Kryolab is the cryogenic facility of Lund University, located at the Department of Physics. The purpose of Kryolab is to supply the university with liquid helium and liquid nitrogen. These liquid gases are used for cooling purpose in different kinds of research around the university and elsewhere. Liquid nitrogen has a boiling temperature of 195.8 C (77K), while liquid helium has a boiling temperature of 267.9 C (4.2K), which makes it the coldest known substance on the planet earth. Helium is a natural resource, and - like mineral oil - will not last forever. It is expensive and the use of it is dependent of an unstable world market situation. Liquid nitrogen is the low-budget alternative for many cooling applications, since it can be easily extracted from air.
From the outside, Kryolab is open Monday to Friday, 08:00 to 16:00. From within the building Kryolab is always open.
The Sulzer LINIT 25 from 1988 produces around 90000 liter liquid nitrogen per year, which is at the limit of the machines capacity.
Liquid nitrogen (LIN) is available for anybody to take them self. You enter your 'user-code' and how many liters you have taken, at the terminal by the liquefier. If you are a new customer, the Kryolab staff will help you to register and get your own 'user-code'.
Liquid helium (LHe) is produced with a Sulzer TCF-20 from 1985 - rebuilt in 1995 - and is nowadays run mainly on recycled gas.
It has a built in auto-purifier which use the coldness of the system to "freeze out" any impurities in the incoming helium gas. As much as 10 % air in the gas can be purified in this way, but less impurities is always better. Any kind of impurities entering into the turbine area of the liqufier will definitely cause problems and blockages.
Liquid helium will be filled in custom owned transport dewar by Kryolab staff.
The typical LHe would come from a well in Texas, USA, where it is liquefied on the spot. From then on, it will be transported in isolated containers, first to the east coast and then with boat to a port in Belgium. A truck will carry this container to some gas company in Sweden or Denmark. Here it will be transferred over to minor dewars - like kryolabs 500 liters dewar, which is then transported on a truck to Lund.
Since helium is a natural resource in limited supply, kryolab and the users of liquid helium have the aim to recycle as much as possible of the used helium gas. The cryostats are closed systems where most of the boiled-off helium gas is collected and sent back in hose to kryolab, where it is stored in high pressure gas bottles. Later on, this gas will again be purified and liquefied. However, helium consists of very small molecules which will leak and cause losses in any system, and there are still some users who are not recycling helium gas, so in reality around 60 % of the delivered liquid helium comes back as gas to kryolab.