Charged Particle Beam Gas Pressure Control
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Solution Overview
Problem
Existing charged particle beam instruments face challenges in performing in situ observations in gaseous atmospheres due to time-consuming diaphragm fabrication, risk of damage, and manual adjustments of gas pressure, which are difficult for unskilled operators and prone to gas leaks.
Innovation Solution
A charged particle beam instrument with a specimen chamber, gas supply, venting system, and automated gas controller that adjusts gas flow and pressure using relational expressions and corrective coefficients, allowing for easy control of gas species and pressure ranges, and includes multiple exhaust systems and a movable gas inlet nozzle for effective gas distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a differential pumping system with orifices is used to introduce gas into the specimen chamber, then in situ observation in gaseous atmosphere becomes possible, but gas may leak into the specimen chamber via the orifices and safety issues arise with high-pressure gas introduction
Solution Approach 1:
The gas introduction system is segmented into multiple independent components: gas supply portion with separate gas sources, flow rate adjusting valve for controlled gas flow, and a movable nozzle that can be positioned independently. This segmentation allows precise control of gas delivery while preventing uncontrolled leakage through the electron optical column.
Solution Approach 2:
A movable nozzle acts as an intermediary component between the gas supply system and the specimen chamber. The nozzle can be retracted to a safe position when not in use, serving as a mediator that enables gas introduction only when needed and prevents direct exposure of the electron optical column to high-pressure gas.
2Ease of operation
If manual adjustment of gas pressure and venting operations is performed, then gas pressure can be controlled, but adjustments take long time and require skilled operators
Solution Approach 1:
A pressure gauge is integrated into the gas supply system to provide real-time feedback on gas pressure within the specimen chamber. This feedback mechanism allows the flow rate adjusting valve to be controlled based on actual pressure conditions, enabling automatic pressure control that reduces adjustment time and eliminates the need for skilled manual operation.
Solution Approach 2:
The gas pressure control system is designed to be self-regulating through the combination of the flow rate adjusting valve and pressure gauge feedback. The system automatically maintains appropriate pressure levels without requiring continuous manual intervention, allowing unskilled operators to perform gas introduction and venting operations efficiently.
3Adaptability or versatility
If a diaphragm holder with custom-fabricated diaphragms is used, then electron beam passage is enabled in gaseous atmosphere, but fabrication takes great deal of time and diaphragms may break suddenly causing damage
Solution Approach 1:
The system replaces fragile, custom-fabricated diaphragms with a durable, movable nozzle that can be retracted when not in use. The nozzle is a robust component that does not require delicate fabrication and can withstand repeated use without breaking, eliminating the risk of sudden failure that could damage the electron microscope.
Solution Approach 2:
The fixed diaphragm structure is replaced with a dynamically movable nozzle that can be extended into the specimen chamber when gas introduction is needed and retracted to a safe position when not in use. This dynamic configuration eliminates the need for custom fabrication while maintaining electron beam transmission capability during observations.
4Quantity of substance
If high-pressure gas is introduced manually into the specimen chamber, then gas supply is achieved, but safety risks increase and unskilled persons cannot perform adjustments
Solution Approach 1:
The gas supply system incorporates a pressure gauge that provides real-time feedback on chamber pressure, allowing the flow rate adjusting valve to be controlled based on actual conditions rather than manual estimation. This feedback control enables unskilled operators to safely introduce high-pressure gas without risking over-pressurization or safety incidents.
Solution Approach 2:
Manual mechanical adjustment of gas flow is replaced with a controlled system using a flow rate adjusting valve that can be precisely regulated. The valve provides fine control over gas flow rates, replacing rough manual adjustment with a refined control mechanism that is safe and easy to operate for unskilled persons.
Data Source
AI summary
A charged particle beam instrument is offered which can easily perform an in situ observation in a gaseous atmosphere. The charged particle beam instrument (100) is used to perform an observation of a specimen (S) placed in a gaseous atmosphere and has a specimen chamber (2), a gas supply portion (6) for supplying a gas into the specimen chamber (2), a venting portion (7) for venting the specimen chamber (2), a gaseous environment adjuster (4), and a gas controller (812) for controlling the gaseous environment adjuster (4). This adjuster (4) has a gas inflow rate adjusting valve (40) for adjusting the flow rate of the gas supplied into the specimen chamber (2) and a first vacuum gauge (CG1) for measuring the pressure of the gas supplied into the specimen chamber (2). The gas controller (812) sets a target value of pressure for the gas supplied into the specimen chamber (2) based on a predetermined relational expression indicating a relationship between the reading of the first vacuum gauge (CG1) and the pressure inside the specimen chamber (2) and on a corrective coefficient for correcting the reading of the first vacuum gauge (CG1) according to the species of the gas supplied into the specimen chamber (2) and controls the gas inflow rate adjusting valve (40) such that the reading of the first vacuum gauge (CG1) reaches the target value of pressure.