1 激光和对撞机 激光和对撞机 高能物理所 张 闯 强激光驱动的伽玛光源及关键技术与 伽玛核物理应用研讨会 2016 年 6 月 24 日

2 激光和对撞机 超强激光和激光加速 伽马 - 伽马对撞机 激光等离子体对撞机

3 1. 超强激光和激光加速 粒子加速器的高能量前沿 超强激光的发展 激光加速器

4 1.1 粒子加速器的高能量前沿

5 5 1 PeV=10 15 eV 1 TeV=10 12 eV “Standard model”HiggsQuarksLeptons 1000 times higher energy 1000 times higher energy “ New paradigm” Leptogenesis SUSY breaking Extra dimension Dark matter Dark matterSupersymmetry Acceleration Technology ILC Two-beam LC Laser-plasma LC Ultra-High Voltage STEM with Superconducting RF cavity Earth Space debris mm waves Earth-based space debris radar T.

6 1.5 PW[6 ] 1.26 PW[5] 0.5PW × 2[3] 1.16 PW[4] 0.56 PW[7] 0.89PW[2] 0.85 PW[1] 1. 2 超强激光的发展 1PW= W First PW laser (glass laser) 1.5PW, OL 24, 160(1999) 1PW[8] 1.1PW[9] 1PW[10] 1PW[12] 0.2 PW[11] [1] Opt. Lett. 28, 1594 (2003) [2] Opt. Express 15, (2007) [3] Opt. Express 16, 8039 (2008) [4] Opt. Lett. 36, 3194 (2011) [5] APLS2012, I2.9 (2012), Laser Phy. Lett.10 (2013) [6] Opt. Express 20, (2012) [7] Opt. Lett. 37, 1913 (2012) [8] IOP,112, (2008) [9] Appl. Opt. 49, 1676 (2010) [10] OPN 16(7) 30 (2005) [11] IOP,112,032021(2008) [12] SPIE 8780, (2013) [13] Opt. Express 21, 29231(2013) ■ SIOM(China) [2, 5,13] ■ APRI(Korea) [6] ● IOP(China) [4] ▼ JAERI(Japan) [1] ▲ THALE (France) [7] ▼ FLEX(Japan) [8] ★ RAL (UK) [3] Texas (US) [9] ◆ Omega EP (US) [10] LULI2000(France) [11] Vulcan(UK) [12] [1-7] and [13]: fs, PW laser at 800 nm [8-12]: ps, PW laser at 1053nm 2.0 PW[13 ]

7 SIOM SJTU IOP PKU LFRC 3 、我国超强激光装置长足发展 3 、我国超强激光装置长足发展，在包括激光加速在内 的诸多前沿领域开展研究，达到国际先进水平。

8 SIOM: 2 PW CPA- Ti:Sapphire Laser system

9 科研院所 中科院上海高等研究院 中科院上海应用物理所 中科院上海光机所 国家蛋白质科学中心 中科院上海药物所 等等 研究型大学 上海科技大学（新） 复旦大学张江校区 上海交通大学张江校区 上海中医药大学 北京大学微电子所 中国科技大学上海研究院 等 SIOM/SARI STU, Zhangjiang 10 Peta Watts Laser project: SSILS SINAP Zhangjiang campus SR light source: SSRF X-ray FEL: SXFEL 上海大科学中心 ：浦东张江

10 Beam Energy MeV 1 GeV 1 TeV ILE UCLA LULI KEK/ILE JAERI/KEK/UT RAL Michigan LLNL PeV ANL KEK SLAC BNL NRL MPI LOA PBWA LWFA SM-LWFA PWFA Mechanism Year RF electron accelerator Advanced Accelerator experiments RAL SLAC ILC Cornell KEK CEBAF Superconducting RF accelerator SLC LBNL SLAC 1.3 激光加速器 Advanced Accelerators gear up to TeV Ch. LWFA KEK/CAEP K. Nakajima, 11-th ACFA-PM

11 Laser plasma accelerators produced “Dream beam” followed up by worldwide experiments Thomas Katsouleas, NATURE, 431, 515, 2004 “Monoenergetic beams of relativistic electrons from intense laser-plasma interactions” S. P. D. Mangles et al., NATURE, 431, 535, “High-quality electron beams from a laser wakefield accelerator using plasma-channel guiding” C. G. R. Geddes et al., NATURE, 431, 538, “A laser-plasma accelerator producing monoenergetic electron beams” J. Faure et al., NATURE, 431, 541, ICL/RAL, UK LBNL, US LOA, France

12 LOA UTEXAS CAEP Year Electron Energy (GeV) LBNL RAL LBNL Staged LWFA Single-stage LWF MPQ GIST LBNL GIST LLNL Commented as “Dream beam” 4.2 GeV Staged LWFA LBNL RAL 100 GeV Z.Z.Xu & R.X.Li 超强激光和激光加速

13 10 cm plasma channel Optimizing electron injection Peak energy ~10 GeV Energy spread <5% Beam charge >10 pC e-beam charge control Seeding phase control SIOM 的激光加速计划 Z.Z.Xu & R.X.Li

强激光在晶体中产生的尾场加速电子，加速梯度可达到 1TeV/cm ，正在做理论与实验研究 （ G. Mourou ） 27 kilometres 100 metres In The Future Zeptosecond X-ray Driver * laser induced solid crystal wakefield * electron, muon, ion collider * 1cm in length * 1 TeV/cm 1 centimetre In Existence Now The Large Hadron Collider (LHC), CERN. * 27kms toroidal tunnel * 175m underground * 1 billion proton collisions per second * TeV In Development Now Laser Wakefield Acceleration visible light * electron/positron collider * 100m in length * 1 GeV/cm

15 2. 伽马 - 伽马对撞机 激光 - 电子汤姆逊散射 伽马 - 伽马直线对撞机 伽马 - 伽马希格斯工厂 Photon beams can be made so energetic and so intense that when brought into collision with each other they can produce copious amounts of elementary particles.

If the electron energy is less than 100MeV, laser photon energy in the moving frame is E photon <<m e c 2. The electron bunch is moving in an EM wave. 2.1 激光电子汤姆逊散射 为避免  光子与激光光子碰撞产生正负电子对 ( 布雷特 - 惠勒过程 ) x 3.93 E e (TeV), 对于 E e =0.25TeV ， ~1  m 为避免激光与 g 光子 取 x=4.8, E , max =0.8E e

~1ps 30fs X-ray ～ 1ps X-ray ～ 100fs Thomson Scattering X-ray Source Compact ， typical size: 5m×5m Tunable monochromatic X-rays Radiation in a small angle (  ~ 1/  ) Ultra-short X-ray Pulse

TTX of Tsinghua University TTX-Ring TTX-Linac

LLNL PLEIADES facility produces > 2 x 10 7 photons per pulse in the keV range, at 10 Hz U K-edge 115.6keV Up: experiment Down: simulation Courtesy of Jae Lim’s report, UCLA May 18,2004 LLNL: 核材料研究

2.2 伽马 - 伽马直线对撞机  Electron beam parameters  Laser beam parameters K.J. Kim & A. Sessler, Symmatry, Spring/Summer 1996

最终聚焦磁铁 伽马 - 伽马 对撞区 入射负电子 入射正电子 出射负电子 出射正电子 最终聚焦磁铁 与正电子的激光反 射镜（次序 1  5 ） 与负电子的激光反 射镜（次序 10  6 ）

2.3 伽马 - 伽马希格斯工厂 e + -e - ring based HF e + -e - linac based HF  Higgs Factory  Higgs Factory  Higgs Factory 

23  Higgs Factory LHeC

Weiren Chou et al., arXiv: L= 5×10 33 cm -2 s -1

25 3. 激光等离子体对撞机 激光等离子体加速器 激光等离子体对撞机 激光等离子体对撞机的挑战

激光等离子体加速 26 Longitudinal acceleration field: E L = mc  p /e = 96  n e (cm -3 ) V/m Example: n e = cm -3, E L  100 GeV/m 27/09/2010

27 Laser-Plasma Acceleration Accelerating field determined by laser intensity a 0 and plasma density n 0 (a 0 1: blowout) E z =12 GV/m λ 0 = 0.8  m, I 0 = 2  W/cm 2, a=1, n 0 =1  cm -3  E z =12 GV/m Wakefield regime determined by a 0 2 Laser pulse length determined by plasma density  k p  σ z ≤ 1, σ z ~ λ p  n 0 -1/2

28 Limitation and Mitigation 3 Ds: Diffraction, Dephasing, Depletion Diffraction: Z R =  r 0 2 /λ 0 ~ 2 cm<< L dephase < L deplete  Plasma channel to guide the laser pulse Dephasing: electrons outrun wake  Lower plasma density  Density tapering Depletion: laser used out energy to wake  Staging = 1  m, n 0 = 10 17, p = 105  m, L deph =0.9 m

29 Wim Leemans and Eric Esarey, LBNL, 《 Physics Today 》, 62(3), 44 (2009) Laser-driven plasma-wave electron accelerators 3.2 激光等离子体对撞机

30 Beamstrahlung An incoming electron undergoes electromagnetic field of the opposite positron bunch at IP emits hard photos  “beamstrahlung”. It generates background for the detectors and adds energy spread to beam: N   (N  z ) 1/3,  E  (N  z ) 1/3, L/P b   z -1/2. n  < 1  E ~ 10% N~10 9 Background: n  < 1, experiment accuracy:  E ~ 10%  N~10 E c.m. =1 TeV,  z ~1  m. C. B. Schroeder et al., Design considerations for a laser-plasma linear collider(2010)

31 Luminosity The event rate of a collider is defined as the collision cross section and luminosity dn/dt=L  For  e+e-  E c.m. -1, the luminosity should be increased with E c.m. to maintain the collision rate. Luminosity of a collider is given as: High luminosity needs high beam power and high beam density. For small beam size, low emittance and strong focusing are required:  x,y =(  x,y  x.y * ) 1/2.  min * is limited chromatic and radiation effects, ~0.1 mm. e+e+e+e+ e-e- xx yy yy yy f

32 Emittance and its Growth For the space-charge shielding provided by the ions in the plasma and the rapid acceleration high beam quality with low emittance can be achieved beyond state-of-the-art photocathodes. Emittance growth occur by elastic scattering of the beam and the ions in the plasma. For  ~1, a 0 =1.5, r L =63 mm,  n ~0.4 nm  rad There are many other sources of emittance growing in the linac, such as collective effects, misalignment between accelerating stages, vibrations, plasma fluctuations, etc., need to be stated.

33 Wall Plug 28 MW Main beam injection, magnets, services, infrastructure and detector Dumps Main linac PETS Drive beam acceleration 253 MW MW 1 GHz RF power MW Drive Beam Power 107 MW  plug/RF ~ 25 %  M =.90  A =.977  TRS =.98  T =.96  D =.84 Drive beam power extr. Power supplies klystrons  RF/main ~ 74 %  tot ~ 5 %  S =.95  RF = MW 12 GHz RF power (2 x 101 kJ x 50 Hz) Main beam  K =.70 ~560 MW Modulator auxiliaries 260 MW AC power  REL =.93 aux = 0.97 ~300 MW CLIC Power flow 3 TeV Exact numbers are under revision – chart included for illustration 3.5 MW 70 MW  tot ~ 5 %  plug/laser ~ 33%  laser/plasma ~ 50%  plasma/beam ~20% (0.5T ILC: 9.9 MW) (ILC: 106 MW) (ILC: 9.6%) (ILC: 22%)  RF/beam ~ 28 % (ILC: 44%)

34 Parameterization Stage vs. Density n 0  E z  2  I 0  E 0  E 0  n 0 1/2  L dephas, L deplat  n 0 -3/2  L stage  n 0 -3/2   E stage  n 0 -1  N  n 0 -1/2 Collider vs. Density n 0 (for fixed luminosity)  F  n 0  N stage  n 0  P b  n 0 1/2  P laser  n 0 -1/2

35 10 cm plasma channel Optimizing electron injection Peak energy ~10 GeV Energy spread <5% Beam charge >10 pC E-beam charge control Seeding phase control a 0 ~1 n 0 ~10 17 f~10 kHz 10 GeV < 1% ~50 pC Stage length ~ 1 m Cooling ? Injected beams? 10 GeV 激光加速单元 Z.Z.Xu & R.X.Li

激光等离子体对撞机的挑战 Laser-plasma technology average power laser  40 J, 15 kHz, 600 kW high average power laser efficiencies  Wall-laser & laser-plasma efficiencies of ~33% & ~50% Repeatable  Repeatable high quality mono-energy beam generation   Accelerator technology nm beam collision   <1%  Generation and preservation of extremely low emittance (  ny ~10nm) and nm beam collision (  y * ~1nm ，   <1%); collective effects  Beam collective effects (  z ~ 1  m, I peak ~ 20 kA) in metal environment (beam pipes, bellows, etc.) Staging  Staging: synchronization, beam quality, efficiency, etc.;  

37 We need (beam) power of a TGV 1 We need (beam) power of a TGV (10MW) 1 TeV, 0.65 nC, 15kHz ( ~10MW)    AC-beam (10 -3 ) ~ 10 GW Improving Average power by , Improving Wall Plug efficiency by Entails a revolutionary change in the Laser Architecture. A Mind Boggling Challenges For Mind Boggling Applications (G. Mourou)

38 ICAN (European Project) G. Mourou, W. Brocklesby, J. Limpert, T. Tajima, Nature Photonics April 2013 « The future of Acceletaor is Fiber » Shanghai SIOM 2015 CAN Coherent Amplification Network 强激光目前的最高重复频率为 10Hz 量级。采用光纤 合成技术，有望提高到 10kHz 以上。

39 Summary The rapid development of the laser technology provides a great opportunity for particle accelerators and colliders. Gamma-gamma colliders and laser plasma colliders are two crucial aspects of development. High energy frontier calls for higher average power laser.

40 Thanks for attention