Contactless Temperature Measurement in Charged Particle Microscopes
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Solution Overview
Problem
Existing methods for measuring the temperature of a sample holder with a fast response time in a charged particle microscope are limited, particularly when rapid heating and cooling are required, and existing solutions interfere with the thermal characteristics of the sample or require contact-based measurements.
Innovation Solution
A contactless temperature measurement method using a solid state detector (SSD) to detect thermal radiation from the sample or sample holder, allowing for non-invasive monitoring of temperature transients, which can be combined with MEMS heaters or other contactless heating methods like laser, microwave, or electron beam heating, enabling rapid heating and cooling rates exceeding 10^4 K/s.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact-based temperature measurement methods are used, then temperature can be measured, but the measurement interferes with the thermal characteristics of the sample and may cause material diffusion
Solution Approach 1:
The patent replaces contact-based mechanical measurement methods with a non-contact optical measurement system. The solid state detector captures thermal radiation emitted by the sample, converting thermal energy directly into electrical signals for temperature measurement without physical contact, thereby eliminating interference with sample thermal characteristics and preventing material diffusion
Solution Approach 2:
The patent introduces thermal radiation as an intermediary medium between the sample and the measurement system. The solid state detector measures the intensity of thermal radiation emitted by the sample, which serves as a mediator that carries temperature information without requiring direct contact, thus avoiding harmful interactions with the sample
2Temperature
If conventional heating methods are used, then heating can be achieved, but the response time is slow and cannot capture rapid temperature transients
Solution Approach 1:
The patent employs a solid state detector with fast response characteristics to detect rapid temperature changes. The detector's ability to respond quickly to changes in thermal radiation intensity allows for the measurement of fast thermal transients, effectively changing the temporal response parameter of the measurement system to match the rapid heating and cooling processes
3Measurement precision
If the solid state detector is used during primary beam irradiation, then secondary particles can be detected, but thermal radiation from the sample interferes with the detection
Solution Approach 1:
The patent implements periodic switching between measurement modes. The solid state detector alternates between detecting secondary particles during primary beam irradiation and measuring thermal radiation during blank periods when the beam is off. This periodic action allows the system to capture both types of information without thermal radiation interfering with secondary particle detection
Solution Approach 2:
The patent performs temperature measurement during blank periods before the next primary beam irradiation cycle begins. By measuring thermal radiation when no primary beam is present, the system prepares temperature data in advance, ensuring that thermal radiation does not interfere with the subsequent secondary particle detection during beam irradiation
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 precise, non-invasive temperature measurement and control of sample holders to temperatures over 1000 K with rapid thermal response times, avoiding material diffusion and maintaining vacuum integrity, suitable for high-temperature experiments and microcalorimetry applications.
Implementation Method 1
a contactless method for measuring the temperature of a sample and/or sample holder in a charged particle microscope... using the solid state detector (SSD)... based on the insight that a solid state detector as used in an electron microscope is not only sensitive to secondary radiation... but is also sensitive to photons in the range of visible light and/or infrared. Therefore exposure to thermal radiation... can be used advantageously to measure the temperature
Implementation Method 2
The Aduro E-chip is a sample holder replacing the standard TEM grid. The E-chip comprises a monolithic ceramic membrane with a build-in heater. It can be heated to a temperature of over 1000 °C... The heater of the E-chip is an Ohmic heater and the temperature of the E-chip is determined by measuring the resistance of the Ohmic heater
Implementation Method 3
Related to heating often also quenching is needed, that is: the rapid cooling of a sample to 'freeze' a condition of the sample. The time in which the E-chip heats up or cools down is very small, in the order of a millisecond. Heating and cooling rates are more than 10^4... It is noted that the heating and cooling rate at temperature dependent as the amount of radiation emitted is strongly temperature dependent: P ≈ T^4
Data Source
Figure 1A~1B
Figure 2~3
AI summary
The invention relates to a method of using a charged particle microscope, the charged particle microscope equipped for inspecting a sample (100) mounted on a sample holder (101) with a primary beam of charged particles (200), the charged particle microscope equipped with a solid state detector (202) for detecting secondary particles emanating from the sample in response to irradiation of the sample with the primary beam, the solid state detector in direct optical view of the sample, the method comprising providing the sample on a heater with a fast thermal response time, characterized in that the method comprises a contactless measurement of the temperature of the sample and/or sample holder using the solid state detector. The heating of the heater (for example a MEMS heater) may be contactless heating caused by a laser, microwave heating, induction or electron beam heating, or may be caused by a metallic heating track.