Honors in Physics
http://hdl.handle.net/1803/833
2024-03-28T15:10:01ZHigh-energy attosecond-width electron diffraction simulations
http://hdl.handle.net/1803/5204
High-energy attosecond-width electron diffraction simulations
Kidd, Daniel
Electron microscopy has been the recent subject of molecular imaging
due to the strength of the electrons' interaction with the target
molecule making for a detailed pattern at a small scale.[1] To achieve
the best 4D image of the target, one needs sufficient
spatial and temporal resolution, the prior being an issue of using
electrons in the keV regime as to achieve an optimally small deBroglie
wavelength, and the latter being improved by the temporal width of the
electron wave packet itself.[2] In order to image the motion of the
electronic structure of the target molecule, this width must be within
the attosecond regime. In this paper, we use the computational method
of time-dependent density functional theory (TDDFT) to model our
targets of Beryllium and the Nitrogen molecule, N2 , and an incoming
electron wave packet with an energy of 1500 eV.
2013-04-22T00:00:00ZData Logistics and the CMS Analysis Model
http://hdl.handle.net/1803/2945
Data Logistics and the CMS Analysis Model
Managan, Julie E.
The Compact Muon Solenoid Experiment (CMS) at the Large Hadron
Collider (LHC) at CERN has brilliant prospects for uncovering new
information about the physical structure of our universe. Soon
physicists around the world will participate together in analyzing CMS
data in search of new physics phenomena and the Higgs Boson. However,
they face a significant problem: with 5 Petabytes of data needing
distribution each year, how will physicists get the data they need?
How and where will they be able to analyze it? Computing resources and
scientists are scattered around the world, while CMS data exists in
localized chunks. The CMS computing model only allows analysis of
locally stored data, "tethering" analysis to storage. The Vanderbilt
CMS team is actively working to solve this problem with the Research
and Education Data Depot Network (REDDnet), a program run by
Vanderbilt's Advanced Computing Center for Research and Education
(ACCRE). I participated in this effort by testing data transfers into
REDDnet via the gridFTP server, a File Transfer Protocol which
incorporates an LHC Computing Grid security layer. I created a test
suite which helped identify and solve a large number of problems with
gridFTP. Once optimized, I achieved sustained throughputs of 700-800
Megabits per second (Mbps) over a 1 Gigabit per second (Gbps)
connection, with remarkably few failures. GridFTP is the gateway
between REDDnet and CMS, and my tests were designed to exercise and
harden this important tool. My results support other indications that
the REDDnet system will be a successful solution to the limitations of
data-tethering in the CMS computing model.
Honors in Physics
2009-04-20T00:00:00ZProgress towards a quantum dot photovoltaic : nanocrystal deposition on structured titanium dioxide nanotubes
http://hdl.handle.net/1803/737
Progress towards a quantum dot photovoltaic : nanocrystal deposition on structured titanium dioxide nanotubes
Emmett, Kevin
While this project did not successfully produce a working photovoltaic device, significant progress has been made in the individual components of the system. This thesis describes two of those components: fabrication of an ordered TiO2 thin film as electron conducting layer, and deposition of nanocrystals onto the TiO2surface. The anodized titanium nanotubes are a significant improvement over the earlier template technique. Additionally, electrophoretic deposition presents a novel approach to nanocrystal deposition techniques and is a promising alternative to the current chemical linking procedure. However, significant new approaches to imaging the deposited nanocrystals must be developed to verify surface coverage by these deposition techniques, particularly due to the highly ordered structure of the TiO2 thin films. Future work will be directed at completing the solar cell device by depositing a hole conducting layer on top of the nanotube array. Nanocrystal-sensitized solar cells may soon prove to be viable alternative to silicon photovoltaics.; College of Arts & Science
Honors in Physics
2008-04-01T00:00:00Z