Development and Commissioning of the Orion Laser Facility

Transcription

1 Development and Commissioning of the Orion Laser Facility Colin Danson, Senior Project Manager, Orion Tom Bett, Colin Brown, Stuart Duffield, Ray Edwards, David Egan, Stephen Elsmere, Jim Firth, Mark Girling, Tim Goldsack, Ed Gumbrell, Ewan Harvey, Matt Hill, David Hillier, David Hoarty, Nick Hopps, Steve James, Mike Norman, Kevin Oades, James Palmer, Stefan Parker, Peter Roberts, Paul Treadwell, David Winter.

2 Introduction to Orion Orion is designed as an entirely new laser facility for AWE for studying high energy density physics. Orion combines ten laser beams operating in the nanosecond regime with two operating below a picosecond. LP performance: 500J per 351nm in 1ns pulse 90% of energy in 100um spot SP performance: 500J per 1054nm in 0.5ps pulse Near-diffraction limited f/3 focussing >10 21 Wcm -2 per beam 2

3 Orion Layout 10 Long Pulse Beams Long Pulse Preamplifiers Target Hall Laser Hall 1.5m thick concrete shield wall 2 Short Pulse Beams Compressors (13m grating separation) Long & Short Pulse Generation & Pulsed Power System (10MJ) on ground floor 3

4 Orion Long Pulse Beamlines 15 mj, 50mm G=2 G=2 170mm G=2 G=2 4 J, 40mm 700 J, 300mm 4

5 Laser Hall Orion Long Pulse Beamlines 5

6 LP beamline performance 1w 3w Near-fields measured at output diagnostics LP05 1 omega Frequency tripling Beamline LP LP05 1 omega Doubling angle Mixing angle 6

7 3w energy balance e.g Shot 1556 (shot 1579 for LP08 only same set points) w Energy Beam Line LP01-LP10 7

8 Orion Short Pulse Beamlines Rod amplifier stage (dual glass) 50mm rod amplifiers Disk amplifier stage 2nd beamline Broadband Preamplifier (OPA) Pulse stretcher OPG2 (Ground Floor) Pulse generation disk amplifiers Faraday Isolator Spatial filter disk amplifiers Spatial filter Spatial filter Spatial filter Compressed pulse beam transport (in vacuum) Diffraction grating Target chamber Off-axis parabola Compressor (vacuum) Final Optics Assembly Harmonic conversion Conventional Backlighter 8

9 OPCPA Stability Results OPA Energy Stability 300 Number of Shots (100 total) OPA Pump Normalised Energy Nominal output energy ~150mJ Energy Stability <1.5% RMS 9

10 OPCPA Contrast Results To date, ns contrast only has been measured using a pair of photodiodes OPA2 compressed contrast Non saturated Saturated Pulse sits on flat, broadband pedestal of parametric fluorescence Signal (V) Results in triangular pedestal through diagnostic compressor (dispersion across compressor grating) Time (ns) OPCPA design ensures good temporal and spatial fill Contrast estimated as 3 x

11 Short Pulse Beamline 11

12 Short Pulse Compressor 12

13 SP Compression Autocorrelation FWHM grenouille AC FWHM Autocorrelation width (fs) Stretcher grating position (mm) 13

14 SP Beamline Characterisation Have demonstrated 4nm of bandwidth through compressor 4nm Further work to optimise spectrum (more silicate gain available) 1.2 Autocorrelation intensity Autocorrelation width of ~1ps Pulse duration around 0.6ps Further work to optimise compression Autocorrelation delay 14

15 SP Beamline Characterisation SP output vs input Output energy (J) Input energy (J) 500TW delivered on SP Beamline 1 100TW delivered on SP Beamline 2 15

16 TARGET INSERTER LPFOA SPFOA TIMs 16

17 X-ray pinhole (10 µm) camera images Long-pulse Short-pulse (aimed at edge of 100µm pinhole target) X-ray spot measured at ~40 µm. For this 100 TW shot, average intensity is about 2 x Wcm -2 17

18 LP Beam Synchronisation 18

19 Orion Objectives Installation complete and all subsystems commissioned at subsystem level 23/12/2010 Long pulse infra-red energy demonstrated (500J) 15/10/2010 Short pulse infra-red demonstrated (300J uncompressed) Single short pulse and long pulse synchronization (+/- 50ps) (Orion Project Completion) 10 LP at 80% max energy (400J 3w each), 2 SP at 0.5PW each, synchronous, ready to start experiments 30/09/ /12/ /03/2012 Opacity experiments at high density, temperature 31/03/2013 Complete Complete Complete Complete Complete (?) 19

20 Orion Timeline 15 months 12 months Orion Project complete 1+1 Full laser performance Opacity data HELEN closed Short & long pulse synch demonstration All Forward Action Plans closed Routine operations Target Chamber Vacuum Demonstration Demonstration of 10+2 synchronisation to target 20

21 Academic access Process has been tested on HELEN No facility charges for collaborative experiments* Limited diagnostic and target fabrication support will be available, but subject to prior negotiation RAL to act as portal Apply through RAL AWE presence on selection board to ensure: Relevance to AWE Consistent with laser and diagnostic capabilities including any proposed upgrades / modifications T&S NOT funded by AWE. Applicants are expected to be self-funding in this regard through Research Councils travel grants etc. * Non-collaborative experiments may be possible, but UK Treasury rules mean that facility time will be chargeable to the user. 21

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23 Petawatt Issues Pulse Contrast Some experiments will require the best possible contrast for the PW beams rather than maximum intensity. Non-linear nature of conversion to 2nd harmonic provides enhancement in contrast of several orders of magnitude. The option for one SP conversion to the second harmonic at reduced aperture (300mm) will be provided in a vessel immediately following the compressor. Dichroic mirrors leak away residual 1w energy. 2w campaigns with HELEN 100TW CPA beam informed Orion design Type I KDP crystal 3mm thick 2ω Diagnostics Compressor Apodiser To Target Chamber Dichroic Mirrors 1ω Diagnostics Gate Valve Vacuum vessel 23

24 Long Pulse performance Output beam size: 300 mm diameter Configuration: 2 cones of 5, 50 half-angle, nonopposed ports Output Energy: 500 J per beam at 351 nm in 1 ns square pulse. Pulse duration: ns arbitrary shaping capability to be provided Power balance: +/-10% in any 100 ps interval Spot size: 90% of energy in 100 μm spot Focus optics: f/4, 1200 mm focal length Jitter: <+/- 50ps over all 10 beams Pre/post pulses: <10-6 within +/-25 ns Focal smoothing: 2D-SSD plus phase plates 24

25 Short Pulse performance Output beam size: 600 mm diameter Configuration: one beam along the axis of one long pulse cone one beam orthogonal to the first, in the horizontal plane. Output Energy: 500 J at 1053 nm in 0.5 ps pulse. Pulse duration: ps Jitter: <5 ps between short-pulse beams <50 ps vs long-pulse beams Contrast ratio: 10 6 :1 at +/-1ns, 10 3 :1 at +/-2ps Focus optics: f/3, 1800 mm focal-length, 13 offaxis parabola Intensity on target: Wcm -2 using f/3 focus parabola Frequency conversion: Optional 2ω operation at subaperture (200 mm) 25

26 CIFS Centre for Inertial Fusion Science at Imperial College Provide a means for AWE to interact with and contribute to, ICF and HEDP work in the international academic community (e.g. HiPER) Through engagement with this community, identify areas of classified work that need to be avoided, to meet our non-proliferation commitments Facilitate academic access to Orion 26