Charged Particle Beam Apparatus for Nano Spatial Resolution Fluorescence Detection
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Solution Overview
Problem
Current electron microscopes are limited in their ability to obtain nano spatial resolution for observing fluorescent viruses, threading dislocations of crystal defects, and quantum dots, primarily providing surface shape and composition information based on secondary electron emission, and existing methods either require damaging the sample or lack sufficient resolution.
Innovation Solution
A charged particle beam apparatus that includes an electromagnetic wave generation source, a charged particle optical system with a pulsing mechanism, a detector, and control units to synchronize the irradiation of pulsed electromagnetic waves and charged particle beams, allowing for the detection of transient changes in electron emission to specify fluorescence wavelengths with nano spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electron microscope is used to obtain nano spatial resolution, then resolution is improved, but the ability to identify fluorescence wavelength is lost
Solution Approach 1:
The patent combines electron beam irradiation with electromagnetic wave (light) irradiation in a single observation system. The electron microscope is modified to include light irradiation means and timing control means, merging the high-resolution imaging capability of electron microscopy with the fluorescence detection capability of optical microscopy into one integrated system.
Solution Approach 2:
The patent employs periodic pulsed irradiation where the electron beam and electromagnetic wave are irradiated in alternating pulses with controlled timing intervals. The timing control means adjusts the interval between electron beam pulses and light pulses, enabling periodic excitation of fluorescent materials followed by detection of emitted electrons during the light emission phase.
2Measurement precision
If a phosphor is selected for CL method, then fluorescence wavelength can be specified, but sample selection is limited
Solution Approach 1:
The patent changes the observation parameter from requiring pre-selected phosphors to detecting transient electron emission changes caused by light-induced carrier generation. By controlling the timing interval between light and electron beam irradiation, the system can detect carriers generated in any fluorescent material regardless of whether it contains phosphors, thus expanding sample versatility while maintaining fluorescence wavelength specification capability.
3Loss of information
If electron beam irradiation is used to detect phosphor damage, then fluorescence information can be acquired, but the sample is damaged
Solution Approach 1:
The patent performs preliminary light irradiation to generate excited carriers in the fluorescent material before electron beam detection. By first exciting the material with electromagnetic waves and then detecting the transient electron emission during the excited state, the system acquires fluorescence information without requiring subsequent high-dose electron beam irradiation that would cause damage.
Solution Approach 2:
The patent replaces the mechanical/damaging electron beam irradiation method with an electromagnetic wave-based excitation method. Instead of using electron beam irradiation to both image and excite phosphors (which causes damage), the system uses non-damaging light irradiation for excitation and detects the resulting electron emission transiently, substituting the harmful electron beam excitation with benign electromagnetic wave excitation.
4Loss of information
If CLEM method is used to superimpose images, then both optical and electron microscopy information is obtained, but resolution problem is not solved
Solution Approach 1:
The patent merges the imaging and fluorescence detection functions into a single electron microscope system. Instead of separately acquiring optical microscope images and electron microscope images for CLEM superposition, the system directly detects fluorescence-related electron emission within the electron microscope, eliminating the need for image alignment and superposition while maintaining nano spatial resolution.
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
Enables the detection of sample information with nano spatial resolution without damaging the sample, allowing for the identification of phosphors based on carrier lifetime and reducing sample damage through controlled electron beam irradiation.
Implementation Method 1
an electromagnetic wave generation source configured to generate an electromagnetic wave with which a sample is irradiated
Implementation Method 2
a detector configured to detect an emitted electron emitted by an interaction between the charged particle beam and the sample
Implementation Method 3
a cathodoluminescence (CL) method for observing a sample stained with a phosphor known in the field of biology. This is a technique of detecting fluorescence generated when a fluorescence-stained sample is irradiated with an electron beam
Data Source
AI summary
A charged particle beam apparatus includes: an electromagnetic wave generation source 16 that generates an electromagnetic wave with which a sample is irradiated; a charged particle optical system that includes a pulsing mechanism 3 and irradiates the sample with a focused charged particle beam; a detector 10 that detects an emitted electron emitted by an interaction between the charged particle beam and the sample; a first irradiation control unit 15 that controls the electromagnetic wave generation source and irradiates the sample with a pulsed electromagnetic wave to generate an excited carrier; a second irradiation control unit 14 that controls the pulsing mechanism and irradiates an electromagnetic wave irradiation region of the sample with a pulsed charged particle beam; and a timing control unit 13. While the emitted electrons are detected by the detector in synchronization with irradiation of the pulsed charged particle beam, the timing control unit controls the first irradiation control unit and the second irradiation control unit, and controls an interval time between the pulsed electromagnetic wave and the pulsed charged particle beam to the electromagnetic wave irradiation region. As a result, based on a transient change in an electron emission amount, it is possible to detect sample information with nano spatial resolution.