Tag: Theses
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Evaporative Cooling of Antiprotons to Cryogenic Temperatures
We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens
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Antihydrogen formation dynamics in a multipolar neutral anti-atom trap
Antihydrogen production in a neutral atom trap formed by an octupole-based magnetic field minimum is demonstrated using field-ionization of weakly bound anti-atoms. Using our unique annihilation imaging detector, we correlate antihydrogen detection by imaging and by field-ionization for the first time. We further establish how field-ionization causes radial redistribution of the antiprotons during antihydrogen formation
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Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector
A microchannel plate (MCP)/phosphor screen assembly has been used to destructively measure the radial profile of cold, confined antiprotons, electrons, and positrons in the ALPHA experiment, with the goal of using these trapped particles for antihydrogen creation and confinement. The response of the MCP to low energy (10-200 eV, <1 eV spread) antiproton extractions is
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Magnetic multipole induced zero-rotation frequency bounce-resonant loss in a Penning-Malmberg trap used for antihydrogen trapping
In many antihydrogen trapping schemes, antiprotons held in a short-well Penning–Malmberg trap are released into a longer well. This process necessarily causes the bounce-averaged rotation frequency \omegar of the antiprotons around the trap axis to pass through zero. In the presence of a transverse magnetic multipole, experiments and simulations show that many antiprotons (over 30%
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Development Of An Antihydrogen Trapping Apparatus
This thesis details the development and commissioning of the ALPHA antihydrogen trapping apparatus. It discusses the history of antimatter physics that led to and enabled the design of the apparatus. It discusses the importance of antihydrogen trapping in testing one of the basic assumptions of the Standard Model of particle physics (that of CPT invariance).
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Antihydrogen Physics at ALPHA/CERN
Cold antihydrogen has been produced at CERN (Amoretti et al. (Nature, 419, 456 (2002)), Gabrielse et al. (Phys. Rev. Lett. 89, 213401 (2002))), with the aim of performing a high-precision spectroscopic comparison with hydrogen as a test of the CPT symmetry. Hydrogen, a unique system used for the development of quantum mechanics and quantum electrodynamics,
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Antiproton compression and radial measurements
Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, achieved by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile, and its relation
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Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN
We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN’s Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of
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First Attempts at Antihydrogen Trapping in ALPHA
The ALPHA apparatus is designed to produce and trap antihydrogen atoms. The device comprises a multifunction Penning trap and a superconducting, neutral atom trap having a minimum-B configuration. The atom trap features an octupole magnet for transverse confinement and solenoidal mirror coils for longitudinal confinement. The magnetic trap employs a fast shutdown system to maximize
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Confronting CPT with cold trapped Antihydrogen
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