an extreme ultraviolet radiation source pellet includes at least one metal particle embedded within a heavy noble gas cluster contained within a noble gas shell cluster . the euv radiation source assembly can be activated by a sequential irradiation of at least one first laser pulse and at least one second laser pulse . each first laser pulse generates plasma by detaching outer orbital electrons from the at least one metal particle and releasing the electrons into the heavy noble gas cluster . each second laser pulse amplifies the plasma embedded in the heavy noble gas cluster triggering a laser - driven self - amplifying process . the amplified plasma induces inter - orbital electron transitions in heavy noble gas and other constitute atoms leading to emission of euv radiation . the laser pulsing units can be combined with a source pellet generation unit to form an integrated euv source system .