Charged Particle Gun Pulse Circuit for Higher Electron Count
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Solution Overview
Problem
Existing charged particle beam systems, such as electron microscopes, face limitations in the number of electrons per pulse due to conventional pulsing methods, leading to issues like increased gas production and emitter temperature rise.
Innovation Solution
A charged particle gun system with a capacitor and switch circuit that varies the extraction voltage in a pulsed manner, allowing for increased electron emission per pulse by alternating between pulsed and continuous modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a high-brightness Schottky emission gun or cold field emission gun is used with a beam blanker for pulsed electron emission, then brightness is improved, but the number of electrons in each pulse is limited
Solution Approach 1:
The capacitor is pre-charged to a first voltage level before the pulse event, storing electrical energy in advance. This preliminary energy storage enables a rapid voltage transition when the switch circuit activates, allowing a larger number of electrons to be emitted in each pulse without compromising brightness
Solution Approach 2:
The invention dynamically changes the voltage parameter applied to the extraction electrode by switching between a first voltage (when capacitor is charged) and a second voltage (when capacitor discharges). This parameter change enables control over both the brightness and the number of electrons per pulse, resolving the contradiction between these two features
2Speed
If conventional beam blanking methods are used for pulsed electron emission, then pulsing capability is achieved, but exposure time increases leading to gas production and emitter temperature rise
Solution Approach 1:
The capacitor is charged during a first time period and discharged during a second time period, creating a periodic action pattern. This periodic charging and discharging enables precise control over the timing and duration of electron pulses, reducing exposure time while maintaining pulsing capability
Solution Approach 2:
The capacitor stores electrical energy in advance during the charging phase, preparing the system for rapid electron emission. This preliminary energy storage reduces the active exposure time during electron emission, thereby reducing gas production and emitter temperature rise
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
The system enhances electron beam pulsing, reducing exposure time and gas production, and minimizing emitter temperature fluctuations, thereby increasing electron count per pulse and extending component lifespan.
Implementation Method 1
a capacitor having one end connected to the extraction electrode; a first power supply for supplying a first voltage to the one end of the capacitor
Implementation Method 2
an emitter; an extraction electrode for extracting the charged particle beam from the emitter
Implementation Method 3
a high-brightness Schottky emission gun or a cold field emission gun is used
Data Source
Figure 1~3
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AI summary
There is provided a charged particle gun capable of increasing the number of charged particles contained in each pulse. The charged particle gun (100) operates to emit a charged particle beam and comprises: an emitter (10), an extraction electrode (12) for extracting the charged particle beam from the emitter (10), a capacitor (50) having one end connected to the extraction electrode (12), an offset power supply (60) for supplying a first voltage to the one end of the capacitor (50) via a resistor (52), a pulsed power supply (40) providing an output of a second voltage, and a switch circuit (30) that switches between whether the second voltage or a reference potential is supplied to the other end of the capacitor (50), based on a reference pulsed signal (SA).