臺灣博碩士論文加值系統

在近代的許多微中子實驗當中, 微中子與原子核之作用扮演了很重要的角色. 針對不同的原子核種類與微中子的能量, 需要有不同的方法來計算微中子與原子核作用的散射截面. 近期的理論研究指出, 核子中的內涵 S 夸克與中性流作用中的 axial isoscalar 部分, 會對某些種類的原子核與微中子之散射截面造成可觀的影響.

在中研院物理所微中子計劃的導航實驗中, 將在位於核二廠反應爐旁處放置一個利用碘化銫晶體的微中子偵測器. 在本篇論文中將闡述, 利用蒙地卡羅電腦模擬的方法來研究碘化銫晶體的偵測器(利用四硼化碳提供硼-11作為微中子流的靶原子核), 所得到的一些結果. 本篇論文模擬由微中子與原子核之中性流作用所造成的核激態所釋放出來的光子之偵測. 藉由改變偵測器不同的幾何組態與空間參數, 我們嘗試找出在特定光子能量下最佳的幾何組態而能得到最好的偵測率. 本篇電腦模擬實驗的結果將提供未來實際偵測器的設計上相當有價值的資訊.

Neutrino-nucleus reactions play an important role in many recent neutrino experiments. Due to the great variety of relevant nuclear targets and the energy of neutrinos, many different approaches are necessary for the estimation of the relevant neutrino-nucleus reaction cross-sections. There are recent theoretical works suggesting that for some specific nuclei, the cross-sections are sensitive to the strange quark content of the nucleon and the axial isoscalar component of neutral-current interaction.

In the planned Taiwan reactor neutrino pilot experiment, proposed by the TEXONO Collaboration, a CsI(Tl) crystal calorimeter will be used to study reactor neutrino interactions. In this thesis, we have studied the Monte Carlo simulation of the CsI crystal calorimeter detector which employs B4C as the passive targets to provide 11-B nuclei. The simulation program simulates the detection of photons from the emission of nuclear excited states which are caused by the neutral current process of neutrino-nucleus scattering. By changing the detector geometry configuration and corresponding spatial parameters, under the specific photon energies, we try to optimize the detector design to have the best detection rate. The Monte Carlo efficiency simulation results can provide some useful information for the realistic design of a detector.

1. Introduction

2. Neutrino-Nucleus Neutral Current Interaction
2.1. Some Calculational Methods of Estimating Neutrino-Nucleus Interaction Cross Sections
2.1.1. Direct Microscopic Calculation
2.1.2. Elementary-Particle Treatment (EPT)
2.1.3. EEOM : Empirical Effective Operator Method
2.1.4. Inclusive and Semi-inclusive Neutrino-Nucleus Reactions
2.2. Strange Quark Matrix Elements in Nucleon and the Effect of the Axial Isoscalar Neutral-Current

3. The TEXONO Pilot Experiment
3.1. Introduction
3.2. Physics Menu of the Crystal Calorimeter for Reactor Neutrino
3.2.1. Neutrino-Electron Scattering
3.2.2. Neutrino Charged and Neutral Currents on Deuteron
3.2.3. Neutral Current Excitation on B-10 and B-11
3.2.4. Neutrino Charged and Neutral Currents on Nuclei
3.3. The Experimental Setup of the Pilot Experiment
3.3.1. Survey of the Pilot Experiment
3.3.2. Few Words on Related Background and Shielding Design

4. Detector Simulation and Efficiency Studies
4.1. Introduction to the Simulation Scheme
4.2. First-Step Study
4.2.1. The ''Boxes Configuration''
4.2.2. The Energy Spectrum of CsI slab
4.2.3. Histogram-Sum Method and Energy-Sum Method for the Clusters of CsI slabs
4.2.4. Some Histogram-Sum Simulation Results and Discussions
4.2.5. Comparison of the Efficiencies of Histogram-Sum and Energy-Sum
4.2.6. Summary
4.3. Further Simulation Study
4.3.1. The Goal of the Simulation Programs
4.3.2. The Boxes Configuration
4.3.3. The Sandwich 1B2C Configuration
4.3.4. The 5-Layers 3B2C Configuration

5. Conclusion and Outlook
5.1. Comparison of the Three Configurations
5.2. Conclusion to the Simulation Studies
5.3. Outlook

Appendix A. The Definition of CsI Clustering Groups in the Boxes Configuration

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