FPGA-Based Interface of Digital DAQ System for Double-Scattering Compton Camera

Area of Science:

• Nuclear Instrumentation
• Radiation Detection and Imaging

Background:

• The double-scattering Compton camera (DSCC) is crucial for radiation imaging, providing source energy spectra and 3D spatial distributions.
• CdZnTe (CZT) detectors are integral to DSCC, measuring energies and locations for image reconstruction.

Purpose of the Study:

• To develop a digital data acquisition (DAQ) board for enhanced coincidence detection in DSCC research.
• To support the reconstruction of emission energies and spatial images using CZT detectors.

Main Methods:

• The DAQ board integrates 12 ADCs and one FPGA to digitize 96-channel CZT signals at 50 MHz.
• Sync calibrations were performed on all ADC channels to align clock signals for accurate data capture within the FPGA.
• FPGA logic incorporated IDELAY, IDDR components, shift registers, and bit slip buffers for signal processing.

Main Results:

• Deskew test patterns determined IDELAY values for optimal bit clock alignment.
• MSB test patterns identified bit slip in 12-bit ADC samples.
• The interface between ADCs and FPGA showed a mean R^2 goodness-of-fit of 0.95 with synthetic Gaussian signals.

Conclusions:

• The developed DAQ board successfully facilitates accurate data acquisition for DSCC systems.
• Sync calibration and FPGA logic ensure reliable performance of the CZT detector interface.
• The system demonstrates high fidelity in capturing and processing radiation detection data.