MRI & HIMM
In the gradient amplifier system of MRI equipment, the output feedback from the high precision current sensor that can control the precise phase of the gradient amplifier in real time is the basis of the entire system. The quality, sharpness and resolution of the image are directly related to the magnetic field generated by the current through the gradient coil. Therefore, the accuracy of the current sensor is one of the most critical factors that determine the current control loop.
The system requires current transducer with the following performance.
· 1ppm nonlinear error
· -40 – 85°C operating temperature range
· <0.1 ppm / K temperature drift
· Very high time stability (the reason is the duration of the MRI scan, which may last for tens of minutes)
· Up to 1000A peak current
3dB bandwidth above 400KHz
In order to ensure the accuracy of the output current of the power supply, the scanning power supply of the medical heavy ion accelerator (HIMM) adopts a hysteresis (closed) loop control strategy to limit the tracking error to a very small error range, so stability and accuracy are very important.
The accelerator power supply of the HIMM equipment is the only source of energy for the main magnet. The performance of the power supply system is mainly affected by feedback accuracy and stability, regulator performance and reference stability. The feedback accuracy depends on the accuracy of high precision current transducer. Medical heavy ion accelerators The development of (HIMM) relies heavily on the development and improvement of implementation means and the accuracy and stability of each subsystem.
Hangzhi multi-point zero magnetic flux gate current sensor can measure the current range of 50A-10000A, with high accuracy, small error, stable performance, and wide operating temperature range. It can be used in the power supply system of various low-energy, medium-energy and high-energy medical accelerators and gradient amplifier of MRI.