Ultra high pressure transmission electron microscope is a high-precision microscopic analysis instrument widely used in multiple fields such as materials science, biology, physics, etc. Due to its complex structure and high precision requirements, operating ultra-high voltage transmission electron microscopy requires certain skills and strict adherence to operating standards. The following are some key techniques and precautions in the operation of ultra-high pressure transmission electron microscopy to ensure the normal operation of the instrument and the reliability of experimental results.

1、 Preparation before operation

（1） Environmental inspection

Before operating the ultra-high pressure transmission electron microscope, it is necessary to ensure that the laboratory environment meets the requirements of the instrument. Ultra high pressure transmission electron microscopy is highly sensitive to environmental conditions, including temperature, humidity, vibration, and electromagnetic interference. The laboratory should be equipped with constant temperature and humidity equipment to maintain a temperature between 20 ℃ and 25 ℃ and a humidity between 40% and 60%. At the same time, the laboratory should be kept away from vibration sources and strong electromagnetic fields to reduce the impact of external interference on instrument performance. Before operation, the environmental conditions of the laboratory should be checked to ensure that they meet the operational requirements of the instrument.

（2） Instrument inspection

Before starting the instrument, a comprehensive inspection should be conducted. The inspection includes the performance of key components such as the electron gun, condenser lens, objective lens, projection lens, as well as the operating status of the vacuum system, cooling system, and power system. Ensure that all components are in normal working condition, the vacuum level meets the requirements (usually below 10 ± 5 Pa), the cooling system is operating normally, and the power supply voltage is stable. If any abnormalities are found, professional technicians should be contacted immediately for handling, and the instrument should not be forcibly started.

（3） Sample preparation

The quality of the sample directly affects the imaging results. The sample of ultra-high voltage transmission electron microscopy must be very thin (usually between tens of nanometers to hundreds of nanometers) to ensure that the electron beam can penetrate the sample. For solid samples, ultra-thin slicing technology is usually used to cut the sample into ultra-thin slices. For liquid samples, freeze-drying technology can be used to freeze and dry the samples to maintain their structural integrity. The surface of the sample should be clean and free of contamination to avoid introducing impurities that may affect the imaging quality.

2、 Operation skills

（1） Startup and adjustment of electronic gun

The electron gun is one of the core components of ultra-high voltage transmission electron microscopy, and its performance directly affects the quality and imaging effect of the electron beam. When starting the electron gun, follow the instructions in the instrument manual step by step to avoid applying high voltage too quickly or too slowly. After starting the electron gun, it is necessary to adjust the spot to ensure the intensity and uniformity of the electron beam. When adjusting the spot, the spot adjustment knob should be used to form a uniform circular spot of the electron beam on the fluorescent screen. The size and brightness of the light spot should be adjusted according to experimental requirements. Generally, the smaller the light spot, the higher the resolution, but the brightness will also decrease accordingly.

（2） Optical path alignment

Optical path alignment is a key step in ultra-high pressure transmission electron microscopy imaging. The alignment of the optical path includes the alignment of the condenser lens, objective lens, and projection lens. The function of a spotlight is to focus the electron beam onto the sample, ensuring that the electron beam has sufficient intensity and uniformity. The objective lens focuses the electron beam passing through the sample for imaging, and its performance directly affects the resolution and contrast of the imaging. The projection mirror further magnifies the intermediate image formed by the objective lens, ultimately forming a clear image on the fluorescent screen or detector. When aligning the optical path, the focusing lens, objective lens, and projection lens should be adjusted in order from top to bottom to ensure that the electron beam passes through the center of each lens. After the alignment of the optical path is completed, an imaging test should be conducted to check the clarity and contrast of the image, and fine adjustments should be made if necessary.

（3） Loading and observation of samples

The loading of samples should be strictly carried out in accordance with the operating procedures of the instrument. Firstly, place the sample on the sample rod and ensure that the sample rod is installed correctly. The installation position and angle of the sample rod directly affect the interaction between the electron beam and the sample, so it is necessary to ensure that the sample rod is firmly installed and accurately positioned. After the sample loading is completed, the sample rod should be slowly inserted into the sample chamber and the sample chamber door should be closed. When observing the sample, low magnification observation should be performed first, and the area of interest should be identified before gradually zooming in. During the magnification process, attention should be paid to adjusting the focal length and aperture to ensure clear image. At the same time, high magnification observation of the same area for a long time should be avoided to prevent the sample from being damaged by electron beam radiation.

（4） Image recording and analysis

Image recording is an important step in the operation of ultra-high pressure transmission electron microscopy. Modern ultra-high voltage transmission electron microscopes are typically equipped with highly sensitive electronic detectors, such as CCD cameras or CMOS cameras, which can convert electronic signals into digital images for subsequent analysis and processing. When recording images, appropriate exposure time and gain settings should be selected according to experimental requirements to ensure that the brightness and contrast of the image are moderate. After the image recording is completed, a preliminary analysis should be conducted to check the quality and information content of the image. If poor image quality or incomplete information is found, instrument parameters should be adjusted or images should be re collected in a timely manner.

3、 Operation precautions

（1） Safe operation

The operation of ultra-high voltage transmission electron microscopy involves dangerous factors such as high voltage, high vacuum, and strong magnetic field, so operators must strictly follow safety operating procedures. During the operation, appropriate protective equipment such as gloves, goggles, etc. should be worn to prevent electric shock, chemical corrosion, or mechanical injury. At the same time, operators should receive professional training and be familiar with the operating procedures and emergency response methods of the instruments. During the operation of the instrument, it is strictly prohibited to touch high-voltage components and vacuum systems to avoid accidents.

（2） Instrument maintenance

Ultra high pressure transmission electron microscopy is a high-precision instrument that requires regular maintenance and upkeep. Operators should regularly clean, inspect, and calibrate the instrument according to the requirements of the instrument manual. When cleaning, specialized cleaning agents and soft cloths should be used to avoid using cleaning agents containing corrosive components, so as not to damage the surface of the instrument. The inspection includes the operation status of key components such as vacuum system, cooling system, electronic optical system, etc., and timely detection and handling of potential faults and hidden dangers. Calibration work should be carried out by professional technicians, including optical path calibration, focal length adjustment, and imaging parameter optimization, to ensure that the imaging quality of the instrument reaches the best state.

（3） Sample protection

The sample is very fragile in ultra-high pressure transmission electron microscopy and is susceptible to radiation damage from electron beams and environmental factors. Therefore, special attention should be paid to the protection of the sample during the operation process. When loading the sample, it should be handled gently to avoid mechanical damage to the sample. When observing the sample, the dose and observation time of the electron beam should be controlled to avoid excessive radiation to the sample. For some environmentally sensitive samples, such as biological samples, operations should be carried out in a vacuum or inert gas environment to prevent oxidation and contamination of the samples.

（4） Data management

The image data collected by ultra-high pressure transmission electron microscopy usually has high resolution and large capacity, so it needs to be managed properly. Operators should establish a complete data management system to classify, store, and backup the collected images. When storing data, dedicated storage devices such as hard drives, CDs, or cloud storage should be used to ensure the security and integrity of the data. At the same time, detailed experimental parameters and operating conditions should be recorded in the data file for subsequent analysis and repeated experiments.

4、 Summary

Ultra high pressure transmission electron microscope is a high-precision microscopic analysis instrument, and its operation requires certain skills and strict adherence to operating specifications. Through preliminary work such as environmental inspection, instrument inspection, and sample preparation, the normal operation of instruments and the reliability of experimental results can be ensured. During the operation, high-quality image data can be obtained through key steps such as starting and adjusting the electron gun, aligning the optical path, loading and observing the sample, and recording and analyzing the image. At the same time, operators must strictly follow safety operating procedures, regularly maintain instruments, pay attention to sample protection and data management, to ensure the long-term stable operation of instruments and the accuracy of experimental data. Only through scientific and standardized operations can the powerful function of ultra-high pressure transmission electron microscopy in microscopic analysis be fully utilized, providing strong support for scientific research and technological innovation.