IT05. Squid sensor development and itsutilization

Abstract

DC SQUID sensors based on Nb-AlOx-Nb Josephson junctions were designed and developed at IGCAR, Kalpakkam. Necessary electronics to linearize the SQUID output was developed in-house. These SQUID sensors were used to develop various measuring systems like SQUID magnetometer, SQUID based NonDestructive Evaluation system and multichannel SQUID based biomagnetic measuring systems. In addition supportive instrumentation for SQUID magnetometer like Variable Temperature Insert(VTI) based on flow control of helium gas through a capillary tube for temperature control of the sample chamber has been designed and developed. A VTI based 7T SQUID magnetometer was developed. Development of VTI incorporated SQUID based Vibration Sample Magnetometer to improve the sensitivity is under progress. SQUID NDE has been utilized to identify subsurface defect locations in aluminum plates and optimum frequency for different defect depths. SQUID NDE system has been utilized to detect fatigue induced transformation of δ-ferrite into non-magnetic phases. Multichannel SQUIDs have been utilized inside a magnetically shielded room to measure the magnetic signals from brain(Magnetoencephalography, MEG) and heart (Magnetocaridocagraphy, MCG). Non invasive MCG has been utilized to measure magnetic signal due to HIS bundle activity in the heart and the results have been corroborated with invasive measurements. The talk outlines the development of these SQUID based instruments and their utilization in research.