Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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Accurately collimated monoenergetic fast neutron beams of small angular width were produced by bombarding heavy ice targets with deuterons, and operating the neutron detector in coincidence with a semiconductor detector detecting the He³ recoil nuclei. Using a bombarding energy of E[subscript d] 50 keV a neutron beam of energy 2.55 MeV and known absolute intensity was produced. The measured beam profile agreed with the theoretically calculated profile. The beam was used to measure the absolute neutron detection efficiency and the pulse spectrum of a plastic scintillation counter bombarded by 2.55 MeV neutrons. Using a bombarding energy of E[subscript d] = 2 MeV a neutron beam of energy 5.08 MeV was produced and the bearers profile was measured. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The purpose of this paper is to study the possible excited states in the nucleus of Cs133. At North Texas State College a 100-Kev Cockcroft-Walton accelerator has been constructed for use as a neutron source for exciting various nuclei and for studying the gamma spectra obtained to determine their energy levels.

The violation of baryon number, is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron-antineutron oscillation via mixing, neutron-antineutron oscillation via regeneration from a sterile neutron state , and neutron disappearance (n → n′); the effective process of neutron regeneration is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches. The opportunity to make such a leap in sensitivity tests should not be squandered. The experiment pulls together a diverse international team of physicists from the particle (collider and low energy) and nuclear physics communities, while also including specialists in neutronics and magnetics.

The state of polarization of neutrons emitted at an angle of 45° (Lab) from the D(d,n)He³ reaction has been determined by observing the asymmetry in scattering from carbon. Neutrons scattered at equal angles to the right and left were detected simultaneously by two cylindrical stilbene crystals, The neutrons were produced by bombarding a heavy ice target with an unanalyzed beam of deuterons from a Cockroft-Walton accelerator. The phase shifts of Meier, Scherrer, and Trumpy* were used to compute the induced polarization of carbon at an average neutron energy of 2.7 Mev. The observed asymmetries in scattering yielded neutron polarizations of 11.1 * 1.5%, 7.8 * 1.4%, and 6.0 * 1.8% at average deuteron energies of 99 Kev, 81.5 Kev, and 67.5 Kev respectively. Polarized neutrons (2.73 Mev) scattered from calcium indicated that the right-left asymmetry, P_nP_Ca changes sign in the interval 87.5° to 120° (CM). P_Ca ≤ 61.7% in the interval 0° to 180° (CM). * Meier, R. W., Scherrer, P., and Trumpy, G., "Elastische Streuung und Polarisationseffekte von D-D Neutronen an Kohlenstoff", Helv. Phys. Acta 27, 577 (1954). / Ph. D.

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.

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