Liquid Nitrogen Jet Cleaning for SRF Cavity Particulate Removal
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Solution Overview
Problem
Existing methods for cleaning superconducting radio-frequency (SRF) cavities and cavity strings are limited in removing microscopic contaminant particles, requiring disassembly and reassembly, which is time-consuming and expensive, and are ineffective in removing a wide size range of particulates down to a few nanometers, leading to field emission and increased radioactive burden.
Innovation Solution
A high-pressure liquid nitrogen jet cleaning method that uses a lance with nozzles to dislodge and transport microscopic particulates from the inner surface of SRF cavities, employing energy transfer via sound waves and cold shrinkage differential, allowing for the removal of particulates down to a few nanometers without disassembly, and utilizing rapid evaporation to create a lifting force for effective particulate removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods (liquid nitrogen immersion, high pressure water rinsing, CO2 snow cleaning, helium processing, plasma cleaning) are used, then some cleaning effect is achieved, but they are limited in removing microscopic particulates down to a few nanometers and require disassembly and reassembly of the cryomodule
Solution Approach 1:
The patent replaces conventional mechanical cleaning methods (brushes, wipes, immersion) with a high-pressure liquid nitrogen jet system. The jet delivers kinetic energy to dislodge particulates through impact force, eliminating the need for disassembly while achieving superior cleaning effectiveness down to nanometer-scale contaminants.
Solution Approach 2:
The patent utilizes extreme parameter changes by employing liquid nitrogen at cryogenic temperatures under high pressure. The rapid phase transition from liquid to gas creates a lifting force that enhances particulate removal. This parameter-based approach (temperature and pressure extremes) enables effective cleaning of microscopic contaminants without mechanical disassembly.
2Reliability
If conventional cleaning methods are used, then cleaning is achieved, but it is time-consuming and expensive due to disassembly and reassembly
Solution Approach 1:
By replacing mechanical disassembly-based cleaning with a high-pressure jet system, the patent enables in-situ cleaning of the cryomodule. This substitution eliminates the time-consuming disassembly and reassembly process while maintaining or improving cleaning effectiveness, reducing overall cleaning time significantly.
Solution Approach 2:
The high-pressure liquid nitrogen jet system can be introduced directly into the operational cryomodule through existing access points. The system performs self-contained cleaning without requiring external disassembly, allowing the cryomodule to remain in place and reducing downtime between cleaning operations.
3Object-generated harmful factors
If conventional cleaning methods are used, then cleaning is achieved, but field emission persists due to incomplete removal of microscopic particulates
Solution Approach 1:
The patent employs extreme parameter changes (cryogenic temperature and high pressure) to achieve effective removal of particulates across a wide size range down to a few nanometers. The rapid phase transition of liquid nitrogen creates a lifting force that targets even the smallest contaminants, eliminating the source of field emission that conventional methods miss.
Solution Approach 2:
The patent exploits the phase transition of liquid nitrogen to gas as a cleaning mechanism. When liquid nitrogen contacts the cavity surfaces, it rapidly evaporates, creating a lifting force that dislodges and removes microscopic particulates. This phase transition-based cleaning effectively eliminates contaminants that cause field emission, achieving superior results compared to conventional methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables rapid and cost-effective cleaning of SRF cavities and cavity strings, reducing field emission and radioactive activation, allowing for increased acceleration gradients and improved operational efficiency without leaving any liquid medium behind, thus reducing downtime and environmental impact.
Implementation Method 1
employing energy transfer via sound waves
Implementation Method 2
cold shrinkage differential
Implementation Method 3
rapid evaporation to create a lifting force
Data Source
AI summary
A method and apparatus for removing microscopic contaminant particulates by high pressure liquid nitrogen jet cleaning from the inner surface of a superconducting radio frequency cavity or a string of multiple cavities and transporting the removed particulates out of the inner space enclosed by the cleaned surfaces. The cleaning method of the invention suppresses field emission, resulting in an increase of the usable accelerating gradient of the cavities and a reduction of the activated radioactivity in accelerator components around cavities.