Liquid helium, particularly helium-4 (4He), is widely used in various scientific and industrial applications. Here are some advantages and disadvantages associated with its use:
Advantages of using liquid helium:
Extremely low temperature: Liquid helium has a boiling point of approximately 4.2 Kelvin (-268.93 degrees Celsius or -452 degrees Fahrenheit), making it one of the coldest substances on Earth. This ultra-low temperature allows for unique experimental conditions, especially in fields like cryogenics, superconductivity, and low-temperature physics.
Superconductivity: At very low temperatures, certain materials exhibit superconductivity, a phenomenon where electrical resistance vanishes. Liquid helium is used to cool superconducting materials, enabling their practical applications in technologies like magnetic resonance imaging (MRI), particle accelerators, and quantum computing.
Cooling and cryogenics: Liquid helium is an efficient coolant for various applications, such as cooling superconducting magnets in MRI machines and particle accelerators, as well as in cryogenic research and cryopreservation of biological samples.
Helium cryostats: Liquid helium is used to create cryostats, which are devices used to maintain extremely low temperatures. Cryostats provide a controlled environment for experiments requiring low temperatures, such as in condensed matter physics and materials science.
Disadvantages of using liquid helium:
Limited supply: Helium is a non-renewable resource and is becoming increasingly scarce. It is primarily obtained as a byproduct of natural gas extraction, and its production is limited. The shortage of helium has led to increasing prices and concerns over its long-term availability.
Cost: Liquid helium is expensive due to its limited supply and the energy-intensive processes required to liquefy and store it at extremely low temperatures. The high cost can be a limiting factor in some research and industrial applications.
Handling and safety: Liquid helium is extremely cold and can cause severe frostbite upon contact with skin or other materials. Special precautions, such as proper protective equipment and handling procedures, are necessary to ensure safety. Additionally, helium gas is non-toxic but can displace oxygen in confined spaces, posing a suffocation risk.
Evaporative loss: Liquid helium is prone to evaporation, even at very low temperatures. The evaporation rate increases with temperature and exposure to heat sources. As a result, the loss of helium through evaporation can be significant, leading to additional costs and logistical challenges in maintaining a constant supply.
Overall, while liquid helium offers unique advantages for low-temperature applications, its limited supply, high cost, and safety considerations necessitate careful management and alternative approaches to address these challenges. Researchers and industries are actively exploring alternative cryogens and developing more efficient helium recycling and recovery methods to mitigate the reliance on this valuable resource.