Tunneling Magnetoresistance DC Current Transformer for Ion Beam Diagnostics

Area of Science:

• Accelerator Physics
• Instrumentation and Measurement

Background:

• Accurate measurement of direct current (DC) components in ion beams is crucial for accelerator diagnostics.
• Existing methods may lack sensitivity or speed for precise DC ion beam characterization.

Purpose of the Study:

• To present and compare open-loop and closed-loop Tunneling Magnetoresistance (TMR) DC Current Transformers (DCCTs) for ion beam diagnostics.
• To evaluate the performance of TMR sensors against Giant Magnetoresistance (GMR) sensors for DCCT applications.
• To demonstrate the effectiveness of a closed-loop feedback system for enhanced DCCT performance.

Main Methods:

• Development and testing of both open-loop and closed-loop TMR DCCT configurations.
• Comparative analysis of TMR and GMR sensor performance for DC current measurement.
• Design and implementation of a closed-loop feedback electronic system for zero-flux operation.
• Theoretical analysis, experimental validation, and noise analysis of the TMR-based DCCTs.

Main Results:

• Both open-loop and closed-loop TMR DCCTs achieve minimum detectable currents in the microampere range.
• The closed-loop TMR DCCT prototype exhibits a settling time of less than 15 μs.
• Measured minimum detectable currents are 128.2 μA/√Hz for open-loop and 10.14 μA/√Hz for closed-loop at 1 Hz.

Conclusions:

• TMR-based DCCTs are highly effective for ion beam diagnostics, offering microampere sensitivity.
• The closed-loop configuration significantly enhances sensitivity and reduces noise compared to the open-loop design.
• The developed TMR DCCTs, particularly the closed-loop version, provide a robust solution for precise ion beam current monitoring.