The Lancaster University Spin-off Lancaster Helium Ltd is potentially the only commercial supplier in the world for isotopically pure helium. Originally developed to satisfy the needs of scientists at the University in the 1980s, when orders became big enough, the company was spun-off from the physics department. 
This He-4 gas has 2 neutrons in the nuclei of its atoms and is the most common naturally occurring form of helium. However, He-3 (which has 1 neutron in the nucleus) tends to be present in small amounts and even tiny trances can have a huge influence and must be removed for certain uses and studies. For example, one of the main reasons for using pure He-4 gas is to reduce pollution as He-3 impurities are converted into radioactive hydrogen (tritium) by reactor neutrons. 
This purified Helium gas can be used for a plethora of things including: a coolant gas for a nuclear reactor, experiments on quantum turbulence, and ultra-low-temperature experiments on solid He-4 . The company is still very connected to the University and still have their facilities in the Physics Department at the University .