MeV electron acceleration at 1 kHz with <10mJ laser pulses
  We demonstrate laser driven acceleration of electrons to MeV-scale energies at 1kHz repetition rate using <10mJ pulses focused on near-critical density He and H2 gas jets. Using the H2 gas jet, electron acceleration to ~0.5MeV in ~10fC bunches was observed with laser pulse energy as low as 1.3mJ. Increasing the pulse energy to 10mJ, we measure ~1pC charge bunches with >1MeV energy for both He and H2 gas jets. 
F. Salehi, A. J. Goers, G. A. Hine, L. Feder, D. Kuk, B. Miao, D.   Woodbury, K. Y. Kim, and H.M. Milchberg
physics.plasm-ph physics.optics