NSF-BSF: Ultrafast Laser-Electron Heating for Tailoring the Emittance and Charge of High-Energy Proton Beams

This award supports a collaboration between Stanford University and Tel Aviv University in Israel to study ion acceleration with high-intensity lasers. The joint effort is motivated by the goal of developing ion beam cancer therapy technology that could be placed in every hospital and would be able to remove cancer cells everywhere in a human body while leaving the surrounding healthy tissue unharmed. The novel concept promises a compact, meter-scale accelerator with the potential to revolutionize the field of ion beam therapy by making it widely accessible to patients. The project will test predictions of recent simulation of the proposed accelerator concept at Tel Aviv’s laser facility by producing large data sets with the goal to fully optimize the ion beam properties needed for successful deployment. The potential benefits, including improved cancer care, are expected to increase public interest and engagement in science and technology while attracting new students into the fields of plasma and accelerator science. This project will build on a prior demonstration of a new proton acceleration regime using high-repetition rate experiments at the high-intensity NEPTUN laser at Tel Aviv University (TAU). The new proton acceleration regime is characterized by the recirculation of electrons within the target. This project will study and optimize this effect using the high repetition rate 10 Hz, 20 TW laser at TAU and state-of-the-art simulations and modeling developed at Stanford. Current theoretical predictions show critical dependence and close correlation of the electron heating with the laser contrast and the ion beam emittance. The combination of experimental and theoretical capabilities of this project provides a unique opportunity to test these theoretical predictions. Focusing on applications in plasma physics and accelerator physics, this study will determine the dependence of the ion spatial and energy distribution on laser intensity and pulse contrast using the NEPTUN laser’s unique picosecond laser pulse-shaping capabilities. The goal of the project is to demonstrate proton beam properties required for injection into a high-gradient linear proton accelerator. The project is expected to provide a clear path towards the development of a compact accelerator capable of reaching the urgently needed 250+ MeV regime for applications in medical therapies and imaging. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.