MSM Radiation Detector Layout for High-Dose Pulse Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solid state detectors face challenges in accurately measuring very high doses of radiation delivered in short pulses, such as in FLASH radiotherapy, due to non-linear responses, saturation, and prolonged exposure effects that lead to performance degradation.
Innovation Solution
A solid state detector comprising Metal-Semiconductor-Metal (MSM) devices with optimized physical features and materials, including a diamond substrate and gold interdigitated metal patterns, is designed to differentiate response times between two active regions, allowing for accurate measurement of high dose rates and reducing active volume to prevent charge accumulation and saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a solid state detector is used to measure very high dose rate radiation, then measurement capability is improved, but saturation and non-linear response occur leading to measurement accuracy degradation
Solution Approach 1:
The detector is divided into two distinct active regions with different response characteristics. The first active region has a first response time and the second active region has a second response time, allowing the detector to handle different timescales of charge accumulation and prevent saturation in a single region.
Solution Approach 2:
The patent changes the response time parameter by creating two active regions with deliberately different response times. This parameter differentiation allows the detector to accurately measure very high dose rates by distributing the measurement function across regions with complementary temporal characteristics.
2Measurement precision
If the active volume is increased to improve detection sensitivity, then measurement capability is improved, but charge accumulation increases leading to saturation
Solution Approach 1:
The active volume is segmented into two separate active regions, each with controlled dimensions and response characteristics. This segmentation prevents excessive charge accumulation in a single large volume while maintaining adequate detection sensitivity through the combined response of both regions.
Solution Approach 2:
Different regions are given different local qualities in terms of response time characteristics. The first active region is optimized for one response time while the second active region is optimized for a different response time, allowing each region to handle charge accumulation appropriately for its specific function.
3Productivity
If the response time is reduced to improve measurement speed, then productivity is improved, but charge drainage capability is reduced leading to residual charge
Solution Approach 1:
The charge drainage function is segmented between two active regions with different response times. The faster region provides rapid initial response while the slower region ensures complete charge drainage, eliminating residual charge without sacrificing overall measurement speed.
Solution Approach 2:
The two active regions operate in a continuous complementary manner where the first region captures the fast initial signal and the second region ensures complete charge collection. This continuous operation across different timescales maintains high productivity while ensuring complete charge drainage.
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 enables precise measurement of high dose rate radiation pulses with reduced saturation and faster response times, maintaining performance over prolonged exposure to ionizing radiation, and effectively differentiates between radiation types based on charge accumulation and response times.
Implementation Method 1
the substrate is configured to be an insulator when the solid state detector is not being irradiated, and to generate electrical charge carriers in the substrate when the solid state detector is irradiated with ionizing radiation
Data Source
AI summary
A solid state detector for ionizing radiation having a semiconductor substrate, a conductive metal layer, a first and a second active region, the first active region having a faster response time to ionizing radiation than the second active region. A first voltage is applied to the first active region and a second voltage applied to the second active region, the first and second voltages having opposite polarities and equal magnitudes. The solid state detector being configured to maintain a constant output voltage when not irradiated and to output an output voltage when irradiated, the output voltage being the time resolved sum of a first charge and a second charge accumulated by the two active regions, the first charge and the second charge having opposite polarities and configured to drain residual charges from the active regions.