Speaker
Description
Accurate characterization of energy deposition is critical for ultra-intense electron irradiations in advanced radiotherapy and microdosimetry. We investigate the impact of Coherent Stopping Power (CSP) on Very High Electron Energy (VHEE) beams under conditions where electron densities approach or exceed the threshold for collective interactions in matter. Using simulations of laser-plasma-accelerated and photoinjector-based electron bunches, we show that CSP can increase the deposited dose in water by up to 10\% in sub-millimeter beam waists, while remaining below 1--2\% for centimeter-scale beams or polymer dosimeters. CSP arises from collective electromagnetic excitations of the medium, which deposit energy without direct ionization, potentially altering the interpretation of dose at micrometer-to-millimeter scales. Our results highlight the importance of including CSP in dosimetric frameworks for ultra-short, high-density electron beams and suggest experimentally observable signatures, such as coherent Cherenkov emission. These findings are directly relevant for high-precision microdosimetry, cell-targeted studies, and ultra-high dose-rate (FLASH) radiotherapy applications by new-generation ultra-intense electron sources.