Electron Microscope Magnetization Yoke Gaps for Thermal Isolation
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Solution Overview
Problem
In electron microscopy, generating magnetic fields for sample examination leads to unwanted heating and deflection of the electron beam due to the spread of magnetic fields, which complicates high-resolution imaging and requires cooling, and existing magnetization devices are limited by space constraints in electron microscopes.
Innovation Solution
A magnetization device comprising a coil and a yoke with gaps to minimize heat transfer and maintain magnetic flux, featuring a sample holder that can be rotated and cooled, allowing precise adjustment of magnetic fields without significantly heating the sample, and designed to be compact for insertion into standard electron microscopes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If magnetic fields are generated using coils to examine samples, then the ability to adjust magnetic field amplitude and polarity is improved, but the sample is heated due to electromagnetic heating
Solution Approach 1:
A water-cooled copper block serves as an intermediary heat sink between the coil and the sample. The coil is mounted on the copper block which has water channels for cooling, allowing the magnetic field to be generated while the heat is conducted away through the copper block to the water cooling system, preventing sample heating
2Volume of moving object
If the magnetization device is made compact to fit in standard electron microscopes, then the installation space requirement is reduced, but the magnetic field generation capability is limited
Solution Approach 1:
The coil is nested within a yoke structure, and the entire assembly is integrated into the electron microscope's existing pole piece structure. The yoke provides magnetic flux path while the coil generates the field, creating a compact nested arrangement that maximizes magnetic field generation within limited space
3Temperature
If the coil is cooled using liquid nitrogen or liquid helium, then the sample heating is reduced, but the device complexity and operational difficulty increase
Solution Approach 1:
The system uses readily available water as a cooling medium instead of expensive cryogenic liquids like liquid nitrogen or helium. The water-cooled copper block provides continuous cooling through simple water circulation, avoiding the complexity of cryogenic systems while effectively managing heat
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 detailed examination of samples in magnetic fields without significant heating or beam deflection, providing reliable and precise imaging results while maintaining a compact form factor suitable for standard electron microscopes.
Implementation Method 1
A magnetization device for an electron microscope comprises a coil and a yoke carrying the coil
Implementation Method 2
A first gap is present in the yoke between the first pole and the coil. A second gap is present in the yoke between the second pole and the coil
Implementation Method 3
The electron beam of the electron microscope reacts to this field area with an undesired deflection
Data Source
AI summary
The disclosure refers to a magnetization device, and an associated method of operation, for an electron microscope that includes a coil, with a yoke carrying the coil, with a sample holder for holding a sample, and with two poles of the yoke adjoining the sample holder. A gap is present in the yoke between each pole and the coil. A sample is placed on the sample holder by means of an optical microscope and subsequently the part of the magnetization device comprising the sample holder is connected to the part of the magnetization device comprising one or more coils.