Helium-4 Nuclei and Isotopes

He-4 Nuclei

• Helium-4 (He-4) nuclei are composed of two protons and two neutrons.
• They exhibit exceptional stability, reflected in their low energy levels.
• Strong nuclear forces bind the protons and neutrons within the He-4 nucleus.

Isotopes

• Isotopes are atoms of the same element with differing neutron counts.
• Helium has two naturally occurring isotopes: He-3 and He-4.
• He-3 has two protons and one neutron, while He-4 has two protons and two neutrons.

Properties of He-4

• He-4 has a mass number of 4 and an atomic number of 2.
• The binding energy per nucleon is exceptionally high in He-4, highlighting the strong nuclear force.
• The nucleus's spin is zero.

Applications of He-4

• Due to its low boiling point, He-4 is used in cryogenics.
• It's crucial for cooling superconducting magnets, essential for MRI machines and other advanced technologies.
• He-4 has applications in atomic physics experiments.

Superfluidity

• At extremely low temperatures, He-4 displays superfluidity.
• Superfluidity implies frictionless flow, a quantum mechanical effect unique to the ground state of He-4.
• Below a critical temperature, He-4 becomes superfluid, exhibiting zero viscosity and flowing through tiny capillary cracks.

Bose-Einstein Condensation

• Bose-Einstein condensation (BEC) is a phenomenon observed in certain substances at ultra-low temperatures.
• He-4 is one substance where BEC manifests.
• BEC occurs when numerous bosons occupy the same quantum state.

He-4 Properties at Different Temperatures

• At higher temperatures, He-4 behaves like a regular liquid.
• As temperatures decrease, He-4 exhibits superfluidity below its critical temperature and displays other quantum behaviors.
• At extremely low temperatures, He-4 transitions into a solid phase.

Quantum Mechanical Nature

• He-4 displays several quantum mechanical properties that distinguish it from other materials.
• Its behavior is intricately tied to quantum mechanics; its properties are fully understood only within this framework.