CS241571B1 - Superconducting gradiometer balancing device - Google Patents

Abstract

The solution concerns a device for balancing manufacturing tolerances of superconducting gradiometers used for measuring weak inhomogeneous magnetic fields using superconducting quantum magnetometers. It reduces the steepness of the regulation of correction elements while maintaining a relatively large regulation range enabling balancing even with large manufacturing deviations. At the same time, it improves the stability of the gradiometer during temperature cycles and increases its resistance to mechanical shocks. This is achieved by consisting of two mutually distant and mechanically linked correction elements (1), mounted on a common supporting body (3), which is mounted slidably in the direction of the gradiometer axis. It is suitable mainly for superconducting gradiometers intended for measuring weak biomagnetic fields, but it can also be used in non-superconducting systems, as long as the correction elements have an analogous effect.

Description

241571

BACKGROUND OF THE INVENTION The present invention relates to a device for balancing superconducting gradiometers for a composite magnetic field perpendicular to a gradiometer axis.

Superconducting gradiometers are used to match weak non-homogeneous magnetic fields to select the measured useful signal from the interfering homogeneous or homogeneous magnetic field. The methods used so far for balancing the manufacturing deviations of the gradiometer geometry, consisting essentially of a combination of the counter-phase-mounted transducers connected to the magnetic field perpendicular to the gradiometer axis, are based on the use of poor defocusing of the field by a movable, finely adjustable superconducting plate or superconductive seal. that loop with a flat perpendicular to the pole direction and parallel to the gradiometer axis. The requirements for adjusting such a coolant element are so high that it is a problem to reach its small regulating bridge without significantly reducing the control range, allowing even larger manufacturing tolerances of the geometry meters to be compensated. This problem is particularly prominent when adjacent gradiometer coils are anti-phase oriented ............

The above-mentioned drawbacks are substantially obviated by the device for balancing superconducting gradiometers of the invention, which consists of two mutually spaced apart and mechanically bonded correction elements mounted on a common carrier body. wherein the support body is displaceable in the direction of the axis of the gradiometer. It is an advantage of the invention that its use of a smaller slope of the control curve while maintaining a sufficient broad regulatory range results in a 10-fold increase compared to a single correction element. This makes it possible to balance the gradiometric systems, using marginal mechanisms to control the position of the correction elements, to a relative value of the order of 10 -5. A further advantage of the invention is a higher stability of the gradiometra of repeated cycles of its cooling to the temperature of the liquid helium and the heating to room temperature after removal from the cryostat. Gradiometer requires less frequent adjustment and is more resistant to mechanical shocks.

In the accompanying drawing, an exemplary arrangement is shown in which, in FIG. 1, the control curve of the 2nd gear gradiometer is shown in conventional balancing with a single correction element and the control line shown in the graph of the same graphiometer. in balancing with two correction elements, and FIG. 2 shows the principle of a device for balancing gradiometers according to the invention.

The superconducting balance balancing device consists of correction elements 1 fixedly mounted on a common non-magnetic bearing carrier 3. The gradiometer support body 4 is provided with sensing holes 2. Correction elements 1 form, in a particular embodiment, superconducting pads Dz and superconducting the Di-plate is still used as a correction element.

The correction elements Ϊ affect the balancing. gradiometer flood homogeneous auxiliary magnetic field By, perpendicular to their root and axes of the gradiometer, in the space of its sensing coils 2. Correction elements 1 are fixedly supported on a common non-magnetic carrier 3, which is correct after The x-axis is set with the o-control mechanism to the minimum gradiometer output signal caused by the magnetic field By. The optimum distance to each other and the size ratio of the surface elements 1, usually formed by superconducting dowels Dz or superconducted loops, depend on the gradiometer and is determined by calculation. The deflection curve of the gradiometer is the dependence of the e-flux magnetic flux ε, which causes the correction element 1 in the axis of the gradiometer, from the position of the correction element 1 expressed by the x-coordinate, whereby the p-axis of the x-axis is in the 1'avine extreme dream plane of a gradiometer coil 2, which is shown in the upper part of FIG. 1. Using a single correction element 1, namely a superconducting plate D1 at small gradiometer manufacturing deviations when a small value of the magnetic induction flux tokuε is required , for example, in the case of magnetic induction flux εει, unfavorable proportions. In such a case, it is necessary to set the superconducting droplet Di of one of the positions corresponding to the steepest part of the control curve. On the contrary, a more favorable situation arises in larger manufacturing deviations where a higher magnetic induction flux Φε, for example Φε2, is required. However, it will be appreciated that the ratios are more favorable in the first of these cases and unchanged in the second. In this case, the superconducting plate D1 is replaced by a pair of plates D2 with a pitch equal to that of adjacent sensor coils 2 gradiometers. Similar ratios apply to 1st order gradiometers, only the optimum distance of the correction elements 1 finer than the distance of the sensing coils of the 2gradiometer and it is necessary that the correction elements 1 do not paint the same area. These parameters can be accurately determined by calculation.

In particular, the present invention can be used for a superconductive gradiometer designed to measure biomagnetic fields and geophysical elevations using superconducting quantum magnetometers.

Claims (1)

SUBJECT Device for balancing superconducting gradiometers for a magnetic pole component perpendicular to the axis of a gradiometer, characterized in that it comprises two spaced and mechanically coupled compensation elements (1) mounted on a common support body (3), the support body (3) being 3) is displaceable in the direction of the axis of the gradiometer.