Division of accelerators, cryogenics and magnetism

Increasing the available laser power results in an high intense production of secondary particles (photons, neutrons). These constitute a radiological risk which needs to be assessed and controlled. Hence, fifty years after the production of the first laser, the use of the new generation research lasers requires a new expertise, specific to radiological risks.

IRFU, which has the knowledge required to meet this need, recently finalised two important studies. The first concerns the Petal project at CEA Cesta. The second was carried out for the Applied Optics Laboratory (LOA), an ENSTA Paris Tech-Ecole polytechnique-CNRS joint research unit, recognised as a major European research infrastructure.  These two original studies based on the physics of particle-matter interactions, each address specific problems, respectively to carry out a precise determination of the radiological inventory after one laser pulse and to control the safety of the facility from the radiological protection point of view.

An IRAMIS team is fitting out a basement area for the purposes of a scientific programme to study laser electron acceleration. Electrons will be generated by the interaction of a laser beam with a helium gas jet. The team called on SENAC, an IRFU department concerned with decommissioning, clean-up and declassification of nuclear facilities, to conduct a biological shielding study with a view to limiting the impact of radiation in the vicinity of the experiment room while the laser is in operation. The study, which lasted two months, pinpointed radiation protection problems caused by the interaction of the laser electron beam with various items of equipment in the new experiment room. The aim was to find suitable solutions to permit the group to use its high-power laser, with the support of SPR, in full compliance with applicable radiation protection regulations concerning personnel.

The study was conducted under a new mutual assistance agreement between SPAM and SENAC for high-power laser projects.