A vacuum technique is one of the most important techniques in cryogenics. The thermal insulation (MLI) and the production of superfluid helium are the main applications of the vacuum techniques. The calculations of vacuum conductances, pumping speed and ultimate pressure including a low temperature case are explained. The vacuum components (pumps, tubings, valves, flanges, gauges) within a vacuum system are also explained. Especially the techniques to maintain the clean vacuum of the thermal insulation are described in detail. The vacuum leak test is also important for making a good cryostat.
