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Zeeman relaxation of cold iron and nickel in collisions with ³He

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dc.contributor.advisor Daniel Kleppner and Thomas Greytak. en_US Johnson, Cort Nolan en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Physics. en_US 2009-04-29T14:49:23Z 2009-04-29T14:49:23Z 2008 en_US 2008 en_US
dc.description Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008. en_US
dc.description This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. en_US
dc.description Includes bibliographical references (p. 143-148). en_US
dc.description.abstract This thesis describes a measurement of the ratio of elastic to Zeeman-projection changing collision cross sections ([gamma]) in the Fe-3He and Ni-3He systems. This ratio is a probe of the anisotropy of the interaction between the colliding species. Theory and experiment confirm that Zeeman-projection collisions are suppressed in transition metals due to the presence of a spherically symmetric, full 4s shell, making them good candidates for loading a magnetic trap with the buffer gas cooling method. Nickel and iron atoms are introduced via laser ablation into an experimental cell containing a background 3He buffer gas. Elastic collisions with the buffer gas thermalize the atoms to less than 1K. The highest energy mJ = J Zeeman state decays via diffusion through the buffer gas and collisional Zeeman relaxation. Therefore the mJ = J lifetime depends on the buffer gas density of the cell. By measuring the mJ = J lifetime as a function of buffer gas density we determine [gamma]. We find [gamma] for Ni [3F4, mJ = 4] is between 2 x 103 and 1:1 x 104 at 0.75 K in a 0.8 T magnetic field. Zeeman relaxation in Fe [5D4, mJ = 4] occurs on time scales too rapid for us to measure accurately, and we are only able to set an upper bound of [gamma] < 3 x 103. The nickel result confirms that Zeeman relaxation is highly suppressed in submerged shell transition metal atoms. en_US
dc.description.statementofresponsibility by Cort Nolan Johnson. en_US
dc.format.extent 148 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri en_US
dc.subject Physics. en_US
dc.title Zeeman relaxation of cold iron and nickel in collisions with ³He en_US
dc.type Thesis en_US Ph.D. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Physics. en_US
dc.identifier.oclc 318124440 en_US

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