Accession Number : AD0657931

Title :   THE MICROWAVE SURFACE RESISTANCE OF SUPERCONDUCTING LEAD, TRAPPED MAGNETIC FLUX, AND A NEW MAGNETOMETER USING SUPERCONDUCTIVITY.

Descriptive Note : Technical rept.,

Corporate Author : STANFORD UNIV CALIF HIGH ENERGY PHYSICS LAB

Personal Author(s) : Pierce,John Morley

Report Date : JUN 1967

Pagination or Media Count : 84

Abstract : An investigation has been made into the causes of the residual surface resistance which is always observed in superconductors at microwave frequencies. A new and extremely sensitive magnetometer has been developed which uses unique properties of superconductivity. Calculations and measurements indicate that this magnetometer can detect a field change of 3 x 10 to the minus 10th power gauss in a loop with 1 cm radius. The magnetometer uses a superconducting loop in which a field change is translated into a persistent current. Linking the loop is a cylinder of superconductor which can be switched alternately between the normal and superconducting states at a frequency of 150 KHz. Since the magnetic flux linking a superconducting cylinder is quantized, inductive impulses are given to the loop, and a large oscillation is built up which is proportional to the persistent current. The result is an output power equivalent to spinning the sensing loop at a frequency approximately 1,000,000 Hz. This accounts for the great sensitivity. (Author)

Descriptors :   (*MAGNETOMETERS, *SUPERCONDUCTIVITY), SUPERCONDUCTORS, LEAD(METAL), MICROWAVE FREQUENCY, DEGRADATION, MEASUREMENT, SENSITIVITY, MAGNETIC FIELDS, SURFACE PROPERTIES, ELECTRICAL RESISTANCE

Subject Categories : Geomagnetism
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE