Andy T. Wu

Status of the production electropolishing system at JLAB

Jefferson Lab has installed, and is in the process of commissioning, a production electropolish system, sized for 805 MHz SNS cavities. This paper describes the basic system design, plans for studying the effectiveness of polishing SNS high-/spl beta/ cavities and early results from cavity tests.

Development of a CW NCRF Photoinjector using Solid Freeform Fabrication (SFF)

A key issue for high average power, normal conducting radio frequency (NCRF), photoinjectors is efficient structure cooling. To that end, RadiaBeam has been developing the use of Solid Freeform Fabrication (SFF) for the production of NCRF photoinjectors. In this paper we describe the preliminary design, developed in collaboration with JLab, of a high gradient, very high duty cycle, photoinjector combining the cooling efficiency only possible through the use of SFF, and the RF efficiency of a re-entrant gun design. Simulations of the RF and thermal-stress performance are presented, as well as material testing of SFF components.

Niobium Thin Film Coating on A 500-MHz Copper Cavity by Plasma Deposition

A system using an Electron Cyclotron Resonance (ECR) plasma source for the deposition of a thin niobium film inside a copper cavity for superconducting accelerator applications has been designed and is being constructed. The system uses a 500-MHz copper cavity as both substrate and vacuum chamber. The ECR plasma will be created to produce direct niobium ion deposition. The central cylindrical grid is DC biased to control the deposition energy. This paper describes the design of several subcomponents including the vacuum chamber, RF supply, biasing grid and magnet coils. Operational parameters are compared between an operating sample deposition system and this system. Engineering progress toward the first plasma creation will be reported here.

Investigation into the effectiveness of the JLab High Pressure Rinse system

As part of a study to reduce field emission in superconducting radio frequency cavities, an investigation into the effectiveness of the Jefferson Labs High Pressure Rinse (HPR) system is underway. This paper describes discoveries from this investigation, the procedural changes made during this investigation, current vertical test results and further plans for improvements and monitoring.