Dual Detector Charged Particle Device for Electron and Ion Detection
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Solution Overview
Problem
Existing charged particle detecting devices face inefficiencies in detecting different species of charged particles, leading to suboptimal image brightness and contrast in charged particle beam systems, particularly when secondary electrons or ions do not provide sufficient detail for imaging.
Innovation Solution
A charged particle detecting device with a dual detector system, including a scintillation detector for electrons and a channel or micro-channel electron multiplier for ions, is designed to generate high signal-to-noise ratio images. This system uses a voltage supply unit to control electrodes, allowing for concurrent detection of electrons and ions, and features a compact design with a grid-like electrode for efficient particle transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single detector is used to detect charged particles, then the device complexity is reduced, but the detection efficiency for different species of charged particles deteriorates
Solution Approach 1:
The detector is divided into two separate detection paths: a first charged particle detector for detecting electrons and a second charged particle detector for detecting ions. Each detector is optimized for its specific particle type, with the second detector including an ion-to-electron converter for ion detection. This segmentation allows each detector to specialize in detecting specific charged particle species, thereby improving detection efficiency without requiring an overly complex unified detector design.
Solution Approach 2:
The detector head is designed with multi-functionality to handle both electron and ion detection through a unified structure. The first electrode serves as a common entrance for both particle types, and the detector head can selectively detect different species by controlling the voltage on the control electrode. This universal design allows a single detector assembly to perform multiple detection functions, reducing overall device complexity while maintaining high detection efficiency for different charged particle species.
2Volume of moving object
If the detector head volume is reduced for compact design, then the device size is minimized, but the detection efficiency deteriorates
Solution Approach 1:
The detector employs a nested arrangement where the second charged particle detector (for ion detection) is positioned within the hollow volume of the detector head, and the first charged particle detector (for electron detection) is arranged at the terminal portion. The ion-to-electron converter is nested within the detector head structure, allowing ions to be converted to electrons that can then be detected by the detection system. This nesting approach maximizes the use of available volume while maintaining effective detection paths for both particle types.
Solution Approach 2:
The detector utilizes three-dimensional spatial arrangement to optimize detection efficiency within a compact volume. The first detector is positioned at the terminal portion while the second detector is arranged within the hollow volume of the detector head, creating a vertical stacking arrangement. The control electrode structure extends in multiple dimensions to provide both electron and ion detection pathways without requiring a large lateral footprint, thus achieving compact design while maintaining detection efficiency.
3Adaptability or versatility
If a control electrode is used to switch between electron and ion detection, then the detector versatility is improved, but the device complexity increases
Solution Approach 1:
The control electrode is designed with multi-functionality to serve both electron detection and ion detection modes within a single detector assembly. By adjusting the voltage on the control electrode, the detector can selectively detect electrons (when the electrode is biased to allow electron passage) or ions (when the electrode is biased to guide ions to the ion-to-electron converter). This universal control mechanism provides versatile detection capability without requiring separate detectors or complex switching systems for different particle types.
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 device achieves high detection efficiency for both secondary electrons and ions, enabling the generation of images with improved brightness and contrast, and allows for distinguishing between materials based on their ion and electron emission rates, facilitating endpoint detection in processes like ion beam milling.
Implementation Method 1
The first charged particle detector can be a scintillation detector including a scintillator and a photo-multiplier tube
Implementation Method 2
a ion-to-electron converter as well as a detector which generates an electrical output signal if electrons impinge on an electron-sensitive surface of the detector
Data Source
AI summary
A charged particle detecting device includes: a holding structure; a first charged particle detector at the terminal portion of the holding structure; a second charged particle detector at the terminal portion of the holding structure; a detector head at the terminal portion of the holding structure; and a first electrode which is transmissive for the first and second species of charged particles covering an entrance opening of the detector head.