Physics Abstracts:

24Al Level Structure and the Corresponding 23Mg(p,) 24Al Astrophysical Reaction Rate. CHRISTOPHER DEATRICK (Western Michigan University, Kalamazoo, Mi, 49008) DARIUSZ SEWERYNIAK (Argonne National Laboratory, Argonne, IL, 60439)

24Al Level Structure and the Corresponding 23Mg(p,) 24Al Astrophysical Reaction Rate. Christopher J. Deatrick (Western Michigan University, Kalamazoo, MI 49008) Dariusz Seweryniak (Argonne National Laboratory, Argonne, IL 60439) In order to better understand the processes involved in heavy nuclide production in explosive stellar environments, the breakout process from the CNO cycles to the NeNa cycle and to the MgAl cycle must be quantified. Better numerical values of proton capture rates are deduced for the 23Mg(p,) 24Al reaction by studying nuclear energy levels in 24Al above the proton capture threshold using high-resolution -ray spectroscopy and -ray angular distribution analysis. 24Al nuclei were produced by colliding an 16O beam delivered by the Argonne Tandem-Linac Accelerator System with a 10B target . Excited states in 24Al were populated after evaporating two neutrons from the compound system. Gamma rays emitted from these states were detected with the GAMASPHERE array of Compton-suppressed Ge detectors. The Argonne Fragment Mass Analyzer was used to separate reaction products from the beam and assign mass and atomic numbers. As a result, states above and below the proton threshold were studied in detail resulting in an improved 24Al level scheme. The analysis of the first state above the proton threshold indicates that the reaction rate contribution of this state could differ by a factor of up to 9 from that of previous calculations in the 0.1-0.5 GK temperature range.

3D Simulation for the ATLAS Education and Outreach Group. BRIAN AMADIO (Rensselaer Polytechnic Institute, Troy, NY, 12180) MICHAEL BARNETT (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

ATLAS is a particle detector under construction at the Large Hadron Collider facility at the CERN Laboratory in Geneva, Switzerland. The project will be the most expansive physics experiment ever attempted. The ATLAS Education and Outreach Group was started to provide information to students and the general public about the importance of this project. A three-dimensional interactive simulation of ATLAS was created, which allows users to explore the detector. This simulation, named the ATLAS Multimedia Educational Laboratory for Interactive Analysis (AMELIA), allows users to view detailed models of each part of the detector, as well as view event data in 3D. A similar project is called ATLANTIS, which allows users to examine events in only two dimensions. Currently ATLANTIS allows more sophisticated analysis of events. AMELIA will provide similar functionality, but in a more intuitive way, which will be much friendlier to the public.

A Catalog of Candidate High-Redshift Blazars for GLAST. TERSI ARIAS (San Francisco State University, San Francisco, CA, 94132) JENNIFER CARSON (Stanford Linear Accelerator Center, Stanford, CA, 94025)

High-redshift blazars are promising candidates for detection by the Gamma-ray Large Area Space Telescope (GLAST). GLAST, expected to be launched in the Fall of 2007, is a high-energy gamma-ray observatory designed for making observations of celestial gamma-ray sources in the energy band extending from 10 MeV to more than 200 GeV. It is estimated that GLAST will find several thousand blazars. The motivations for measuring the gamma-ray emission from distant blazars include the study of the high-energy emission processes occurring in these sources and an indirect measurement of the extragalactic background light. In anticipation of the launch of GLAST we have compiled a catalog of candidate high-redshift blazars. The criteria for sources chosen for the catalog were: high radio emission, high redshift, and a flat radio spectrum. A preliminary list of 307 radio sources brighter than 70mJy with a redshift z = 2.5 was acquired using data from the NASA Extragalactic Database. Flux measurements of each source were obtained at two or more radio frequencies from surveys and catalogs to calculate their radio spectral indices . The sources with a flat-radio spectrum ( = 0.5) were selected for the catalog, and the final catalog includes about 200 sources.

A Geant4 Simulation of the COUPP Bubble Chamber. CHARLES CAPPS (Carnegie Mellon University, Pittsburgh, PA, 15289) ANDREW SONNENSCHEIN (Fermi National Accelerator Laboratory, Batavia, IL, 60510)

It is known that a sensitivity on the order of 1 event per year per ton of detector material is necessary to detect a WIMP (Weakly Interacting Massive Particle) dark matter candidate. After successful veto of cosmic radiation, the neutron background will become the greatest obstacle for COUPP (Chicagoland Observatory for Underground Particle Physics) to achieve this level of sensitivity. Thus, understanding the COUPP bubble chamber's response to low-energy neutrons (< 50 MeV) is crucial. A Geant4 simulation of the COUPP bubble chamber response to an Am/Be neutron source is described. The recoil energy spectra given by the simulation are presented. Simulation results of event rate as a function of chamber pressure are compared to experimental data. Moreover, multiple bubble events--indicative of neutrons--are examined. The ratio of single to multiple bubble events is determined for different energy thresholds. To verify Geant4 for neutrons in this energy regime, cross-sections and differential cross-sections are computed from the simulation and compared to the JENDL, JEFF, and ENDF nuclear databases. Elements present in the COUPP experiment are considered. Good agreement is found between simulation cross-sections and the above nuclear databases.

A Numerical Model of the Critical Charge Density Surface of Ultra High Energy Cosmic Ray Induced Extensive Air Showers Using the SCILAB Programming Language. ALLEN SHARPER (Florida A&M University, Tallahassee, FL, 32301) HELIO TAKAI (Brookhaven National Laboratory, Upton, NY, 11973)

A numerical model of the critical charge density surface of ultra high-energy cosmic ray (UHECR) induced extensive air showers (EAS) has been computed. The critical charge density surface defines the surface for specula reflection of radio waves with frequency less than the natural oscillation frequency (plasma frequency) of the EAS charges. Using a numerical model to understand how radio waves reflect from the air shower will help improve the design of devices (antennas, arrays) used to detect the reflected waves. The numerical model will allow the power and direction of the reflected waves to be calculated which will provide a map of the spatial distribution of reflected wave power and polarization incident to the surface of the earth. The program of the numerical model, written in the SCILAB language, calculates the density of ionization electrons as a function of radial distance from the shower axis and location along the axis. The cosmic ray tracing model is part of the Mixed Apparatus for Radar investigation of Cosmic-rays of High Ionization (MARIACHI) project. The MARIACHI project, consist of research that investigates an unconventional way of detecting UHECR. Based upon a method successfully used to detect meteors entering the upper atmosphere. Mariachi seeks to listen to television signals reflected off the ionization trail of an UHECR.

A Plasma Gun for the Next Generation of Spallation Neutron Source H- Ion Sources. JUSTIN CARMICHAEL (Worcester Polytechnic Institute, Worcester, MA, 1609) ROBERT F. WELTON (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

The ion source for the Spallation Neutron Source (SNS) is required produce 40-50 mA of H- current depending on emittance with a duty factor of ~7% for baseline facility operation. The SNS Power Upgrade Project requires this current to be increased to 75-100 mA at the same duty factor. In its present form, the baseline SNS ion source is unable to deliver this performance over sustained periods of time. A new generation of RF-driven, multicusp, ion sources based on external antennas are therefore being designed to meet these requirements. It was found that by injecting a stream of plasma particles from a simple, steady-state, DC glow-discharge into the RF-plasma (i) H- production can be dramatically increased and (ii) H- pulse rise time can be significantly reduced. The design of a suitable plasma gun is presented which features a hollow anode and mechanical compatibility with the new ion sources. The Finite Element Method (FEM) has been employed to optimize the design: coupled fluid dynamic, heat transfer, mechanical stress and deformation, and ion/electron trajectory simulations were performed. Several design improvements over earlier versions were implemented such as the addition of an extraction system. The FEM simulations showed that the design of the new plasma gun is sufficient to handle the thermal stresses resulting from a 1 kW load on the cathode face. The ion/electron simulations demonstrated a high degree of control over the plasma beam, allowing for manipulation of the intensity, mean energy, and divergence of the streaming plasma. The extraction system also allows for selective emission of electrons or ions. It is anticipated that the plasma beam can be optimized with the extraction system to significantly increase the H- current in the new ion sources.

A Portable Water Cherenkov Detector: Measuring Particle Flux at Different Altitudes. LUKAS BAUMGARTEL (University of New Mexico, Albuquerque, NM, 87131) BRENDA DINGUS (Los Alamos National Laboratory, Los Alamos, NM, 87545)

High-energy cosmic particles initiate extensive air showers (EAS) as they interact with the air molecules in Earth’s upper atmosphere. If the primary particle carries sufficient energy, the shower reaches the ground. With an array of photo-multiplier tubes (PMT’s) located in a pool of water, the direction and energy of the primary particle can be reconstructed from the Cherenkov light generated as the EAS hits the detector. Milagro is one such detector, and has observed high energy (~1TeV) gammas and protons from high energy cosmic phenomena such as active galactic nuclei and supernova. A new detector called HAWC (High Altitude Water Cherenkov), similar to Milagro but with new electronics and high-altitude location (4000m), data was taken at University of New Mexico to perfect the measurement method and to characterize how other factors, such as weather, tank configuration, and power sources affect count rates. Once these variables were well understood, the detector was used to measure particle flux at four different altitudes: 1540m, 2650m, 3231m, and 4308m. The rates of the low energy electromagnetic particles were found to increase with altitude, and had values of 4.38 kHz, 4.82 kHz, 5.50 kHz, and 6.92 kHz, respectively. The 2650m data was taken at the Milagro site as a reference point. Based on the current data acquisition and analysis algorithm used for Milagro, singles rates at the HAWC site should be less than a factor of two greater then they are at Milagro. The rates measured at >4000m were 1.44 times greater than the rates at Milagro, leading to the conclusion that singles rates at a HAWC site >4000m will have a negligible effect on triggering and pulse height measurement.

A Preliminary CCD Cosmetic Grading System for the Dark Energy Survey Camera Focal Plane CCDs. SARAH CARLSON (DePauw University, Greencastle, IN, 46135) JUAN ESTRADA (Fermi National Accelerator Laboratory, Batavia, IL, 60510)

The Dark Energy Survey (DES) is a 5000 sq-degrees sky survey that will strive to make more precise measurements of dark energy. The DES team at Fermilab is responsible for the construction of the Dark Energy Camera (DECam) that will be mounted along with corrective optics and electronics on the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. The camera will be comprised of 62 image charge-coupled devices (CCDs) and 8 guiding, focusing and aligning CCDs. These CCDs are made of silicon and manufactured at Lawrence-Berkley National Laboratory (LBNL). Part of the task of building the DECam is understanding how each CCD functions. This understanding includes knowing the limitations of each CCD. Cosmetic defects can be crippling to the performance of a CCD. Cosmetic defects include white and dark pixels, bad columns, as well as defects caused by dark current and quantum efficiency (QE) non-uniformity problems. Dark current is a small electric current generated by the thermal motion of the silicon atoms in the CCD. QE is the measure of the CCD’s sensitivity to a certain wavelength. Using the popular astronomical source detection program Source Extractor we make two separate analyses: a flat-fielding analysis and a uniformity analysis which includes both the dark current and QE uniformity. Catalogs of all the defects found are created for each analysis and analyzed. To be an acceptable candidate for the DECam focal plane, each CCD must meet the requirement of no more than 5% non-usable image area. Using this requirement as a starting point, we have devised a preliminary cosmetic grading system to be used for each CCD. Each CCD will be given two grades, one for the flat-fielding analysis and one for the uniformity analysis. The CCD will receive a grade of 0 if the affected area is 2.5% or less of the total CCD area. A grade of 1 will be given if the affected area is between 2.5% and 5% of the total CCD area. A grade of 2 will be given if the affected area is 5% or more of the total CCD area. Our logic for giving each CCD two grades instead of one overall grade is that we will be able to better characterize CCDs, and if the occasion should arise that we need to pick between groups of CCDs for the DECam focal plane the two grades will assist us in making our choice.

A Study of Gas Electron Multiplier (GEM) Foils. MATTHEW RUMORE (Worcester Polytechnic Insitute, Worcester, MA, 1609) CRAIG WOODY (Brookhaven National Laboratory, Upton, NY, 11973)

Advances have been made in the field of high-energy nuclear physics due to the increased usage of Gas Electron Multiplier (GEM) foils, which are known for their versatility and their ability to detect and amplify charge. For instance, GEM foils will be implemented in the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) and Solenoidal Tracker At RHIC (STAR) experiments at the Relativistic Heavy Ion Collider (RHIC) for the detection of signals from high-energy particle interactions. The reliable production of GEM foils depends on a study of their properties and operating conditions. Two of the most important properties are the absolute gain and the gain stability over time. To test the gain, each foil is placed in an Argon/Carbon Dioxide environment in the ratio of 70:30. An alpha particle emitted above the foil by an Americium-241 source ionizes the gas and produces a cluster of electrons. This primary charge is then collected and amplified by the GEM foil. The amplified signals are read out through a conductive pad on the bottom of the GEM detector using a digital oscilloscope. Because the amount of primary charge is known, the absolute gain will be calculated for each GEM foil as a function of voltage. The gain stability measurements entail taking successive gain measurements over time for a constant voltage. The manufacturing process strongly influences the performance of each GEM foil. As a result, a number of foils produced under different manufacturing conditions were studied in terms of their overall gain and gain stability. This study, which will mostly likely continue until August 2006, will allow the scientific community to understand the properties of the GEM foils and improve the ability to manufacture better foils in the future.

A Twin Ionization Chamber Arrangement for the Study of 12C(a,)16O Through the ß-Delayed a Spectrum of 16N. ALESSANDRO LAURO (University of Chicago, Chicago, IL, 60637) ERNST REHM (Argonne National Laboratory, Argonne, IL, 60439)

The most fundamental reactions that describe the complex process of helium burning during stellar evolution include the ¹²C(a,)¹⁶O reaction and the 3 ⁴He  ¹²C +  reaction. While the latter has been studied quantitatively over the last decades, the properties of the ¹²C(a,)¹⁶O are surrounded by a great deal of uncertainty due to its very small cross section of 10^-41 cm². Despite this restriction, the ¹²C(a,)¹⁶O reaction can be studied indirectly by observing the ß-delayed a spectrum of ¹⁶N. While it is energetically impossible for ground state ¹⁶O to a decay to ¹²C, it is possible to examine ¹⁶O*, excited states of ¹⁶O, that result from the ß-decay of ¹⁶N. Even though the branching ratio of this reaction favors  decay over a decay by a factor of about 10⁵, a precise measurement of a-particles can be carried out by a specially designed dual twin ionization chamber located at the Argonne Tandem Linear Accelerator System (ATLAS) at Argonne National Laboratory. An important step in this experiment involves the calibration of the ionization chamber using a Pu-Be neutron source in order to test the a emission produced by the ¹⁰B(n,a)⁷Li and ⁶Li(n,a)t reactions. It is from this procedure that a new method of obtaining information about the emission angle of a-particles from the source has been found.

Afterglow Radiation from Gamma-Ray Bursts. HUGH DESMOND (Katholieke Universiteit Leuven, Leuven, Belgium, 3000) WEIQUN ZHANG (Stanford Linear Accelerator Center, Stanford, CA, 94025)

Gamma-ray bursts (GRB) are huge fluxes of gamma rays that appear randomly in the sky about once a day. It is now commonly accepted that GRBs are caused by a stellar object shooting off a powerful plasma jet along its rotation axis. After the initial outburst of gamma rays, a lower intensity radiation remains, called the afterglow. Using the data from a hydrodynamical numerical simulation that models the dynamics of the jet, we calculated the expected light curve of the afterglow radiation that would be observed on earth. We calculated the light curve and spectrum and compared them to the light curves and spectra predicted by two analytical models of the expansion of the jet (which are based on the Blandford and McKee solution of a relativistic isotropic expansion; see Sari's model and Granot's model). We found that the light curve did not decay as fast as predicted by Sari; the predictions by Granot were largely corroborated. Some results, however, did not match Granot's predictions, and more research is needed to explain these discrepancies.

AMELIA: ATLAS Multimedia Educational Lab for Interactive Analysis. DAVID MEDOVOY (Columbia University, New York, NY, 10027) MICHAEL BARNETT (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

AMELIA is an educational software program designed to allow the public to view, on a home computer, a 3D model of ATLAS detector at CERN, as well as visualization of recorded particle tracks. Models of the detector’s geometry, created in ‘3ds Max,’ are loaded by the software, which is written using the C++ language and the ‘Irrlicht’ visualization engine. Particle track data in the JiveXML file format is loaded and displayed simultaneously. The use of the standard JiveXML format allows for file-type compatibility with other software, such as the 2D visualization tool ATLANTIS. The ‘camera’ is fully movable by the user, and custom cutaway views can be created based on the camera’s position, to facilitate viewing the interior parts of the detector, as well the particle tracks within. Tracks are color-coded based on particle type, and will soon be individually selectable. Programs exist to visualize particle track data in 3D, and to simplify scientific data for outreach purposes, but only AMELIA is designed for both. Further, AMELIA is the only project of its kind designed to take advantage of technology developed for video games. An early 2007 public release is anticipated.

Analysis of a Proposed Very Long Baseline Neutrino Oscillation Experiment. CHRISTINE LEWIS (Columbia University, New York, NY, 10027) MILIND DIWAN (Brookhaven National Laboratory, Upton, NY, 11973)

The Very Long Baseline Neutrino Oscillation (VLBNO) study aims to determine how to best design a second generation experiment to measure the neutrino oscillation parameters and possible violation of charge/parity (CP) invariance. Using the General Long Baseline Experiment Simulation (GLoBES) software and considering a 500kT water Cherenkov detector at 1300km, corresponding to a baseline from Fermilab to the Homestake mine, we calculate the sensitivity to ₁₃ and the CP phase. We find that with 2500kT*MW*10⁷s of neutrino running and 5000kT*MW*10⁷s of antineutrino running the experiment could measure sin²2₁₃ to 9-14% and d_CP to ~15° at 1s. Moreover, the experiment is sensitive to non-zero sin²2₁₃ as low as 4x10^-3 at 99% confidence.

Analysis of Beam Deviation Due to Quadrupole Misalignment Caused by Ambient Ground Motion in the Relativistic Heavy Ion Collider. BRANDON BELEW (Rensselaer Polytechnic Institute, Troy, NY, 12180) CHRISTOPH MONTAG (Brookhaven National Laboratory, Upton, NY, 11973)

Within the Relativistic Heavy Ion Collider (RHIC) and particle accelerators in general, proper alignment of the focusing and defocusing quadrupole magnets is essential to maintaining a stable beam orbit. However, it is also a fact that there will always be some misalignment due to ambient ground motion. The extent of this displacement is given by a simple linear formula of time, distance and a site-specific constant (the ‘ATL Rule’). Using known values of the beta function, phase advance, and focusing strength at the RHIC quadrupoles, code was written to simulate expected beam deviation at specific monitor points according to the ATL rule, for arbitrary values of the constant A. This expected deviation was then compared with actual logged beam data over the course of several months to arrive at the site-specific value of A. The end result, the constant of ambient ground motion specific to the RHIC location, was calculated to be around 3e-11 mm^2/m*s. Knowing this value will allow for more accurate predictions of future beam deviation, and facilitate the proper application of correcting dipole magnets to counteract these effects.

Analysis of Creep in Polyvinyl Chloride for the NOvA Detector. CHRISTINE MIDDLETON (Wesleyan University, Middletown, CT, 6459) HANS JOSTLEIN (Fermi National Accelerator Laboratory, Batavia, IL, 60510)

This analysis is an attempt to predict creep in the NOvA detector, a proposed electron neutrino detector for the NuMI beamline at Fermilab. The NOvA detector is constructed of large PVC extrusions which contain 25 ktons of scintillating oil. Due to the scale of this detector and the proposed experiment length of 20 years, creep in the structural PVC of the detector is a concern. Creep data was taken on 18 samples over 188 days. Stress levels ranged from 500 PSI to 2100 PSI, with 2 samples being tested at each stress. A variety of models and fit functions from the literature were used, however a best fit function was not readily apparent. Although the data could be fit reasonably well, these functions were unable to give a reasonable prediction for the creep after 20 years. In order to improve these results, more data is needed which represents the secondary and tertiary creep stages. We anticipate being able to study this behavior using accelerated high temperature creep tests.

Analysis of Off-Nuclear X-Ray Sources in Galaxy NGC 4945. SARAH HARRISON (Massachusetts Institute of Technology, Cambridge, MA, 22901) GRZEGORZ MADEJSKI (Stanford Linear Accelerator Center, Stanford, CA, 94025)

Recently, X-ray astronomy has been used to investigate objects such as galaxies, clusters of galaxies, Active Galactic Nuclei (AGN), quasars, starburst superbubbles of hot gas, X-ray binary systems, stars, supernova remnants, and interstellar and intergalactic material. By studying the x-ray emission patterns of these objects, we can gain a greater understanding of their structure and evolution. We analyze X-ray emission from the galaxy NGC 4945 using data taken by the Chandra X-ray Observatory. The Chandra Interactive Analysis of Observations (CIAO) software package was used to extract and fit energy spectra and to extract light curves for the brightest off-nuclear sources in two different observations of NGC 4945 (January, 2000 and May, 2004). A majority of sources were closely fit by both absorbed power law and absorbed bremsstrahlung models, with a significantly poorer Χ²/dof for the absorbed blackbody model, and most sources had little variability. This indicates that the sources are accreting binary systems with either a neutron star or black hole as the compact object. The calculated luminosities were about 10³⁸ erg/s, which implies that the mass of the accreting object is close to 10 solar masses and must be a black hole.

Analysis of the properties of particles emerging from Deep Inelastic Scattering off a range of nuclei. SERERES JOHNSTON (Andrews University, Berrien Springs, MI, 49103) KAWTAR HAFIDI (Argonne National Laboratory, Argonne, IL, 60439)

Hadronization, the process by which a struck quark evolves into a hadron, is not well understood in the nuclear medium. Experiments done with medium energy electron beams and multiple nuclear targets can investigate hadronization at nuclear scales. Understanding this process would provide insight into the confinement property of the nuclear strong force. The data collected by the E02-104 Nuclear Semi Inclusive Deep Inelastic Scattering experiment, performed at Jefferson Laboratory with a 5 GeV electron beam, can be used to characterize hadronization as a function of multiple variables. E02-104 ran with several solid targets of differing atomic radius and the data taken is sensitive to early hadronization processes. Programs were written which compared the hadron attenuation and transverse momentum broadening in the three nuclear targets, carbon, iron, and lead. Greater attenuation is observed in large nuclei. Hadron attenuation is described by the multiplicity ratio, R^h_M, which is a multivariable function. The high statistics of the E02-104 data allowed its dependence on four different variables to be examined in detail. The quark energy loss indicated by the transverse momentum broadening is seen to increase with the square of the nuclear distance traveled. This agrees with QCD predictions based on quark energy loss through gluon radiation. There is also some evidence that the transverse momentum broadening approaches a limit in larger nuclei. Not enough nuclear targets were examined for this last result to be definitive.

Analysis Strategy of Powder Diffraction Data with 2-D Detector. ABHIK KUMAR (Austin College, Sherman, TX, 75090) APURVA MEHTA (Stanford Linear Accelerator Center, Stanford, CA, 94025)

To gain a clearer understanding of orientation and grain deformation of crystalline materials, x-ray powder diffraction has played an integral role in extracting three-dimensional structural information from one-dimensional diffraction patterns. Powder diffraction models identical geometry to the intersection of a normal right cone with a plane. The purpose of this paper is to develop a general expression defining the conic sections based on the geometry of a powder diffraction experiment. Applying the derived formulation of a diffraction arc to experimental data will give insight to the molecular and structural properties of the sample in question. Instead of using complex three-dimensional Euclidian geometry, we define the problem solving technique with a simpler two-dimensional transformation approach to arrive at a final equation describing the conic sections. Using the diffraction geometry parameters, we can use this equation to calibrate the diffractometer from the diffraction pattern of a known reference material, or to determine the crystalline lattice structure of the compound.

Analytical Data Acquisition via Radar of Ionization Electrons in Cosmic-ray Extensive Air Showers. JEREMY MARTIN (FAMU-FSU College of Engineering, Tallahassee, FL, 32310) HELIO TAKAI (Brookhaven National Laboratory, Upton, NY, 11973)

Ultrahigh-energy cosmic-rays initiate cosmic showers of high-energy, electrically charged particles upon interaction with the atmosphere of the earth. Evidence of radio wave reflection is collected from ultrahigh-energy comic-ray (UHECR)-induced extensive air showers (EAS) of high energy electrically charged particles when entering the stratosphere. Optimal detection of UHECR entails facilitating a more pertinent understanding of the high-energy particle and its celestial origin. The challenge is using a type of radar detection to separate the radio signals reflected by EAS from radio waves reflected from other sources (i.e., clouds, meteor trails, air crafts, emissions from lightening). This requires an approach involving Fourier transform, power spectrum analysis, as well as other series evaluation techniques to discriminate between the EAS reflected waves which contain data from high ionization particle interaction and oscillations that are irrelevant to this research. To distinguish EAS radio waves from other atmospheric sources of radio waves, a set of software tools were developed. Using this uniquely developed data acquisition software, randomly reflected radio waves about the atmosphere can be manipulated from their intrinsic state to isolate the power spectrum of the EAS waveforms in an attempt to efficiently identify these particular signatures of undulation in greater proportion. By analyzing the frequencies of these signals the intention is to later demonstrate a correlation between the radio waves occurring in specific VHF radio frequencies and cosmic-ray events detected by other means. This research is a portion of a process in which the goal is to develop a basis for further study of UHECR within the Mixed Apparatus for Radar Investigation of Cosmic-rays of High Ionizations (MARIACHI) project, which seeks to develop radar detection techniques for related studies of high energy physics.

Calculation of Particle Bounce and Transit Times on General Geometry Flux Surfaces. DOUGLAS SWANSON (Yale University, New Haven, CT, 6520) DR. JONATHAN MENARD (Princeton Plasma Physics Laboratory, Princeton, NJ, 8543)

Minimizing magnetohydrodynamic (MHD) instabilities is essential to maximizing the plasma pressure and the fusion power output from toroidal plasmas. One such instability is the resistive wall mode (RWM). Plasma rotation above a critical frequency has been observed to stabilize the RWM. The critical frequency is predicted in some theories to depend strongly on characteristic bounce and transit times particles take to complete orbits. Bounce times are orbit times for particles with large magnetic moments that are trapped poloidally in banana orbits. Transit times are orbit times for particles with small magnetic moments that are able to complete full poloidal circuits around the plasma. Previous calculations of these bounce and transit times have assumed high aspect ratio and circular flux surfaces, approximations unsuitable for the National Spherical Torus Experiment (NSTX). Analytic solutions for the bounce and transit times were derived as functions of particle energy and magnetic moment for low aspect ratio and elliptical flux surfaces. Numeric solutions for arbitrary aspect ratio and flux surface geometry were also computed using Mathematica and IDL and agree with the analytic forms. The solutions were found to scale as the elongation at low aspect ratio, and as the square root of the elongation at high aspect ratio. For typical values of the parameters the bounce and transit times can differ from the high aspect ratio, circular results by as much as 40%. Analytic transformations to map the high aspect ratio, circular solutions into the general geometry solutions are being investigated. Such transformations could be easily incorporated into existing stability codes such as MARS to refine models of RWM rotational stabilization.

Calibration of Small Pb-Glass Photomultiplier Cells in the FPD++ (Forward Pion Detector). SHAWN PEREZ (State University of New York at Stony Brook, Stony Brook, NY, 11790) LESLIE BLAND (Brookhaven National Laboratory, Upton, NY, 11973)

The FPD++ (Forward Pion Detector) at Brookhaven National Lab, consists of two matrices of Pb-glass bars viewed by photomultiplier tubes that are positioned left and right of the colliding beam axis. These detectors are used to explore transverse single spin asymmetries through analysis of forward pion production and its corresponding jet shape. In order to extract information from polarized proton - proton collisions, the FPD++ had to be calibrated cell by cell. Reconstructed di-photon invariant mass is associated with the highest energy cell in the inner matrix. Distributions of high tower invariant mass are fit by a Gamma function to describe background in the detectors and a Gaussian to describe the Pi0 peak. The absolute gain of each tower is then varied until the Pi0 peak is centered at its known position of .135 GeV/c^2. Once the relative gain correction factors of each iteration performed have converged, the cells have been calibrated. Currently the Small cells of the FPD++ are calibrated within an accuracy of 2%, while the large cells still need to be calibrated. Comparing the summed energy spectra of polarized up and down proton collisions in the west-north and west-south modules of the FPD++, will reveal more information about transverse single spin asymmetries and possibly the relative contributions from the Collins and Sivers effect toward these asymmetries observed in forward pion production. The Collins and Sivers effect are theoretical models developed to explain transverse single spin asymmetries, dependent on spin and transverse momentum distribution functions or fragmentation functions. Analyzing the pseudorapidity (-ln(tan(/2)) dependence on particle production will explore parton distributions within the proton.

CCD Quantum Efficiency Characterization for LSST. XIAOQIAN ZHANG (Cornell University, Ithaca, NY, 14853) JAMES S. FRANK (Brookhaven National Laboratory, Upton, NY, 11973)

The optical performance of charge coupled devices (CCDs), the fundamental units used for digital cameras, can be characterized by their quantum efficiency. The Large Synoptic Survey Telescope (LSST) project, an ongoing project aiming for completion in 2013, needs a high-efficiency digital camera with 3.2 Giga-pixels of CCDs for its acquisition of astronomical images. The CCDs used in this camera need to attain nearly 50 % quantum efficiency in the near-infrared (1000nm) while operating in a vacuum Dewar at a temperature of 173K. To test this requirement, instrumentation of a device that measures quantum efficiency of manufactured CCDs is under development at Brookhaven National Laboratory (BNL) and is based partially on the similar instrumentation developed in 2004 and 2005 in the Lawrence Berkeley National Laboratory (LBNL). This device consists of multiple light sources, a shutter, several filters, a coupled monochromator, a 12-inch diameter integrating sphere, a black box, and a dewar where the cooled CCD is to be placed. The equipment is assembled in the order listed above so that the monochromator first selects the desired wavelength of light emitted from the light source. This beam is then monitored in the integrating sphere, and made uniform through the black box before it reaches the CCD in the dewar. Picoammeters and photodiodes are placed in several locations for light intensity measurements. After examining the light leakage of the integrating sphere, calibration of the coupled monochromator was performed using a Hg light source. Properties of gratings, filters, and slits were studied by comparing measured spectral lines of Hg and Xe light source. A LabView program was developed and used to operate the assembled devices and take readings from the photodiodes. These programs, devices, and data will be used to measure the quantum efficiency as a function of wavelength in CCDs currently under development for LSST.

Centrality Determination in Heavy Ion Collisions for the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) at the Relativistic Heavy Ion Collider (RHIC). ELI LANSEY (Yeshiva University, New York, NY, 10033) ALEXANDER MILOV (Brookhaven National Laboratory, Upton, NY, 11973)

In the physics of Relativistic Heavy Ions (RHI), the centrality related parameters (such as the number of participating nucleons or number of binary collisions between nucleons) are the essential characteristics of the collisions. The majority of publications from all four RHIC experiments related to RHI physics present their results as functions of one or more centrality-related parameters. Centrality's precise determination is therefore critical to understand most of the RHI results. The distribution of the number of participating nucleons can be obtained with the commonly used Glauber model. In the PHENIX experiment, this distribution is related to the number of particle hits in the Beam-Beam Counters via statistics of the Negative Binomial Distribution (NBD). These properties allow us to achieve two principle goals: to validate the commonly used theoretical model and to establish an accurate relationship between the observable quantity (number of hits) and the number of participating nucleons. Using the data collected during full energy (200 GeV) Au+Au Run4 of the PHENIX experiment we studied the parameters of the NBD, their systematic dependencies and accuracy to which they can be determined. The work is done by using the MINUIT minimization tool in the ROOT environment. This work will contribute to future analysis by many members of the PHENIX collaboration, yielding better measurements of the centrality-related parameters.

Characterization of an Electromagnetic Calorimeter for the Proposed International Linear Collider. MERIDETH FREY (Wellesley College, Wellesley, MA, 2481) NORMAN GRAF (Stanford Linear Accelerator Center, Stanford, CA, 94025)

The International Linear Collider (ILC) is part of a new generation of accelerators enabling physicists to gain a deeper understanding of the fundamental components of the universe. The proposed ILC will accelerate positrons and electrons towards each other with two facing linear colliders, each twenty kilometers long. Designing and planning for the future accelerator has been undertaken as a global collaboration, with groups working on several possible detectors to be used at the ILC. The following research at the Stanford Linear Accelerator Center (SLAC) pertained to the design of an electromagnetic calorimeter. The energy and spatial resolution of the calorimeter was tested by using computer simulations for proposed detectors. In order to optimize this accuracy, different designs of the electromagnetic calorimeter were investigated along with various methods to analyze the data from the simulated detector. A low-cost calorimeter design was found to provide energy resolution comparable to more expensive designs, and new clustering algorithms offered better spatial resolution. Energy distribution and shape characteristics of electromagnetic showers were also identified to differentiate various showers in the calorimeter. With further research, a well-designed detector will enable the ILC to observe new realms of physics.

Characterization of Long Cosmic Ray Muon Tracks in IceCube detector at South Pole. DANIEL HART (Southern University, Baton Rouge, LA, 70813) AZRIEL GOLDSCHMIDT (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

Ice Cube is studying high-energy neutrino astronomy. IceCube uses an array of optical modules to detect faint Cerenkov light produced by muons. These muons are the result of nuetrino interactions with matter. Using the information received from data acquisition systems at the South Pole, software was developed using the C language to read this data and use it to produce possible muon paths. Events were filtered through by placing cuts on the calculated paths that passed through the full geometry of IceCube, had velocity within 5% the speed of light, and were of low multiplicity. This resulted in path distance distributions that showed exponential decay of modules to receive light as a function of distance. The probability curves produced, followed along the same traits. However, the distance distributions were not exactly smooth as would be expected, and the selection of paths that were to be considered as neutrino candidates behaved similarly. These impurities are interpreted as the integration of multiple muons in a single event. In further studies, the plan is not only to add in more data from additional days, but also to employ more sophisticated methods for separating true events from those produced by multiple muons.

Characterization of Sub-diffusion within Benard-Rayleigh Advective Cells by Examination of a Velocity Field with Additive Noise. MARSHA LAROSEE (University of Michigan, Dearborn, Mi, 48128) BEN CARRERAS (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

Normal diffusion worked out by Einstein and Taylor is modeled by averaged particle ‘Brownian motion’ such that a given particle’s motion is determined by random collisions with surrounding particles. Less well understood is the subject of anomalous diffusion, which is studied in many fields where diffusion influences the system (e.g. heat, fluids, chemical kinetics). The distinction between normal diffusion, a random mechanism and anomalous diffusion, that is a mixture of random and deterministic processes, is the time scale at which the transport occurs. Both diffusion and anomalous diffusion follow a power law relation < r ^s > ^1/s ˜ t ^q(s), where q(s) = 1/2, < 1/2, > 1/2 for diffusion, sub-diffusion, and super-diffusion. Thus, sub-diffusion and super-diffusion scale with time differently than random motion predicts. In order to study sub-diffusion a deterministic model must be used while adding randomness, or noise to the system. A model referred to as the random walk with pauses or trapping events was investigated in order to characterize sub-diffusion in a fluid system. The system that was studied is an array of Benard Rayleigh advective cells where the velocity fields cause 10,000 tracer particles to circulate within a cell. Noise added to the velocity field causes diffusion between cells. Moments of the displacement were calculated as a function of time while varying the frequency and magnitude of noise in order to magnify the region where sub-diffusion is observed. Frequency of the additive noise extended the time frame in which sub-diffusion was observed and appears to extend the time frame non-linearly. Moments of the displacement show that the diffusive exponent q(s) is the same for all higher moments which indicates scale invariance, or q(s) = constant. This property is characteristic of both anomalous and normal diffusion. The exponent observed q(s) ~ 0.4, was larger than the typical exponent of sub-diffusive systems q(s) ~ 1/3. The reason for this is undetermined but may indicate an influence of normal diffusion within the system and future investigation is planned.

Characterizing the Charge Collection of the 0.13 µm IBMPIX Prototype Pixel Detector. ANJALI TRIPATHI (Massachusetts Institute of Technology, Cambridge, MA, 2139) RONALD LIPTON (Fermi National Accelerator Laboratory, Batavia, IL, 60510)

Central to collider physics experiments are silicon detectors, which track the trajectory of particles produced during collisions. With the drive for ever more precise resolution in particle tracking, a prototype pixel detector (IBMPIX) manufactured by IBM in a 0.13 µm RF CMOS process, was investigated to understand its charge collection and individual pixel behavior. As a Monolithic Active Pixel Sensor, it was comprised of arrays of pixels (10µm by 150µm) divided into three diode types - a standard N-well, a deep (or triple) N-well, and a control without a diode. To measure the pixel to pixel variations from the readout electronics, a signal generator pulsed charge directly into the analog circuitry, bypassing the diodes, at different threshold settings. Upon characterizing the response of the readout electronics for each pixel, a pulsed 1.06 µm Nd:YAG laser was used to determine the relationship between the input charge and the output pulse width. This pulse width was the amount of time that the input charge was above a set threshold. With the data from both the laser and the signal generator, a mathematical model was made for charge diffusion across the chip. From the signal generator tests, the readout electronics showed significant pixel to pixel variation. This variation was nearly proportional to the threshold current setting. Additionally, testing of the diodes yielded a precise equation relating pulse-width to charge. For an idealized laser beam of zero width, a diffusion length of approximately 80 microns was determined. The source of the pixel to pixel variation can be attributed to gain variations due to the fabrication. Further studies should employ a laser with a spot size contained within one pixel, include a diffusion model incorporating variable beam width, and use an additional current source to set the threshold value.

Comparison of Non-Redundant Array and Double Pinhole CoherenceMeasurements with Soft X-rays. GABRIEL WEIL (Northwestern University, Evanston, IL, 60201) JAN LUNING (Stanford Linear Accelerator Center, Stanford, CA, 94025)

Experiments on the future Linac Coherent Light Source (LCLS) and other Free Electron Lasers will need to be performed on a single-shot basis. The double pinhole method of measuring spatial coherence requires a separate measurement, with a different pinhole separation distance, for each length scale sampled. This limits its utility for LCLS. A potential alternative uses a Non-Redundant Array (NRA) of apertures designed to probe the coherence over the range of length scales defined by their physical extent, in a single measurement. This approach was tested by comparing diffraction patterns from soft x-rays incident on double pinhole and NRA absorption mask structures. The double pinhole fringe visibility data serve as discrete reference points that verify the continuous spectrum of the NRA coherence data. The results present a quantitative analysis of the double pinhole coherence measurements and a qualitative comparison to the NRA images.

Conceptual Overview of the NPDGamma Experiment. JOSEPH JANOSIK (University of Dayton, Dayton, OH, 45469) W. SCOTT WILBURN (Los Alamos National Laboratory, Los Alamos, NM, 87545)

The magnitude of the weak force is not yet well defined. The NPDGamma experiment at the Los Alamos Neutron Science Center will soon be taking data that will place bounds on the hadronic weak coupling constant H_π¹. This experiment uses polarized cold neutrons which capture on a liquid hydrogen (proton) target, and emit gamma rays that have a directional dependence on the spin of the incident neutrons only according to the weak force. Thus, a measured asymmetry in gamma ray detection can be used to extrapolate the weak coupling. The asymmetry is expected to be very small, around 5 x 10^-8, so careful experimental design and construction have been executed to ensure accuracy of this measurement. This document provides a conceptual overview of the workings of this experiment.

Construction and Commissioning of a Micro-Mott Polarimeter for Photocathode Research and Development. APRIL COOK (Monmouth College, Monmouth, IL, 61462) MARCY STUTZMAN (Thomas Jefferson National Accelerator Facility, Newport News, VA, 23606)

Thomas Jefferson National Accelerator Facility uses polarized electrons to further the understanding of the atomic nucleus. The polarized source produces electrons by directing laser light onto a specially prepared gallium arsenide (GaAs) photocathode. During the course of this project, an off-beamline micro-Mott polarimeter has been built and commissioned within the Source Lab for photocathode research and development. A polarimeter measures the polarization, or spin direction, of electrons. The micro-Mott runs at 30 keV and can be used directly in the Source Lab, off of the main accelerator beamline. Construction of the Mott system began with a polarized source, which consists of a vacuum chamber complete with a cesiator and nitrogen triflouride (NF3) to activate the photocathode, residual gas analyzer (RGA), ultra-high vacuum pumps, an electrostatic deflector to bend the electron beam 90 degrees, and electrostatic lenses. The polarimeter is housed in an adjacent vacuum chamber. The circularly polarized laser light enters the polarized source, hits the GaAs photocathode, and liberates polarized electrons. The original longitudinally-polarized electrons are transformed into transversely-polarized electrons by the electrostatic bend. They are then directed onto a gold target inside the Mott and scattered for data analysis. The polarized source has been commissioned, achieving photoemission from the activated GaAs crystal, and the electrostatic optics have been tuned to direct the electrons onto the gold target. Nearly ten percent of the electrons from the photocathode reach the target, giving adequate current for polarization measurement. The micro-Mott polarimeter will aid in photocathode research and pre-qualification of material for use in the injector.

Construction of the La-Bi-O Phase Equilibria: The Search for Inorganic Scintillators. STEVEN VILAYVONG (North Carolina A&T State University, Greensboro, NC, 27411) YETTA PORTER-CHAPMAN (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

Scintillators have been around forever, however the demand for scintillators has risen exponentially since World War II. This need for viable scintillators to be used in the detection of ionizing radiation has spurred research around the world. The New Detector Group of the Department of Functional Imaging in the Life Sciences Division of Lawrence Berkeley National Laboratory conducts systematic searches of various compounds to find the most effective scintillator. Much of their work focuses on compounds that contain Bismuth (III) and Lanthanum (III) ions. Bismuth (III) ions have the capability to be luminescent sometimes providing intrinsic scintillation as seen in the commonly used scintillator, Bi₄Ge₃O₁₂, (BGO). Phases containing lanthanum (III) ions are also investigated to utilize their sites for cerium (III) (another luminescent ion) doping. In this work, various molar ratios of La₂O₃ and Bi₂O₃ were reacted by solid state chemistry techniques to find phases that may exhibit scintillation. To be classified as a good scintillator, one must characterize these phases by x-ray diffraction (XRD), fluorescence spectroscopy, and pulsed x-ray measurements. Four La-Bi-O phases, La_0.176Bi_0.824O_1.5, La_0.12Bi_1.88O₃, La₄Bi₂O₉, and an unknown phase were found however, none are good scintillators.

Design, Fabrication and Measurement of Nb/Si multilayers and Nb Transmission Filters. SUNEIDY LEMOS FIGUEREO (University of Puerto Rico, Rio Piedras, P.R, 979) DAVID ATTWOOD (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

The extreme ultraviolet (EUV) region of the electromagnetic spectrum is being used in multilayer optical systems to design technology projected for use in the fabrication of nano-electronics. Multilayer optical systems with high reflectivity have been produced in the soft x-ray and EUV regions of the spectrum. Due to the limited understanding of the Nb/Si optical systems, our research group fabricated and measured Nb/Si multilayers and Nb transmission filters for the soft x-ray and EUV regions. Multilayer optical systems are used in applications ranging from EUV lithography to synchrotron radiation. The films were deposited using dc magnetron sputtering in the Center for X-Ray Optics at the Lawrence Berkeley National Laboratory. Reflectivity and transmission measurements were performed at the Advanced Light Source beamline 6.3.2. The Nb/Si multilayer mirrors fabricated have a reflectivity of approximately 65% in the extreme ultraviolet region, which makes these systems practical for applications where a high reflectivity is required, such as Astronomy and instrumentation development. Transmission measurements of up to 90% were observed in the soft x-ray and EUV regions as well. Future work in the research group includes the design and fabrication of an Nb/Si multilayer with a B4C interface. The Nb/B4C/Si optical systems are expected to have a higher reflectivity than Nb/Si systems.

Detection of Ionizing Radiation Based on Metastable States of Polymer Dispersed Liquid Crystals. TIMOTHY PHUNG (University of California, Berkeley, Berkeley, CA, 94720) CARL HABER (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

Polymer dispersed liquid crystals (PDLCs) may be a suitable medium for future tracking detectors used in particle physics. Such a detector will work in analogy with the bubble chamber by using the metastable states in LC materials. A PDLC cell is fabricated and the optical transmission of the cell is measured as a function of the voltage applied across the cell and the temperature. The optical transmission of the PDLC is found to be temperature dependent below the nematic-isotropic phase transition temperature when a field is applied across the cell as is reported in the literature. When no field is applied, the PDLC cell is strongly temperature dependent near the nematic-isotropic phase transition temperature, which also agrees with previous results. Future research in this area will focus on finding the metastable phenomena that exist near phase transitions of LC materials and on the use of electric fields to shift the transition temperature.

Determining Micromechanical Strain in Nitinol. MATTHEW STRASBERG (Cornell University, Ithaca, NY, 14850) APURVA MEHTA (Stanford Linear Accelerator Center, Stanford, CA, 94025)

Nitinol is a superelastic alloy made of equal parts nickel and titanium. Due to its unique shape memory properties, nitinol is used to make medical stents, lifesaving devices used to allow blood flow in occluded arteries. Micromechanical models and even nitinol-specific finite element analysis (FEA) software are insufficient for unerringly predicting fatigue and resultant failure. Due to the sensitive nature of its application, a better understanding of nitinol on a granular scale is being pursued through X-ray diffraction techniques at the Stanford Synchrotron Radiation Laboratory (SSRL) at the Stanford Linear Accelerator Center (SLAC). Through analysis of powder diffraction patterns of nitinol under increasing tensile loads, localized strain can be calculated. We compare these results with micromechanical predictions in order to advance nitinol-relevant FEA tools. From this we hope to gain a greater understanding of how nitinol fatigues under multi-axial loads.

Development of Emittance Analysis Software for Ion Beam Characterization. MARIANO PADILLA (Fullerton College, Fullerton, CA, 92832) YUAN LIU (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

Transverse beam emittance is a crucial property which describes the angular and spatial spread of charged particle beams. It is a figure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally a high quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifield Radioactive Ion beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, an emittance analysis software was developed to perform various data processing tasks for noise reduction and to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profiles, emittance contours, and ellipses. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fitting are also incorporated into the software. The software will provide a simplified and fast tool for comprehensive emittance analyses. The main functions of the software package have been completed. In preliminary tests with real experimental emittance data, the analysis results using the software were proven to be correct.

Development of Nanofluidic Cells for Ultrafast X-ray Studies of Water. MELVIN IRIZARRY (University of Puerto Rico, Mayaguez, PR, 667) AARON LINDENBEREG (Stanford Linear Accelerator Center, Stanford, CA, 94025)

In order to study the molecular structure and dynamics of liquid water with soft x-ray probes, samples with nanoscale dimensions are needed. This paper describes a simple method for preparing nanofluidic water cells. The idea is to confine a thin layer of water between two silicon nitride windows. The windows are 1 mm × 1 mm and 0.5 mm × 0.5 mm in size and have a thickness of 150 nm. The thickness of the water layer was measured experimentally by probing the infrared spectrum of water in the cells with a Fourier Transform InfraRed (FTIR) apparatus and from soft x-ray static measurements at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. Water layers ranging from 10 nm to more than 2 µm were observed. Evidence for changes in the water structure compared to bulk water is observed in the ultrathin cells.

Development of Powder Diffraction Analysis Tools for a Nanocrystalline Specimen: An Emphasis upon NiTi (Nitinol). ERICH OWENS (Albion College, Albion, MI, 49224) APURVA MEHTA (Stanford Linear Accelerator Center, Stanford, CA, 94025)

Powder diffraction is a specialized technique whose investigatory limits are constrained by the scale of the crystallized substance being scanned versus the probe beam used. When disparate in scale, with the photon spot size larger than the crystal being probed, many are employed, the resulting diffraction image being cast from all possible incident angles, constructing -arcs containing information about the crystalline structure of the material under examination. Of particular interest to our collaboration is the structure of Nitinol, a superelastic Nickel-Titanium alloy, whose phase transformations and load bearing deformations can be studied by usage of diffraction, with wide sweeping biomedical uses. Analysis of this data is complicated by phase transformation and material fluorescence, which make difficult the computational modeling of the peaks within concentric -arcs. We endeavored to construct a series of computational tools (the amalgamation of them known as 2DPeakFinder) for refining and extracting this relevant data, toward the end of employing previously developed algorithms in the material’s structural analysis. We succeeded to a large degree with the use of an iterative algorithm to navigate radial complexity of the signal and manage to retain a distinction between useful signal and superfluous background noise. The tools developed in this project are a small step in readily streamlining the analysis and physical modeling of a Nanocrystalline material’s structural properties.

Diffusion-controlled Apparatus' for Microgravity. PRADEEP RAJENDRAN (Stanford University, Stanford, CA, 94305) DR. P. THIYAGARAJAN (Argonne National Laboratory, Argonne, IL, 60439)

Large photoactive yellow protein (PYP) crystals are being grown using diffusion-controlled apparatus’ for microgravity (DCAMs) for proposed neutron crystallography experiments. The basis for this experiment is that a short strong hydrogen bond (SSHB) appears to play an important role in the function of PYP in the photocycle. In order to fully understand the structure and dynamics of the SSHB, it is necessary to accurately locate the nuclear position of the proton (or deuteron) with respect to the heavy atoms involved in the hydrogen bond. Pervious attempts to grow PYP crystals using the batch and hanging drop method have had limited success. The resolution of diffraction data collected from PYP crystals grown using these methods was determined to be between 0.95  to 1.40 . PYP crystallizes best between a concentration range of 2.3 M to 2.5 M. Two DCAM units have been set up. The units have a concentration of 1.6 M and 2.0 M (ND₄)₂SO₄ in the small chamber, respectively, and a concentration of 3.0 M (ND₄)₂SO₄ in the large chambers. As the higher concentration solution in the large chamber equilibrates with the lower concentration solution in the small chamber through the diffusion control plug, the concentration increases within the "button" containing the PYP sample, causing crystallization to begin. Large PYP crystals have been grown following these procedures using DCAMs.

Eddy Current Non-destructive Inspection Using Giant Magnetoresistive Technology. STEVEN GARDNER (Brigham Young University - Idaho, Rexburg, ID, 83460) DENNIS C. KUNERTH, PH.D. (Idaho National Laboratory, Idaho Falls, ID, 83415)

A prototype eddy current probe utilizing giant Magnetoresistive technology was found to have the following benefits: 1. It functions at very low frequencies (DC to 30 kHz) and deep sample depths. 2. The probe can be characterized to reveal thickness of an aluminum sample up to 10 mm thick, and much thicker in stainless steel and other less conductive metals. 3. The probe design uses a noise reduction coil and shield system which increases signal to noise ratio by nulling drive coil noise. This probe would be ideal for testing thickness of metals with low magnetic permeability. It is also effective at locating defects greater than 0.25 mm on the surface or within the depth of penetration as determined by the relationship depth (m) = v(1/ (p*f*µ0*µr*s)) where µ0 is the permeability of free space, µr is the relative magnetic permeability and s is the electrical conductivity. Its limitations include: 1. It was unable to function at frequencies greater than 30 kHz. 2. It was not able to detect defects smaller than .25 mm or surface defects which did not extend this same distance or more into the metal. Attempts were also made to operate the probe using pulse and linear sweep drives. These attempts did not create satisfactory results. Much of the lack of success could be due to the fact that it was not possible to null the drive signal using the noise reduction coil for either the pulse or the sweep drive methods. The inability to resolve small defects, and the limitations on the frequency range appear to be caused by the large coil geometry and the inductance change introduced by the iron shield.

Effect of Acid Agitation on Buffered Chemical Polishing of Niobium for Radiofrequency Cavities. SARA MOHON (The College of William and Mary, Williamsburg, VA, 23186) ANDY WU (Thomas Jefferson National Accelerator Facility, Newport News, VA, 23606)

The performance of niobium superconducting radiofrequency (SRF) cavities can be affected by the smoothness of their inner surfaces. Smoother inner surfaces tend to result in better performance. Normally, smooth niobium surfaces are obtained by buffered chemical polish (BCP). BCP is necessary to remove the damaged layer created during fabrication and machining of the cavities. Previous experiments conducted in the Surface Science Lab at Thomas Jefferson National Accelerator Facility have shown that the morphology of niobium surfaces may be altered via different agitation constraints during BCP. The focus of this research is a systematic study of the effect of agitation on the BCP treatment of niobium. Six samples of niobium, each one square centimeter in size, were prepared using a 1:1:2 BCP mixture for 75 minutes. A control sample was also analyzed with no BCP treatment. Each BCP treated sample was agitated after a certain amount of time, varying from 0 to 75 minutes. After this treatment, the samples were examined by a 3D profilometer, where quantitative information about surface morphology was extracted. Qualitative inspection of the surface of each sample was performed a metallographic optical microscope (MOM). It was found that the surface roughness increased up to a certain asymptotic limit as the time interval between agitations increased, and that a green unidentified cloud-like material appeared above the inner surface area of niobium samples when there was no agitation. The MOM photographs show evidence that the BCP mixture attacked the grain boundaries and defect locations more than it did elsewhere, making a BCP treated surface rougher in comparison to some other polishing methods. The treated samples became smoother as the time interval between agitations decreased although they never become as smooth as the control sample. Smoother surfaces were also found in areas where the green cloud formed than in areas where it was absent. A model is proposed to qualitatively explain the experimental results. Further investigation is warranted for different BCP ratios to see if a smoother surface finish is possible and what agitation it requires. In addition, a BCP study of how larger grain samples affect niobium surface morphology is promising to the improvement of SRF cavities. These endeavors and the experimental results are useful for the BCP treatment of niobium SRF cavities to be used in particle accelerators.

Effects of Tellurium Precipitates in CdZnTe (CZT) Radiation Detectors. KYLE KOHMAN (Kansas State University, Manhattan, KS, 66506) ALEKSEY BOLOTNIKOV (Brookhaven National Laboratory, Upton, NY, 11973)

CdZnTe (CZT) crystal is a material that has great potential for high-resolution detection of gamma and X-rays because of its high gamma ray stopping power, durability, and abilities to be made portable operated at room temperature. It is well known that tellurium (Te) precipitates may affect performance of CZT detectors; however, it is not specifically known how, or to what extent these inclusions affect spectral response in CZT detectors. This study sought a quantitative correlation between precipitate sizes and concentrations of CZT material and the spectral response of the material as a detector. Te precipitate sizes and concentrations were observed in CZT crystals using an infrared microscope coupled with a digital camera. A program written in Interactive Data Language (IDL) counted Te precipitates within sample images at different magnifications throughout the material and characterized each individual inclusion by size and location. The crystals were then made into Frisch-ring detectors by placing gold contacts on each side and wrapping them in Teflon tape and copper. Spectral responses of the detectors were measured by placing them into a pre-amplifier connected to standard nuclear instrumentation module components. The results indicate that detector response has a strong dependence on concentrations of Te precipitates greater than 5 µm. 1-µm precipitates were very close to the resolution limit of the IR system and so accuracy was insufficient for quantitative measurements of correlations between device spectral responses, precipitate concentrations, and crystal thicknesses (etch pit technique would be more appropriate for measurements of such small precipitates). Nevertheless, based on these measurements, an upper limit can be given. Te precipitates with diameters

Effects of UV light on a fluorescent dust cloud. ENRIQUE MERINO (Ramapo College of New Jersey, Mahwah, NJ, 7430) ANDREW POST-ZWICKER (Princeton Plasma Physics Laboratory, Princeton, NJ, 8543)

Dusty plasma research has applications ranging from microchip fabrication to the study of planetary rings. Typically, the behavior of laboratory dusty plasmas is studied by laser scattering techniques. A new diagnostic technique developed at the Science Education Laboratory at the Princeton Plasma Physics Laboratory uses a 100W ultra-violet (UV) light to illuminate a fluorescent organic dust cloud created in an argon DC glow discharge plasma. By using the UV light, the fluorescent particles can be clearly seen during and after cloud formation and their 3D properties analyzed. This technique has been successfully used to study formation and transport of the dust cloud. Observations have shown that after the dust cloud has formed, the UV light causes rotation of the edge of the cloud (˜ 3mm/s), while particles in the center of the cloud remain stable. Displacements of several millimeters up and towards the UV light have also been recorded by modulating the UV light. Through the use of a Langmuir probe, changes in the charge of the plasma were recorded whenever UV light was introduced. These changes occurred both in the presence of a dust cloud and with a clean plasma as well. Although these experiments were helpful in demonstrating that UV light had an effect on the plasma, it is left as future work to determine the effect of UV light on the dust particles themselves and propose analytical models for the displacements experienced.

Energizing a Superconducting Solenoid for Applications in Precise Mass Measurements. DAVID DANAHER (Monmouth College, Monmouth, IL, 61462) GUY SAVARD (Argonne National Laboratory, Argonne, IL, 60439)

The precise mass measurement of ions is the main objective of the Canadian Penning Trap (CPT) collaboration at Argonne National Laboratory. The mass measurements require a beam from the Argonne Tandem Linear Accelerator System (ATLAS) to fuse with a target to create the desired reaction products. A new beamline has nearly been completed in Area II of ATLAS for the purpose of taking mass measurements of ions with greater divergence angles that were previously hard or nearly impossible to measure, which diverge due to alpha decay and are refocused for later measurement. A solenoid can be used to refocus the ions before they can be sent through the rest of the system and, consequently, measured. This component of the new beamline in Area II is a superconducting solenoid with a 68 centimeter inner bore and a central field of 1.5 Tesla, weighing over 10 tons with all of the necessary shielding and support in place. For the solenoid to produce a magnetic field, it must be energized and continually carry a current of about 200 Amps within its coils. The process of energizing such a device is a subtle exercise and requires creating a vacuum within the solenoid, pre-cooling of the cryostat with liquid Nitrogen, filling the cryostat with liquid Helium, running a cryo-compressor to limit Helium boil-off, and well-regulated power sources to bring the solenoid to maximum field. Once carefully assembled, however, the components of the energization process may be used to safely energize and de-energize the system time and time again. My project was to help locate all the components of the energization process, facilitate the interconnections between components, and, finally, to aide with the powering of the magnet.

Error Reduction in Polarization Measurement. DONALD JONES (Acadia University, Wolfville, NS, 0) ROBERT MICHAELS (Thomas Jefferson National Accelerator Facility, Newport News, VA, 23606)

One of the greatest barriers to definitive conclusions in any scientific experiment is the accumulation of errors. Due to the precision required in parity-violation experiments, an effort has been made in Hall A at Jefferson Lab (JLab) to reduce the cumulative error by targeting specific sources. A particular focus has been placed on reduction of error in beam polarization measurements. Compton polarimetry is utilized at JLab because of its unique advantage of allowing polarization to be determined while an experiment is running, without interrupting the beam. Electrical signals produced by scattered photons and electrons are used to determine beam polarization. The helicity of the beam is reversed every 33 milliseconds (ms) and the asymmetry that arises from pulse measurements during consecutive 33 ms intervals, is used to calculate beam polarization. While this asymmetry has been created in the past by counting photons, electrons or electron-photon coincidences, this method gives rise to many systematic errors. New methods are being sought to more accurately calculate polarization. The focus of this research has been to determine whether signal integration can be used to effectively reduce the error to under the 1% level within a feasible time frame. Extensive tests have been done to determine the reliability of signal integration across the full 33ms gate, in order to determine if the background noise is too great to make this technique useful. Because of difficulties encountered, and the lack of beam operation during the time this research was done, a pulse generator was used to simulate the electrical pulses that arise from electron scattering in the Compton polarimeter. The data from the pulse-generated asymmetry indicates that polarization can be accurately determined within three hours of beam operation. Because experiments can last for days, this is a reasonable length of time. To ensure the reliability of this technique, the results were then verified using Monte Carlo simulations. The results of this research show that this method of beam polarization measurement has great promise of being able to reduce the measurement error from the present 3%, to below 1%. This method has yet to be tested during beam operation, but its success would enhance future parity violation experiments.

Experimental Studies of Electrode Biased Compact Toroid Plasmas in the Magnetic Reconnection Experiment. ELIJAH MARTIN (North Carolina State University, Raleigh, NC, 27609) DR. MASAAKI YAMADA (Princeton Plasma Physics Laboratory, Princeton, NJ, 8543)

Compact Toroid (CT) plasmas such as Field-Reversed Configurations (FRC’s) and Spheromaks are known to exhibit a global instability known as the tilt mode, where the magnetic moment of the CT tilts to align itself with the external magnetic field, as well other non-rigid body instabilities. Possible tilt stabilizing mechanisms for these instabilities include external field shaping, nearby passive stabilizers, and plasma rotation. This research focuses on reducing the growth of the tilt instability by introducing toroidal rotation in spheromaks formed in the Magnetic Reconnection Experiment (MRX). Rotation is introduced by the use of interior and exterior electrodes; the result is a J_bias x B_internal torque on the CT plasma which in turn leads to toroidal rotation of the CT plasma. In order to power the bias electrode a 450 V 8800 µF capacitor bank capable of delivering up to 450 amperes was constructed along with the required control and triggering circuitry. Solid state switches allow for fast turn on and turn off times of J_bias. The bias current and the voltage drop across the electrodes are measured using a current shunt and voltage divider respectively, and the resulting flow in the CT plasma is measured with a Mach probe. Internal arrays of magnetic probes and optical diagnostics will be used to parameterize the performance of the CT plasma during bias. Construction and testing of all necessary components and diagnostics is complete; preliminary experiments were designed such that the resistivity of the plasma could be determined. It was found that a typical CT plasma has a resistivity of 34.1 ± 3.6 ohm m, a leaky capacitor model of the CT plasma was applied to determine the resistivity theoretically. A theoretical resistivity of 4.9 x 10^-3 ohm m was calculated based on conditions of a typical CT plasma. The strong disagreement between experimentally and theoretically determined values is hypothesized to be due to non-optimal control of CT plasmas formed in MRX. The focus of future research will be optimizing control of the CT plasma; agreement between the model and experiment will then be studied as well as experiments designed to induce toroidal rotation.

Formation and Transport of a Fluorescent Dust Cloud: a New Diagnostic Technique in Dusty Plasma Research. ENRIQUE MERINO (Ramapo College of New Jersey, Mahwah, NJ, 7430) ANDREW POST-ZWICKER (Princeton Plasma Physics Laboratory, Princeton, NJ, 8543)

Dusty plasma research has applications ranging from microchip fabrication to the study of planetary rings. Typically, the behavior of laboratory dusty plasmas is studied by laser scattering techniques which give a 2D slice of the dust cloud or by the use of 3D particle image velocimetry methods (PIV). Although these diagnostic techniques allow for the study of cloud formation, they require extensive computer processing or simulations to study the formation processes. A new diagnostic technique has been devised to study 3D behavior and cloud formation, without the need for the complicated and usually expensive methods mentioned above. A fluorescent organic dust is used to create a cloud in an argon DC glow discharge plasma, illuminated by a 100W ultra-violet (UV) light. By using UV light, the fluorescent particles can be clearly seen during cloud formation and their 3D properties analyzed. One question remaining, however, is whether the UV light perturbs the plasma by changing the local charge balance or actively changing the dust cloud charge by photoelectric emission. In fact, initial observations show that particles in the back of the dust cloud experience a displacement towards the UV light, while particles in the front move away from it. Velocities ranging in the order of 1.5 mm/sec to 3 mm/sec were recorded for different areas of the cloud. Future work will use a Langmuir probe to separate changes in plasma parameters from changes in dust charge.

G0++: Creating a User Interface for Fastbus Data. JONATHAN HOOD (University of Maryland, College Park, MD, 20742) TANJA HORN (Thomas Jefferson National Accelerator Facility, Newport News, VA, 23606)

The G0 collaboration at Thomas Jefferson National Accelerator Facility (Jefferson Lab) investigates the contribution of strange quarks to the fundamental properties of the nucleon. To do this, the G0 experiment sends a highly energized electron beam into a target, such as liquid hydrogen. When the electrons in the beam collide with nucleons in the target, a spray of particles radiates from the collision point. This spray of particles travels across a magnetic field into a variety of particle detectors, resulting in large amounts of unanalyzed data. Data taken during the G0 experiment pertaining to the time of flight and amplitudes of particle trajectories is referred to as Fastbus data, which is organized by Root, a C++ interpreter designed for manipulating large number of data points. For the G0 experiment, Fastbus data provide a general evaluation of the performance of the detector and electronic systems. Therefore, an efficient analysis of these data is essential at the startup and during the running of an experiment. The goal of this project was to make the Fastbus data more accessible, especially to people who are not familiar with the Root language. To do this, a good understanding of the data acquisition and its analysis was required. By collaborating with scientists at the National Jefferson Laboratory, a design was constructed and implemented. Scientists need to look at the data in many different ways, and the program was designed to include a variety of tools that allows them to do so. In order to analyze the data quickly and effectively, a Graphical User Interface (GUI) was programmed to give users a convenient way to create, display, and manipulate graphs. The interface has been constructed with many useful tools that aid scientists in the G0 experiment, including such features as the ability to add cuts to remove unwanted data points and the ability to fit the data with numerical equations. The program, titled “G0++: GoFast Goes Fast” will be used by G0 scientists, and eventually the program could be used for general Hall C data analysis in a C++ framework.

Gain Mapping and Response Uniformity Testing of the Hamamatsu R8900 Multianode Photomultiplier Tube and the Burle Planacon Microchannel Plate Photomultiplier Tube for the Picosecond Timing Project. MELINDA MORANG (University of Chicago, Chicago, IL, 60637) KAREN BYRUM (Argonne National Laboratory, Argonne, IL, 60439)

Research is currently underway for the development of a microchannel plate photomultiplier tube with picosecond timing capabilities, a property that would be extremely useful in many fields of physics and in radiology. It is important in a research and development study such as this one to fully understand the currently available technology, and the study presented in this paper focuses on characterizing gain and response uniformity in the Hamamatsu R8900-00-M16 multianode photomultiplier tube (R8900) and the Burle Planacon 85011-501 microchannel plate photomultiplier tube (MCPPMT). The tubes were tested using a dark box setup in which a moveable fiber carrying an LED pulse could be directed into each pixel in the tube. The gains for each pixel of ten R8900 tubes and for part of an MCPPMT were calculated, and a horizontal scan in 1mm steps was performed across the breadth of the R8900 and across one quadrant of an MCPPMT. Plots showing the signal output in the horizontal scans showed that the MCPPMT had much greater response uniformity across the tube, but due to time and equipment restraints, these results are only preliminary, and more extensive study of uniformity is necessary, as is study of many other properties of these tubes.

GEANT Simulations of the Preshower Calorimeter for CLAS12 Upgrade of the Forward Electromagnetic Calorimeter. KRISTIN WHITLOW (University of Florida, Gainesville, FL, 32612) STEPAN STEPANYAN (Thomas Jefferson National Accelerator Facility, Newport News, VA, 23606)

Hall B at the Thomas Jefferson Natio