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Fall 2006

Schedule Fall 2006

September 12, 2006
3:00 pm (Tuesday)

Dr. Jean Delayen
Jefferson Lab

Two Topics in Accelerator Science: A General Model of Cumulative Beam Breakup in Linear Accelerators and The Critical Fields of Superconductors as Fundamental Limitations in Superconducting Accelerating Structures

Accelerator science is not an easily well defined and self-contained subject. It touches and includes many areas of science such as: classical, relativistic, and quantum mechanics; electromagnetism; solid state and condensed matter physics; surface physics and chemistry; vacuum science; and most branches of engineering. To illustrate the breadth of accelerator science, two seemingly disparate topics will be addressed. A recently developed general model of cumulative beam breakup will be presented as an example of the beam physics problems that are active areas of research. Many of today's (e.g. JLab) and tomorrow's (e.g. the International Linear Collider) accelerators will be based on superconducting cavities. While the rf critical field of the superconducting material will limit the ultimate performance of superconducting cavities, its nature is at present poorly understood, both theoretically and experimentally. Our present knowledge of the critical field of superconductors for linear accelerator applications will be the subject of the second topic.

September 19, 2006
3:00 pm (Tuesday)

Dr. Geoff Krafft
Jefferson Laboratory

New (and some old) Accelerators based on Superconducting RF Cavities

The first accelerators built from Superconducting RF (SRF) cavities were built at Stanford University and the University of Illinois in the mid-to-late 1970s. The main requirement driving the development of these accelerators was the wish to perform high-duty factor coincidence experiments in nuclear physics. Somewhat later, and in parallel, the high energy physics community started building SRF cavities as a natural energy source for electron storage rings because of the high efficiency of energy transfer into the electrons circulating in such rings. These days, hardly a proposal for a new accelerator on the large scale is made without some part of it being based on SRF cavities. In this talk, after reviewing some of the properties of SRF cavities that make them so desirable, the substantial progress in the field of SRF accelerators is discussed from a mainly historical perspective. In the later portions of the talk, some of the multitude of new ideas applying SRF accelerators are shown, on scales ranging from university-scale devices all the way up to huge accelerators based on multinational collaborations.

September 26, 2006
3:00 pm (Tuesday)

Dr. Brett DePaola
Kansas State University

Novel Experiments using the MOTRIMS Methodology

MOTRIMS (magneto-optical trap recoil ion momentum spectroscopy) was initially developed as an offshoot of the more common COLTRIMS technique in order to study in greater detail ionizing collisions between neutral atoms and ions or photons. In the years since those first experiments were carried out it was discovered that the MOTRIMS apparatus had far greater potential and its usage had far greater breadth than had initially been foreseen. In this talk we will present two examples of novel usages of the MOTRIMS methodology. In the first, MOTRIMS will be directed inwards to study the physics of magneto-optical traps themselves. In the second example, the temporal evolution of populations in a 3-level ladder system undergoing a particular scheme for coherent excitation known as STIRAP (stimulated Raman adiabatic rapid passage) is measured using MOTRIMS. In addition, anticipated future directions for MOTRIMS experiments will discussed.

October 3, 2006
3:00 pm (Tuesday)

Dr. Hari Areti
Jefferson Lab

Research Opportunities in Accelerator Physics at Jefferson Lab

Jefferson Lab's Accelerator Division has an active research program in polarized electron sources, superconducting radio frequency structures, beam diagnostics and future accelerators. This talk is an overview of the present research, the available facilities, the need and opportunities for participation in this less than well known, but an exciting and rewarding field.

October 17, 2006
3:00 pm (Tuesday)

Dr. Brian Fields
University of Illinois at Urbana-Champaign

When Stars Attack! Live Radioactivities as Signatures of Nearby Supernova Explosions

The lives of the most massive stars unfold in a symphony of the fundamental forces, culminating in a spectacular and violent supernova explosion. While these events are awesome to observe, they can take a more sinister shade when they occur closer to home, because an explosion inside a certain "minimum safe distance" would pose a grave threat to life on Earth. We will show how such events can leave fossil traces, in the form of live radioisotopes in geological samples. We will then present recent evidence that a star exploded near the Earth about 3 million years ago. Furthermore, these data for the first time allow sea sediments to be used as a telescope, probing the nuclear reactions occurring deep within massive stars.

October 31, 2006
3:00 pm (Tuesday)

Dr. Farideh Jalilehvand
University of Calgary

A New Battle for Historical Shipwrecks!

Dr. Farideh Jalilehvand will share her experience with us on how important chemistry is for saving historical shipwrecks, in museums around the world. Together with her international collaborators, she found large quantities of reduced sulfur compounds, e.g. thiols, disulfides, elemental sulfur and sulfides, embedded in the oakwood of the famous well-preserved wreck of the Swedish 17th century warship Vasa, to be the cause of severe problems of high acidity and salt precipitation, which may destroy the wood (Nature 2002, 415, 893). Similar sulfur problem has been found in the Mary Rose, the principle warship in the Henry VIII's navy, which is under conservation procedure in Portsmouth harbour, UK (PNAS 2005, 102, 14156). Recent investigations using synchrotron-based scanning X-ray spectro-microscopy (SXM) show that organosulfur compounds are accumulated in the lignin-rich middle lamella between cell walls, while chemically reactive iron sulfides (e.g. pyrite), which are susceptible to oxidation in humid environment, are distributed as separate particles and are the primary source of acid production in PEG treated marine-archaeological wood.

November 8, 2006
3:00 pm (Wednesday)

Note unusual date

Dr. Ian MacLeod
Western Australian Maritime Museum

Cape Hatteras to Pearl Harbour: Saving America's iron shipwreck heritage

Corroding iron shipwrecks were once believed to be unworthy of study, since they appeared to offer little to the classically trained maritime archaeologist. Pioneering work by Australian conservators helped to demonstrate that the corrosion matrixes created in the sea reflect the changes in the microenvironment of the wreck from the time of sinking to that of recovery. Concretion matrices of marine organisms and iron corrosion products track the changes in the chemical and physical environment of the shipwrecks. Truk lagoon shipwrecks from WW II have shown that in-situ corrosion studies enable those managing the sites to make informed decisions on how to preserve this unique memorial to the Battle of the Pacific. Lying upside down, on the side, on a submerged cliff or flat on the bottom of the lagoon cause differences in corrosion rates which means that some wrecks will soon become unsafe for penetration diving. It is now possible to discern the effect of being torpedoed, sunk by bombs or rammed by a warship. The role of conservators in determining the impact of dynamite fishing on the marine ecology and iron corrosion will be highlighted. The potential role for in-situ conservation to prevent leaking fuel oil from iron shipwrecks will be discussed. The latest results of Earthwatch Institute sponsored research has established a direct relationship between coral growth and corroding iron shipwrecks

November 9, 2006
7:00 pm (Thursday)

Dr. Ian MacLeod
Western Australian Maritime Museum

Confederate and Union forces unite to conserve America's historic iron shipwrecks: a tale of the submarine H. L. Hunley & USS Monitor

The past decade has seen submerged cultural resources rise to the forefront of public attention across the eastern seaboard of the USA. The Hunley Commission brought the world's best shipwreck conservators and archaeologists to Charleston to determine how best to recover the 1864 wreck of the H.L. Hunley submarine and she is now being fully conserved in the Warren Lasch laboratory in Charleston. Apart from sinking the Housatonic the submarine entombed its gallant crew. New excavation and conservation methods are being applied to produce the ultimate exhibition and to solve the final mystery of why it sank. The remains of the USS Monitor which sank in 1862 off Cape Hatteras have also been recovered and are under active conservation at The Mariners Museum in Newport News. The US Navy team and NOAA combined to recover the turret, engine and condenser of the vessel that single-handedly turned the tide of naval architecture. A combination of committed souls, passionate professionals and inspired academics has worked on solving the problems of halting the decay of mineralised metals that express themselves in the decayed structures of the Hunley and the Monitor. American scientists are developing new conservation methods that promise to be the most significant developments in maritime conservation in the past 100 years. This presentation will present exciting results arising from corrosion studies on these archetypal remains of what was the turning point in the development of a mighty nation.

November 14, 2006
3:00 pm (Tuesday)

Dr. Irina Novikova
College of William and Mary

Manipulation of light with atomic ensembles (and vice versa)

Electromagnetically Induced Transparency (EIT) and related coherent interactions of light and atomic ensembles enable a wide range of powerful new tools, for example, miniature (chip-scale) atomic clocks and magnetometers. EIT also allows the reversible mapping of quantum states between light and matter - i.e., the realization of a quantum memory. I will describe recent progress and future prospects in these areas.

November 28, 2006
3:00 pm (Tuesday)

Dr. Hui Cao
Northwestern University

Light Localization and Its Applications

In the latest development of nano-optics, light localization is a key issue. In this talk, I will review our recent research activities of utilizing optical scattering to achieve light localization. I will present three examples: (i) spatial localization of light in disordered nanostructures; (ii) light localization in the phase space as a result of scattering at the boundary of a chaotic microcavity; (iii) localization of surface plasmon polaritons in metal-dielectric nanocomposites. The application of light localization to microlasers will be demonstrated.

December 5, 2006
3:00 pm (Tuesday)

Old Dominion University

Senior Thesis Presentations

The Behavior of a Radial Time Projection Chamber"
Mr. Peter Bradshaw

Mr. Ben Tokarz

"An Analysis of the Doppler Method for Detection of Exoplanets"
Mr. Matthew J. Weinberg

December 12, 2006
12:30 pm (Tuesday)

Note unusual time

Old Dominion University

Senior Thesis Presentations

"The Effects of Nickel on Corrosive Properties in Fe-Ni Alloys"
Mr. Eric Stauffer

"Design Study of a Permanent Magnet Zeeman Slower"
Mr. Robert Horne