The Technique for Making a Two Hole Symmetric SQUID and for the Adjustment of the Point-Contact Weak Link

Abstract

Practical techniques for making a two hole symmetric SQUID and for the adjustment of the point-contact weak link are described. The relation among the critical current, the room temperature resistance of the junction, and the Q decrease of a coil placed in one hole to obtain the optimum response, is discussed in terms of a simplified equivalent circuit. The optimum range of the room temperature resistance of the junction has been found to be 10-17Ω. Stability of the junction has been enhanced by mounting the device in a helium gas sealed can.