CERN Yellow Reports: Monographs, Vol. 7 (2025): The DEFT facility: An accelerator for very-high-energy electron FLASH radiotherapy—Technical design report

The design of an accelerator facility capable of delivering FLASH radiotherapy to large, deep-seatedtumours is presented. The facility, called DEFT (Deep Electron Flash Therapy), produces 140 MeVelectrons so is capable of treating tumours located at depths up to 25 cm. It is capable of deliveringsufficient electron intensity to treat tumours up to 20 cm in diameter, in less than 0.1 s with doses upto 20 to 30 Gy. The full facility, including electron source, accelerator and beam delivery system aredescribed along with extensive performance simulations.