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Helium liquefier for PTB in Braunschweig

28.11.2016

In May 2016, a helium liquefier was commissioned in the Electricity Division; it now provides the whole of PTB's Braunschweig site with liquid helium during routine operation. The facility especially covers the helium needs for research, development and the use of electric quantum standards. This improved supply reliability also benefits other areas of PTB.

 

 

The electric standards based on quantum effects for voltage, resistance - and, in future, also for current - can only be exploited for high-precision measurements at liquid helium temperatures of 4 K or lower. Also for other metrological tasks such as cryogenic radiometry or certain spectroscopic investigations of the properties of solids, the availability of liquid helium is a prerequisite.


In order to ensure the supply of liquid helium in the long run, a helium liquefier facility has now been commissioned at PTB's Braunschweig site. Liquid helium was previously purchased, but in the past few years, deliveries had become increasingly unreliable due to fluctuations in the world helium production. One of the side-effects was obviously increasing prices, but the shortages were the main criterion which led to the decision to produce liquid helium on site.


Since the recovery plant, which is a prerequisite to operate such a liquefier facility economically, already existed, the funds were allocated quickly and the facility could already be ordered as early as the end of 2014. The planning for the building required to accommodate the facility was completed at the beginning of 2015, and after it was completed very timely, the first component of the facility started being set up that same year.


At the same time, the recovery plant was modernized to be connected to the new liquefier which was commissioned last May. Since then, the facility has produced up to 30 liters of liquid helium per hour, which not only suffices to cover consumption peaks which occurred in the past, but also offers enough reserve to cover even stronger needs that may occur in the future.

 

helium liquefier and filling station

Picture: The new helium liquefier (left) and helium filling station with 4000 liter storage tank.