PIN: Table-top QHR standard (only fridge and graphene sample)

Description

This is a Prior Information Notice for Table-top QHR standard (only fridge and graphene sample). The National Physical Laboratory requires a Table-top QHR standard (only fridge and graphene sample). Lot 1: This is a Prior Information Notice for Table-top QHR standard (only fridge and graphene sample). The National Physical Laboratory requires a Table-top QHR standard (only fridge and graphene sample). A refrigerator for the operation of a Cryogenic Current Comparator (CCC)/Squid system at 4 K. The system should provide an experimental space of minimum size 15 cm diameter by 20 cm height, with a temperature stability of ±5 mK or better, and a supplied cooling power at base temperature of at least 0.5 W. The experimental space can be either in vacuum or immersed in self-condensed liquid helium, but the system must require no liquid helium to be supplied for either cool-down or regular running. The system should be designed for continuous operation for periods of at least 6 months.