1. Cryostat Evolution

    Hardware development continued in parallel with device development. Generally Canberra was not the leader in hardware innovation but we tried to stay competitive by developing better versions of popular products. For example our Multi-attitude Cryostat (MAC) and Big-MAC both had about twice the holding time of ORTECs portables. Ironically, one case in which we did pioneering work by inventing and patenting (in 1983) the Convertible Cryostat, came to a disappointing end when ORTEC introduced their so called POP-TOP cryostat, operating on exactly the same principle as that of our Convertible.  They even got a patent on it despite having been notified of the existence of our patent. Our patent was poorly written by our patent attorney and ORTEC filed their application in a different category never advising the patent office of the existence of our prior art.

    Competitive pressure forced us to introduce our Slim-line Cryostats which we could not make using our metal seal technology so long term reliability suffered a bit from this option.

    Over the years we introduced a succession of electrically cooled cryostats starting with the Cryolectric, around 1988, which was based on a Gifford-McMann helium refrigerator from Helix Technology. This was an expensive option but we sold quite a few of these over a period of years. Unfortunately the presence of moving parts in the cold head limited the time between (expensive) episodes of factory service so we did not push this option unless the application demanded LN2-free operation.

    Later we introduced a mixed-gas refrigerator in the Freolectric. This less expensive option was promoted for laboratory use and many were sold and worked well until the manufacturer bowed to international pressure to eliminate the fluorocarbons from the refrigerant mix. After this they were never able to guarantee 24-7 operation because the cold head would clog up periodically and the unit would stop cooling.

    The next cooler was introduced around 1997. This unit was also a mixed-gas refrigerator but it was very versatile and the performance was outstanding. This CFC-free cooler contained a small amount of flammable refrigerant in the mix but it was deemed safe for transport and use in most environments. The refrigerator was developed by Air Products in Allentown, Pennsylvania and was later sold to a California company. Unfortunately this product developed a clogging problem with continuous operation and this limited its use in 24-7 applications.

    Around 2003 we developed a really innovative product that we called a hybrid cryostat. This unit was dubbed “The Ever-Ready” for a short time before a certain battery company objected rather strenuously whereupon we changed the name to The Cryo-Cycle. Using a compact Stirling Cooler built into a custom Dewar assembly we are able to re-condense the nitrogen boil-off gas and thus operate virtually indefinitely without adding liquid nitrogen. In case of power failure the unit will provide cooling for 10 days or so until power can be restored. It will even make liquid nitrogen from nitrogen gas if needed.  This has been a very popular product easily outselling all the previous generations of electric coolers combined. 

    At the same time our new associates at Canberra Lingolsheim developed a Cooler based on Pulse-Tube  technology. This refrigerator is similar to the Stirling cycle, but it employs a pressure wave instead of a moving displacer in the cold head. It has proven to be a very reliable cooler and has been widely used in diverse applications since its introduction.