A Controlled Magnetic Clamp

Abstract

A clamp for establishing a thermal contact between cryostat components in a vacuum is described. The contact is established by pressing heat conductors to each other using a permanent magnet and is broken or established by applying a current pulse of the required polarity to the winding around an iron magnetic core. The device is held in the open state by a second permanent magnet. Through the pressed contacts, a copper block with a mass of ∼600 g is cooled in the vacuum from the liquid-nitrogen temperature to the liquid- helium temperature within 4–5 h.