Abstract: A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop.

Abstract: An expansion joint lock for transmitting forces between structural members that contract as they are cooled down to operating temperatures. A piston member mounted to one structural member is slidingly engaged with a chamber in a reception member which is mounted to a second structural member. The remaining space in the chamber is filled with a liquid which freezes at a temperature somewhat above the operating temperature of the structure, allowing forces to be transmitted between the structural members by the frozen liquid.