The possibility to use an intensive rearrange incoherent γ-source of the cold nuclear isomers localized in magnetic trap (MT) is presented. It is shown by X-ray pumping of active γ-transition of the cold isomeric nuclei into MT. The X-ray pumping has taken of laser plasma which is produced by interaction between very intensive laser optical pulse and target surface. A γ-radiation pulse duration of 10²-10³ picosecond with a pulse energy about 10^-3 J is obtained.