Photocathode transport system for VELACLARA photoinjector B L

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Photocathode transport system for VELA/CLARA photoinjector B. L. Militsyn on behalf of the photoinjector

Photocathode transport system for VELA/CLARA photoinjector B. L. Militsyn on behalf of the photoinjector development team Accelerator Science and Technology Centre, Science & Technology Facility Council, Daresbury, UK Eu. CARD-2 is co-funded by the partners and the European Commission under Capacities 7 th Framework Programme, Grant Agreement 312453

Outline • CLARA/VELA FEL test facility • Photoinjector for CLARA/VELA - 400 Hz electron

Outline • CLARA/VELA FEL test facility • Photoinjector for CLARA/VELA - 400 Hz electron source • Metal photocathodes research • Photocathode preparation and transportation • Photocathode transport vessel • Gun load-lock system • Conclusion B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

CLARA/VELA FEL test facility (2016) Phase 1 parameters: Max Energy Max Charge Norm. Emitt.

CLARA/VELA FEL test facility (2016) Phase 1 parameters: Max Energy Max Charge Norm. Emitt. Min Bunch Length Max Peak Current Bunches/RF pulse Pulse Rep Rate ~50 Me. V 250 p. C <1 mm mrad 50 fs (rms), (10 Me. V) 2 k. A 1 10 Hz (400 Hz later) B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

CLARA beamline B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April

CLARA beamline B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

CLARA injector area B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5

CLARA injector area B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

400 Hz electron source concept H shape coupler RF probe* Cathode plug and spring

400 Hz electron source concept H shape coupler RF probe* Cathode plug and spring retaining plate • 1. 5 cell S-band gun with RF probe designed and fabricated • Maximum gradient of 120 MV/m @100 Hz, or 100 MV/m @400 Hz (10 k. W cooling capacity) • Vacuum load lock system for easy replacement of cathode • Will be installed 2016 Cooling channels RF Cavity B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016 Cathode plug

400 Hz photoinjector RF cavity B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury,

400 Hz photoinjector RF cavity B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

400 Hz electron source. Low Power RF test Pre limi nar Resonance frequency scaled

400 Hz electron source. Low Power RF test Pre limi nar Resonance frequency scaled to the operational temperature of 50 2998. 49 y Field flatness 98 1% B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

Photocathodes for VELA/CLARA photoinjector • • • Baseline – metal photocathodes Photocathode plug is

Photocathodes for VELA/CLARA photoinjector • • • Baseline – metal photocathodes Photocathode plug is based on FNAL/INFN/DESY design with reduced 10 mm emission tip Emission materials § § • Extensive R&D program started on metal photocathodes with the goals § § § • Bulk metal Metal coating Develop preparation procedure of bulk metal photocathodes delivered high quantum efficiency Select metal photocathodes with higher possible quantum efficiency Investigate possibility of using metal deposited thin films as photocathode Research facility with extensive analytical instrumentation has been set up § § Numerous instrumentation for investigation of the photocathode samples Photocathode transport systems compatible with other laboratories Photocathode Preparation and Characterisation Facility dedicated for VELA/CLARA operational photocathodes VELA beamline is equipped with diagnostic suite allowing for comprehensive characterisation of the operational photocathodes B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

Photocathode circulation Preliminary cleaning Preparation and characterisation facility Transport vessel New and rejuvenated photocathodes

Photocathode circulation Preliminary cleaning Preparation and characterisation facility Transport vessel New and rejuvenated photocathodes in vacuum transport Used photocathodes in vacuum transport Non clean new and used photocathodes on air transport Transport vessel Load-Lock System Photocathode gun B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

Photocathode cleaning oxygen plasma processing • Oxygen plasma processing to remove carbon contamination •

Photocathode cleaning oxygen plasma processing • Oxygen plasma processing to remove carbon contamination • Annealing to remove oxygen • Reached QE at a level of 2· 10 -5 for Cu • Photocathode operated at VELA 10 Hz photoinjector B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

Photocathode preparation and characterisation facility Cleaning/Deposition Chamber: • Radiative heating source (600 ) •

Photocathode preparation and characterisation facility Cleaning/Deposition Chamber: • Radiative heating source (600 ) • Argon ion sputter gun (0. 1 -3 ke. V, 15 µA) • Atomic hydrogen source • Two magnetron sputtering • sources UV laser Cleaning/Deposition Chamber Transport vessel Transfer arm Analysis Chamber: • UV 266 nm CW laser • Pico-ammeter for photocurrent measurement • Electron spectrometer used with § X-ray source (XPS) § Ultra-violet lamp (UPS) Analysis Chamber B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

ESCALAB-II based PPCF Upgrade of the VG ESCALAB-II instrument: • • Replaced vacuum seals

ESCALAB-II based PPCF Upgrade of the VG ESCALAB-II instrument: • • Replaced vacuum seals to all metal to accommodate UHV requirements Replaced pumping system with high performance turbomolecular pumps to reach vacuum of 10 -10 mbar Original loading chamber replaced with a new cleaning/deposition chamber Numerous new instruments are installed B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

Photocathode transport to the electron source In air Load-Lock system commissioning. Transport of the

Photocathode transport to the electron source In air Load-Lock system commissioning. Transport of the photocathode into the “mock” gun socket First assembly of the Load-Lock system and the transport vessel B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

Conclusion • Developed, manufactured and Low Power RF commissioned RF cavity for the VELA/CLARA

Conclusion • Developed, manufactured and Low Power RF commissioned RF cavity for the VELA/CLARA High Repetition Rate Photocathode Injector • Selected design of the photocathode. First Mo photocathode plugs manufactured and delivered • Designed manufactured and commissioned photoinjector Load. Lock system and photocathode transport vessel • Designed manufactured and assembled ESCALAB-II based Photocathode Preparation and Characterisation Facility. Commissioning will begin soon • Developed technology for bulk metal photocathode preparation • First experiments with bulk metal photocathodes will begin in 2016 B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016

Acknowledgements Eu. CARD-2 participants T. C. Q. Noakes R. Valizadeh S. Mistry K. J.

Acknowledgements Eu. CARD-2 participants T. C. Q. Noakes R. Valizadeh S. Mistry K. J. Middleman R. J. Cash B. D. Fell Photoinjector development team G. C. Burt L. S. Cowie P. A. Goudket T. J. Jones J. W. Mc. Kenzie V. V. Paramonov B. L. Militsyn, Eu. CARD-2 WP 12 meeting, Daresbury, 4 -5 April 2016