Mark Sims wrote: > Commercial JJ arrays, cryoprobes, and standards: > http://www.prema.com/D/JVSe.htm > > Also Supracon (who have a cryocooler version - No helium dewar): http://www.supracon.com/en/josephson_voltage_standard.html and Hypres: http://www.hypres.com/products/primary-voltage-standard-system-liquid-helium/ Bruce