3D printing linear accelerators reduces cost and complexity
Drift tube linear accelerators (DTLs) use long radio frequency cavities in which an electric field alternates to efficiently accelerate particles. The drift tubes, installed at intervals within the cavity, create a shield from any component of the electric field that would decelerate the particles.
DTLs are often the most efficient accelerators between 1% and 50% of the speed of light. As such, they are an essential component of many accelerator facilities. However, building the DTL cavity is complicated because it requires joining many individual parts. The manufacturing method is time consuming, error prone, and expensive.
By optimizing the geometry of the cavity, Mayerhofer et al. developed a prototype DTL that can be 3D printed in a single piece of pure copper. The prototype reduces cost by about a factor of three compared to traditionally manufactured structures while maintaining a similar efficiency.
The team used selective laser melting to print the cavity, which requires structures to support overhanging components. The support structures must eventually be removed after printing to obtain the actual desired geometry, which is made difficult by the geometric dimensions of the cavity. The team’s changes to cavity geometry avoided or reduced overhangs so that support structures became unnecessary.
“We wanted to demonstrate the fundamental potential of 3D printing for manufacturing cavity geometries,” said author Michael Mayerhofer. “A variety of cavity geometries are used worldwide in many areas and the potential of 3D printing processes is not limited to special radio frequency cavity geometries.”
The researchers plan to reduce the surface roughness on the inner walls of the cavity and optimize the prototype in terms of printing costs.
Source: “A 3D printed pure copper drift tube linac prototype,” by M. Mayerhofer, J. Mitteneder, and G. Dollinger, Review of Scientific Instruments (2022). The article can be accessed at https://doi.org/10.1063/5.0068494 .