Towards additive manufacturing of dielectric accelerating structures

Max Kellermeier,Benedikt Hermann,Csaba Lombosi,Hannes Dinter,Marijo Magjar,Lukas Stingelin,Jonas Lehmann,Klaus Flöttmann,Rasmus Ischebeck,François Lemery,Ulrich Dorda,Simon Zinsli,Ralph Aßmann,Wolfgang Hillert

doi:10.1088/1742-6596/1596/1/012020

Abstract

Additive manufacturing techniques such as stereolithography have developed rapidly in the last decade and provide the ability to simplify prototyping and manufacturing of unique, complex structures. For the application to dielectric accelerating structures a precise knowledge of the dielectric permittivity of the material is essential to the design. Here we present the characterization of commercially available polymers used in stereolithographic manufacturing by means of refractive index and absorption in the frequency range from 220 GHz to 330 GHz, and around 60 GHz. Vacuum compatibility has been tested with respect to achievable pressure level and residual gas mass spectra. In the future the polymer properties will be applied to designs of accelerating structures as well as couplers for terahertz-driven dielectric accelerator components.

Highlights

Additive manufacturing, often denoted as 3D printing, gained a lot of interest in the general public in the last few years but due to technological advances in the accelerator community
We present the characterization of commercially available polymers used in stereolithographic manufacturing by means of refractive index and absorption in the frequency range from 220 GHz to 330 GHz, and around 60 GHz
Refractive index of FormLabs Clear, FormLabs High Temperature and Asiga FusionGRAY was measured at 60 GHz as 1.609 ± 0.024, 1.648 ± 0.036 and 1.670 ± 0.015, respectively

Summary

Introduction

Often denoted as 3D printing, gained a lot of interest in the general public in the last few years but due to technological advances in the accelerator community. Progress in printable materials paved the road for 3D printed beam position monitors [1], while smaller feature sizes are especially interesting for novel laserdriven accelerators, such as the woodpile structure printed with a Nanoscribe [2]. The optical properties of printable polymers for the well-known fused deposition modeling (FDM) have been studied extensively in the past [5] in order to manufacture waveguides and splitters [6], metamaterial lenses, gratings and other optical components for terahertz frequencies [7, 8, 9] These printers are limited in vertical and transverse resolution to about 100 μm, depending on the nozzle size, the print head movement and the layer height.

Results

Discussion

Conclusion