Outlook for FLASH and FLASH II FLASH Upgrade

Outlook for FLASH and FLASH II FLASH Upgrade FLASH II Siegfried Schreiber Workshop on Linac Operations on Long Bunch Trains DESY 22 -February-2010 FLASH. Free-Electron Laser in Hamburg

FLASH. FLASH at DESY, Hamburg Free-Electron Laser in Hamburg FLASH Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH at DESY in Hamburg > Single-pass high-gain SASE FEL § SASE = self-amplified spontaneous emission > Photon wavelength range from vacuum ultraviolet to soft x-rays > Free-electron laser user facility since summer 2005 § 1 st period: Jun 2005 – Mar 2007 § 2 nd period: Nov 2007 – Aug 2009 § FLASH. Free-Electron Laser in Hamburg 3 rd period: starting summer 2010 > FLASH is also a test bench for the European XFEL and the International Linear Collider (ILC) Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. FLASH layout – after this upgrade Diagnostics Accelerating Structures Bunch Compressor 5 Me. V 160 Me. V Bunch Compressor 500 Me. V s. FLASH 1200 Me. V Free-Electron Laser in Hamburg Undulators Bypass FEL Experiments 315 m Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Electron Source: RF-Gun and Laser FLASH. Free-Electron Laser in Hamburg > New RF-Gun from PITZ with strongly reduced darkcurrent – by a factor of ~10 (at 3. 8 MW) > Prepared for higher RF power > 5 MW – once a 10 MW klystron is available > Two fully diode pumped laser systems – replacing the old flash lamp pumped heads > 10 Hz operation > Improved low level RF controls of RF Gun and 1 st accelerating module > New synchronization system based on fiber laser reference – phase control over bunch train Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Laser System: 1 MHz Flashlamp Pumped Diode-pumped Nd: YLF Oscillator Modulators (AOM EOM AOM) 108 MHz 1. 3 GHz 13. 5 MHz Piezo tuning of cavity length fround trip= 27 MHz Stabilized by quartz tubes Fiber-coupled pump diodes Epulse= 6 µJ Fast current Pulse control picker In cooperation DESY/Max-Born-Institute, Berlin Now being replaced by fully diode pumped system similar to 3 MHz laser Faraday Epulse= 0. 3 µJ isolator Pulse picker Pockels cell Remote controlled mirror box Diode pumped Nd: YLF amplifiers Imaging to the cathode Faraday isolator Flashlamp pumped Nd: YLF amplifiers Relay imaging telescopes FLASH. Free-Electron Laser in Hamburg Beam shutter Fast current Epulse< 0. 3 m. J control LBO BBO Remote Epulse< 50 µJ controlled attenuator IR→ UV 3 MHz Laser Photodiode Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

3. 9 GHz (3 rd harmonic) Module and Module 1 FLASH. Free-Electron Laser in Hamburg > New 1 st accelerating module with improved cavities and Piezo tuners > 3 rd harmonic module with four nine-cell superconducting cavities operated at 3. 9 GHz § includes RF system and LLRF regulation > Built at FNAL in a collaboration with DESY Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Accelerating Modules FLASH. Free-Electron Laser in Hamburg > 7 TESLA type accelerating modules § Superconducting 9 -cell cavities at 1. 3 GHz > Electron beam energy at least 1. 2 Ge. V > 7 RF stations § five 5 MW, one 10 MW klystron, one 3. 9 GHz > XFEL type waveguide system on modules 1, 6, and 7 § RF power to cavity pairs individually adjusted → optimization of performance > 10 Hz operation Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

7 th Accelerating Module FLASH. Free-Electron Laser in Hamburg > 7 th superconducting accelerating module (XFEL prototype PXFEL 1) > Reaches more than 200 Me. V – excellent state of the art cavities > Electron beam energy at least 1. 2 Ge. V ↔ < 5 nm photon wavelength Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Flying Modules in the Injector FLASH. Free-Electron Laser in Hamburg Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Transport of the 7 th Accelerator Module FLASH. Free-Electron Laser in Hamburg Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Upgrade of RF Stations and Waveguide System FLASH. Free-Electron Laser in Hamburg > 2 RF stations + 1 Modulator replaced – all stations of same type now § two of them have been operated more than 10 years > One additional RF station to optimize operation with seventh module > Optimized XFEL type waveguide distribution for the 1 st, 6 th, 7 th module ACC 39 § power for each cavity pair adjusted individually to optimize energy reach Kly 3. 9 GHz Kly: 5 MW Kly: 5 MW Kly: 10 MW Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

s. FLASH: Experiment for Seeded FEL Radiation FLASH. Free-Electron Laser in Hamburg > Generation of seeded FEL radiation for piloting experiments > Synchronisation goal for pump probe experiments: 10 fs > Installed between the collimator and SASE undulators → new electron beamline with a length of ~ 40 m > Collaboration of DESY and U Hamburg > HHG seeding at ~ 35 nm (13 nm as an option) Top-view s. FLASH Experimental hut In-coupling (seed) Out-coupling (photons) FLASH Exp. Hall Optical replica synthesizer (longitudinal beam diagnostics) 4 variable gap undulators SASE undulators Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

s. FLASH Section with new Undulators and Mirror Chambers FLASH. Free-Electron Laser in Hamburg Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. Undulators Free-Electron Laser in Hamburg > High-gain single-pass FEL requires a long undulator system § 6 modules with a total length 27 m § permanent Nd. Fe. B magnets § fixed gap of 12 mm > changing photon wavelength requires a change of the electron beam energy Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. Experimental Hall Free-Electron Laser in Hamburg PG 2 BL 3 unfocused (5 -10 mm), optional multilayer mirror in experiment for few to sub-μm focus BL 1 BL 2 100 μm focus 20 μm focus 50 μm focus, monochromatized PG 1 sub-10 μm focus, monochromatized 2 -stage Raman. Spectrometer (under commissioning) Visible Laser FIR -Beamline Plane Grating Monochromator > ~ 75 publications on photon science at FLASH in high impact journals § http: //hasylab. desy. de/facilities/flash/publications/selected_publications Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Organization of beam time FLASH. Free-Electron Laser in Hamburg > 2 nd user period: Nov-26, 2007 – Aug-16, 2009 § ~ 300 days has been scheduled for user operation § distributed in blocks of 4 weeks each > Between user blocks: study weeks and user run preparation § FEL physics studies § improvements of the FLASH facility § preparation of the next user block § general accelerator studies 2 -3 weeks three times per year related to e. g. XFEL and ILC > 3 rd user period to be started summer 2010 with > 350 shifts for user experiments > Accelerator study blocks to be negotiated Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Beam time distribution during 2 nd user period FLASH. Free-Electron Laser in Hamburg Nov-26, 2007 – Aug-16, 2009 Accelerator studies 10% Scheduled off 11 % FEL studies + user preparation 30% FEL user experiments 49% SASE FEL radiation delivery 78 % Tuning 14 % > up-time during user experiments: 93% Down 7 % Set-up 1 % Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. Summary Upgrade 2009 / 2010 Free-Electron Laser in Hamburg > Upgrade shutdown started September-21, 2009 > Commissioning started February-15, 2010 > First beam expected in April, user runs to be started in late summer 2010 exchanged RF stations 3 rd harmonic module + RF station additional RF station + exchanged RF station seeding experiment s. FLASH + redesigned electron beamline upgraded photon diagnostics and beamlines new RF gun exchanged 1 st accelerating module new diode pumped photocathode laser; upgraded old laser system new cabling/layout injector llrf electronics 7 th accelerating module transverse deflecting cavity + spectrometer arm / tuning dump exchanged injector steerers upgraded magnet controls maintenance of infrastructure: water supplies, cryogenics new synchronization and feedback systems optimized llrf controls improved survey and alignment of accelerator components (incl. SASE undulators) installation of a second master oscillator (as backup) upgraded and optimized waveguide distribution upgraded personnel interlock und radiation safety systems Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Operation with Long Electron Bunch Trains FLASH. Free-Electron Laser in Hamburg > Besides the increase in repetition rate from 5 to 10 Hz, FLASH will now operate on a regular bases with long bunch trains > Trains of a few hundred pulses § number of pulses / train depends on the pulse spacing within the train, and on the demands concerning the photon beam parameters > Lasing with 800 bunches / train (1 MHz bunch spacing, 5 Hz rep. rate) demonstrated in spring 2007 > Some user runs with long trains (~100 bunches/train) in spring 2008 > Long train operation has not been possible from Sep-2008 to Aug-2009 § Due leak in electron beam dump line → repaired successfully in August 2009 → upgraded dump line diagnostics successfully tested in Sept 2009 § Demonstration of long-pulse high beam-loading operation in Sep-2009 § ILC driven international collaboration; important experiment for FLASH and also XFEL § Electron beam through by-pass line, no lasing Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Lasing with long bunch trains in 2006 FLASH. Free-Electron Laser in Hamburg > up to 600 bunches to beam dump 1 MHz 599 bunches § 1 MHz, 500 k. Hz, 100 k. Hz, and 50 k. Hz > Lasing with at least 450 bunches (limited by photon diagnostics) 50 k. Hz 100 k. Hz 500 k. Hz Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. FLASH design goals reached in 2007 Free-Electron Laser in Hamburg Lasing with a complete bunch train of 800 bunches at 13. 4 nm charge (n. C) GMD - gas monitor detector - signal 800 µs @ 0. 6 n. C max. 1 MHz, 800 bunches Lasing at 6. 5 nm actual average Electron beam energy of 1 Ge. V and lasing at 6. 5 nm Averaged over 125 pulses Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Long Bunch Train Run at 7 nm in 2008 FLASH. Free-Electron Laser in Hamburg > 5 days continuous running with 100 bunches 500 k. Hz for two experiments in March 2008 > Wavelength: 7. 05 ± 0. 1 nm > Average SASE level ~30 μJ (14 m. W average power) Wavelength (nm) Bunch Number Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Exception Handling with Long Bunch Trains FLASH. Free-Electron Laser in Hamburg > How should the adaptive feed forwards and other beam based feedbacks react on an exception? > On what should it act, what should it limit or modify? > Examples of issues which came up: 1. loss in the middle of the train produces an exception which switches off ACC 1 § problem: darkcurrent now is transmitted in a way, that it produces a series of trips § solution: better not to switch ACC 1, but the gun (darkcurrent is from gun) § problem: recovery of the gun takes 10 to 20 min to settle temperature 2. loss triggers the 3 MHz laser to cut the train § problem: laser shows severe beam loading effects and produces new loss trips 3. feed forward overwrites some tables and produces large forward power in ACC 1 § no exception is triggered, the couplers run into severe trips 4. some cavities are starting to quench § problem: cryogenic system itself reacts too late and gets instable Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. The MPS acts on both Lasers Free-Electron Laser in Hamburg > On an MPS fast trip, the 2 nd pulse picker Pockels cell is switched off MPS trip within ~ 3 us, the slow system closes the beam shutter Diode pumped Nd: YLF pulsed oscillator Pulse picker Pockels cell 1 Diode pumped Nd: YLF amplifiers Pulse picker Pockels cell 2 Beam shutter Flashlamp pumped Nd: YLF amplifiers LBO BBO IR→ UV 3 MHz Laser Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

Effect of MPS trips on the 3 MHz laser 2 > Laser 2 runs with flat train, 3 MHz, 800 us length MPS trip > After MPS trip: UV out decreases by a factor of ~2 > Following an MPS trip signal to the pulse train > Due to phase mismatch in the BBO doubling crystal > Tuning the BBO would bring the energy back > If one now switches back to a long train, the energy would not recover immediately FLASH. Free-Electron Laser in Hamburg UV (262 nm) Green (532 nm) IR (1047 nm) before after trip > It requires a couple of minutes to stabilize before the initial energy is back Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH II – 2 nd Undulator Line and Experimental Hall FLASH. Free-Electron Laser in Hamburg > Common proposal by DESY and HZB with participation of PSI > In planning phase, kick-off meeting 28 -Jan-2010 FLASH II Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. FLASH II layout Free-Electron Laser in Hamburg > Main features: Seeding and polarized radiation > Extend user capacity with SASE and HHG/HGHG seeding > Tunability of FLASH II by undulator gap change > Use of existing infrastructure up to last accelerating module > Separation FLASH and FLASH II behind last accelerator module Diagnostics Accelerating Structures Bunch Compressor 5 Me. V 160 Me. V Bunch Compressor 500 Me. V s. FLASH Undulators Bypass 1200 Me. V FEL Experiments 315 m Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. Artist view of FLASH II Free-Electron Laser in Hamburg T PE FLASH II EXP HALL RA FLASH III FLASH II Extraction area Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. Beamline switching. Free-Electron Laser in Hamburg From pulse to FLASH or FLASH II FLASH, 1 MHz 800 ms FLASH II, 0. 1 MHz 99 ms 800 ms FLASH II 99 ms 800 ms t Within 1 RF pulse part to FLASH and part to FLASH II 800 ms 99 ms t 800 ms 99 ms Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010 800 ms

FLASH. Free-Electron Laser in Hamburg FLASH II FLASH Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010

FLASH. Summary Free-Electron Laser in Hamburg > FLASH finished in August 2009 a very successful 2 nd user period > ~ 75 publications on photon science at FLASH up to now > Upgrade shutdown started in autumn 2009, beam to be expected in April 2010 > Major modifications of FLASH § energy reach of 1. 2 Ge. V to approach wavelengths below 5 nm § shaping of longitudinal phase space with 3 rd harmonic module § synchronization to 10 fs level with new system based on fiber lasers § s. FLASH: test of seeding option > One aim is it to provide routinely long bunch trains to users > FLASH II in sight: seeding and polarization § Second undulator beamline + new experimental hall (FLASH II) in the planning phase Siegfried Schreiber | Workshop on Linac Operation an Long Bunch Trains | 22 Feb 2010