Laser plasma acceleration of very high energy electron (VHEE) beams: Using ultra-high dose rate pulses for in vitro radiobiology studies.

VHEE beams (100-250 MeV) are being considered for the treatment of deep-seated tumors with FLASH-radiotherapy (RT). Laser-plasma acceleration (LPA) through the laser wakefield acceleration (LWFA) mechanism has been proposed for compactly delivering VHEE beams. LWFA process enables accelerating gradients orders of magnitude higher than conventional RF-based accelerators. This feature makes laser-driven accelerators potential ideal candidates to generate VHEE for clinical applications. Moreover, LPA provides inherently ultra-high dose rate (UHDR) electrons beams. DNA damage associated with UHDR irradiation is a crucial radiobiological process to understand the underlying mechanisms associated with FLASH-RT. We will present recent results on the dosimetric characterization and stability control of our VHEE source based on LWFA at ILIL and its application to in vitro radiobiology measurements. We investigated the induction of micronuclei in cytokinetic-blocked human blood lymphocytes after irradiation with different doses and dose rates. Beam-line implementation with a magnetic transport line for stabilising beams and our upgrade program for FLASH-RT dose compliance will be outlined.