Session S2: Nuclear/Atomic/Molecular Physics

The Neutron Induced Fission Fragment Tracking Experiment

The Neutron Induced Fission Fragment Tracking Experiment will employ a novel, high granularity, pressurized time projection chamber (TPC) to measure ?ssion cross-sections of the major actinides to sub-1\% precision. This talk will present an overview of the design of the NIFFTE TPC, current status of the project and why we believe this device may produce a renaissance in low energy nuclear physics experiments.   

NIFFTE Software and Computing: Results from the First Mock Data Challenge

The Neutron Induced Fission Fragment Tracking Experiment will employ a novel, high granularity, pressurized time projection chamber to measure fission cross-sections of the major actinides to sub-1\% precision. The first suite of GEANT4 simulation and reconstruction software has been developed and run in a ``mock data challenge'' to validate the detector design and demonstrate the capabilities of the experiment. This talk will present the current status of results from this exercise, details for future simulation runs and plans for analysis of the first experimental data.   

CUORE: The Three Towers Test

Cryogenic Underground Observatory for Rare Events (CUORE) will be part of the next generation of detectors used to search for neutrinoless double beta decay (0vBB). Located in Assergi, Italy at the Gran Sasso National Laboratory (LNGS), CUORE will be a large cryogenic bolometer composed of 988 tellurium dioxide (TeO2) detectors with a total mass of 750 kg, and will search for 0vBB in 130Te. As the experiment will monitor the extremely rare event of 0vBB, all factors contributing to background need to be minimized to effectively increase the sensitivity. We assisted the LNGS researchers over the summer of 2008 by supporting Research and Development efforts to reduce the radioactive background of the experiment. Activities involved decontaminating the copper frame of radon daughters, and chemically etching and lapping the TeO2 crystals with nitric acid and silicon dioxide, respectively, to remove surface contaminants that contribute to background counts. This work was supported in part by NSF grant PHY-0653284 and the California State Faculty Support Grant.   

Introducing Accelerator Physics to a Wider Audience

Over the last century, particle accelerators have changed the way we look at nature, and have become integral to the nation's technical infrastructure. Nevertheless, many non-scientists do not understand the term \textit{accelerator}. And even within the broader physics community \textit{accelerator physics} is not often taught as a course. The APS Division of Physics of Beams, to acquaint a wider audience with Accelerator and Beam Physics, recently published a 28-page brochure: \textbf{Accelerators and Beams, Tools of Discovery and Innovation}. Requests for copies have been quite wide ranging: policy makers; faculty for distribution to physics students and to raise awareness on campuses; APS staff to use in annual APS Teachers Days; and for a gifted high school student program. Copies are handed out by scientists presenting lectures on accelerators. And it is available at many labs, industries, education offices, libraries and public information offices. Nearly 12,000 copies have been printed. Most copies have been distributed and a new edition is being considered. I edited this brochure and am pleased with its success. In this talk I will run through highlights and will have copies available.   

Towards the first \textit{ab initio} description of the deuterium-tritium fusion

The deuterium-tritium reaction is important for the future fusion energy generation. It is used in laser-induced fusion at NIF and magnetic-confinement fusion at ITER. Even though it has been well studied experimentally, its first principles theoretical understanding is important. We are building a new capability to describe light-ion fusion reactions from first principles, known as \textit{ab initio} NCSM/RGM approach [1,2]. We have completed a promising preliminary study of nucleon-nucleus scattering, particularly $n-^{4}$He scattering below the $d+^{3}$H threshold [1,2]. Now we are developing the deuterium-nucleus formalism that coupled with the nucleon-nucleus basis will allow us the first \textit{ab initio} calculation of the $^{3}$H($d$,$n)^{4}$He fusion. We will present recent results and work in progress. \\[4pt] [1] S. Quaglioni and P. Navratil, Phys. Rev. Lett. \textbf{101}, 092501 (2008). \\[0pt] [2] S. Quaglioni and P. Navratil, Phys. Rev. C \textbf{79}, 044606 (2009).   

Two-Body with Confining Potentials

A formalism is presented that allows an asymptotically exact solution of non-relativistic and semi-relativistic two-body problems with infinitely rising confining potentials. We consider both linear and quadratic confinement. The additional short-range terms are expanded in a Coulomb-Sturmian basis. Such kinds of Hamiltonians are frequently used in atomic, nuclear, and particle physics.   

The Proof of the ``Vortex Theory of Matter''

According to the Vortex Theory, protons and electrons are three-dimensional holes connected by fourth-dimensional vortices. It was further theorized that when photons are absorbed then readmitted by atoms, the photon is absorbed into the proton, moves through the fourth-dimensional vortex, then reemerges back into three-dimensional space through the electron. To prove this hypothesis, an experiment was conducted using a hollow aluminum sphere containing a powerful permanent magnet suspended directly above a zinc plate. Ultraviolet light was then shined upon the zinc. The zinc emits electrons via the photoelectric effect that are attracted to the surface of the aluminum sphere. The sphere was removed from above the zinc plate and repositioned above a sensitive infrared digital camera in another room. The ball and camera were placed within a darkened box inside a Faraday cage. Light was shined upon the zinc plate and the picture taken by the camera was observed. When the light was turned on above the zinc plate in one room, the camera recorded increased light coming from the surface of the sphere within the other room; when the light was turned off, the intensity of the infrared light coming from the surface of the sphere was suddenly diminished. Five other tests were then performed to eliminate other possible explanations such as quantum-entangled electrons.   

Hierarchical Cross-linked F-actin Networks: Understanding Structure and Assembly

The protein, F-actin provides us with an interesting system in which to investigate the assembly properties of semi-flexible filaments in the presence of cross-linkers. Recently it was observed that F-actin, in the presence of the cross-linker alpha-actinin at high molar ratios will generate a novel hierarchical network of filament bundles. We investigate this system using coarse-grained molecular dynamics (MD) simulation, confocal microscopy and x-ray scattering. We have studied the F-actin/alpha-actinin system in detail with different actin conc. (C) and alpha-actinin/actin molar ratios (gamma). Confocal microscopy and analysis shows that the assembled systems fall into one of 3 phases depending on C and gamma: (1) loosely connected network of F-actin and bundles, (2) loosely connected network of dense domains and (3) uniform network of bundles. This can be explained and replicated using MD simulation. We have also examined different types of cross-linkers to represent the proteins, fascin and filamin. Results show that phase formation is related to the flexibility in binding between F-actin and cross-linkers. This degree of freedom, possible with longer cross-linkers allows the formation of branch points and thus bundle networks.   

Measurement of Colloidal Interactions Using Holographic Microscopy and Multi-particle Scattering Theory

Holographic microscopy provides the ability to record particle information in three dimensions with rapid time resolution. Lorenz-Mie scattering theory has been used to interpret holographic images of single colloids and provide highest available resolution for imaging single colloids in three dimensions. This method, however, has yet to be employed to interpret images of multiple particles. We demonstrate the implementation of a multiple-particle generalization of Lorenz-Mie scattering solution to interpret holographic images of clusters of spherical colloids. Highly precise theoretical holograms of multiple spherical colloids are calculated using the multiple-particle scattering theory, and recorded holographic images of colloidal clusters are fit to those of the theoretical method. The parameters of the fitting routine are used to characterize colloids' sizes, indices of refraction and separation radii, amongst other properties.   

Cesium Iodide Crystal Calorimeter of the Proton Computed Tomography (pCT) Imager

Researchers at SCIPP, LLMU and NIU have collaborated to make a functioning proton imager. Proton Computed Tomography (pCT) is designated to be applied in proton therapy of human cancer systems. It will image head-sized phantom objects and provide excellent space and energy resolution using a silicon microstrip tracker and crystal calorimetry. The residual energy could be measured with precision of a few percent using a Cesium Iodide crystal calorimeter. A single element of the CsI(TI) calorimeter was tested in order to understand the behavior of the future calorimeter system. We present test results on a CsI(TI) calorimeter element with proton beams of 35, 100 and 200MeV. The detector element was designed to comply with the demands of high energy resolution of a few percent and a dynamic range of two orders of magnitude (1-300MeV) under a counting rate of 10 kHz per channel. We also report on cosmic measurement results of each crystal of the future calorimeter matrix. A detailed description of the calorimeter data acquisition system will be given.