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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Studium produkce charmonií v proton-protonových a těžko-iontových srážkách na LHC / Study of charmonia production in proton-proton and heavy-ion collisions at the LHC

Krivoš, Martin January 2018 (has links)
In this thesis a production of J/ψ meson in pp and heavy-ion collisions was investigated. A comparison between Monte Carlo generator and data by ATLAS experiment at CERN was done. PYTHIA version 8.2 was chosen for the Monte Carlo generator. In the first part, comparisons of several configurations of PYTHIA were used to establish the best matching of the Monte Carlo to the data using collisions with centre-of-mass energy of 7 TeV. Choice of parton distribution functions was found not to be important, while presence or absence of initial and final state radiation were proven to have an important impact on the result. In the second part, correlation of J/ψ meson and the jet production was quantified. Anti-kt algorithm with R = 0.4 was used to reconstruct jets. Pairs of muons were used to identify J/ψ meson candidates. Only less than 10% of J/ψ mesons were found to be associated with jets. 1
112

Isotope harvesting at heavy ion fragmentation facilities

Mastren, T., Pen, A., Peaslee, G. F., Wosniak, N., Loveless, S., Essenmacher, S., Sobotka, L., Morrissey, D., Lapi, S. E. January 2015 (has links)
Introduction The National Superconducting Cyclotron Laboratory (NSCL) is a national nuclear physics facility in which heavy ion beams are fragmented to produce exotic nuclei. In this process of fragmentation many nuclei are created, however, only one isotope is selected for experimentation. The remaining isotopes that are created go unused. The future upgrade of the NSCL to the Facility for Rare Isotope Beams (FRIB) will increase the incident energy of these heavy ion beams and amplify the current by three orders of magnitude. An aqueous beam dump will be created to collect the unused isotopes created in the process of fragmentation. Several of these isotopes are of interest for many applications including nuclear security, medical imaging, and therapy and are not currently available or are only available in very limited supply. Harvesting these isotopes from the aqueous beam dump could provide a consistent supply of these im-portant isotopes as an ancillary service to the existing experimental program. Material and Methods A liquid water target system was designed and tested to serve as a mock beam dump for exper-iments at the NSCL1. A 25 pnA 130 MeV/u 76Ge beam was fragmented using a 493 mg/cm2 thick beryllium production target. After fragmentation the beam was separated using the A1900 frag-ment separator2 set up for maximum 67Cu pro-duction using a 240 mg/cm2 aluminum wedge and a 2% momentum acceptance. The secondary beam was collected for four hours in the liquid water target system before being transferred to a collection vessel. Four additional four hour collections were made before finally shipping the five collections to Washington University and Hope College for chemical separation. Four of the five samples were separated using a two part separation scheme. First they were passed through and 3M Empore iminodiacetic acid functionalized chelation disk in a 1.25M ammonium acetate solution at pH 5. The flow through was collected and analyzed using an HPGe detector. Then 10mL of 6M HCl acid was passed through the chelation disk to remove the 2+ transition metals. The 10mL of 6M HCl acid was collected after passing through the disk and added to an anion-exchange column with 2.5 g AG1-X8 resin. The eluate was collected and then an additional 10mL of 6M HCl was passed through the column to remove the nickel. The 67Cu was then collected by passing 10mL of 0.5M HCl and the eluate was collected in 1mL fractions each analyzed by HPGe for 67Cu concentration and purity. The two highest 67Cu fractions were heated to dryness and reconstituted in 50 μL 0.1M ammonium acetate pH 5.5. 2 μL of 7.9 mg/mL NOTA-Bz-Trastuzumab was added to 45 μL of 67Cu and 3 μL 0.1M ammonium acetate pH 5.5. This solution was placed in a shaking incubator at 37 °C for twenty minutes and then analyzed by radio-instant thin layer chromatography in order to determine the per-cent of 67Cu bound to the antibody. Results and Conclusion 67Cu was collected into the liquid water target system with an average efficiency of 85 ± 5 %. The secondary beam was 73 % pure with the impurities, half-lives greater than 1 minute, listed in TABLE 1. Separation of 67Cu from the impurities resulted in an average recovery of 88 ± 3 % for a total recovery of 67Cu from the beam and separation of 75 ± 4 %. No detectable radioactive impurities were found in the final samples when analyzed using an HPGe detector. TABLE 2 shows the amount of 67Cu collected from the beam and the amount recovered decay corrected to end of bombardment. Labeling NOTA-Bz-Trastuzumab with 67Cu resulted in > 95 % radiochemical yield. Collection of the 73 % pure 67Cu beam in water and the resulting separation proved successful. These results demonstrate that radioisotopes can be collected from fragmented heavy ion beams and isolated in usable quantities and purity for many radiochemical applications. Further experimentation with an unpurified beam to better simulate conditions in the beam dump at the Facility for Rare Isotope Beams will be performed in the near future.
113

Heavy Ion Temperature Anisotropies in the Venus Plasma Environment

Lindblom, Ville January 2021 (has links)
In a plasma environment particles and plasma waves have complex interactions and can affect each other significantly. The velocity distribution functions (VDFs) can effectively be used to try and understand these interactions. This study uses VDFs to investigate heavy ion temperatures in the Venusian plasma environment. A Maxwellian fitting methodology previously used to obtain proton plasma parameters is used to obtain plasma parameters for heavy ions instead. Ion and magnetic-field data are gathered from the ion mass analyser IMA and the magnetometer MAG which were on board the European spacecraft Venus Express. The temperature anisotropies are analysed to see if they may affect the observed plasma waves around Venus. Spatial maps of the obtained plasma parameters are presented, and the average values are shown. The temperature ratio T⊥/T∥ is calculated to look for anisotropies. Case studies were made to investigate how well the methodology worked with heavy ion data. The methodology is shown to work well in the magnetotail, where heavy ions are expected, and less well in the magnetosheath and solar wind, where heavy ions were not expected. No statistically significant anisotropies were found for the heavy ions in the Venusian plasma environment.
114

Transverse momentum balance of b-jet pairs in PbPb collisions with the CMS experiment at the LHC / L'asymmétrie de l'impulsion transverse des paires des jets de b dans les collisions d'ions lourds dans l'expérience CMS au LHC

Lisniak, Stanislav 27 October 2016 (has links)
Les collisions d’ions lourds à haute énergieproduisentunnouvelétatdelamatièreappelé le plasma de quarks et de gluons. Un parton traversant le plasma perds de l’énergie, en atténuant les gerbeshadroniques:c’estl’effetde"jetquenching". La dépendance du jet quenching dans la saveur du parton fournit des contraintes sur les modèles de perte d’énergie. Le déséquilibre d’une paire de jets issus de quarks b est une observable appropriée pour étudier ce phénomène. Cette thèse présente lamesure du déséquilibre en impulsion transverse des jets de b et des jets inclusifs (non-identifiés), dans des collisions PbPb a √sNN = 5.02 TeV, réalisée avecledétecteurCMSauLHCpouruneluminosité intégrée de 404 µb−1. Aucune différence n’est observée dans le jet quenching entre les jets issus de partons légers et lourds. Une analyse des résultats à l’aide d’un modèle simple de perte d’énergie est présentée. / The collisions of heavy ions at high energy produce the new state of matter called the quark gluon plasma. A parton traversing the plasma loses its energy which results in the jet quenching phenomenon. The dependence of the jet quenchingonthepartonflavorprovidesconstraints the models describing energy loss. The imbalance of b-jets is a very suitable observable to study this phenomena. This dissertation presents the measurement of the transverse momentum imbalance of b-jets and inclusive (non-identified) jets in PbPb collisions at √sNN = 5.02 TeV which is performed with the CMS detector at the LHC with total integral luminosity of 404 µb−1. No significant difference in jet quenching between light and heavy flavor jets is observed. The interpretation of results with a simple model of energy loss is performed.
115

Parametric instabilities of the Yang-Mills field and far-from-equilibrium dynamics of overpopulated bosons / ヤン・ミルズ場のパラメトリック不安定性と過占有ボソン系の非平衡ダイナミクス

Tsutsui, Shoichiro 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20173号 / 理博第4258号 / 新制||理||1612(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 大西 明, 教授 國廣 悌二, 教授 川合 光 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
116

Photon-Related Elliptic Azimuthal Asymmetry and Photon-Hadron Correlations with an Isolation Cut in Au+Au Collisions at v(s_NN )= 200 GeV at RHIC-PHENIX

Danley, Tyler W. January 2018 (has links)
No description available.
117

QUALITY ASSURANCE (QA) ANALYSIS IN √(s_NN )=54 GEV AU+AU COLLISIONS

Alshammri, Albandry 28 November 2018 (has links)
No description available.
118

Verification and Simulations of Two Particle Correlation Background in Heavy Ion Collisions Using Mean Seed Mean Partners Method

Raisbeck, Cole January 2018 (has links)
No description available.
119

Hydrodynamic description of the baryon-charged quark-gluon plasma

Du, Lipei January 2021 (has links)
No description available.
120

Heavy Ion Reactions Proceeding Via 221*Ac Compound Nuclei

Gough, Richard Arthur 02 1900 (has links)
<p> A high speed recoil transport system is developed making possible the simultaneous study of many decay products of the compound nucleus 221*Ac. Oeterminati ons of the efficiency properties of the transport system, essential for absolute cross section measurements , are discussed in detail. </p> <p> A study of angular momentum effects is made possibly by synthesis of 221*Ac using three heavy ion reactions. Absolute cross sections for (HI,xn) and (HI,pxn) reaction products are determined relative to established cross sections for production of 150Dy. Relative cross sections for francium production are also determined. </p> <p> A sophisticated statistical model calculation is adapted to provide a framework for interpretation of the results. Some insight is gained into the roles played by basic physical concepts in the systematic of compound nucleus decay in this mass region </p> / Thesis / Doctor of Philosophy (PhD)

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