Engineering topics
Publications and source records attributed to Parise, Mattia [Fermilab].
Building a simulation tool to select a suitable radiation mapping device for FE detection during Cold Testing. Evaluating asymmetries in photons angular distribution to get information about the FE site position. The final goal is to focus cleaning efforts in that point to reduce employed resources, iterations and costs.
Field emission and multipacting are critical factors that limit the achievable operational gradient of superconducting radio frequency (SRF) cavities. Plasma processing (PP) has been demonstrated as an effective in-situ technique for mitigating hydrocarbon-induced field emission and multipacting across a range of cavity geometries. In this work, we present the initial development and subsequent application of plasma processing for PIP-II type II spoke resonators (SSR2). The process was carried out at room temperature on an SSR2 cavity equipped with the CM-style high-power coupler and installed in the cryostat. Cavity performance was evaluated through comparative cold tests conducted before and after plasma processing.
Overview of plasma processing setup for SSR1 cavities at IJCLab and for SSR2 cavities at Fermilab. Talk presented by Mattia Parise (Fermilab), Materials provided by Bianca Giaccone (Fermilab) and Camille Cheney (IJCLab).
The SSR2 cavities for PIP-II have consistently been affected by field emission since the first cold tests with the unity coupler. A comprehensive root cause analysis was conducted to investigate the origin of this issue and to identify the fabrication, processing, and handling factors that have the greatest impact on field emission onset. New techniques were developed and effectively implemented to achieve field emission-free SSR2 cavities. In addition, effort was dedicated both to relating the radiation level measured at the test stand with the expected levels in the LINAC tunnel and to understand the evolution of field emission through the assembly steps. The challenge of overcoming field emission also led to a reassessment of design choices, enhancing our understanding of their effects on cavity performance.