3.9x10 30 **12x10 30 **247x10 30 ** Peak Spectral Brightness (100fs pulse) (full charge, 100pC) 3.0x10 30 **6.9x10 30 **121x10 30 ** * Limited by beam power on optics **N_photons/(s*mm^2*mrad^2*0.1% bandwidth)

4 High Level Schedule Insert Presentation Title in Slide Master

5 More Immediate Schedule Insert Presentation Title in Slide Master 1.Mid-October Workshop to review design, cost and schedule with collaborators 2.Mid-December Director’s Review for CD1 Review 3.Mid-January CD1 Lehman Review Also may need to have a FAC review prior to CD1 review  Mid-November ??

6 Assumed Beam Parameters Insert Presentation Title in Slide Master 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 NLSNGLSLCLS-IISC Beam energy [GeV] Bunch charge [pC] Emittance [mm-mrad] Energy spread [keV] keV300 keV Peak current [kA] Useful bunch fraction [%]4050

7 Example of Injector: APEX Insert Presentation Title in Slide Master

8 SCRF Linac Insert Presentation Title in Slide Master Roughly 400 meters long including laser heater at ~100 MeV, BC1 at ~300 MeV and BC2 at GeV. Long bypass line starting at Sector 9  BSY. LTU similar to LCLS-IISA discussed last month. Based on 1.3 GHz TESLA 9-cell cavity with minor mods for cw operation

9 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)\

10 Linac v Linac parameters Energy4GeV Cavity Gradient16MV/m Cavity Q_02E+10 Operational temperature1.8deg_K rate1E+06Hz Average current0.3mA Beam power1.2MW Cryogenics power3.0MW Total SC RF AC Power3.4MW SC Layout 1.3 GHz Cryomodules34 (+1 spare)count 1.3 GHz Voltage4.2GV 1.3 GHz Cavities264count 1.3 GHz Rf power/cavity7kW 1.3 GHz Cavities/klystron32count 1.3 GHz SSA24count 1.3 GHz Cryomodules/klystron4count 1.3 GHz Dist. Between klystrons57m 1.3 GHz Klystron avg. power3.0E+05W 1.3 GHz Klystron (10% margin)8 1.3 GHz Mod V50kV 1.3 GHz Mod A10A 1.3 GHz Sector-pair RF AC power1.32E+06W 1.3 GHz Cryomodule spacing13m 3.9 GHz cryomodules3count 3.9 GHz Voltage60MV 3.9 GHz Cavities12count 3.9 GHz Cavities/klystron4count L0 length8m L1 RF length16m LC length (3.9 GHz)4m L2 RF length96m L3 RF length144m Total Linac length; not incl BC1 BC2405m No warm breaks except BC: 1 cryo circuit per 3 kW load

11 Linac View SLAC Linac (11 wide x 10 feet high) (3.35 x 3.05 m) x

12 First 800 m of SLAC linac (1964): Cryoplant placement and construction 350 m Injector Length

13 Assumed FEL Configuration Insert Presentation Title in Slide Master 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

14 Undulator Requirements Insert Presentation Title in Slide Master 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

15 Undulator Parameters Insert Presentation Title in Slide Master 1.To cover the range of 0.2 to 1.3 keV using SASE in less than 50 meters (to allow for seeding)  w ~ 40 mm A conventional hybrid undulator with 40 mm and a 7.2 mm minimum gap would have K max ~ 6.0 which easily covers the desired wavelength range at 4 GeV 2.To achieve 5 keV using SASE with less than 144 m at 4 GeV  TXR w <= 26 mm A conventional hybrid undulator with 26 mm and a 7.2 mm minimum gap would have K max ~ 2.4 which covers desired wavelength range at 4 GeV Provides reasonable performance with LCLS beam

Baseline Tuning Range for 4 GeV HXR: u = 26 mm, L = 144 m SXR: u = 41 mm, L = 75 m SASE Self-Seeding K max = 6.0 K min = 1.6 K max = 2.44 K min = 0.91 K min = 0.55 K min is chosen to saturate within given length for SASE or Self-seeding K max is set to the maximum value for a 7.2 mm gap variable gap undulator E beam [GeV] E photon [keV]

17 X-ray pulse energy at High Rate Insert Presentation Title in Slide Master More than enough FEL power although results assume full beam and are ~2x optimistic

18 Comparison of HXR with LCLS performance at 120 Hz (1) Insert Presentation Title in Slide Master 26 mm HXR covers 2 keV at ~4 GeV to 30+ keV at 14 GeV – beam energy might be reduced further if desired

19 Comparison of HXR with LCLS performance at 120 Hz (2) Insert Presentation Title in Slide Master 26 mm HXR provides lower pulse energy than 30 mm LCLS but much shorter

20 Options for HXR: SCU, IV, or 30 mm period (1) Insert Presentation Title in Slide Master To recover the LCLS performance, we need to increase K. Can (1) increase the period, (2) adopt an in-vacuum design, or (3) consider a planar or helical SCU. Example of a helical SCU below however have not included poorer SCU fill factor  results are optimistic

21 Options for HXR: SCU, IV, or 30 mm period (2) Insert Presentation Title in Slide Master 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

22 SCU options Insert Presentation Title in Slide Master 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.

J. Wu (SLAC), 08/05/ GENESIS SIMULATION ELECTRON PARAMETERS Centroid energy 4 GeV; 100 pC compressed to 1 kA; normalized emittance: 0.45  rad; slice energy spread:  E = 300 keV except for LCLS case with 15 GeV 6 cases – details in following pages Case 1: HXR K min = 0.91; w = 26 mm; L w = 144 m (study SS 4keV) Case 2: SXR K min = 1.6; w = 41 mm; L w = 75 m (study 1.6 keV) Case 3: SXR K max = 6.0; w = 41 mm; L w = 75 m (study 200 eV) Case 4: SXR K = 1.9; w = 41 mm; L w = 75 m (study 1.3 keV) Case 5: SXR K = 2.0; w = 30 mm; L w = 75 m (short gain len.) Case 6: HXR in LCLS TW parameters but K too high for hybrid undulator Bad Barely Good OK

24 Potential Areas of Collaboration with Partner Labs SLACLBNLFNALJLABANLCornell Wisconsin InjectorXXX UndulatorXX SC linac prototypeXXX SC LinacXX SC cryo lineXX Cryo plantXX LLRFXXXX RF systemsX Beam PhysicsXX Instruments/ Detectors XX PM/IntegrationX InstallationXXX CommissioningX LCLS-II Overview

25 Points of Contact Insert Presentation Title in Slide Master

26 CDR Writing Insert Presentation Title in Slide Master 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)