Helium (He), atomic number 2, is a unique element found at the top of the noble gas group on the periodic table. Helium is the second lightest element, surpassed only by hydrogen, and it is non-reactive, meaning it does not readily form chemical bonds with other substances. This colorless, odorless gas also possesses the lowest boiling point of any known element, making it a substance of considerable scientific and industrial importance.
Revolutionizing Medical Imaging and Research
Helium’s exceptionally low boiling point, approximately 4.2 Kelvin or -269°C (-452.2°F), makes it an ideal coolant for achieving extremely cold temperatures. This property is important in medical imaging, where liquid helium cools the superconducting magnets within Magnetic Resonance Imaging (MRI) machines. These magnets must operate at near-absolute zero temperatures to become superconducting, allowing electricity to flow with virtually no resistance and generate powerful magnetic fields for detailed internal body images.
Without the ultra-cold environment provided by liquid helium, the MRI system would overheat, preventing proper function. Maintaining these temperatures enables precise medical diagnostics, offering high-resolution images for assessing conditions like heart damage, seizures, or tumor locations. Beyond medical applications, liquid helium is instrumental in scientific research, cooling quantum computers and particle accelerators like the Large Hadron Collider (LHC), where ultra-low temperatures are essential for superconducting components.
Lifting to New Heights
Another application of helium stems from its low density and non-flammable nature. Helium is lighter than air, which provides buoyancy, allowing it to generate lift. This characteristic makes it suitable for various lifting purposes, from common party balloons to specialized atmospheric research tools.
Its non-flammable property offers a safety advantage over hydrogen, which, despite being lighter, is highly combustible, as demonstrated by historical airship disasters. Therefore, helium is the preferred gas for meteorological balloons used to gather weather data and in the envelopes of modern airships and blimps, ensuring safe operation for advertising, surveillance, and potential future cargo transport.
Protecting Delicate Processes
Helium’s inertness, meaning its lack of reactivity with other substances, makes it an excellent shielding gas in various industrial processes. In arc welding, for example, helium creates an oxygen-free atmosphere around the molten metal. This protective shield prevents oxidation and contamination, which can otherwise compromise the quality and strength of the weld, especially when working with reactive metals like aluminum or titanium.
Helium helps ensure strong, clean welds. Beyond welding, helium’s inert environment is leveraged in other high-precision manufacturing sectors, such as the growth of silicon crystals for semiconductors and the production of fiber optics. In these industries, helium helps prevent impurities and ensures the integrity of delicate materials during their complex manufacturing stages.