Ultra-strong laser pulses: streak-camera for gamma-rays via pair   production and quantum radiative reaction
  We show that a strong laser pulse combined with a strong x-ray pulse can be employed in a detection scheme for characterizing high-energy $\gamma$-ray pulses down to the zeptosecond timescale. The scheme employs streak imaging technique built upon the high-energy process of electron-positron pair production in vacuum through the collision of a test pulse with intense laser pulses. The role of quantum radiation reaction in multiphoton Compton scattering process and limitations imposed by it on the detection scheme are examined. 
K. Z. Hatsagortsyan, A. Ipp, J. Evers, A. Di Piazza and C. H. Keitel
physics.ins-det physics.acc-ph physics.atom-ph physics.optics