Qualification of SSR1 cavities for PIP-II Soniya Samani Queen Mary University of London Supervisors: Dr Alexander Sukhanov, Dr Donato Passarelli 13 th of July 2018
PIP-II Superconducting (SC) Linac • ! " beam to deliver > # $% power to DUNE/LBNF. &'' $() SC linac • 2
Single Spoke Resonator Cavities (SSR1) ! = #. %% • • EM cavities that resonate with a radio frequency (RF) at &%' ()* Niobium cavity operates at %+ - • cooled via superfluid He Acceleration of , - : /# − /1' (23 • • Intrinsic quality factor. 67 8 9 ~/# /# 4 5 = 3 7/12/18 Soniya Samani | Qualification of SSR1 cavities for PIP-II
Qualification of 12 bare SSR1 cavities 4 7/12/18 Soniya Samani | Qualification of SSR1 cavities for PIP-II
Limitation of cavity performance: Multipacting Resonant exponential increase in electron discharge. Prevents SSR1 from gaining RF power. Dependent on: ! " synchronized with RF field • • Impact energy such that secondary emission yield # > 1 $ = # & Processed via: MULTIPACTOR CONDITIONING 5 7/12/18 Soniya Samani | Qualification of SSR1 cavities for PIP-II
Multipactor Conditioning Analysis Gradual increase of RF power whilst allowing multipacting to progress; / 0 improves. • ! "## ∝ % &'( • Power loss calculated by: % &'( − % *!+ − % ,*-. • Increasing RF power increases power loss. • Conditioning limited by cryogenic capability of helium vessel. 6 7/12/18 Soniya Samani | Qualification of SSR1 cavities for PIP-II
Initial Results: Project aim: Multipactor conditioning data analysis. Relate microscopic behaviour of multipactor to macroscopic parameters. 1. Write a script using C++/ROOT to read data from Acnet. 2. Correlate power loss/energy consumption with radiation emission. 3. Compare with model simulation. Integral of power loss Power loss as a function of time 7 7/12/18 Soniya Samani | Qualification of SSR1 cavities for PIP-II
Summary… • Proton Improvement Plan II (PIP II) • Cavity under analysis: Single Spoke Resonator (SSR1) • Problem: Limitation of cavity performance due to multipacting • Current solution: Multipacting conditioning • My project: Correlate multipactor data with cavity parameters 8 7/12/18 Soniya Samani | Qualification of SSR1 cavities for PIP-II
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