Exploring ultra-high dose rate radiobiology with laser-driven protons at BELLA PW iP2

High power laser-solid interactions are capable of accelerating proton bunches with clinically relevant energies (10’s MeV) with an ultra-short duration (picosecond at source) together with high charge and low emittance. The ultra-short duration makes this a unique source offering potential advantages in radiation cancer therapy as differential sparing to healthy tissue compared to tumors has been observed at high doses >10Gy at high dose rates. The molecular and cellular responses at these unprecedented dose rates is not well understood and so we have implemented a beamline at the short focal length experimental area at the BELLA PW facility, known as iP2, that delivers laser driven proton (LDP) bunches at ultra-high instantaneous DR (UHIDR) up to 108 Gy/s. We investigated in vivo the acute skin damage and late radiation-induced fibrosis in mouse ears after UHIDR with 10 MeV LDPs at doses of 40 Gy. We observe sparing of healthy mouse ear tissue with LDP bunches at UHIDR compared to 300 kV x-rays at clinical dose rates and similar total dose. Recent improvements to the LDP source, beam transport, and diagnostic suite have also enabled first peptide sample irradiations to explore the FLASH effect on the molecular level. This talk will provide a summary of radiobiology research activities at BELLA PW iP2 conducted through the LaserNetUS user program.