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Laser Beam Transport and Integration. AWAKE Collaboration meeting. Mikhail Martyanov Christoph Hessler CERN, EN-STI-LP Valentin Fedosseev CERN 09-11.04.2014. AWAKE Experiment. Control room 1km. AWAKE gallery. e-gun room. Laser room. SAS. CV. e - beam. p + / e -
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Laser Beam Transport and Integration.AWAKE Collaboration meeting.Mikhail Martyanov ChristophHessler CERN, EN-STI-LPValentin FedosseevCERN 09-11.04.2014
AWAKE Experiment Control room 1km AWAKE gallery e-gun room Laser room SAS CV e- beam p+ / e- diagnostics Laser safety shutters Fast valves Laser dump plasma laser beam p+ beam Laser / p+ merging point e- spectrometer Laser shutters M.Martyanov, CERN
Overview • Short intense laser pulse is needed for: • to create a 100% ionized plasma • moving ionization front is a source of perturbation for proton-laser instability (micro-bunching and wake-field with a stable phase) • Plan for the Laser system: • First it is delivered to MPP Munich for plasma experiments - mid 2014 • Then it goes to CERN - Autumn 2015 M.Martyanov, CERN
Overview • Laser system comprises: - laser with 2 beams (for plasma and for the e-gun) - delay line is possible in either one of these beams - focusing telescope (lenses, in air), long 40m focusing - optical compressor (in vacuum) - small optical in-air compressor and 3rd harmonics generator for e-gun • Laser parameters for plasma: - max energy 450 mJ - pulse duration 120 fs after compression - max beam diameter 40 mm Only reflective optics on the way Rule of thumb (B<1): I[GW/cm2]L[cm]<36 M.Martyanov, CERN
Laser System Base-line • Laser, Telescope and Compressor are in the laser room • Focusing down to 40 meters to the center of the plasma • Back solution: Compressor and Telescope are next tomerging point in the proton tunnel • Focusing down to 25 meters to the center of the plasma • Question is if this possible? Crucial points are: • Focusability of the laser beam down to 40 meters, ionization dynamics, diffraction? • No detailed information on the laser system yet (beam quality) • The placement of the optical compressor and the focusing telescope has an impact on the position of the anew drilled connection tunnel • Availability of vacuum components for the compressor and telescope is under study. • 10-6Torr “easily” achievable. Pellicle or differential pumping as an option to go better M.Martyanov, CERN
Scope of Laser Line WP • Laser room preparation • Clean room, cooling and ventilation, facilities • Access control • Laser transfer line to the plasma cell • HV vacuum line • Remote control of the mirrors • Laser beam position monitoring • Laser transfer line to the photo-gun • Fore-vacuum line • Remote control of the mirrors • Laser beam position monitoring • In-air compressor and 3rd harmonic generation <- Electron source WP • Laser installation • Laser arrangement on the tables • Integration to the AWAKE environment M.Martyanov, CERN
Arrangement in the Laser Room Fore-vacuum laser transfer line for e-gun (on the ceiling) 0.9m 2 x 1 m optical table 2.5 x 1 m optical table 2 x 1 m optical table 2.5 x 1 m optical table ~1m CV units 1m compressor SAS PP+ power supply 600x600x(H)850 CCM rack 700x800x(H)1400 3m 4m M.Martyanov, CERN
Laser Arrangement on the Tables Three optical tables: 2x1, 2.5x1, 2.5x1 m 1 – MENLO oscillator, 500x500 2 – Stretcher, 1000x500 3 – Regen / preamp, 1000x800 4 – Green pump for (3) 5 – 600mJ amplifier, 1500x800 6 – Green pump for (5), 500x200 7 – Focusing telescope, 1000x200 8 – Delay line for e-gun 8 4 6 5 3 1 2 7 M.Martyanov, CERN
Laser room air-conditioning principal (by Michele Battistin) Technical Room Laser Room SAS • CV technical room already quite small. Other solutions? • Access to CV technicians in the clean room for M&O. • Very dry air from surface -> comfort and electronics? 4.000 m3/h 30 Pa 15 Pa 0 Pa 4 m 14 m 2 m F M.Martyanov, CERN
CV first integration (by Michele Battistin) Air supply duct to the clean room Fresh air supply from surface Air extraction to TCV4 M.Martyanov, CERN
Laser Room – Integration 3D Model (by Frederic Galleazzi) M.Martyanov, CERN
Laser Room – Integration 3D Model (by Frederic Galleazzi) M.Martyanov, CERN
TT41 – Laser Beam – Civil Engineering (by Frederic Galleazzi) Vacuum shutter Vacuum pump Laser shutter Safety laser shutter M.Martyanov, CERN
Mirror Chambers Preliminary Design (by Nicolas Chritin) M.Martyanov, CERN
Laser and p+ merging Laser beam is not centered on the mirror in horizontal plane, but centered in vertical. The gap between beams is 21-6-13=2mm The gap between proton beam and a mirror is 1mm Footprint of the laser beam on the mirror 37=26sqrt(2) 50 26 37 Mirror 50, S=12 Fused silica Laser beam 26 Beams separation 21mm Towards the plasma Proton beam 12 p+ from SPS M.Martyanov, CERN
Laser Beam Size Downstream Merging (not to scale) Be-window for p+ Experimental area Additional laser shutters Mirror 50, S=12 Fused silica Plasma cell Beams separation 21mm 26 Fast valves Laser dump p+ from SPS Proton beam 12 20m 10m 20m Laser beam 26 @ merging Laser Safety Shutter M.Martyanov, CERN
Laser installation in laser room M.Martyanov, CERN
Laser installation in p-tunnel and in e-gun room M.Martyanov, CERN
Thank you! M.Martyanov, CERN
Laser room air-conditioning principal (our proposal) 4.000 m3/h Technical Room Laser Room SAS • CV technical room already quite small. Other solutions? • Makeitevensmaller ! • Access to CV technicians in the clean room for M&O • Assume itis a rare event ! • Very dry air from surface -> comfort and electronics? • Poor comfort (manageable), for electronics – to be considered 30 Pa 15 Pa 0 Pa 3 m 2 m ! 15 m F M.Martyanov, CERN
Focusing geometry, 40 meters Simple propagation of a super-Gaussian beam, no plasma Very smooth focusing Max 100 mJ Full energy focusing option Max 450 mJ Attenuated energy option Max 280 mJ Plasma here Last turning mirror
Focusing geometry, 40 meters Attenuated energy option, Super-Gaussian beam ionizing plasma, 100mJ pulse Ionization ratio in plasma dE = -30mJ