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Final Technical Report For Closeout of Award No. DE-FG02-03ER41250

Description: Michigan State University (MSU) activities in support of this grant were made as part of a larger collaboration including Los Alamos National Laboratory, Argonne National Laboratory, and Lawrence Berkeley National Laboratory. The main task of the collaboration was the development of an end-to-end multiparticle beam-dynamics simulation tool for computation of beam losses in the RIA driver linac. As the first part of this task, it was planned to modify PARMTEQ for multicharge-state beam-dynamics simulation in the LEBT and RFQ. The next part of this task was to develop a new multiparticle parallel code to model the superconducting driver linac. The output particle distributions from PARMTEQ could then be used as input for simulations through the superconducting linac, using the new parallel code with different random number seeds. The stripping of heavy ions is proposed for the RIA driver linac to increase acceleration efficiency. MSU developed a complete charge stripping foil model to evaluate the impact of the stripping foil on the beam transverse and longitudinal emittance. The stripping foil model was developed in LANA [1] and included the effects of elastic and inelastic scattering, ionization energy loss, and thickness variation in the stripping foil using the code SRIM [2]. This model was provided to the collaboration for inclusion in the new simulation tools. Benchmarking information in support of the new code development was provided by supplying the collaboration with the MSU driver linac model consisting of input information for LANA and DIMAD [3] The output of simulations using LANA and DIMAD were also provided. As an element of these activities, LANA was modified to provide simulation results with high statistics. The simulation results from the newly developed simulation tools and those of MSU gave statistically equivalent results.
Date: July 20, 2005
Creator: York, Richard C.
Partner: UNT Libraries Government Documents Department

FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

Description: A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the cluster's ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K{sub 2}Mo{sub 6}Cl{sub 14}) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175 C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection.
Date: July 1, 2005
Creator: Baker, Gregory L.; Ghosh, Ruby N.; III, D.J. Osborn & Zhang, Po
Partner: UNT Libraries Government Documents Department

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

Description: A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we immobilized the potassium salt of a molybdenum cluster, K{sub 2}M{sub 6}Cl{sub 14}, in a sol-gel matrix and showed that the luminescence is stable after 54 hours at 200 C, but the quenching ratios were low and the films delaminated after thermal cycling due to densification of the matrix. Three new approaches to solve decreased quenching over time and delamination of films off fiber tips were investigated. In the first approach K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were incorporated into a TEOS based sol-gel. These gave enhanced quenching (6x), but delaminated. Our second approach was to use a commercial cyanoacrylate glue to immobilize the particles onto the tip of an optical fiber. This gave better adhesion and good quenching initially, but eventually the glue degraded upon heating. Our third approach was to use a 55% OtMOS/ TEOS sol-gel binder. Films based on this new sol-gel binder show high quenching ({approx}6x) and superior mechanical stability even after thermal cycling. Sensor measurements on an optical fiber containing K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were obtained from 100 to 25 C. The signal intensity in nitrogen was stable at 2.8 {+-} 0.2 nW, and the quenching ratio (ratio of signal in N{sub 2} vs. 21 % O{sub 2}) varied from 4.4 to 6.9X. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.
Date: October 1, 2005
Creator: Baker, Gregory L.; Ghosh, Ruby N.; III, D.J. Osborn & Zhang, Po
Partner: UNT Libraries Government Documents Department

Final Report for Radiaiton Resistant Magnets for RIA

Description: Report on techniques for the fabrication of radiation resistant magnets for the RIA Fragment Separator. The development of magnet designs capable of reasonable life times in high-radiation environments and having reasonable performance is of paramount importance for RIA as well as other high-intensity projects under consideration, such as the Neutrino Factory and FAIR project at GSI. Several approaches were evaluated for radiation resistant superconducting magnets. One approach was to simply use a more radiation resistant epoxy for the coil fabrication. Another approach for cryostable magnets, like the S800 Spectrograph dipole, is the use of all-inorganic materials. The final approach was the development of radiation resistant Cable-In-Conduit-Conductor (CICC) like that used in fusion magnets; though these are not radiation resistant because an organic insulator is used. Simulations have shown that the nuclear radiation heating of the first quadrupoles in the RIA Fragment Separator will be so large that cold mass minimization will be necessary with the magnet iron being at room temperature. Three different types of conductor for radiation resistant superconducting magnets have been built and successfully tested. The cyanate ester potted coils will work nicely for magnets where the lifetime dose is a factor of 20 less than the end of life of the superconductor and the rate of energy deposition is below the heat-removal limit of the coil. The all-inorganic cryostable coil and the metal oxide insulated CICC will provide conductor that will work up to the life of the superconductor and have the ability to remove large quantities of nuclear heating. Obviously, more work needs to be done on the CICC to increase the current density and to develop different insulations; and on the cyanate esters to increase the heat transfer.
Date: July 27, 2005
Creator: Zeller, A. F.
Partner: UNT Libraries Government Documents Department

Final Report: 17th international Symposium on Plant Lipids

Description: This meeting covered several emerging areas in the plant lipid field such as the biosynthesis of cuticle components, interorganelle lipid trafficking, the regulation of lipid homeostasis, and the utilization of algal models. Stimulating new insights were provided not only based on research reports based on plant models, but also due to several excellent talks by experts from the yeast field.
Date: March 7, 2007
Creator: Benning, Christoph
Partner: UNT Libraries Government Documents Department

Making the Standard Candle: A study of how the progenitor white dwarf modulates the peak luminosity of type Ia supernovae

Description: The goals of the proposed research as stated in the proposal were to: • Build a suite of one-dimensional initial models of different metallicities and central densities. • Using the improved flame capturing scheme, simulate the explosion of a white dwarf with embedded Lagrangian tracer particles, and post-process the thermal histories of the tracers to reconstruct the nucleosynthesis of the explosion. • Survey the effects of a changing progenitor metallicity on the isotopic yields. Of particular interest is 1) whether the linear relation between the mass of 56Ni synthesized and the pro- genitor metallicity is moderated by the effect of electron captures in the core; and 2) how a varying central density alters the relation between metallicity and 56Ni mass. • Using these results, examine how the observed metallicity distribution would affect the brightness distribution of SNe Ia and the isotopic ratios about the Fe-peak.
Date: January 21, 2010
Creator: Brown, Edward F
Partner: UNT Libraries Government Documents Department

Studies of Limits on Uncontrolled Heavy Ion Beam Losses for Allowing Hands-On Maintenance

Description: Dose rates from accelerator components activated by 1 W/m beam losses are obtained semiempirically for a 1 GeV proton beam and by use of Monte Carlo transport codes for the proton beam and for 777 MeV/u 3He, 500 MeV/u 48Ca, 86Kr, 136Xe, and 400 MeV/u 238U ions. The dose rate obtained by the semi-empirical method, 0.99 mSv/h (99 mrem/h) at 30 cm, 4 h after 100 d irradiation by a 1-GeV proton beam, is consistent with studies at several accelerator facilities and with adopted hands-on maintenance dose rate limits. Monte Carlo simulations verify this result for protons and extend studies to heavy ion beam losses in drift-tube linac and superconducting linac accelerating structures. The studies indicate that the 1 W/m limit imposed on uncontrolled beam losses for high-energy proton beams might be relaxed for heavy ion beams. These studies further suggest that using the ratio of neutrons produced by a heavy ion beam to neutrons produced by a proton beam along with the dose rate from the proton beam (for thin-target scenarios) should allow an estimate of the dose rates expected from heavy ion beam losses.
Date: September 11, 2010
Creator: Ronningen, Reginald M. & Remec, Igor
Partner: UNT Libraries Government Documents Department