Design, fabrication, and characterization of a drift tube linac type double gap re-buncher cavity.

This article focuses on the design, fabrication, and testing of a double gap re-buncher cavity integrated into the Medium Energy Beam Transport (MEBT) line of the Low Energy High Intensity Proton Accelerator (LEHIPA) at Bhabha Atomic Research Centre, India. The double gap cavity, operating in the TM010 mode at 352 MHz, was chosen over the conventional single gap design based on beam dynamics simulations and electromagnetic performance metrics, demonstrating higher power efficiency, shunt impedance, and transit time factor. Detailed electromagnetic simulations, mechanical design considerations including cooling and RF sealing, and low-power RF characterizations such as quality factor and field flatness measurements are presented, showing good agreement with simulations. Beam tests using a 3 MeV proton beam confirmed the cavity’s operational parameters and phase settings, establishing the double gap re-buncher cavity as an effective component for high-intensity linac beam transport.