Tag: Theses
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Adiabatic expansion cooling of antihydrogen
Magnetically trapped antihydrogen atoms can be cooled by expanding the volume of the trap in which they are confined. We report a proof-of-principle experiment in which antiatoms are deliberately released from expanded and static traps. Antiatoms escape at an average trap depth of 0 . 0 8 ± 0 . 0 1 K (statistical errors
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Exploiting Electron Magnetron Motion in a Penning-Malmberg Trap to Measure Patch Potentials, Misalignment, and Magnetic Fields.
A sequence of electron clouds is extracted from an electron plasma reservoir. These clouds are highly reproducible and their E×B drift motion is nearly identical to that of a single particle, making them useful for measurements of electric and magnetic fields. First, by weakening the trapping potential confining the clouds we observe that they move
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Measurements of Penning-Malmberg trap patch potentials and associated performance degradation
Antiprotons created by laser ionization of antihydrogen are observed to rapidly escape the ALPHA trap. Further, positron plasmas heat more quickly after the trap is illuminated by laser light for several hours. These phenomena can be caused by patch potentials—variations in the electrical potential along metal surfaces. A simple model of the effects of patch
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Laser-cooled Be+ for improved antihydrogen trapping and magnetometry
We have laser cooled beryllium ions in a Penning-Malmberg trap dedicated for antihydrogen formation. This trap is combined with a magnetic minimum trap to confine antihydrogen.This can be used to assist in the studies of antihydrogen in two distinct ways. The first application of the cold 9Be+ is to sympathetically cool positrons, which are used
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Observation of the effect of gravity on the motion of antimatter
Einstein’s general theory of relativity (GR), from 19151, remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating
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A proton source in the ALPHA apparatus for precision measurements of antihydrogen and hydrogen
The apparent lack of antimatter within our local solar system, the Milky Way, and at Galactic boundaries is inconsistent with the Big Bang hypothesis. This disagreement has motivated many experiments to compare the properties and behaviour of antimatter and matter. The ALPHA (Antihydrogen Laser PHysics Apparatus) experiment produce, trap and study antihydrogen. This synthesis involves
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Design and performance of a novel low energy multispecies beamline for an antihydrogen experiment
The ALPHA Collaboration, based at the CERN Antiproton Decelerator, has recently implemented a novel beamline for low energy (<100 eV) positron and antiproton transport between cylindrical Penning traps that have strong axial magnetic fields. Here, we describe how a combination of semi analytical and numerical calculations was used to optimize the layout and design of
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Measuring the Properties of Antihydrogen
This thesis describes the latest results of the on-going efforts to measure the properties of antihydrogen within the ALPHA collaboration. More specifically, it covers the construction and commissioning of the ALPHA-g experiment [1], and the plans to measure how antimatter behaves in Earth’s gravitational field. A special emphasis is on the ALPHA-g magnet system used
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Efficient calculations of magnetic fields of solenoids for simulations
This paper examines different models for calculating the magnetic field of solenoids. Accuracy and computation time are compared for a range of different simplified models: a current loop and a thin shell solenoid, and solenoids with finite length and thickness. There is no definitive answer to “what model is the best”, as it depends on
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On the Dynamics of Adiabatically Cooled Antihydrogen in an Octupole-Based Ioffe-Pritchard Magnetic Trap
Antihydrogen is now routinely formed in ALPHA by combination of antiproton and positron plasmas. Formed anti-atoms with energy <∼0.5 K are trapped in an octupole- based Ioffe-Pritchard magnetic trap. Reducing trapped antihydrogen energy is expected to increase precision in experiments that measure fundamental antihydrogen properties for precise comparison to hydrogen. Cooling is expected to permit