Laser-plasma accelerators can produce ultra-short electron bunches in the femtosecond to picosecond duration range, resulting in very high peak dose rates in comparison with clinical accelerators. This unique characteristic motivates their possible application to radiation biology studies to elucidate the effect of high peak dose rates and peculiar temporal structures on the biological response of living cells, which might improve the differential response between tumour and healthy tissues. Electron beams driven by kHz laser systems are an attractive option among laser-plasma accelerators since the high repetition rate can boost the mean dose rate and improve the stability of the delivered dose in comparison with J-class laser accelerators running at few Hz. In this work, we present the dosimetric characterisation of a kHz, low energy laser-driven electron source and preliminary results on in-vitro irradiation of cancer cells. A shot-to-shot dosimetry protocol enabled monitoring of the beam stability and the irradiation conditions for each cell sample. Results of survival assays on HCT116 colorectal cancer cells are in good agreement with previous findings reported in the literature and validate the robustness of the dosimetry and irradiation protocol.

激光等离子体加速器可以在飞秒到皮秒的持续时间范围内产生超短电子束，与临床加速器相比，产生非常高的峰值剂量率。这一独特的特性激发了它们在放射生物学研究中的可能应用，以阐明高剂量率和特殊的时间结构对活细胞生物学反应的影响，这可能会改善肿瘤与健康组织之间的差异反应。由kHz激光系统驱动的电子束是激光等离子加速器中的一个有吸引力的选择，因为与在几赫兹下运行的J级激光加速器相比，高重复率可以提高平均剂量率并提高所输送剂量的稳定性。在这项工作中，我们提出了kHz的剂量学表征，低能量激光驱动电子源以及癌细胞体外照射的初步结果。逐次剂量协议可以监视每个细胞样本的光束稳定性和照射条件。HCT116大肠癌细胞的存活测定结果与文献报道的先前发现非常吻合，并证实了剂量测定法和辐照方案的稳健性。