270 likes | 434 Views
LCLS-IISC Parameters. Tor Raubenheimer 10/1/2013. LCLS-II - Linac and Compressor Layout for 4 GeV. L0 j 0 V 0 97 MV. L1 j = - 26° V 0 =235 MV. HL j = - 170 ° V 0 =40 MV. L2 j = - 28° V 0 = 1448 MV. L3 j = 0 V 0 = 2460 MV. CM01. CM2,3. CM15. CM35. CM04.
E N D
LCLS-IISC Parameters • Tor Raubenheimer • 10/1/2013
LCLS-II - Linac and Compressor Layout for 4 GeV L0 j 0 V0 97 MV L1 j =-26° V0=235 MV HL j =-170° V0 =40 MV L2 j = -28° V0= 1448 MV L3 j = 0 V0= 2460 MV CM01 CM2,3 CM15 CM35 CM04 CM16 3.9GHz LTU 4.0 GeV R56 = 0 Ipk = 1000 A Lb = 0.024 mm sd 0.02 % LH 98 MeV R56 = -5 mm Ipk = 12 A Lb = 2.0 mm sd = 0.006 % BC1 270 MeV R56 = -65 mm Ipk = 60 A Lb = 0.40 mm sd = 1.4 % BC2 1550 MeV R56 = -65 mm Ipk = 1000 A Lb = 0.024 mm sd = 0.50 % GUN 0.75 MeV 100 pC; Machine layout 26SEP2013; Bunch length Lb is FWHM Start from 10A APEX beam Includes 2-km RW wake * L0 phases: (-40, -52, 0, 0, 0, 13, 33), with cav-2 at 20% of other L0 cav’s. Paul Emma
Operating modes Concurrent operation of 1-5 keV and 5-18 keV is not possible 0.2-1.2 keV (100kHz) 4 GeV SC Linac Cu Linac 1.0 - 18 keV (120 Hz) 1.0 - 5 keV (100 kHz) • Two sources: high rate SCRF linac and 120 Hz NCu LCLS-I linac • North and south undulators always operate simultaneously in any mode LCLS-II Overview
Preliminary Operating Parameters LCLS-II Overview
High Level Schedule Insert Presentation Title in Slide Master
More Immediate Schedule Insert Presentation Title in Slide Master Mid-October Workshop to review design, cost and schedule with collaborators Late November FAC review of the draft CDR Mid-December Director’s Review for CD1 Review Early-February CD1 Lehman Review
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
Example of Injector: APEX Insert Presentation Title in Slide Master
Example of Litrack fromAPEX Simulation 100pC 20A peak current Slice emittance0.2-0.25 um Projected emittance ~ 0.35 um • better current/energy profile Charge =100pC R56@BC1=-38.5mm R56@BC2=-54.7mm L1 phase =-21.7 degree L2 phase =-29.2 degree L3 phase =-2 degree 3rd HC phase =-158 degree L1voltage =211 MV L2 voltage =1.54GV 3rdHC Voltage=47MV Lanfa Wang
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 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
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)\
Linac View in SLAC Tunnel SLAC Linac (11 wide x 10 feet high) (3.35 x 3.05 m) x
First 800 m of SLAC linac (1964): 350 m Injector Length Cryoplant placement and construction
Geometry downstream of SC linac Plan view old LCLS2 linac 120 Hz LCLS2SC bypass 100 kHz fast kicker Elevation view 100 kHz LCLS2SC bypass dump old LCLS2 linac
LCLS2SC bypass (from sec-21) to dump dump bypass extension LTU dogleg + V-bend diagnostic undulator
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
Undulator Requirements Insert Presentation Title in Slide Master Requirements: SXR self-seeding operation between 0.2 and 1.3 keV in ESA tunnel (<75 meters) with 2.5 to 4 GeV beam HXR self-seeding operation between 1.3 and 4 keV in LCLS tunnel (~144 meters) with 4 GeV beam HXR SASE operation up to 5 keV with 4 GeV beam Primary operation of SXR and TXR at constant beam energy large K variation HXR operation comparable to present LCLS with 2 to 15 GeV beam
Baseline Tuning Range With overhead LCLS-IISC Undulator Options
X-ray pulse energy at High Rate Results assume full beam and are somewhat optimistic LCLS-IISC Undulator Options
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 LCLS-IISC Undulator Options
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 LCLS-IISC Undulator Options
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 not5 keVas with 26 mm period and 5 keV would require 4.4 GeV beams. LCLS-IISC Undulator Options
SuperrConducting Undulator options Insert Presentation Title in Slide Master • An SCU has a number of benefits: • Would attain comparable performance as LCLS even while achieving 5 keV at 4 GeV at high rate by operating with high K • 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.
Potential Areas of Collaboration with Partner Labs LCLS-II Overview
Points of Contact Insert Presentation Title in Slide Master
CDR Writing Insert Presentation Title in Slide Master • Must keep the document concise – it is a conceptual design • Executive Summary (Galayda) • Scientific Objectives (TBD) • Machine Performance and Parameters (Raubenheimer) • Project Overview (Galayda) • Electron Injector (Schmerge) • Superconducting Linac Technologies (Ross,Corlett) • Electron Bunch Compression and Transport (Raubenheimer, Emma) • FEL Systems (Nuhn) • Electron Beam Diagnostics (Frisch, Smith) • Start-to-End Tracking Simulations (Emma) • Photon Transport and Diagnostics (Rowen) • Experimental End-Stations (Schlotter) • Timing and Synchronization (Frisch) • Controls and Machine Protection (Shoaee, Welch) • Conventional Facilities (Law) • Environment, Safety and Health (Healy) • Radiological Issues (Rokni) • Future Upgrade Options (Galayda)