A computerised 8-channel data acquisition unit constructed by the Durham University Microprocessor Unit is described and the calibration of this unit is given in chapter 2. A test for the data acquisition unit using a Geiger-Mul1er cosmic ray telescope is described in Chapter 3. In Chapter 4 the main experiment is described. Two plastic scintillation counters each of 0.4 area and 5cm thick in coincidence were used in this experiment to measure the density spectrum of electrons at sea level in the range 20 - 600 electrons per m(^2). The microcomputer data acquisition system is employed to record the scintillator pulse heights. The measured integral density spectrum has been used to calculate the integral size spectrum at sea level. A brief description of the theory of electron-photon cascades and the formation of extensive are showers is give in Chapter 5.A FORTRAN program which uses Monte Carlo method to simulate extensive air showers generated by high energy protons with a given energy is described in Chapter 6. Using the relation between primary energy and average number of electrons arriving at sea level found by Monte Carlo calculation in Chapter 6 an estimate has been made of the integral primary energy spectrum in the range lO(^14)-lQ(^16)eV, and the result is given in Chapter 7.

Tam, Yiu Ho = 宇宙射線渺子及其引致中子的研究 / 譚耀豪. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 148-153). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Tam, Yiu Ho = Yu zhou she xian miao zi ji qi yin zhi zhong zi de yan jiu / Tan Yaohao.

Ngan, Sze Yuen = 渺子及其於香港仔隧道實驗室內的綜合研究 / 顏思遠. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 84-85). / Abstracts in English and Chinese. / Ngan, Sze Yuen = Miao zi ji qi yu Xianggangzi sui dao shi yan shi nei de zong he yan jiu / Yan Siyuan. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Cosmic Rays --- p.1 / Chapter 1.2 --- Muons --- p.3 / Chapter 1.3 --- Neutrino Oscillation --- p.5 / Chapter 1.4 --- The Daya Bay Reactor Neutrino Experiment --- p.8 / Chapter 1.4.1 --- Overview --- p.8 / Chapter 1.4.2 --- Detection Mechanism --- p.9 / Chapter 1.5 --- The Aberdeen Tunnel Experiment --- p.11 / Chapter 1.5.1 --- Overview --- p.11 / Chapter 1.5.2 --- Muon Tracker --- p.13 / Chapter 1.5.3 --- Neutron Detector --- p.16 / Chapter 2 --- Underground Muons --- p.18 / Chapter 2.1 --- Muon Simulation in the Daya Bay Experiment --- p.18 / Chapter 2.1.1 --- Gaisser's Formula --- p.20 / Chapter 2.1.2 --- Digitization of the Geographical Profile --- p.23 / Chapter 2.1.3 --- Underground Muon Flux --- p.24 / Chapter 2.2 --- Muon Simulation in the Aberdeen Tunnel Experiment --- p.25 / Chapter 3 --- Muon Behaviors in the Aberdeen Tunnel Laboratory --- p.28 / Chapter 3.1 --- Preparation --- p.29 / Chapter 3.1.1 --- Definition of the Coordinate System --- p.29 / Chapter 3.1.2 --- Generation of Muon Events --- p.30 / Chapter 3.1.3 --- Muon Trajectory --- p.35 / Chapter 3.1.4 --- Muon Energy Dissipation --- p.36 / Chapter 3.2 --- Muon Detection by the ND --- p.38 / Chapter 3.2.1 --- Energy Deposition in Gd-LS --- p.38 / Chapter 3.2.2 --- Experimental Measurements and Comparison --- p.40 / Chapter 3.2.3 --- Energy Deposition in MO --- p.42 / Chapter 3.2.4 --- ND Muon Rate --- p.43 / Chapter 3.2.5 --- Stopping Muons and Muon Decay --- p.44 / Chapter 3.3 --- Muon Detection by the Muon Tracker --- p.46 / Chapter 3.3.1 --- Selection of Top-Bottom Muons --- p.47 / Chapter 3.3.2 --- Selection of Muons which cut the Gd-LS Volume Diagonally --- p.49 / Chapter 4 --- Optimization of the Photomultiplier Tubes --- p.52 / Chapter 4.1 --- Photomultiplier Tube --- p.52 / Chapter 4.2 --- The Earth Field Effect --- p.55 / Chapter 4.2.1 --- FINEMET Magnetic Shield on PMT --- p.56 / Chapter 4.2.2 --- Magnetic Fields Measurement near the PMT Mount --- p.63 / Chapter 4.3 --- p-sec Region Ringing in PMT Signal --- p.65 / Chapter 4.3.1 --- The PMT Body and Simulated PMT Signal --- p.67 / Chapter 4.3.2 --- The Dummy Base --- p.69 / Chapter 4.3.3 --- High Voltage and the PMT Base Design --- p.71 / Chapter 5 --- Summary --- p.81 / Chapter 5.1 --- Underground Muon simulation --- p.81 / Chapter 5.2 --- Optimization of the PMTs in the Daya Bay Experiment --- p.82 / Bibliography --- p.84

Wong, Koon Kei Jackie = 香港仔地底實驗室中的宇宙渺子研究 / 黃冠棋. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 74-76). / Abstracts in English and Chinese. / Wong, Koon Kei Jackie = Xianggangzi di di shi yan shi zhong de yu zhou miao zi yan jiu / Huang Guanqi. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.1.1 --- Neutrino Oscillation --- p.1 / Chapter 1.1.2 --- The Daya Bay Reactor Neutrino Experiment --- p.5 / Chapter 1.2 --- Cosmic muons --- p.8 / Chapter 1.2.1 --- Propagation of cosmic muons --- p.10 / Chapter 1.3 --- Aberdeen Tunnel Experiment --- p.11 / Chapter 1.3.1 --- Detection principles of Muon Tracker --- p.13 / Chapter 1.3.2 --- Detection principles of Neutron Detector --- p.16 / Chapter 1.3.3 --- The data acquisition (DAQ) and online monitoring system --- p.17 / Chapter 2 --- Study of Angular distribution of the Expected Muon Flux --- p.20 / Chapter 2.1 --- Determination of muon angular distribution detected by the muon tracker --- p.21 / Chapter 2.2 --- Spherical Harmonics Expansion of muon angular distribution --- p.29 / Chapter 3 --- Hardware Development of the Muon Tracker --- p.35 / Chapter 3.1 --- Front-end electronics board --- p.35 / Chapter 3.1.1 --- The circuit of front-end daughter board --- p.37 / Chapter 3.1.2 --- Test of the front-end daughter board --- p.39 / Chapter 3.2 --- Muon tracker PMT gain calibration --- p.45 / Chapter 4 --- Photomultiplier tubes (PMT) characterization --- p.48 / Chapter 4.1 --- Magnetic field test --- p.49 / Chapter 4.2 --- Nonlinearity test --- p.54 / Chapter 4.2.1 --- Two-LED system --- p.54 / Chapter 4.2.2 --- LED and reference PMT system --- p.56 / Chapter 4.3 --- Optimization of waveform --- p.59 / Chapter 4.4 --- Comparison with Hamamatsu's recommended PMT bases --- p.65 / Chapter 5 --- Summary --- p.71 / Chapter 5.1 --- Calculations about muon angular distribution --- p.71 / Chapter 5.2 --- Front-end electronics tests and PMT measurements --- p.71 / Chapter 5.3 --- Outlook for the Aberdeen Tunnel Experiment --- p.72 / Bibliography --- p.74

Luk, Wing Hong Antony = 地底實驗室的渺子致中子本底研究 / 陸永康. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 74-77). / Abstracts in English and Chinese. / Luk, Wing Hong Antony = Di di shi yan shi de miao zi zhi zhong zi ben di yan jiu / Lu Yongkang. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Muons at Earth´ةs Surface --- p.1 / Chapter 1.2 --- Underground Muons --- p.2 / Chapter 1.2.1 --- Muon Intensity --- p.2 / Chapter 1.2.2 --- Muon Energy --- p.6 / Chapter 1.3 --- Muon-induced Neutrons --- p.7 / Chapter 1.3.1 --- Production of Neutrons from Muons --- p.7 / Chapter 1.3.2 --- The Influence of Muon-induced Neutrons on Underground Experiments --- p.9 / Chapter 1.4 --- Aberdeen Tunnel Laboratory --- p.11 / Chapter 1.4.1 --- Geological Properties --- p.12 / Chapter 1.4.2 --- Detectors Description --- p.14 / Chapter 1.4.3 --- Detection Principles --- p.18 / Chapter 2 --- Simulation of Cosmic Muons for Aberdeen Tunnel Laboratory --- p.22 / Chapter 2.1 --- Muon Spectrum at Sea level --- p.22 / Chapter 2.2 --- Simulation of Muon Propagation through Rock --- p.23 / Chapter 2.3 --- Estimation of Expected Event Rate for the Muon Tracker --- p.28 / Chapter 3 --- Neutron Detector Simulation --- p.30 / Chapter 3.1 --- Simulation Parameters --- p.32 / Chapter 3.2 --- Energy Response --- p.35 / Chapter 3.3 --- Energy Resolution --- p.35 / Chapter 3.4 --- Neutron Drift Distance and Capture Efficiency --- p.40 / Chapter 3.5 --- Neutron Detection Efficiency --- p.42 / Chapter 3.6 --- Photons Arrival Time --- p.45 / Chapter 3.6.1 --- Cobalt-60 Source --- p.45 / Chapter 3.6.2 --- LED --- p.47 / Chapter 4 --- Simulation of Muon-induced Neutron Background --- p.49 / Chapter 4.1 --- Review on Muon-induced Neutron Simulations --- p.50 / Chapter 4.1.1 --- Methodology --- p.50 / Chapter 4.1.2 --- Results in the Literature --- p.52 / Chapter 4.1.3 --- Simulation of Muon-induced Neutrons in GdLS --- p.56 / Chapter 4.2 --- Full Monte Carlo Simulation of Expected Neutron Rate --- p.64 / Chapter 4.2.1 --- Simulation Details --- p.65 / Chapter 4.2.2 --- Results --- p.65 / Chapter 4.3 --- Estimation of the Expected Neutron Rate using Parameterization from Monte Carlo Simulations --- p.68 / Chapter 4.3.1 --- Simulation Details --- p.68 / Chapter 4.3.2 --- Results --- p.69 / Chapter 4.4 --- Summary --- p.71 / Chapter 5 --- Future Work --- p.72 / Chapter 5.1 --- Neutrons from Rock Radioactivity --- p.72 / Chapter 5.2 --- Muon-induced Neutrons from Rock --- p.73 / Chapter 5.3 --- Variation of Muon flux --- p.73 / Bibliography --- p.74

以香港為重點，我們對於地表和地下中由地球圈內因子所引致的宇宙射線變化進行了研究。 / 借用圖像重建演算方法，我們定立了一種可於格狀排列的宇宙射線探測器觀測中重塑宇宙射線分佈的方法，並將其用於香港仔隧道實驗室的渺子探測器中。其結果表明地形對地下宇宙射線分佈的影響。 / 在地面上，我們用微擾蒙地卡羅方法研究了大氣變化對地表宇宙射線的影響。由此我們得到了一考慮到所有高度的空氣密度以還原大氣變化對地表宇宙射線影響的修正方案。 / 我們亦演算了宇宙射線粒子在地球磁場內的軌跡，並以探測器收納向量的概念，表達地面儀器所觀測的宇宙射線量與地球以外的原初宇宙射線之關係。 / 最後，藉我們對地球圈內做成宇宙射線變化的眾因子之認識，我們試圖還原它們的作用，以使我們能於地表宇宙射線觀測中探測地外原初宇宙射線的變化。我們的結果表明，在地表宇宙射線中的晝夜變化，有部分是由宇宙中的原初宇宙射線淨流引起。 / Cosmic ray (CR) variations of terrestrial origin were examined, with focus on Hong Kong at both the surface and underground. / Using image reconstruction algorithm, we developed a method to reconstruct CR distribution with measurement from a gridded CR detector, which we then applied to the muon tracker in the Aberdeen Tunnel Lab. The result demonstrated the eect of landscape on underground CR distribution. The good agreement between the measured CR distribution and MUSIC simulation validates the use of such simulation for other underground laboratories. / At the surface, we used perturbative Monte Carlo method to study the effect of atmospheric variations on surface CR counts. The result was a correction scheme to eliminate atmospheric variation in surface CR counts that took the air density at all height levels into consideration. / We also used particle tracing techniques to study the motion of CR particles in Earth’s magnetic field, and how CR counts from surface detectors are related to primary CR beyond Earth through the concept of detector acceptance vector. / With our understanding of CR variations of terrestrial origin, we attempted to undo their effects, and probe primary CR with surface CR observations. Our results suggested that parts of the diurnal variation in surface CR count are related to net streaming in the primary CR. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chan, Yat Long = 在香港的宇宙射線變化研究 / 陳日朗. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 91-95). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Chan, Yat Long = Zai Xianggang de yu zhou she xian bian hua yan jiu / Chen Rilang. / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background --- p.3 / Chapter 2.1 --- Primary and secondary cosmic ray --- p.3 / Chapter 2.2 --- General review on CR variation --- p.5 / Chapter 2.2.1 --- Variation in time --- p.5 / Chapter 2.2.2 --- Variation in directions --- p.6 / Chapter 2.3 --- CR variation of extra-terrestrial origin --- p.6 / Chapter 2.3.1 --- Forbush decrease --- p.6 / Chapter 2.3.2 --- CR co-rotation with sun --- p.7 / Chapter 2.3.3 --- CR variations and periodic solar activities --- p.8 / Chapter 2.3.4 --- Anisotropy of galactic origin --- p.9 / Chapter 2.4 --- CR variations of geomagnetic origin --- p.9 / Chapter 2.4.1 --- Geomagnetic cut off at different latitudes and longitudes --- p.9 / Chapter 2.4.2 --- East-West asymmetry --- p.10 / Chapter 2.4.3 --- Time variations of geomagnetic cut-off --- p.10 / Chapter 2.5 --- CR variations of atmospheric origin --- p.12 / Chapter 2.6 --- CR variations from lab overburden --- p.14 / Chapter 2.7 --- Round Up --- p.15 / Chapter 3 --- Muon directional variations in Aberdeen Tunnel Lab --- p.17 / Chapter 3.1 --- Introduction --- p.17 / Chapter 3.1.1 --- The Aberdeen Tunnel Lab --- p.17 / Chapter 3.1.2 --- The muon tracker --- p.18 / Chapter 3.2 --- Simulation of muon directional distribution --- p.19 / Chapter 3.3 --- Reconstruction of muon directional distribution --- p.21 / Chapter 3.3.1 --- Image restoration analogy --- p.21 / Chapter 3.3.2 --- Damped Richardson-Lucy deconvolution algorithm --- p.23 / Chapter 3.3.3 --- Obtaining the PSF --- p.24 / Chapter 3.3.4 --- Reconstruction result --- p.25 / Chapter 3.4 --- Comparison of simulation and reconstruction --- p.26 / Chapter 3.5 --- Conclusion --- p.29 / Chapter 4 --- Simulating Cosmic Ray variations at Ground Surface --- p.30 / Chapter 4.1 --- Scope of study --- p.30 / Chapter 4.1.1 --- Geomagnetic variation --- p.30 / Chapter 4.1.2 --- Atmospheric variation --- p.31 / Chapter 4.2 --- Layout of Simulation --- p.31 / Chapter 4.3 --- Modelling of Primary CR --- p.32 / Chapter 4.4 --- Modelling of Earth's magnetic field --- p.35 / Chapter 4.5 --- Modelling of atmosphere --- p.36 / Chapter 4.6 --- Modelling of lab overburden --- p.37 / Chapter 4.7 --- Modelling of Physics in cosmic ray cascades --- p.37 / Chapter 4.8 --- Counting considerations --- p.38 / Chapter 4.9 --- Monte Carlo speed up --- p.39 / Chapter 4.9.1 --- Primary particle event biasing --- p.41 / Chapter 4.9.2 --- Weight window technique --- p.41 / Chapter 4.10 --- Differential operator sampling --- p.44 / Chapter 4.10.1 --- Finite perturbation --- p.44 / Chapter 4.10.2 --- In nitesimal perturbation --- p.45 / Chapter 4.11 --- Simulation Result --- p.48 / Chapter 4.11.1 --- Rigidity map at HK --- p.48 / Chapter 4.11.2 --- Zenith angle dependence of muon flux --- p.50 / Chapter 4.11.3 --- Density correction coefficients --- p.51 / Chapter 5 --- Analysis of surface CR data --- p.55 / Chapter 5.1 --- Detector description --- p.55 / Chapter 5.1.1 --- The CUHK Muon Telescope --- p.55 / Chapter 5.1.2 --- The Nagoya Multi-Directional Muon Telescope --- p.56 / Chapter 5.2 --- Characterizing the detectors --- p.58 / Chapter 5.2.1 --- Coupling function for rigidity --- p.60 / Chapter 5.2.2 --- Acceptance vectors of detectors --- p.60 / Chapter 5.2.3 --- Sensitivity towards Atmospheric conditions --- p.64 / Chapter 5.3 --- Time series of surface CR data --- p.65 / Chapter 5.4 --- Diurnal variations in CR data --- p.67 / Chapter 5.5 --- Inferring CR streaming from surface measurement --- p.69 / Chapter 6 --- Conclusion --- p.75 / Chapter A --- Density correction coefficients and averaged atmospheric profile --- p.77 / Chapter B --- Acceptance vector of the detectors --- p.87 / Bibliography --- p.91

Thesis--Ph. D., University of Hong Kong, 1983.

Thesis (M. Phil.)--University of Hong Kong, 1981.

published_or_final_version / abstract / Physics / Doctoral / Doctor of Philosophy

published_or_final_version / Physics / Doctoral / Doctor of Philosophy