[1] Physics Department,
[2] University of California at Berkeley,undefined
[3] Berkeley,undefined
[4] CA 94720,undefined
[5] USA (E-mail: jorgen@physics.berkeley.edu),undefined
[6] Advanced Light Source,undefined
[7] Accelerator and Fusion Research Division,undefined
[8] Lawrence Berkeley National Laboratory,undefined
[9] Berkeley,undefined
[10] CA 94720,undefined
[11] USA,undefined
[12] Physics Department and Center for Ultrafast Optical Science,undefined
[13] University of Michigan,undefined
[14] Ann Arbor,undefined
[15] MI 48109,undefined
[16] USA,undefined
[17] Lawrence Livermore National Laboratory,undefined
[18] Livermore,undefined
[19] CA 94551,undefined
[20] USA,undefined
[21] Physics Department,undefined
[22] Clarendon Laboratory,undefined
[23] University of Oxford,undefined
[24] Oxford OX13PU,undefined
[25] UK,undefined
[26] Center for Beam Physics,undefined
[27] Accelerator and Fusion Research Division,undefined
[28] Lawrence Berkeley National Laboratory,undefined
[29] Berkeley,undefined
[30] CA 94720,undefined
[31] USA,undefined