Design of a Real Time FPGA-based Three Dimensional Positioning Algorithm.

Area of Science:

• Medical Physics
• Nuclear Instrumentation
• Detector Technology

Background:

• Previous work established a 2D Field Programmable Gate Array (FPGA) implementation for Statistics-Based Processing (SBP) to determine detector spatial resolution.
• Continuous miniature crystal element (cMiCE) detectors require advanced processing for accurate spatial resolution determination.

Purpose of the Study:

• To implement and evaluate a real-time 3D Statistics-Based Processing (SBP) method with depth of interaction for cMiCE detectors.
• To improve intrinsic spatial resolution, particularly at the edges of the crystal elements.

Main Methods:

• Utilized a sensor on the entrance surface design for cMiCE detectors.
• Developed a 3D look-up table approach within the SBP algorithm.
• Implemented a pipelined Field Programmable Gate Array (FPGA) hardware platform for real-time event processing.
• Incorporated DETECT2000 simulations including Compton scatter effects.

Main Results:

• Achieved an intrinsic spatial resolution of approximately 0.90 mm FWHM in X and Y, and 1.90 mm FWHM in Z.
• The FPGA implementation processes events exceeding 220k events per second.
• The 3D algorithm significantly improves resolution at crystal edges compared to 2D methods.
• A prototype was tested, demonstrating feasibility despite memory limitations.

Conclusions:

• The 3D SBP method with depth of interaction processing offers improved intrinsic spatial resolution for cMiCE detectors.
• The pipelined FPGA implementation provides high-speed, distributed processing, reducing computational load on a central host.
• This approach enhances detector performance, especially in regions previously limited by 2D algorithms.