Development of improved superconductive axial gradiometers for SQUID biomagnetic application
M.M. Budnyk1, Yu.D. Minov1, V.Yu. Lyakhno2, V.A. Desnenko2, A.S. Linnik2, and O.B. Shopen3
1Glushkov Institute of Cybernetic of NAS of Ukraine, 40 Glushkova ave., Kyiv, Ukraine, 03187
2B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Nauky Ave., Kharkiv 61103, Ukraine
3ООО «НПП Пластар», ул. Разина, 8, пгт. Золочев, 62203, Харьковская область, Украина
Received November 7, 2017
SQUID magnetometers for biomagnetic measurements are equipped with superconductive gradiometers that must have high SNR at low frequencies, mechanical strength and sustained performance during numerous thermal cycling, with low own magnetic noise. This paper describes the design of the gradiometer intended to operate in magnetic cardiography studies and is made of a composite material reinforced with carbon fibers. Coefficient of thermal expansion (CTE) of proposed carbon-filled plastic can be precisely adjusted to match to that of the detector coils wire. This is guaranteed due to different CTEs for carbon fibbers in their longitudinal and cross directions by putting the filaments in various orientations when forming the composite. The data of measurements of magnetic susceptibility of carbon-filled plastic are re-ported showing it is about 6 times smaller as compared to that of graphite. The gradiometer design provides its high balance due to advanced patented methods.
PACS: 07.55.Ge Magnetometers for magnetic field measurements;
Key words: SQUID gradiometer, magnetic susceptibility, coefficient of thermal expansion, carbon-filled plastic.
Published online: January 25, 2018