Events at Physics |
Events During the Week of May 1st through May 8th, 2011
Monday, May 2nd, 2011
- Plasma Physics (Physics/ECE/NE 922) Seminar
- What can we learn from the glow? Optical emission spectroscopy (OES) diagnostics of non-equilibrium electron energy distributions in low-temperature plasmas
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Amy Wendt, UW-Madison Dept. of Electrical & Computer Engineering
Tuesday, May 3rd, 2011
- Chaos & Complex Systems Seminar
- GPU Accelerated Simulations of Chaotic PDEs
- Time: 12:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Jon Seaton, UW-Madison Dept. of Physics
- Abstract: It is well known that chaos exists in systems of ordinary differential equations (ODEs), however, the study of chaos in partial differential equations (PDEs) remains rather new and unexplored. This is in part due to the computational resources needed to accurately simulate such systems. However, recent improvements of graphics processing units (GPUs) for use in general computing may provide a fast and economical way to solve complex systems such as PDEs. This talk will discuss the development of an algorithm which both numerically solves and determines the existence of chaos in nonlinear PDEs while utilizing the multiprocessor architecture of the GPU. This new method will aid in our search for simple examples of chaotic PDEs.
- High Energy Seminar
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Exciting Prospects in the Study of the Ghostly Neutrino: the Reactor Anti-Neutrino Anomaly
- Time: 3:00 pm
- Place: 4274 Chamberlin
- Speaker: John G. Learned, University of Hawaii, Manoa
- Abstract: While we have made great progress in understanding neutrinos, with all their surprises, it seems the fun may not be behind us, with new anomalies coming over the horizon. I will focus on the emerging "reactor anti-neutrino anomaly," and the potentially revolutionary implications, which may point towards the existence of new sterile neutrinos. Finally, I will describe a little detector we are building which relates to some of these issues.
- Host: Karsten Heeger
- Astronomy Colloquium
- Hilldale Lecture
- The Small Star Opportunity
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Prof David Charbonneau, Harvard CfA
- Abstract: When exoplanets are observed to transit their parent stars, we are granted direct estimates of their masses, radii, and (by inference) composition, and we can undertake studies of their atmospheres. I will begin by summarizing the findings of the NASA EPOXI Mission, which re-used the Deep Impact Spacecraft to conduct a search for rocky worlds in a handful of known exoplanet systems. I will then report on the latest findings from the NASA Kepler Mission, which is conducting a transit search of 160,000<br>
Sun-like stars for rocky, habitable planets. I will then turn my attention to the particular opportunities afforded by nearby low-mass stars: TheMEarth Project uses an array of modest telescopes to search such stars for planets as small as 2 Earth radii in the stellar habitable zones. Should we succeed in identifying such worlds, their proximity to us would enable spectroscopic investigations of their atmospheres with facilities such as the James Webb Space Telescope.<br>
- Host: Astronomy Department
Wednesday, May 4th, 2011
- Physics & Astronomy Departments
- Senior Send off Pizza Party
- Time: 11:30 am
- Place: Rooftop of Sterling Hall
- Abstract: Pizza & Soda
(weather permitting) - Public 2011 Physical Sciences Hilldale Lecture
- The Last Generation of Lonely Astronomers
- Time: 6:00 pm
- Place: 1310 Sterling Hall
- Speaker: Dr David Charbonneau, Harvard Smithsonian Center for Astrophysics
- Abstract: For centuries humans have gazed up at the stars and asked whether there are inhabited worlds other than our own. We are fortunate to live at the moment in history when we have the technological ability to answer that question. Astronomers have now uncovered hundreds of worlds orbiting nearby stars, and have studied the chemical content of their atmospheres.<br>
However, those studies have been restricted to planets that are both too hot and too large to be likely abodes for life. The coming year offers the very real opportunity to detect small, temperate worlds similar to the Earth. Once identified, we will probe the atmospheres that enshroud these distant orbs for chemical evidence of biological activity. - Host: Astronomy Department
Thursday, May 5th, 2011
- R. G. Herb Condensed Matter Seminar
- Complex Materials, Calorimetry, and Energy Landscapes
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Alexandra Navrotsky, University of California - Davis
- Abstract: Freed from the "tyranny of equilibrium", modern synthetic solid state chemists are producing nanomaterials, metastable phases, cluster compounds, and mixed organic-inorganic materials in a wealth of structures with amazing properties. Calorimetric studies have shown that many of these polymorphs or closely related materials are in fact very similar in energy, tracing out "energy landscapes" as a function of density, crystallinity, hydration, or other parameters. This talk focuses on new experimental thermodynamic results in three classes of materials: (1) amorphous and crystalline carbonates in the CaCO3 - MgCO3 - H2O system, (2) zeolites, mesoporous silicas, and metal organic frameworks (MOF), and (3) polynuclear cluster compounds in aluminum and uranium based systems.
- Host: Pupa Gilbert
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- The Development of Large Area Microchannel Plate Photodetectors
- Time: 4:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Bob Wagner, Argonne
- Abstract: The Large Area Picosecond Photodetector Development Collaboration is comprised of groups from three national laboratories, five U.S. universities, and two small U.S. companies working on a three-year project to develop a new generation of economical, large area (400 cm2) microchannel plate photomultipliers that can be tailored for a wide variety of applications in particle physics, medical imaging, and high energy astrophysics. In parallel with the development of the detector, a readout technology based on a switched capacitor array waveform sampling chip with time resolution in the 10 picosecond range is being developed that would allow particle identification by time-of-flight in the multi-GeV energy range. The basic photomultiplier incorporates a bialkali photocathode and a glass capillary microchannel plate pair functionalized by atomic layer deposition (ALD) to produce photoelectrons from incident visible light photons and produce gains of greater 106. Borosilicate glass capillary plates with pore size of 20-40 microns provide an inexpensive substrate compared to the standard lead-glass used in commercial microchannel plates. ALD allows the resistive and secondary emissive functions of the plates to be fabricated separately and economically. The collaboration is characterizing a variety of candidate materials for the coatings in order to optimize the gain and stability of the microchannel plates. Plates with gain of 50,000-70,000 at 1000V. bias have been produced on 33mm diameter substrates. The first 20cm by 20cm square glass capillaries were recently delivered to the project. Two alternatives for assembly and hermetic sealing of the photodetector are being pursued in parallel: a traditional ceramic housing with a strip line anode structure with embedded pins for signal output and high voltage connection, and an all borosilicate glass housing with a silk-screened silver strip line anode readout. The latter represents a potentially very inexpensive method of tube fabrication. An external printed circuit board with a matching strip line layout provides a means of transmitting the signal to the waveform sampling chips while maintaining a 50 ohm impedance from strip line to front-end input. The talk will review the history and current status of the project, summarize potential applications of the photodetector, and outline plans for the future development and production of the photomultiplier.
- Host: Teresa Montaruli
Friday, May 6th, 2011
- Last Day of Class
- Physics Department Colloquium
- First Results from the T2K Neutrino Oscillation Experiment
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Scott Oser, University of British Columbia
- Abstract: The past decade has shown us that, contrary to expectations, neutrinos have both masses and mixings between flavors. In a study of contrasts, their masses are ridiculously small, but the rates at which neutrinos change from one flavor to another are remarkably large. T2K is a new experiment to study what happens to a beam of neutrinos as it passes through the Honshu island in Japan. By shoot a beam of muon neutrinos from Japan's Pacific coast to the Super-Kamiokande detector 295km away, T2K hopes to observe muon neutrinos turning into electron neutrinos. This measurement is the cornerstone of a long-term effort to determine if neutrinos and anti-neutrinos behave identically, and may ultimately address the question of why our universe is made of matter and not anti-matter. I will present the first oscillation results from T2K and report on the current status of the experiment, including recovery efforts after the March 11 earthquake.
- Host: Heeger