A study on magnetic flux concentrator to enhance sensitivity of SQUID in magnetoenterogram

The Magnetoenterogram (MENG) utilizes the superconducting quantum interference device (SQUID) with ultra-high sensitivity to detect magnetic signals emanating from the intestines. The magnetic field distribution reflects the ischemic condition of the mesentery to diagnose the acute mesenteric ischemia. In practice, the intestinal magnetic signal is very weak and difficult to be identified from noises, i.e., the signal to noise ratio (SNR) is relatively low. An innovative magnetic flux concentrator (MFC) combined with the MENG is presented in the paper in order to enhance the SNR. The specific work includes the selection of MFC material with suitable permeability, optimization of the diameters and heights. The enhancements for various directional magnetic signals were simulated. Finally, some of preliminary experiments were conducted to test the MFC enhancements. The intestinal signal was simulated using a powered coil at low frequencies. Approximately a 10-fold enhancement is achieved, remaining constant during the 0.2Hz to 1Hz range.