Design and Simulation of the Superconducting Quantum Interference Device Measurement System with Planar Gradiometers

• Main Authors: Pei-Yu Cheng, 鄭培煜
• Other Authors: 孫允武
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/26411779958457707859

碩士 === 國立中興大學 === 物理學系所 === 98 === Superconducting QUantum Interference Devices (SQUIDs) have been extensively used in the detection of very small magnetic signals. We have designed a SQUID measurement system including a pick-up coil in a gradiometer configuration which can cancel the background noise and strong uniform DC magnetic field. We use this system to detect the variation of the magnetic dipoles of GaAs in a strong magnetic field. We have estimated the flux from the sample, inductance of the coils and also the detecting limit of the voltage signal. We demonstrate the operation method of the feedback loop worked in our SQUIDs measurement system. At the end, we propose several methods to improve the sensitivity, such as increasing the number of the coil and the frequency of the AC signal. We expect the detected signal can be enhanced around 2 to 3 orders of magnitude.