The Need

Transmission electron microscopy (TEM) is used to capture fine detail of specimens less than 100 nm thick making it ideal for physical, chemical, and biological sciences. To generate an image of a physical science specimen, the sample must be cooled to cryogenic temperatures to halt atomic movement. Current cryogenic sample holders use evaporative cooling from liquid nitrogen to stabilize samples. The nitrogen sufficiently cools a sample to 77K, but in the process, the boiling liquid transmits vibrations to the sample thereby distorting the resulting images. Furthermore, this liquid nitrogen process is limited to only one temperature, the boiling point of nitrogen. Therefore, there is a need for an innovative design approach for the TEM sample holder to regulate the temperature of the specimen and eliminate vibrations when viewing samples at the atomic level.

The Technology

Researchers at The Ohio State University’s Center for Electron Microscopy and Analysis have created a sample holder free of vibrations with the ability to cool samples to targeted temperatures of 233K and lower. As compared to traditional nitrogen cooling, this invention gives researchers several distinct advantages with the flexibility of sample temperature and elimination of vibrations. A thermoelectric cooler (TEC) is used to remove heat from the sample. The TEC is a conventional solid-state heat pump, operating without the flow of fluids or gases, and thus without vibrations. Using a TEC allows a sample to reach any temperature between the temperature of the coolant and the maximum cooling capability of the TEC. The TEC can also heat a sample to 333k by reversing the polarity. A vibration free sample holder with the ability to change temperature will offer researchers the flexibility to beam-sensitive and temperature dependent systems with unprecedented clarity.

Commercial Applications

• Transmission electron microscopy of temperature dependent systems

• Transmission electron microscopy of beam-sensitive samples

• Structural biology research

Benefits/Advantages

• Adds low temperature imaging to any side-entry transmission electron microscope

• Minimize vibration resulting from cooling

• Variable temperature from 233-333K