Introduction to super conducting quantum interfacing device Seminar Topic:
Squid is sensitive magnetometer which is used to detect extremely weak electromagnetic signals. The construction of squid based of the principle of Josephson junction. In this paper we will discuss the construction details and working model and applications of squid. It can detect signals which are 100 billion times weaker than a electromagnetic signals.
Construction and working of Squid:
The squid is made up of lead alloy where a tunnel barrier is sandwiched between a base electrode and a top electrode of the lead alloy. A josephson junction consists of superconductors separated by a thin insulator which allows the electrons to pass through them. The josephson junction is mounted on the conducting ring so as to achieve superposition which makes the electrons to pass in both directions. The voltage changes occur between the ring and conducting when applied current with an external oscillator. These voltage fluctuations are measured so as to measure the values. Due to resistive property of the device we can measure the minute changes accurately.
Applications of Squid:
These devices are used in medical fields. MEG is device which is based on the principle of squid which is used to measure the minute neural changes in the brain. These are used to trace out the path of the drugs injected in the body. The devices are employed to take MRI of the body. The squid devices are used in exploiting minerals and to find changes in the earth’s gravitation to predict the chances of earthquakes.
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