Accelerators in Society

Transcription

1 Accelerators in Society? Wim Leemans Lawrence Berkeley National Laboratory Office of Office of Science Science 1 Flanders, Belgium and CERN Brussel, Belgium, November 30 th

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3 A Series of US Workshops Looked at Accelerators and their Impact on Society Accelerators are Modern ships of Discovery* *: Maury Tigner, Accelerators for America s Future,

4 Accelerators Touch Our Lives in Many Ways 4

5 Many applications require very high average power (>500 kw) beams Courtesy: Y. Jongen, IBA Other applications E-beams Flu gas treatment Water treatment Ion beams Cleaving Si wafers Medical Microfiltration systems 5

6 More than 40,000 accelerators are used for research, medical treatment and to create more than $500B/yr end products 6

7 Computers shrunk and became super powerful in the past 60 years NORC Supercomputer, 1954 Can the same be done with particle accelerators? What new applications will this enable? 7

8 Science with accelerators has always pushed the performance to new heights 1929 LHC, MJ stored energy Size x 10 5 Energy x

9 Some people think that future governments will be unwilling to fund larger and more expensive facilities. Do you think a collider bigger than the LHC will ever be built? And will it depend on the LHC finding something new? The outstanding questions in physics are important and complex and difficult, and they require the deployment of all the approaches the discipline has developed, from highenergy colliders to precision experiments and cosmic surveys. High-energy accelerators have been our most powerful tools of exploration in particle physics, so we cannot abandon them. What we have to do is push the research and development in accelerator technology, so that we will be able to reach higher energy with compact accelerators. 9

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11 1979: Seminal paper by Tajima and Dawson launches the pursuit of laser plasma accelerators Large longitudinal electric fields propagating near speed of light surfer boat water electrons laser plasma 11

12 1993: Acceleration of externally injected electrons in beatwave CO 2 laser 5.2 MeV tracks 10 s of electrons 12

13 The technology that is used in today s lasers was first proposed 33 yrs ago by Strickland and Mourou 2018 Nobel Prize in Physics 13

14 Laser performance has increased rapidly since CPA (albeit not as rapid as predicted) (after T. Tajima and G. Mourou, PRSTAB2002) Focused Intensity vs. Year Non-linear QED Compact accelerators Ultra-high harmonics FEL s Ultra-source 14

15 Mid 90 s -2003: lasers generate 100 MeV level electron beams with 100 % energy spread, confirming large accelerating gradients dn/de [a. u.] 10 4 Energy spectrum obtained with a magnetic spectrometer 10 3 Ebeams: MeV, nc 10 2 <100 fs, ~ mrad divergence 10 1 Gas jet typically few mm long 10 0 Detection Threshold E[MeV] Modena et al. (95); Nakajima et al. (95); Umstadter et al. (96); Ting et al. (97); Gahn et al. (99); Leemans et al. (01); Malka et al. (02) 15

16 We follow the paradigm of conventional accelerator designs to think about laser plasma accelerators Leemans et al., Phys. Plasmas 1998 Esarey, Schroeder, Leemans RMP

17 Electrons accelerating on a wave: controlled injection Self Injection Injected Electrons Injected Out of Phase 17

18 Intense Laser Pulse Creates a Plasma Structure Capable of Creating Strong Accelerating and Focusing Fields Trapped particle orbit T. Tajima and J.Dawson, PRL, 43, (1979) 267 Esarey, Schroeder, WL, RMP, 81, (2009), 1229 laser High energy particles Hard x-ray generation Accelerating + focusing fields 18

19 Limits to energy gain in laser-plasma accelerator (LPA): the 3-D s of LPAs Diffraction: Dephasing: Depletion: Staging 19

20 Channel guided laser plasma accelerators produced up to GeV beams from cm-scale structures powered using 40 TW 2004 result: 10 TW laser, mm-scale plasma ~100 MeV 2006 result: 40 TW laser, cm-scale plasma C. G. R. Geddes,et al, Nature,431, p538 (2004) *S. Mangles et al., Nature 431, p535 (2004) *J. Faure et al., Nature 431, p541 (2004) *: did not use channel guiding 1.1 GeV <2.9% <1 mrad pc W.P. Leemans et. al, Nature Physics 2, p696 (2006) K. Nakamura et al., Phys. Plasmas 14, (2007) 20

21 Beam energy (MeV) Experiments indicated that reaching higher energy gain requires operation at lower density, consistent with theory LLNL 2010 LBNL 2006 RAL n MPQ 2007 LOA 2006 APRI 2008 LOA 2004 U.Mich 2008 RAL 2004 LBNL 2004 Plasma density, n p (cm -3 ) Shadwick et al., Phys. Plasmas (2009) Lowering density operation requires higher peak power lasers 21

22 BELLA laser was built to explore collider relevant concepts BELLA 10 GeV 22

23 23 42 J in 35 fs 53 micron spot 23

24 Up to 27 cm capillary discharges are used to guide high power laser pulses over many Rayleigh ranges High n e Low n e Capillary out Capillary in High n e D. J. Spence & S. M. Hooker Phys. Rev. E 63 (2001); A. J. Gonsalves Phys. Rev. Lett. 98 (2007) Laser mode Laser mode W.P. Leemans et al., PRL

25 Angle (mrad) 4.25 GeV beams were obtained from 9 cm plasma channel powered by 310 TW laser pulses (16 J) 1/3 of BELLA peak power Electron beam spectrum Beam energy [GeV] 5 Leemans et al., PRL

26 : Laser Heater Pre-pulse Dynamically Controls Plasma Channel Shape Guided full Petawatt Peak Power over 20 cm and Generated Electron Beams with Tails Exceeding 8 GeV High energy laser guiding 20 cm High energy electron beams: up to 8 GeV ~10pC of >300pC Embargoed till publication release A.J. Gonsalves et al., submitted 26

27 We Are Approaching 10 GeV by Lowering the Density and Engineering the Plasma Guiding Structures BELLA PW BELLA PW BELLA PW CORELS PW CORELS PW TPW PW 27

28 Just Like in Lawrence s Days Our Accelerators Are Getting a Little Bit Bigger 11 inch 60 inch 184 inch 3cm 40TW ~ cm GeV 9cm 300TW ~ cm GeV 20cm; 950TW; ~ cm GeV 28

29 Although the laser built with today s technology is rather large, the overall facility footprint to reach multi-gev electron beams is small Laser plasma technology Conventional accelerator reaching 10 billion volt (10 GeV) 29

30 BUILDING COMPACT ACCELERATORS CAN TRANSFORM THE RANGE OF APPLICATIONS OF ACCELERATOR TECHNOLOGY Beam Energy Light Sources Low High Colliders Medicine Security Industry Parameter space where first applications of new technology can be demonstrated. Environment Low Beam Power High Bring the machine to the problem 30

31 Compact accelerators will have broad impact and enable bringing the accelerator to the problem Colliders Leemans&Esarey, Physics Today 2009 FELs of the future Compact MeV Thomson gamma ray source Arthroscopic accelerator for biomedical applications Betatron based x-ray source phase contrast imaging Laser based, narrowbandwidth, tunable S. G. Rykovanov, C.G.R. Geddes et al., J. Phys. B, (2014) US Patent LBNL/VARIAN MPQ: J. Wenz et al., Nature Comm. (2014) 31

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33 We Are Developing a Concept Where the Accelerator Can Be Inserted Near the Tumor as a Replacement for Radio-Isotope Brachytherapy Sources Depth Dose Curve 2 MeV electron Dose Profile HDR Brachytherapy 192IR Decay 97% reduction in radiation dose to healthy tissue 33

34 Laser technology has broadly been recognized as a key element underpinning accelerator development and must be able to produce much higher average power Multi-kW average power lasers with peak power >100 TW are now doable 34

35 Revolutionary accelerators will require revolutionary lasers: Laser Technologies for k-bella and Beyond: 3kW to 300 kw Ti:sapphire based - fiber laser pumped (MIT-LL, URochester) - thin disk (ELI-ALPS) - diode laser pumped (CSU) Injector Stage 1 Laser Technology for k-bella and Beyond, May 9-11, 2017 Tm:YLF (LLNL) Coherent combining - Novel material - LBNL/UMich/LLNL - Great potential Multi-core fibers (Fraunhofer Jena) - Potential to go to 300 kw Modules Stage 2-N 35

36 People who say it cannot be done should not interrupt those who are doing it. George Bernard Shaw 1929 LHC, now 300 MJ stored energy Size x 10 5 Energy x