Study and Test of a Triode Gun for the FLASH Electron LINAC at Sapienza

A 24 MeV prototype LINAC is under development at Sapienza University of Rome for FLASH radiobiological studies. The injector is a 12 keV triode thermionic electron gun from HeatWave Labs, providing grid-controlled cur rent modulation for high current, low perveance, and short pulse operation. To optimize its integration with the 24 MeV C-band hybrid standing- and travelling-wave structure, extensive particle tracking simulations of the electron gun were performed using CST Particle Studio. Parametric scans of the anode voltage and grid potential were used to evaluate beam current, perveance, and emit tance, identifying operating points that balance beam sta bility and charge for FLASH applications. As the modern dispenser cathode requires stringent vacuum conditions be low 1×10−6 mbar, the LINAC was also modeled in Mol flow+ to predict pressure profiles under realistic gas-load scenarios. Simulations revealed a potential vacuum limita tion near the gun, leading to the design and implementation of an additional pumping port for better evacuation of gas molecules. These results are benchmarked with initial ex perimental tests performed on an electron gun test bench at Sordina IORT Technologies. The combined simulation and experimental validation provide key design requirements for compact FLASH LINAC injectors.