New publication in Nature Physics with JINR participation On 13 April, a scientific paper by an international scientific group was published in Nature Physics. A LIT staff member O. Chuluunbaatar and a BLTP employee Yu. V. Popov were members of the group in the frames of JINR international cooperation. The group conducted a kinematically complete experimental measurement of characteristics of Compton scattering at free atoms using the highly efficient method of COLD Target Recoil Ion Momentum Spectroscopy (COLTRIMS). The group also provided a relevant theoretical description of it. Experimentalists from the Goethe University (Frankfurt am Main, Germany) targeted a strong photon beam of the Petra III synchrotron (DESY, Hamburg) through the helium supersonic flow. The COLTRIMS method allowed measuring not only the scattered electron momentum but also the momentum of helium recoil-ion for separate scattering processes. Taking into account the law of pulse energy conservation, it gave an opportunity to fully restore the kinematic properties of the scattering process. Moreover, the use of the method solved the problem of a very low cross-section of the Compton ionization in the photon energy diapason of several KeV that is about 6 times lower than the typical cross-section of the photoabsorption. All this opens opportunities for the use of Compton scattering as yet another instrument of atomic spectroscopy along with such powerful methods of study of atoms and molecules as (e, 2e), (ion, ion e) and others. Theoretical description of this phenomenon is based on the calculations carried out at the supercomputer “Govorun”.
