Optimization of the Antenna Unit of the Superconducting Magnetometer: Research of Weak Magnetic Signals

Abstract

Introduction. The article describes the optimization of the superconducting antenna design and balancing method of the superconducting antenna of magnetometer. This magnetometer is designed to study the magnetic properties of materials, as well as non-invasive study of the distribution of magnetic particles in organs of small laboratory animals, when toxic particles or drugs are introduced into the animal's body. The superconducting antenna of the magnetometer is a second-order axial gradiometer and is a part of the flux transformer of the SQUID sensor. For stable operation within the dynamic range of the magnetometer, the antenna must have a balance degree of at least 1/1000. Traditionally, it is balanced in a separate tuning module (Helmholtz coils), which creates a homogeneous magnetic field with a high degree of uniformity. The purpose. The problem is that the subsequent displacement of the SQUID magnetometer unit into the measuring complex, even within the laboratory, reduces the degree of balance of the magnetometer due to objects that create a strong gradient magnetic field, which negatively affects the measurements. Results. As a solution of this problem, the some approaches are described in the article. In order to increase the uniformity of the field inside the solenoid and eliminate field distortions at its edges, the using of solenoid with a special arrangement of turns to balance the antenna directly at the measurement site was proposed. The balancing elements for the horizontal components of the magnetic field were eliminated. Also the antenna balancing element in the form of a ring along the vertical component of the magnetic field, which does not violate the symmetry of the antenna was applied. Conclusions. Using this approach, it is possible to optimize the design of the antenna unit and the balancing process of the magnetometer antenna with a sufficient degree of balance in the vertical component directly in the geometric center of the measuring system, which reduced the time of preparing the system for work and improved the metrological indicators of the system. Keywords: superconductivity, SQUID-magnetometry, axial gradiometer, antenna balance, optimization.