Summarized Proceedings of a Symposium on Electronic Devices at Helium Temperatures - London, November 1960

Abstract

A one-day symposium on electronic devices which work at helium temperatures was held jointly by the Low Temperature Group and the Electronics Group of The Institute of Physics and The Physical Society on 15th November, 1960. The emphasis was on devices which could be used in electronic computers. Recently there have been considerable advances in the research on Crowe cells and cryotrons. Both devices can be switched at high speed (~ 10-15 ns) and the factors governing their performance are fairly well understood. There have been equal advances in the development of a helium refrigerator of great reliability and efficiency. With cryotrons, the conditions for reproducibility are far less stringent than with the Crowe cell and, as four terminal devices with current gain, they offer great flexibility to computer designers, being capable of use both in the store and in logical components. The p-n junction, tunnel diode, and cryosar are all based on semiconductors and all work at helium temperatures. They could be very useful ancillary devices in computers based on superconductors or, on the other hand, computers could be based on these devices entirely and the use of liquid helium is then unnecessary. However, taking into account the low heat dissipation and close packing feasible with superconductive devices (107 bits in a 35cm cube), where fast computing is concerned the cryotron offers great advantages. It is, moreover, a device of universal application throughout a computer which may demand a new approach to logical design and the layout of the machine.