Synchronisation Activities for 4GLS Supported by EUROFEL DS3 G J Hirst CCLRC Central Laser Facility

G J Hirst CLF 4GLS Schematic CW gun (4 MeV) 600 MeV 750 MeV 4 MeV dump (~400kW) 1 GeV dump (~1 kW) BC 2 XUV-FEL Spontaneous source XUV experiments Seed laser Visible XUV-FEL gun BC 1 3 rd harm. THz source Photon diagnostics & filtering High average current VUV-FEL Spontaneous sources and beam optics/compression High bunch charge 200 MeV Beam transport & compression Bending magnet source 550 MeV - Linac 1 Matching & diagnostics 200 MeV IR-FEL 50 MeV

G J Hirst CLF 4GLS Time Structures XUV FEL: ~1 kHz, using high-charge bunches substituted into the low-charge train “XUV” spontaneous:From same bunches as XUV FEL VUV FEL:~5 MHz cavity round-trip rate Undulators & BMs:Up to the accelerator RF rate ( GHz - TBD) IR FEL:~5 MHz cavity round-trip rate Conventional lasers:Arbitrary

G J Hirst CLF 4GLS Synchronisation User synchronisation requests (from 53 experiments*): ConventionalVUV FELUndulators lasers IR FEL1104 VUV FEL47 XUV FEL221 Undulators/BMs2 (It is suspected that conventional laser requirements have been underestimated) *See the 4GLS Science Case at

G J Hirst CLF 4GLS Synchronisation User synchronisation requests (from 53 experiments*): ConventionalVUV FELUndulators lasers IR FEL1104 VUV FEL47 XUV FEL2 + seeding21 Undulators/BMs2 (It is suspected that conventional laser requirements have been underestimated) *See the 4GLS Science Case at

G J Hirst CLF 4GLS/DS3 Programme Machine stability: Can a machine like 4GLS be designed and built with enough stability for a distributed RF system to be a good timing reference everywhere ? Local sensors: If the machine is not stable enough then local sensors will be needed. Can these be sufficiently accurate and cheap to be fielded in many locations ? Complex time structures: Can signal processing systems be developed to allow feedback jitter correction when the pulse time structure is irregular ?

G J Hirst CLF ERLP Tests ERLP is a 35 MeV ERL with 1.3 GHz SCRF and an MHz, 6mA photoinjector Bunch compression to 600 fs is planned Photoinjector laser locked to RF to <400 fs Complex time structures will be trialled Separate kHz/mJ TiS laser for EO measurements Local pickup sensors will be tested

G J Hirst CLF 4GLS Project Plan ERLP Electron gun complete Accelerator assembled Commissioning & testing 4GLS Conceptual Design Report Technical Design Report Bid submitted Bid decision EUROFEL DS3 Local timing sensor report Machine stability report Complex time structure report Q1 Q2 Q3 Q4