The series production of bare and jacketed Radio-Frequency Dipole (RFD) cavities is progressing steadily at Zanon Research & Innovation Srl (ZRI) within the framework of the HL-LHC Accelerator Upgrade Project (AUP), coordinated by Fermilab. Manufacturing is proceeding at full capacity with multiple production activities – including cavity fabrication, chemical processing, and cleanroom assembly – executed in parallel. To date, two prototype cavities and four series production units have been completed. Two additional cavities are undergoing final electron-beam welding, and the production of the remaining six units is expected to conclude by early next year, completing the planned series of twelve cavities.
Figure 1. RF dipole series production at Zanon.
A significant collaborative effort between Fermilab, CERN, and ZRI led to the development and implementation of enhanced metrology inspection protocols for both bare and jacketed cavities. These inspections are critical due to the stringent geometric tolerances imposed by the cryomodule design. Precise dimensional verification is essential to ensure proper alignment and mechanical integration with adjacent accelerator subsystems, thereby minimizing the risk of interference, installation errors, or degradation of operational performance.
To date, four bare cavities have undergone cryogenic testing. Two have met the required RF performance specifications and have been approved to proceed through the subsequent stages of assembly. One of these cavities has been successfully jacketed and delivered to TRIUMF (Canada) in its final configuration, which includes higher order mode (HOM) dampers co-developed by Jefferson Lab (Jlab) and CERN. Shipping procedures and associated transport tooling were validated during this delivery, with no measurable impact on cavity integrity or performance.
Additionally, cryogenic testing infrastructure at TRIUMF has been qualified for handling and testing RFD cavities received from AUP. A second cavity is currently undergoing the final stages of jacketing at ZRI and is scheduled for shipment to JLab later this summer for HOM installation and final cold testing, prior to delivery to TRIUMF. This unit will constitute the first official RFD cavity deliverable from AUP to CERN.
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