Hệ đo siêu nhạy từ dựa trên kỹ thuật khuếch đại Lock-in và cảm biến từ trở khổng lồ=Ultra high sensitive magnetic measurement system based on Lock-in amplifier technique and giant magnetoresistance sensor

0 Người đánh giá. Xếp hạng trung bình 0

Tác giả: Xuân Mạnh Vũ

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Khoa học và Công nghệ Việt Nam, 2025

Mô tả vật lý: tr.43-49

Bộ sưu tập: Metadata

ID: 478463

Thêm vào giỏ

Mạch xử lý tín hiệu sử dụng kỹ thuật Lock-in được phát triển cho thiết bị đo từ trường, giúp xử lý tín hiệu từ các cảm biến có biên độ nhỏ hơn nhiễu nhiều lần. Mạch này được tích hợp với cảm biến từ trở khổng lồ (GMR) để đo các nguồn từ trường yếu. Thiết bị đề xuất được kiểm chứng bằng thí nghiệm đo từ trường xoay chiều trong khoảng 0-0,04 G. Nguồn từ trường này được tạo ra bởi một cặp cuộn dây Helmholtz chế tạo bằng công nghệ in 3D, có thể duy trì từ trường đều và điều chỉnh được cường độ, tần số cũng như hướng. Kết quả thực nghiệm cho thấy, thiết bị có giới hạn phát hiện (LOD) 3,81 nT, tương ứng với sự thay đổi 6,5 μV từ ngõ ra cảm biến. Mạch xử lý tín hiệu đạt hệ số khuếch đại thực nghiệm 1386 lần, vùng làm việc tuyến tính 0-7 mV đầu vào, cho đầu ra 0-10 V, với LOD tín hiệu đầu vào khoảng 631 nV. Trong dải tín hiệu nhỏ, thiết bị đề xuất có khả năng phát hiện tín hiệu tốt hơn các thiết bị đo thương mại. Hệ thống đo từ trường này có thể phát hiện từ tính của hạt nano siêu thuận từ (SPMNP) liên kết với đối tượng sinh học phân tử, hỗ trợ phát triển thiết bị phân tích y sinh.The signal processing circuit utilising the Lock-in technique has been developed for a magnetic field measurement device, enabling the processing of signals from sensors with amplitudes significantly smaller than noise levels. This circuit is integrated with a giant magnetoresistance (GMR) sensor to measure weak magnetic field sources. The proposed device was validated through experiments measuring alternating magnetic fields in the range of 0-0.04 G. The magnetic field source was generated by a Helmholtz coil pair fabricated using 3D printing technology, capable of producing a uniform magnetic field with adjustable intensity, frequency, and direction. Experimental results showed that the device has a limit of detection (LOD) of 3.81 nT, corresponding to a change of 6.5 μV at the sensor output. The signal processing circuit achieves an experimental gain factor of 1386, with a linear operating range from 0-7 mV input, corresponding to an output range of 0-10 V, with the circuit’s input LOD being approximately 631 nV. In the low-signal range, the proposed device demonstrates a better ability to detect magnetic field and voltage signals than commercial measurement devices. This magnetic field measurement system can detect the magnetism of superparamagnetic nanoparticles (SPMNPs) associated with molecular biological targets, supporting the development of biomedical analysis devices.

1. Đọc trực tuyến

1. Đọc trực tuyến

Tạo bộ sưu tập với mã QR