本文選題：水下中子活化元素分析儀　切入點(diǎn)：蒙特卡羅模擬　出處：《成都理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：根據(jù)初步調(diào)研顯示海洋中蘊(yùn)含著大量礦產(chǎn)資源,水下中子活化分析可以為海底金屬礦產(chǎn)資源開發(fā)提供一種新的勘探方法。論文選題來源于863計劃“資源與環(huán)境技術(shù)領(lǐng)域”主題項目課題“高精度能譜探測儀器研發(fā)”(課題編號:2012AA061803)和國家自然科學(xué)基金“地球和月球表面誘發(fā)輻射場及其地質(zhì)響應(yīng)研究”(項目批準(zhǔn)號:41374136)。論文以水下中子活化元素分析儀為主體,以插入式模型和拖拽式模型為手段,以MCNP5軟件為工具,以水下4000m處的污泥為研究對象,通過蒙特卡羅模擬數(shù)值分析研究對儀器內(nèi)部結(jié)構(gòu)參數(shù)的優(yōu)化,兩種不同模型下探測器計數(shù)隨源距和孔隙度變化規(guī)律性所在,Na、Al、Si、Mn四種元素活化后感生特征γ射線計數(shù)對孔隙度的靈敏度,整個插入式模型感生特征γ射線能譜做了研究工作。本文的主要研究工作有:(1)調(diào)研了可控中子管的發(fā)展現(xiàn)狀,選擇適合當(dāng)作水下中子活化元素分析儀的激發(fā)源,在MC模擬分析過程中激發(fā)源當(dāng)作一個理想點(diǎn)源進(jìn)行模擬研究。(2)在國內(nèi)外多方學(xué)者所設(shè)計的儀器基礎(chǔ)之上,利用MC模擬軟件建立水下中子活化元素分析儀的整體結(jié)構(gòu),根據(jù)需要采用NaI(Tl)作為探測器,外圍包有0.5cm厚的釓,防止熱中子進(jìn)入探測器,起到保護(hù)探測器的作用。在激發(fā)源和探測器之間設(shè)計三層復(fù)合體屏蔽結(jié)構(gòu),第一層研究了鎢和鎢鎳合金兩種屏蔽物質(zhì),第二層研究了石蠟和20%的含硼聚乙烯,第三層使用了屏蔽γ射線常用物質(zhì)鉛,得到三層屏蔽體的最佳厚度。(3)模擬分析了插入式模型和拖拽式模型探測器記錄到感生γ射線總量隨源距和孔隙度變化的規(guī)律,并且對探測器記錄到Na、Al、Si、Mn四種元素的感生特征γ射線計數(shù)隨孔隙度變化的靈敏度進(jìn)行模擬分析研究。(4)對水下4000m下污泥所含65種元素中百分含量比較大的12種元素模擬分析了其感生特征γ射線譜;在此基礎(chǔ)之上模擬分析了插入式模型源距為54cm時,在含水孔隙度為35%的水下污泥中,整體被中子活化產(chǎn)生的感生特征γ射線能譜。
[Abstract]:According to preliminary research, the ocean contains a lot of mineral resources. Underwater neutron activation analysis can provide a new exploration method for the exploitation of submarine metallic mineral resources. "(subject No. 2012AA061803) and National Natural Science Foundation of China" Research on Earth and Moon Surface induced radiation Field and its Geological response "(Project Grant No.: 41374136). The main body of the paper is the underwater neutron activation element analyzer. By means of plug-in model and towing model, with MCNP5 software as the tool and sludge at 4000m underwater as the research object, the optimization of the internal structure parameters of the instrument is studied by Monte Carlo simulation numerical analysis. The sensitivity of 緯 -ray counting to porosity after activation of four elements, NaAL-AlSiSi-Mn, is the regularity of detector counting with the variation of source distance and porosity under two different models. The main work of this paper is to investigate the development status of controllable neutron tube, and select suitable excitation source for underwater neutron activation element analyzer. In the process of MC simulation analysis, the excitation source is used as an ideal point source to simulate and study. (2) on the basis of the instruments designed by many scholars at home and abroad, the whole structure of underwater neutron activation element analyzer is established by using MC simulation software. According to the need to use NaIN Tl) as the detector, the peripheral is covered with 0.5 cm thick gadolinium, which prevents thermal neutron from entering the detector and plays the role of protecting the detector. A three-layer complex shielding structure is designed between the excitation source and the detector. The first layer studies tungsten and tungsten nickel alloy shielding materials, the second layer studies paraffin and 20% boron polyethylene, and the third layer uses lead, which is used to screen 緯 -rays. The optimum thickness of the three-layer shield is obtained. The law of the total amount of induced 緯 rays with the source distance and porosity recorded by the plug-in model and the drag model detector is analyzed. The sensitivity of 緯 -ray counting with porosity was simulated and analyzed. The sensitivity of 緯 -ray counting on 65 elements in sludge at 4000m underwater was simulated and analyzed. The results showed that the sensitivity of 緯 -ray counting to 65 elements in the sludge was higher than that of the other 12 elemental modes with a high percentage content of 65 elements in the sludge at 4000m under water. The 緯 -ray spectrum of its inductive characteristics is analyzed. On this basis, the inductive characteristic 緯 -ray energy spectrum produced by neutron activation in underwater sludge with water porosity of 35% was simulated and analyzed when the source distance of the plugged model was 54 cm.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.6;P744

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本文編號：1635758