Application of hybrid laser powder bed fusion additive manufacturing to microwave radio frequency quarter wave cavity resonators

Additive Manufacturing of Side-Coupled Cavity Linac Structures from Pure Copper: A First Concept

“…Here, σ denotes the electrical conductivity (for pure copper, around 5.8 × 10 7 S m ), and δ denotes the skin depth, after which the current density drops to 1 e due to the skin effect (δ ≈ 1.1 µm for f R = 3 GHz). The surface resistance increases with the surface roughness, which can be taken into account by a loss enhancement factor η > 1 through the relationship R S = η • R S0 [18]. The most common models to estimate η for accelera-tor design are certainly phenomenological models, such as the Hammerstad model [30].…”

“…As a result of continuous improvements since the 1980s, additive manufacturing processes are now being considered for the manufacturing of RF cavities. Cavity prototypes already fully or partially manufactured by AM include a radio frequency quadrupole cavity (750 MHz) [12,13], an interdigital H-mode cavity (433 MHz) [14,15], superconducting cavities (up to 11.2 GHz) [16,17], a quarter-wave cavity resonator (6 GHz) [18], and a 3 GHz drift tube cavity (DTL prototype) that we presented in 2022 [19,20]. All presented prototypes demonstrate the enormous potential of AM for cavity fabrication and motivate further studies.…”

Improving Fabrication and Performance of Additively Manufactured RF Cavities by Employing Co-Printed Support Structures and Their Subsequent Removal

“…The latest research results obtained on various cavity prototypes indicate that additive manufacturing has the potential to overcome the limitations of the conventional manufacturing process [15][16][17][18][19][20][21][22][23]. For example, the laser powder bed fusion process (L-PBF, also known as PBF-LB) [13,24,25] makes it possible to manufacture cavities made of high-purity copper, including the internal geometry, in one piece [22,23].…”

Additive Manufacturing of an IH-Type Linac Structure from Stainless Steel and Pure Copper

“…Additionally, the relative freedom for design and production of various geometries, bears the potential for more efficient linac cavities by shape optimization. In recent years, a number of studies on the topic of AM for linear accelerator components have been published [4][5][6][7][8][9][10][11][12][13][14][15]. Motivated by successful preliminary vacuum studies with 3D printed pipes, a prototype IH-type linac cavity with a fully printed drift-tube structure was constructed (A CAD model of a current revision of this cavity is shown in Figure 1).…”