Summary WG5 R&D for Innovative Accelerators Greg LeBlanc

Recent studies of laser-driven electron acceleration and x-ray radiation in IOP Wenchao Yan Laboratory of Optical Physics, Institute of Physics, CAS, Beijing , China ) AFAD 2014 and ACAS Workshop on Future Light Sources, Melbourne, Australia Jan , 2014

Betatron radiation enhancement (>3 keV, 10mrad, 2x10^8 phs, >10 21 phs/s/../0.1%BW) Betatron radiation enhancement (>3 keV, 10mrad, 2x10^8 phs, >10 21 phs/s/../0.1%BW) By using Ar clusters, electron beam with large charge will be accelerated which enhance the betatron radiation. ElectronsBetatron x-ray Betatron rad. using 3TW laser + clusters

He uniform density distributionAr clustering density distribution e- distribution He, >3MeV, t=160T >30MeV, t=200T>20MeV, t=160TAr, >10MeV, t=160T simulation results show that the direct laser acceleration (DLA) has important contribution to drive electrons with large oscillations in the case of a clustering gas target. It turns out that the energy gain from DLA counts for 76% of the total energy gain with clustering target. Betatron rad. using 3TW laser + clusters

Room-temperature Burst-mode GHz and THz Pulse Rate Photoinjector for Future Light Sources Yen-Chieh Huang * Chia-Hsiang Chen, Kuan-Yan Huang, Fu-Han Chao HOPE Laboratory, Institute of Photonics Technologies National Tsinghua University (NTHU), Hsinchu, Taiwan AFAD 2014 and ACAS Workshop on Future Light Sources, Jan , 2014 (2E-33)

photoinjector velocity bunching Pulse-train Photoinjector: high average power, bunched beam GHz ~ THz Bunching Frequency Multiplication macropulse Compressed macropulse Magnetic bunching PHz (Yen-Chieh Huang, NTHU, Taiwan)

10 MW power at THz Photocathode gun Solenoid ~50 cm Single-pass undulator 50 cm 12 cm Nrrow line THz THz DFG Narrow-line mW THz wave (Nonlinear material) THz-pulse-train laser Desktop MW THz Free-electron Laser 1.2 m (Yen-Chieh Huang, NTHU, Taiwan)

“Hand-held” XFEL Dielectric laser accelerator (~1 GeV/m) Dielectric laser undulator T. Plettner, R. L. Byer, Phys. Rev. ST Accel. Beams 11, (2008). Huang & Byer Design Example for a 1 Å XFEL Beam energy = 300 MeV, peak current = 12 kA, undulator period = 100  m, gain length = 3 mm, 36 cm (Yen-Chieh Huang, NTHU, Taiwan)

Research on Novel Acceleration Technology at KEK Laser driven dielectric accelerator Expected features and applications K. KEK

Key technologies for afterburner experiments Hollow plasma channel Z-pinch, gas-fill capillary (are just started) Wakefield excitation in linear regime and diagnostics under designing New laser for accelerators Yb-laser (high efficiency) Short bunch of the rf-linac output < 80 fs (injector linac of KEK or small linac of AIST will be used) Afterburner technology will be accomplished by 2020 and transferred to SACLA-II. 1. Present problems stability, luminosity 2. Possible solutions separate the acc. stage from el. source Afterburner (post-acceleration) plan For achieving the energy gain of 5 GeV ， parameters of the plasma channel are n e ≈2x10 17 cm -3, L acc =30 cm, the laser power and pulse width are P L =200 TW, τ L =80 fs (a 0 = 1.5), r L =37 µm

Recent Studies on Laser-Plasma IHEP Dr. Dazhang LI & Prof. Jie GAO IHEP laser plasma acceleration research group

LPA experiment on TW-level lasers Laser: XL-II laser facility in IOP 200mJ/80fs/2-3TW, OAP ： f/6 ， ASE contrast: >10 8 Nozzle ： 1.2mm (long)×10mm (width) GAS: 0.5~7.5MPa, He gas/Ar cluster Beam quality ： 23 MeV/~7%/6 pC/2 mrad ♦ Best beam quality by using several TW lasers, narrow plasma density interval is ♦ Lowest NDA in LPA domain (92 mrad, at least 5 times smaller than previous experiment results) ♦ Has the potential to obtain monoenergetic electron beam with ultrasmall normalized emittance ♦ Valid in a narrow plasma density interval, 2D PIC simulation suggests the smooth transfer from SM-LWFA to LWFA is the key point

13 EXP. SIMU. Jupiter Laser Facilities: 6-12J/60fs/ TW OAP: f/12; Nozzle: 10mm×1.2mm LPA experiment on 100 TW-level lasers