SiPM Radiation Detection Device with Integrated Timestamping
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Solution Overview
Problem
Conventional radiation detection systems for cosmic rays and sub-atomic particles, such as muons, rely on photomultiplier tubes (PMTs) which require high voltage, are fragile, expensive, and cumbersome, while Silicon Photomultipliers (SiPMs) face challenges with dark current, temperature sensitivity, and capacitance.
Innovation Solution
A compact, integrated radiation detection device featuring a single circuit board with a silicon photomultiplier (SiPM) or photomultiplier device, a charge sensitive amplifier, an edge-peak detector circuit, and a local microcontroller for timestamping and pulse height recording, which communicates with a central controller unit for coincidence event detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photomultiplier tubes (PMTs) are used for radiation detection, then detection capability is improved, but device size, cost, and fragility increase
Solution Approach 1:
The patent replaces traditional photomultiplier tubes with silicon photomultipliers (SiPMs) that replicate the light detection functionality of PMTs but in a compact, solid-state format. The SiPM array is positioned adjacent to the scintillator to convert optical photons to electrical signals, achieving the same detection capability without the large vacuum tube structure, high voltage requirements, and fragility associated with conventional PMTs.
2Device complexity
If silicon photomultipliers (SiPMs) are used to replace PMTs, then device size and power requirements are reduced, but dark current and temperature sensitivity increase
Solution Approach 1:
The patent introduces a scintillator as an intermediary material between the radiation source and the SiPM array. The scintillator converts incoming radiation into optical photons, which then trigger the SiPMs. This indirect detection method allows the SiPMs to operate at lower voltages and with reduced dark current compared to direct radiation detection, while the scintillator's light output provides the necessary signal amplification.
Solution Approach 2:
The patent optimizes the operating parameters of the SiPMs, including bias voltage and temperature compensation, to minimize dark current effects. By carefully controlling the electrical and thermal parameters of the SiPM array, the system achieves low noise performance despite the inherent temperature sensitivity of silicon-based photodetectors.
3Measurement precision
If specialized electronic modules are used for signal processing, then measurement precision is improved, but system cost and complexity increase
Solution Approach 1:
The patent integrates multiple signal processing functions directly into the SiPM module, including charge-sensitive amplification, pulse shaping, and timestamp generation. The local microcontroller embedded in each SiPM module performs real-time coincidence detection and data formatting, eliminating the need for separate, expensive specialized electronic modules and reducing overall system complexity while maintaining high timing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective, lightweight, and portable radiation detection system capable of detecting coincidence events with high timing accuracy, suitable for a range of applications including cosmic ray detection and muon tomography.
Implementation Method 1
a photomultiplier device powered by an input power signal and configured to receive incident optical pulses of photons from an associated scintillator device and, in response, generate an input electrical signal having corresponding electrical pulses
Implementation Method 2
receive incident optical pulses of photons from an associated scintillator device
Data Source
AI summary
A sensor for a coincidence radiation detection device comprises a photomultiplier device to receive incident optical pulses of photons from an associated scintillator device and responsively generate an input electrical signal having corresponding electrical pulses. A charge sensitive amplifier receives the input electrical signal and outputs an electrical signal. An edge-peak detector circuit detects a fast rising edge of the electrical pulses; a beginning of a trailing edge of the electrical pulses; and a peak value of the electrical pulses. A local microcontroller includes: a timing circuit to generate timestamp values for detected pulses in response to a detected pulse edge and to synchronise the timestamp values with a reference clock signal to generate timestamp values for the pulses; an analog to digital converter to record pulse height values of the electrical pulses; and a communications interface to communicate the timestamp values and pulse height values to a memory device.