New Electron Beam Test Facility EBTF at Daresbury Laboratory B.L. Militsyn on behalf of the ASTeC team Accelerator Science and Technology Centre Science & Technology Facility Council, Daresbury, UK

Outline High brightness Electron Beam Test Facility EBTF –General considerations –Diagnostic beam line –Photoinjector –Transverse deflecting cavity –High power RF system –Current status and research program CLARA – ultra short pulse high brightness research accelerator Conclusion B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 2/25

Electron Beam Test Facility EBTF Objective: To provide a suite of accelerator testing facilities which can be utilised in partnership with industry, academic and scientific collaborators Scope: The provision of a common high performance and flexible injector facility comprising an RF gun, associated RF power systems, beam diagnostics and manipulators, a high power photo-injector driver laser and associated enclosures Costs: £2.5M capital from DBIS has been assigned for this facility. This investment will be supplemented by £447k capital allocation from STFC’s baseline capital allocation for the accelerator test facilities Timescales: Purchase the majority of the equipment in financial year 2011/12, with build in It is planned that first electrons from the facility are delivered in September 2012 B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 3/25

EBTF. General layout B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 4/25

EBTF. Injector and dignostic beam line B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 5/25

EBTF. Beam transport line B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 6/25

EBTF. Beam parameters Beam Energy 4 ‐ 6.5 MeV Bunch Charge (minimum)~1 pC - 20 pCElectron diffraction CLARA Bunch Charge (max)250 pC RMS bunch length40 fsecWith 100 fsec FWHM laser pulse (low charge mode) Normalised beam emittance (min – max) 0.1 ‐ 2 mm  mrad changing due to space charge. Minimum at low charge RMS beam size (min ‐ max)0.1 ‐ 3.5 mmLow ‐ high charge Energy spread (maximum)3.3 %changing due to space charge RF repetition rate 1 ‐ 400 Hz Modulator 400 Hz Maximum laser repetition rate 1 kHz B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 7/52

EBTF. Construction Modules Module 1 Module 2 Module 3 Module 4 Module 5 Module 6 B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 8/25

Photocathode Gun Lightbox Beam diagnostic station Stripline BPM WCM Laser In EBTF. Photoinjector section RF coupler B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/2011 9/25

EBTF photoinjector based on the ALPHA-X 2.5-cell S-band gun B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Photocathode gun cavity ParameterValueUnits Frequency2998.5MHz Bandwidth< 5MHz Maximum beam energy6MeV Maximum accelerating field100MV/m Peak RF Input Power10MW Maximum repetition rate10Hz Maximum bunch charge250pC Operational Temperature °C Input couplingWR284 B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /52

Tuning studs Input coupler Dummy Load/Vacuum port CF70 entrance flange CF70 exit flange 9 cell Transverse Deflecting Cavity B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

H-field E-field On-axis fields of the transverse deflecting cavity Estimated peak transverse voltage 5 MV (limited by available RF power) Estimated resolution at 25 MeV beam energy ~30fs B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

EBTF beam dynamics simulation. Bunch charge1pC, RMS laser pulse length 40fs B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

EBTF beam dynamics simulation. Bunch charge250 pC, RMS laser pulse length 40fs B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Beam transport through transverse deflecting cavity. Transverse kick amplitude 3.5 MV B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Simulation of the transport of 250 pC bunch to the user area B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

RF Requirements ParameterValueUnits Frequency MHz Bandwidth (1 dB points)<10 MHz Total peak output power> 8 MW MW Power gain> 45 dB Nominal efficiency> 45 % Pulse Repetition Rate Range1 – 400 Hz RF Pulse Duration<3.5 µs RF Flat Top Pulse Width>2.5 µs Amplitude stability Phase Stability0.1 ° Noise Power Within the Bandwidth< -60 dB Spurious Noise Power Outside the Bandwidth< -35 dB dB B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

TH 2157A Data Sheet RF PerformanceTH 2157 TH 2157A Units Frequency MHz Output power: Peak MW Average108 kW RF Pulse Width863.5 μsμsMax Saturated Gain454850dBMin Efficiency48 %Typ Electrical characteristics Cathode Voltage kVTyp Beam Current ATyp Heater Voltage15 VMax Heater Current15 AMax B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /52

3D CAD model of the EBTF layout B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Positioning of the first block B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

CLARA Compact Linear Advanced Research Accelerator Ultimate Aim To develop a normal conducting test accelerator able to generate longitudinally and transversely bright electron bunches To use these bunches in the experimental production of stable, synchronised, ultra short photon pulses of coherent light from a single pass FEL with techniques directly applicable to the future generation of light source facilities. –Stable in terms of transverse position, angle, and intensity from shot to shot. –A target synchronisation level for the photon pulse ‘arrival time’ of better than 10 fs rms is proposed. –In this context “ultra short” means less than the FEL cooperation length, which is typically ~100 wavelengths long (i.e. this equates to a pulse length of 400 as at 1keV, or 40 as at 10 keV). A SASE FEL normally generates pulses that are dictated by the electron bunch length, which can be orders of magnitude larger than the cooperation length. B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Preliminary Parameters of the CLARA FEL Beam Energy ~250MeV SASE Saturation length <15m Seed with Ti:Sa 800nm, lase up to 8 th harmonic Seeding with HHG at 100nm also possible Single spike SASE driven by electron bunches length ~50fs FWHM and charge <20pC Seeding driven by electron bunches with a peak current ~400A, flat top ~300fs and charge <200pC B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Conceptual Layout B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Conclusion ASTeC is successfully leading experimental work on the development of high current, high brightness electron accelerators, with the following particular goals: EBTF high brightness electron photoinjector electron is funded and under construction –Operation with ultra short bunches –Front end for ongoing project CLARA –Experiments with electron diffraction B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25

Thank you for your attention! B.L. Militsyn, STFC ASTeC, Daresbury, UK DESY-Zeuthen 28/10/ /25