Method and apparatus to digitize pulse shapes from radiation detectors
Inventors
Weisenberger, Andrew • McKisson, John E. • Dong, Hai • Cuevas, Chris • Mckisson, John • Xi, Wenze
Assignees
Jefferson Science Associates LLC
Publication Number
US-10027340-B1
Publication Date
2018-07-17
Expiration Date
2032-12-31
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Abstract
A field programmable gate array based multi-channel flash ADC unit combined with a high speed multi-lane data communications channel/Ethernet-like modular intercommunication providing a complete but easily expandable high-speed data acquisition system. This apparatus and method permits high-speed pulse-shape digitalization allowing position resolution imaging of particles having a range of energies and is scalable to achieve the efficient capture of coincident data from large electromagnetic detector arrays.
Core Innovation
The invention discloses a modular data acquisition apparatus integrating a field programmable gate array (FPGA) based multi-channel flash analog-to-digital converter (ADC) with an Ethernet type communication system. This apparatus enables high speed pulse-shape digitization allowing position resolution imaging of particles across a range of energies. The system incorporates embedded software within the FPGA to collect data from multiple channels, detect coincident events on these channels, and selectively present only these valid coincident event waveforms to an external processor for further processing, significantly reducing data transmission and processing load.
The background describes the challenges in radiation detector systems for gamma rays, X-rays, and particle detection that provide imaging of interaction positions. Existing DAQ systems digitize analog pulses for measurement but face issues handling large multi-channel inputs, coincident event detection, and data transmission requirements, especially for large detector arrays used in nuclear physics or medical imaging. Conventional methods either require extensive cabling for direct timing coincidence detection or rely on time tagging with heavy data transmission and post-processing, both being impractical for frequently reconfigurable or high event rate systems.
This invention solves these problems by providing an expandable, FPGA-based multi-channel flash ADC system combined with high speed laser transceiver or Ethernet-like modular intercommunication. It uses local coincidence detection and hierarchical coincidence matrix processors to perform near real-time coincidence determination with minimal data transmission. The system is scalable, supports online digital signal processing for pulse shape filtering and charge calculation, and can adapt to various scales and complexities of applications without burdensome cabling or excessive data storage.
Claims Coverage
The patent includes three independent claims covering an expandable system for digitizing pulse shapes from radiation detectors and methods employing field programmable gate arrays for multi-channel data acquisition and coincidence detection.
Expandable multi-channel digital pulse shape acquisition system
A system comprising multiple collection and processing units each with a field programmable gate array; a coincidence matrix processor (also FPGA based) communicating with these units through a high speed multi-lane data channel; a data acquisition module; and algorithms on the coincidence matrix processor to identify valid coincidences within digitized pulse charge shape data.
Method for digitizing and processing coincident pulse shapes
A method including providing a collection module with multiple FPGA-based conversion units having flash ADC electronics digitizing at least sixteen simultaneous channels; a processor module with FPGA and embedded algorithm detecting time-coincident signals from multiple channels; capturing, digitizing, transmitting, processing waveform data; communicating triggers for valid coincidences; and forwarding tagged waveforms to an external processor.
Hierarchical multi-module coincidence detection method
A method employing at least three collection modules with FPGA-based flash ADC electronics and at least one coincidence processor module (FPGA based) detecting time-coincident pulses, transmitting waveform data, performing real-time tagging upon valid coincidence detection, and hierarchically cascading lower and upper-level FPGA coincidence processors to manage data streams and coincidence determination, forwarding only tagged waveforms to an external processor.
The claims collectively cover a scalable, FPGA-based multi-channel ADC system integrated with high speed communication for real-time coincidence detection, data reduction, and hierarchical processing applicable to radiation detector pulse shape digitization and position resolution imaging.
Stated Advantages
Provides a scalable, versatile, and easily expandable high-speed data acquisition system.
Enables high-speed pulse-shape digitization allowing position resolution imaging for particles with a range of energies.
Reduces data transmission and storage needs by transmitting only valid coincident event waveforms to external processors.
Supports online digital signal processing including pulse shape filtering, charge calculation, and dynamic feedback for DAQ reconfiguration.
Incorporates universal high-speed data interlinks using fiber optics and Gigabit Ethernet compatible with major computer platforms.
Documented Applications
Single photon-imaging gamma camera with fewer than 16 channels in standalone mode.
Clinical single-photon emission computed tomography (SPECT) scanner with combined channels and fewer than 100 channels.
Clinical positron emission tomography (PET) scanner with multi-layer coincidence processors and typically less than 200 channels.
Nuclear physics calorimeters using hierarchical modes with hybrid combined channels supporting several thousand channels.
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