Nuclear-Recoil Differential Cross Sections for the Two Photon Double Ionization of Helium*

In support of the reaction microscope measurements at the free-electron laser facility at Hamburg (FLASH) [1], we use the time-dependent close-coupling method (TDCC) to calculate fully differential nuclear-recoil cross sections for the two-photon double ionization of He at photon energy of 44 eV. The total cross section for the double ionization is in good agreement with previous calculations. The nuclear-recoil distribution is in good agreement with the experimental measurements. In contrast to the single-photon double ionization, maximum nuclear recoil triple differential cross section is obtained at small nuclear momenta. \\[4pt] [1] A. Rudenko \emph{et al}, Phys Rev. Letts. {\bf 101}, 073003 (2008).