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Focal Plane Metrology for the LSST Camera
Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane.
Date:
January 10, 2007
Creator:
A Rasmussen, Andrew P.; Hale, Layton; Kim, Peter; Lee, Eric; Perl, Martin; Schindler, Rafe et al.
Object Type:
Article
System:
The UNT Digital Library
SEISMIC SOURCE SCALING AND DISCRIMINATION IN DIVERSE TECTONIC ENVIRONMENTS
The objectives of this study are to improve low-magnitude regional seismic discrimination by performing a thorough investigation of earthquake source scaling using diverse, high-quality datasets from varied tectonic regions. Local-to-regional high-frequency discrimination requires an estimate of how earthquakes scale with size. Walter and Taylor (2002) developed the MDAC (Magnitude and Distance Amplitude Corrections) method to empirically account for these effects through regional calibration. The accuracy of these corrections has a direct impact on our ability to identify clandestine explosions in the broad regional areas characterized by low seismicity. Unfortunately our knowledge of source scaling at small magnitudes (i.e., m{sub b} < {approx}4.0) is poorly resolved. It is not clear whether different studies obtain contradictory results because they analyze different earthquakes, or because they use different methods. Even in regions that are well studied, such as test sites or areas of high seismicity, we still rely on empirical scaling relations derived from studies taken from half-way around the world at inter-plate regions. We investigate earthquake sources and scaling from different tectonic settings, comparing direct and coda wave analysis methods. We begin by developing and improving the two different methods, and then in future years we will apply them both to each …
Date:
July 10, 2007
Creator:
Abercrombie, Rachel E.; Mayeda, Kevin; Walter, William R.; Viegas, Gisela M. & Murphy, Katherine
Object Type:
Article
System:
The UNT Digital Library
Inversion of Airborne Contaminants in a Regional Model
We are interested in a DDDAS problem of localization of airborne contaminant releases in regional atmospheric transport models from sparse observations. Given measurements of the contaminant over an observation window at a small number of points in space, and a velocity field as predicted for example by a mesoscopic weather model, we seek an estimate of the state of the contaminant at the beginning of the observation interval that minimizes the least squares misfit between measured and predicted contaminant field, subject to the convection-diffusion equation for the contaminant. Once the ''initial'' conditions are estimated by solution of the inverse problem, we issue predictions of the evolution of the contaminant, the observation window is advanced in time, and the process repeated to issue a new prediction, in the style of 4D-Var. We design an appropriate numerical strategy that exploits the spectral structure of the inverse operator, and leads to efficient and accurate resolution of the inverse problem. Numerical experiments verify that high resolution inversion can be carried out rapidly for a well-resolved terrain model of the greater Los Angeles area.
Date:
January 10, 2007
Creator:
Akcelik, V.; Biros, G.; Draganescu, A.; Ghattas, O.; Hill, J.; van Bloemen Waanders, B. et al.
Object Type:
Article
System:
The UNT Digital Library
Shape Determination for Deformed Electromagnetic Cavities
The measured physical parameters of a superconducting cavity differ from those of the designed ideal cavity. This is due to shape deviations caused by both loose machine tolerances during fabrication and by the tuning process for the accelerating mode. We present a shape determination algorithm to solve for the unknown deviations from the ideal cavity using experimentally measured cavity data. The objective is to match the results of the deformed cavity model to experimental data through least-squares minimization. The inversion variables are unknown shape deformation parameters that describe perturbations of the ideal cavity. The constraint is the Maxwell eigenvalue problem. We solve the nonlinear optimization problem using a line-search based reduced space Gauss-Newton method where we compute shape sensitivities with a discrete adjoint approach. We present two shape determination examples, one from synthetic and the other from experimental data. The results demonstrate that the proposed algorithm is very effective in determining the deformed cavity shape.
Date:
December 10, 2007
Creator:
Akcelik, Volkan; Ko, Kwok; Lee, Lie-Quan; Li, Zhenghai; Ng, Cho-Kuen & Xiao, Liling
Object Type:
Article
System:
The UNT Digital Library
Oral History Interview with Joel D. Alderson, April 10, 2007
Transcript of an oral interview with Joel Alderson and his wife Nila. He discusses going to boot camp in Texas, shipping off to France in early 1945 and working as an engineer, constructing bridges and demolishing German fortifications for the Army as it made it's way through Germany, blowing up Hilter's bunker in Salzburg, Austria and using bulldozers to cover piles of dead Jews the Germans left in the open (likely at Dachau). He ancedotes about meeting Eisenhower, carrying fuel up to Patton's limo when it ran out of gas, seeing Bob Hope, soldiers getting poisoned from confiscated alcohol, and getting met by his family and the town sheriff when he came home after the war.
Date:
April 10, 2007
Creator:
Alderson, Joel D.
Object Type:
Sound
System:
The Portal to Texas History
Oral History Interview with Joel D. Alderson, April 10, 2007
Transcript of an oral interview with Joel Alderson and his wife Nila. He discusses going to boot camp in Texas, shipping off to France in early 1945 and working as an engineer, constructing bridges and demolishing German fortifications for the Army as it made it's way through Germany, blowing up Hilter's bunker in Salzburg, Austria and using bulldozers to cover piles of dead Jews the Germans left in the open (likely at Dachau). He ancedotes about meeting Eisenhower, carrying fuel up to Patton's limo when it ran out of gas, seeing Bob Hope, soldiers getting poisoned from confiscated alcohol, and getting met by his family and the town sheriff when he came home after the war.
Date:
April 10, 2007
Creator:
Alderson, Joel D.
Object Type:
Text
System:
The Portal to Texas History
Framework for Interactive Parallel Dataset Analysis on the Grid
We present a framework for use at a typical Grid site to facilitate custom interactive parallel dataset analysis targeting terabyte-scale datasets of the type typically produced by large multi-institutional science experiments. We summarize the needs for interactive analysis and show a prototype solution that satisfies those needs. The solution consists of desktop client tool and a set of Web Services that allow scientists to sign onto a Grid site, compose analysis script code to carry out physics analysis on datasets, distribute the code and datasets to worker nodes, collect the results back to the client, and to construct professional-quality visualizations of the results.
Date:
January 10, 2007
Creator:
Alexander, David A.; Ananthan, Balamurali; Johnson, Tony & Serbo, Victor
Object Type:
Article
System:
The UNT Digital Library
Timpson & Tenaha News (Timpson, Tex.), Vol. 24, No. 19, Ed. 1 Thursday, May 10, 2007
Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.
Date:
May 10, 2007
Creator:
Alexander, Nancy
Object Type:
Newspaper
System:
The Portal to Texas History
Osmose Experiment Representativity Studies.
The OSMOSE program aims at improving the neutronic predictions of advanced nuclear fuels through measurements in the MINERVE facility at the CEA-Cadarache (France) on samples containing the following separated actinides: Th-232, U-233, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-243, Cm-244 and Cm-245. The goal of the experimental measurements is to produce a database of reactivity-worth measurements in different neutron spectra for the separated heavy nuclides. This database can then be used as a benchmark for integral reactivity-worth measurements to verify and validate reactor analysis codes and integral cross-section values for the isotopes tested. In particular, the OSMOSE experimental program will produce very accurate sample reactivity-worth measurements for a series of actinides in various spectra, from very thermalized to very fast. The objective of the analytical program is to make use of the experimental data to establish deficiencies in the basic nuclear data libraries, identify their origins, and provide guidelines for nuclear data improvements in coordination with international programs. To achieve the proposed goals, seven different neutron spectra can be created in the MINERVE facility: UO2 dissolved in water (representative of over-moderated LWR systems), UO2 matrix in water (representative of LWRs), a mixed oxide fuel matrix, …
Date:
October 10, 2007
Creator:
Aliberti, G. & Klann, R.
Object Type:
Report
System:
The UNT Digital Library
Urban Dispersion Program: Urban Measurements Applied to Emergency Response
Air motions in and around cities are highly complex, and the increasing threat of harmful releases into urban atmospheres makes advancing the state-of-science of understanding and modeling atmospheric flows and dispersion in and around cities essential. The four-year Urban Dispersion Program (UDP) funded primarily by the U.S. Department of Homeland Security and the Defense Threat Reduction Agency has recently been completed. The program’s primary focus was to conduct tracer and meteorological field studies in Manhattan to improve our understanding of flow and dispersion of airborne contaminants through and around the deep street canyons of New York City, including outdoor-indoor-subway exchange mechanisms. Additionally, urban dispersion models are being validated and first-responder guidance are being refined using data collected during the two UDP field studies. Pacific Northwest National Laboratory led several government laboratories, universities and private companies in conducting the two UDP field studies. The first study was a small-scale study that investigated dispersion in the immediate vicinity of the Madison Square Garden during March 2005 (MSG05), while the second UDP study was an extensive study conducted during August 2005 in Midtown Manhattan (MID05). A brief overview of the UDP field studies will be given followed by a discussion of some limitations …
Date:
September 10, 2007
Creator:
Allwine, K. Jerry; Clawson, Kirk L.; Flaherty, Julia E.; Heiser, John H.; Hosker, Rayford P.; Leach, Martin J. et al.
Object Type:
Article
System:
The UNT Digital Library
Puzzling differences in bismuth and lead plasmas: evidence for thesignificant role of neutrals in cathodic vacuum arcs
Time-dependent ion charge state measurements for Pb and Bicathodic arc plasmas revealed unexpectedly strong differences: the meanBi ion charge state dropped much stronger and with a longer time constantthan the mean Pb ion charge state. It is shown that the difference inthermal conductivity led to much higher vapor pressure for Bi, which inturn much more effectively caused charge exchange collisions. The resultshave implications beyond Pb and Bi plasmas, most importantly that the"true" charge states as emitted from the cathode spot are higher thanwhat is generally measured and published.
Date:
May 10, 2007
Creator:
Anders, Andre & Yushkov, Georgy Yu.
Object Type:
Article
System:
The UNT Digital Library
Advanced Communication and Control Solutions of Distributed Energy Resources (DER)
This report covers work performed in Phase II of a two phase project whose objective was to demonstrate the aggregation of multiple Distributed Energy Resources (DERs) and to offer them into the energy market. The Phase I work (DE-FC36-03CH11161) created an integrated, but distributed, system and procedures to monitor and control multiple DERs from numerous manufacturers connected to the electric distribution system. Procedures were created which protect the distribution network and personnel that may be working on the network. Using the web as the communication medium for control and monitoring of the DERs, the integration of information and security was accomplished through the use of industry standard protocols such as secure SSL,VPN and ICCP. The primary objective of Phase II was to develop the procedures for marketing the power of the Phase I aggregated DERs in the energy market, increase the number of DER units, and implement the marketing procedures (interface with ISOs) for the DER generated power. The team partnered with the Midwest Independent System Operator (MISO), the local ISO, to address the energy market and demonstrate the economic dispatch of DERs in response to market signals. The selection of standards-based communication technologies offers the ability of the system …
Date:
January 10, 2007
Creator:
Asgeirsson, Haukur; Seguin, Richard; Sherding, Cameron; de Bruet, Andre, G.; Broadwater, Robert & Dilek, Murat
Object Type:
Report
System:
The UNT Digital Library
HIGH ENERGY HADRON POLARIMETRY.
Proton polarimetry at RHIC uses the interference of electromagnetic (EM) and hadronic scattering amplitudes. The EM spin-flip amplitude for protons is responsible for the proton's anomalous magnetic moment, and is large. This then generates a significant analyzing power for small angle elastic scattering. RHIC polarimetry has reached a 5% uncertainty on the beam polarization, and seem capable of reducing this uncertainty further. Polarized neutron beams ax also interesting for RHIC and for a polarized electron-polarized proton/ion collider in the fume. In this case, deuterons, for example, have a very small anomalous magnetic moment, making the approach used for protons impractical. Although it might be possible to use quasielastic scattering from the protons in the deuteron to monitor the polarization. 3-He beams can provide polarized neutrons, and do have a large anomalous magnetic moment, making a similar approach to proton polarimetry possible.
Date:
September 10, 2007
Creator:
BUNCE,G.
Object Type:
Article
System:
The UNT Digital Library
Oral History Interview with Ken Babcock, April 10, 2007
The National Museum of the Pacific War presents an oral interview with Ken Babcock. Babcock served as a civilian flight instructor for two years employed by the Army Air Forces. He describes the training he provided and how he worked with his students. Babcock volunteer to join the Army Air Forces when the training program was discontinued. He became a flight officer and served as a ferry pilot and then was transferred to China where he flew with the 2nd Air Transport Squadron. Babcock describes transporting supplies and Chinese soldiers in his C-46. He also details a typical flight over the Hump. Babcock discusses the types of food that made up his diet and how they were instructed not to eat locally grown crops. He left the service in 1946.
Date:
April 10, 2007
Creator:
Babcock, Kenneth
Object Type:
Sound
System:
The Portal to Texas History
Oral History Interview with Ken Babcock, April 10, 2007
The National Museum of the Pacific War presents an oral interview with Ken Babcock. Babcock served as a civilian flight instructor for two years employed by the Army Air Forces. He describes the training he provided and how he worked with his students. Babcock volunteer to join the Army Air Forces when the training program was discontinued. He became a flight officer and served as a ferry pilot and then was transferred to China where he flew with the 2nd Air Transport Squadron. Babcock describes transporting supplies and Chinese soldiers in his C-46. He also details a typical flight over the Hump. Babcock discusses the types of food that made up his diet and how they were instructed not to eat locally grown crops. He left the service in 1946.
Date:
April 10, 2007
Creator:
Babcock, Kenneth
Object Type:
Text
System:
The Portal to Texas History
Computer-Assisted Discovery and Proof
With the advent of powerful, widely-available mathematical software, combined with ever-faster computer hardware, we are approaching a day when both the discovery and proof of mathematical facts can be done in a computer-assisted manner. his article presents several specific examples of this new paradigm in action.
Date:
December 10, 2007
Creator:
Bailey, David H. & Borwein, Jonathan M.
Object Type:
Report
System:
The UNT Digital Library
A Measurement of the Rate of Muon Capture in Hydrogen Gas andDetermination of the Proton's Induced Pseudoscalar Coupling gP
This dissertation describes a measurement of the rate ofnuclear muon capture by the proton, performed by the MuCap Collaborationusing a new technique based on a time projection chamber operating inultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPapressure. The hydrogen target's low gas density of 1 percent compared toliquid hydrogen is key to avoiding uncertainties that arise from theformation of muonic molecules. The capture rate was obtained from thedifference between the mu- disappearance rate in hydrogen--as determinedfrom data collected in the experiment's first physics run in fall2004--and the world averagefor the mu+ decay rate. After combining theresults of my analysis with the results from another independent analysisof the 2004 data, the muon capture rate from the hyperfine singlet groundstate of the mu-p atom is found to be Lambda_S = 725.0 +- 17.4 1/s, fromwhich the induced pseudoscalar coupling of the nucleon, gP(q2 = -0.88m2mu)= 7.3 +- 1.1, is extracted. This result for gP is consistent withtheoretical predictions that are based on the approximate chiral symmetryof QCD.
Date:
July 10, 2007
Creator:
Banks, Thomas Ira
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Characterizing the production and retention of dissolved iron as Fe(II) across a natural gradient in chlorophyll concentrations in the Southern Drake Passage - Final Technical Report
Recent mesoscale iron fertilization studies in the Southern Ocean (e.g. SOIREE, EisenEx, SOFeX) have demonstrated the importance of iron as a limiting factor for phytoplankton growth in these high nutrient, low-chlorophyll (HNLC) waters. Results of these experiments have demonstrated that factors which influence the biological availability of the iron supplied to phytoplankton are crucial in bloom development, longevity, and generation of carbon export flux. These findings have important implications for the future development of iron fertilization protocols to enhance carbon sequestration in high-latitude oceans. In particular, processes which lead to the mobilization and retention of iron in dissolved form in the upper ocean are important in promoting continued biological availability of iron. Such processes can include photochemical redox cycling, which leads to the formation of soluble reduced iron, Fe(II), within iron-enriched waters. Creation of effective fertilization schemes will thus require more information about Fe(II) photoproduction in Southern Ocean waters as a means to retain new iron within the euphotic zone. To contribute to our knowledge base in this area, this project was funded by DOE with a goal of characterizing the production and retention of dissolved Fe as Fe(II) in an area of the southern Drake Passage near the Shackleton …
Date:
April 10, 2007
Creator:
Barbeau, Katherine
Object Type:
Report
System:
The UNT Digital Library
Field Theory On the World Sheet: Mean Field Expansion And Cutoff Dependence
Continuing earlier work, we apply the mean field method to the world sheet representation of a simple field theory. In particular, we study the higher order terms in the mean field expansion, and show that their cutoff dependence can be absorbed into a running coupling constant. The coupling constant runs towards zero in the infrared, and the model tends towards a free string. One cannot fully reach this limit because of infrared problems, however, one can still apply the mean field method to the high energy limit (high mass states) of the string.
Date:
January 10, 2007
Creator:
Bardakci, Korkut
Object Type:
Report
System:
The UNT Digital Library
[Anthony Broussard crouched on golf course]
Photograph of Anthony Broussard, a UNT senior on the golf team, crouching at the Lantana Golf Course. He is considering his next shot while practicing and behind him a house and a tree are visible.
Date:
September 10, 2007
Creator:
Baugh, Brian
Object Type:
Photograph
System:
The UNT Digital Library
[Anthony Broussard following through swing]
Photograph of Anthony Broussard, a UNT senior on the golf team, practicing on the Lantana Golf Course. He is standing on the course and is following through with his swing. A house is visible behind him.
Date:
September 10, 2007
Creator:
Baugh, Brian
Object Type:
Photograph
System:
The UNT Digital Library
[Anthony Broussard following through with swing]
Photograph of Anthony Broussard, a UNT senior on the golf team, practicing on the Lantana Golf Course. He is following through with his swing and there are materials on the ground beside him. In the distance a sand bunker and a house are visible.
Date:
September 10, 2007
Creator:
Baugh, Brian
Object Type:
Photograph
System:
The UNT Digital Library
[Anthony Broussard planning shot]
Photograph of Anthony Broussard, a members of the UNT golf team, practicing at the Lantana Golf Course. He is crouched down on the green to plan the angle of his next shot.
Date:
September 10, 2007
Creator:
Baugh, Brian
Object Type:
Photograph
System:
The UNT Digital Library
[Anthony Broussard standing on course with bunkers]
Photograph of Anthony Broussard, a UNT senior on the golf team, practicing on the Lantana Golf Course. He is standing on the course in the distance and is looking forwards. There are several sand bunkers around him.
Date:
September 10, 2007
Creator:
Baugh, Brian
Object Type:
Photograph
System:
The UNT Digital Library