Slim Tip Sample Holder for Transmission Kikuchi Diffraction
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Solution Overview
Problem
Existing sample holders for transmission Kikuchi diffraction (TKD) measurements in electron microscopes are inadequate for handling fragile samples, leading to contamination and reduced measurement quality due to shadowing and limited flexibility in sample positioning.
Innovation Solution
A sample holder with a slim, tapered tip portion and a rotatable element that provides a snap action for secure, form-locking fixation of samples, minimizing shadowing and allowing for optimal sample-detector geometry, enabling TKD and EDS measurements with improved spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a massive fixed jaw is used to secure the sample, then the sample is firmly fixed, but the minimum distance between the column surface and the sample increases, reducing measurement resolution
Solution Approach 1:
The sample holder features a slim tip portion with a maximum cross-section dimension of less than 15 mm (preferably less than 10 mm, especially less than 8 mm) that positions the sample close to the column surface, while the main body can be relatively massive for structural stability. This local quality differentiation allows firm fixation without increasing the minimum working distance.
2Ease of operation
If jaws and screw are arranged close to the EBSD detector, then the sample can be easily accessed, but shadowing and background electron and X-ray signal increase
Solution Approach 1:
The design extracts the sample positioning function to the slim tip portion that extends forward, away from the EBSD detector. The sample is positioned at the front end of the tip portion, maximizing the distance from the detector and minimizing shadowing effects on the phosphor screen.
3Reliability
If adhesive is used to fix the sample to the stub, then the sample is secured, but C contamination increases and the sample cannot be separated without damage
Solution Approach 1:
The sample holder provides self-service fixation through the elastic element that automatically engages the movable jaw with the sample upon insertion, eliminating the need for adhesive. The form-locking and force-locking mechanisms secure the sample without introducing carbon contamination from adhesives.
4Length of moving object
If the sample is positioned far from the column surface, then the working distance is sufficient for equipment clearance, but the spatial resolution of TKD measurements decreases
Solution Approach 1:
The sample holder enables dynamic adjustment of the sample position relative to the column surface through the movable jaw mechanism. The sample can be positioned at optimal distances (less than 5 mm, preferably less than 4 mm, more preferably less than 3.5 mm) while maintaining secure fixation, allowing optimization of both working distance and 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
The sample holder enhances handling and measurement quality by reducing shadowing, allowing for precise positioning of fragile samples close to the electron lenses, thereby improving the spatial resolution in TKD mode by an order of magnitude compared to conventional EBSD methods.
Implementation Method 1
the sample holder comprises an elastic element, preferably a spring, configured to actuate the movable or rotatable element
Implementation Method 2
transmitted electrons are detected by the EBSD detector. Thus a diffraction pattern from the lower surface (exit surface) of the electron transparent sample is obtained
Data Source
AI summary
The present invention refers to a sample holder (10) for positioning a sample (12) in an electron microscope (EM) (60), which is configured to perform transmission Kikuchi diffraction (TKD) measurements, wherein the sample holder comprises a tip portion (14) and is configured to fix a sample (12) or a sample carrier (13) comprising the sample (12) in a form-locking and/or a force-locking manner at or in the tip portion (14). Moreover the present invention refers to an electron microscope (EM) (60) comprising the sample holder (10) according to the invention, wherein the EM (60) is configured to perform transmission Kikuchi diffraction (TKD) measurements.