High Efficiency Low-Beta Accelerating Section

In traditional ion linacs, the beam is accelerated with a synchronous harmonic of the radio- frequency RF) field. For bunching, focusing and acceleration of high current protons and heavy- ion beams, radio-frequency quadrupole RFQ) linacs are used. However, the acceleration rate and effective shunt impedance of RFQs remain 1- 2 orders of magnitude lower than those of the subsequent accelerating stages. At the same time, the beam currents are limited to ~150 mA. Increasing the intensity requires managing the challenging problem of space charge. In response to this problem, RadiaBeam Systems proposes to develop a novel low energy, continuous wave RF linear accelerator with higher efficiency and acceleration rate than the RFQ. This will be enabled by the acceleration of ribbon beams, which significantly reduces the space charge forces, and the concept of the linear undulator accelerator, where the acceleration and focusing is realized in a superposition of two fields, asynchronous with the beam. In Phase I we will perform in-depth analyses of the static and RF undulator alternatives. Then we will perform detailed electromagnetic design and beam dynamic studies of a high shunt impedance structure to maximally cover the range of ion velocities available for RFQs. Finally, we will perform conceptual system engineering to prepare for prototype fabrication and testing in Phase II. The results of this work will be of immediate benefit to a future Electron Ion Collider facility. In addition, a similar linac could be used at ATLAS or FRIB to allow the acceleration of beams with larger mass-to-charge ratios. The other research, industrial, and defense applications include efficient isotope production, neutron generation and injectors for medical proton/carbon therapy systems.