Diamond Sensor for Simultaneous Microdosimetry and Dosimetry
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Solution Overview
Problem
Current micro-dosimetry systems for hadron therapy lack a reliable, simultaneous measurement of absorbed dose and micro-dosimetric spectra, requiring additional dosimeters or Monte Carlo simulations for verification, and suffer from limitations such as high-voltage requirements, gas supply needs, pulse pile-up issues, and low spatial resolution.
Innovation Solution
A diamond-based sensor system with micro-sensitive volumes and dual readout channels, one for micro-dosimetric measurements using a charge-sensitive preamplifier and another for dosimetry using a picoammeter, enabling precise and accurate measurements of lineal energy spectra and dose rates simultaneously with high spatial resolution and low noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TEPC detectors are used for microdosimetry measurements, then measurement capability is achieved, but device complexity increases due to high-voltage requirements and gas supply systems
Solution Approach 1:
The patent replaces the mechanical and gaseous systems of TEPC detectors with a solid-state diamond-based sensor. The diamond sensor uses electrical biasing instead of high-voltage gas multiplication, eliminating the need for gas supply systems and complex high-voltage electronics while maintaining microdosimetry measurement capability through direct charge collection in the diamond material.
Solution Approach 2:
The patent changes the physical state and operating parameters from gaseous detection medium requiring high voltage to solid-state diamond operating at low voltage. The diamond sensor operates with a simple bias voltage applied to collect charges generated in the bulk material, fundamentally changing the detection parameter regime from gas electron multiplication to solid-state charge collection.
2Measurement precision
If mini-TEPCs with smaller sensitive volumes are developed, then spatial resolution improves, but manufacturing complexity and maintenance demands increase
Solution Approach 1:
The patent replaces the mechanically complex mini-TEPC structure with a solid-state diamond sensor that achieves high spatial resolution through the intrinsic properties of diamond and micro-fabricated electrode structures. The diamond sensor requires no gas handling, no high-voltage components, and no complex maintenance, eliminating manufacturing and maintenance difficulties while maintaining small sensitive volume dimensions.
3Measurement precision
If silicon-based microdosimeters are used, then spatial resolution and cost-effectiveness improve, but tissue equivalence deteriorates requiring complex correction factors
Solution Approach 1:
The patent uses diamond material which has atomic number Z=6, closer to the effective Z of soft tissue (approximately Z=7.4) compared to silicon (Z=14). This homogeneity in atomic number between the detector material and tissue allows direct measurement without complex correction factors, while maintaining the spatial resolution and cost-effectiveness of solid-state microdosimetry.
4Reliability
If additional dosimeters or Monte Carlo simulations are used for dose verification, then measurement reliability improves, but device complexity and measurement time increase
Solution Approach 1:
The patent makes the diamond sensor universal by enabling it to perform both microdosimetry measurements (lineal energy spectra) and dosimetry measurements (absorbed dose) simultaneously through dual readout channels. This multi-functionality eliminates the need for separate dosimeters and Monte Carlo simulations, reducing device complexity and measurement time while maintaining reliability through cross-validation of measurements from the same sensor.
5Stability of the object's composition
If TEPC detectors with larger sensitive volumes are used, then measurement stability improves, but spatial resolution deteriorates
Solution Approach 1:
The patent changes the detection parameter regime by using the high density and high atomic number of diamond to achieve sufficient signal generation in small volumes. The diamond material's intrinsic properties (high charge carrier mobility, low noise, high radiation hardness) enable stable measurements from micro-scale sensitive volumes, reversing the traditional trade-off where larger volumes were needed for stability.
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 system allows for accurate and reliable measurements of lineal energy spectra and dose rates, improving the precision and reliability of ion beam characterization in hadron therapy, and enhancing Quality Assurance and radiobiological optimization of treatment plans without the need for additional dosimeters or simulations.
Implementation Method 1
at least one micro-dosimetric readout channel comprising a charge sensitive preamplifier connected to said sensor for outputting a signal representative of the distribution of the energy deposited by the ionizing radiation
Implementation Method 2
at least one dosimetry readout channel comprising a picoammeter for reading current induced by said ionizing radiation in said at least one micro-sensitive volume
Data Source
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AI summary
The invention relates to a system for dosimetric and micro-dosimetric ionizing radiation characterization, comprising: - at least one diamond-based sensor (10) comprising at least one micro-sensitive volume (12), - at least one micro-dosimetric readout channel (20) comprising a charge sensitive preamplifier (CSA) connected to said sensor for outputting a signal representative of the distribution of the energy deposited by the ionizing radiation impacting said at least one micro-sensitive volume (12), - at least one dosimetry readout channel (30) comprising a picoammeter (31) for reading current induced by said ionizing radiation in said at least one micro-sensitive volume (12) and generating a signal representative of a dose rate.