基于超导量子干涉仪的磁性颗粒检测单元分析

Analysis on magnetic particles detection unit based on SQUID

带有磁化退磁样品处理单元的扫描超导量子干涉仪(SQUID)显微镜系统,配合样品移动定位平台,可以实现生物样品内源磁性颗粒磁学特性和磁场分布的测量。基于SQUID的磁场检测单元为系统重要组成部分,介绍检测单元基本结构、检测原理,推导磁通、磁场和电压间的转换公式,建立磁性颗粒模型。通过仿真分析线圈参数对系统磁场灵敏度和空间分辨率的影响,设计绕制了直径500μm,30匝的超导接收线圈,系统磁场灵敏度为1.46×10-13 T/(Hz)^(1/2),空间分辨率为500μm。磁性颗粒模型和仿真分析为系统设计、实验数据分析提供了理论依据。

Scanning superconductivity quantum interference device （SQUID）microscopy with sample handling unit and the movable and positioning sample platform, can realize measurement of the magnetic characteristics and magnetic field distribution of magnetic particles in biological sample. The magnetic field detecting unit is an important component of the system. Introducing the structure and detection principle of the magnetic field detecting unit, deriving conversion formula of the magnetic flux, magnetic field and voltage, establishing magnetic particle model,and analyzing the influence of different coil parameters on the magnetic field sensitivity and spatial resolution through simulation. Superconducting receiving coil with diameter of 500 μm,30 turns is made, magnetic field sensitivity is 1.46×10-13 T/（Hz）, and spatial resolution is 500 μm. Magnetic particle model and simulation analysis provide theory basis for system design and experimental data analysis.