Spherical Neutron Detector Using Nitrogen Gas Mixture
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Solution Overview
Problem
Existing neutron detection devices are inefficient for detecting both thermal and fast neutrons, and they often use expensive or toxic gases like Helium 3 and Boron trifluoride.
Innovation Solution
A neutron detection device using dinitrogen as the ionization gas, with a mixture of dinitrogen and a hydrocarbon quencher, such as ethane, to enhance avalanche triggering and reduce costs and toxicity, while maintaining efficiency for both thermal and fast neutron detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Helium 3 is used as ionization gas, then thermal neutron detection is achieved, but cost increases and fast neutron detection efficiency remains poor
Solution Approach 1:
The patent changes the gas composition parameter from pure Helium 3 to a nitrogen-based mixture (N2 with additives like CF4 or C2H6), fundamentally altering the detection mechanism to enable both thermal and fast neutron detection while reducing cost
Solution Approach 2:
The patent uses a composite gas mixture consisting of nitrogen as the primary ionization gas combined with small amounts of fluorocarbon or hydrocarbon additives, creating a detector that leverages multiple interaction mechanisms for comprehensive neutron detection
2Reliability
If Boron trifluoride is used as ionization gas, then neutron detection is achieved, but cost increases and toxicity increases
Solution Approach 1:
The patent replaces expensive and toxic gases (Helium 3, Boron trifluoride) with inexpensive, non-toxic nitrogen gas, significantly reducing both cost and harmful effects while maintaining detection capability
Solution Approach 2:
The patent changes the chemical composition from toxic fluorocarbon-based gases to atmospheric nitrogen, fundamentally eliminating toxicity while preserving neutron detection functionality through alternative interaction mechanisms
3Object-affected harmful factors
If pure nitrogen is used as ionization gas, then cost decreases and toxicity decreases, but avalanche triggering becomes difficult
Solution Approach 1:
The patent introduces fluorocarbon or hydrocarbon additives as intermediary substances that facilitate avalanche triggering in the nitrogen gas, these additives act as mediators that enable the detection mechanism while remaining present in small concentrations
Solution Approach 2:
The patent creates a composite gas system where nitrogen serves as the primary medium and fluorocarbon/hydrocarbon additives serve as avalanche-initiating agents, combining the benefits of low-cost nitrogen with the avalanche-triggering capability of fluorocarbon compounds
4Reliability
If hydrocarbon quencher is added to nitrogen, then avalanche triggering improves and gain increases, but noise signals from hydrogen collisions increase
Solution Approach 1:
The patent optimizes the concentration parameter of hydrocarbon additives to specific ranges (0.1-5%) where the beneficial avalanche triggering effect maximizes while the harmful hydrogen collision noise remains minimized, finding an optimal balance point
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 device effectively detects thermal and fast neutrons with improved gain and reduced noise signals, offering a cost-effective and safer alternative to previous technologies, with the ability to discriminate between different neutron reactions based on signal rise time.
Implementation Method 1
The detection of neutrons is done by the ionization of gas particles which then produce a positively charged ion and a negatively charged electron
Implementation Method 2
to produce an avalanche near the ball to amplify the signal
Implementation Method 3
The role of the quencher is to absorb any photons created during the excitation of the gas molecules
Implementation Method 4
Fast neutrons interact with nitrogen according to the reaction described in the case of thermal neutrons, but also according to the following reaction: 14N(n,p)14C
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a spherical neutron detection device (1) comprising a spherical cathode (2) and a spherical anode (3). The cathode (2) forms a chamber (6) filled with an ionization gas. The invention is particularly noteworthy in that the ionization gas is pure nitrogen. The ionization gas can also be mixed with a quencher. In this case, the quencher is preferably ethane.