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AGS tune jump power supply design and test (open access)

AGS tune jump power supply design and test

A horizontal tune jump system has been installed to overcome the horizontal intrinsic spin resonances, which requires jumping the horizontal tune 0.04 units 82 times, 41 up and 41 down. Two quadruple magnets have been installed in AGS ring to perform this. The pulsed magnet current ranges from about 140A near injection to about 1400A later. The current pulse rise and fall time are around 100uS and flat tops time is around 4mS. These quadruples have separated supplies. This tune jump pulse power supply employees all semiconductor parts as well as the main switches. During dummy load and magnet testing, the test results showed that the power supply could meet the specification. This article will describe some details of power supply simulation, design and testing. Some test waveforms and pictures are presented in this paper.
Date: March 28, 2011
Creator: Mi, J.; Glenn, J.W.; Huang, H.; Marneris, I.; Rosas, P.; Sandberg, J. et al.
System: The UNT Digital Library
AGS tune jump system to cross horizontal depolarization resonances overview (open access)

AGS tune jump system to cross horizontal depolarization resonances overview

Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations …
Date: March 28, 2011
Creator: Glenn, J.W.; Ahrens, L.; Fu, W.; Mi, J.L.; Rosas, P.; Schoefer, V. et al.
System: The UNT Digital Library
Airfoil sampling of a pulsed Laval beam with tunable vacuum ultraviolet (VUV) synchrotron ionization quadrupole mass spectrometry: Application to low--temperature kinetics and product detection (open access)

Airfoil sampling of a pulsed Laval beam with tunable vacuum ultraviolet (VUV) synchrotron ionization quadrupole mass spectrometry: Application to low--temperature kinetics and product detection

A new pulsed Laval nozzle apparatus with vacuum ultraviolet (VUV) synchrotron photoionization quadrupole mass spectrometry is constructed to study low-temperature radicalneutralchemical reactions of importance for modeling the atmosphere of Titan and the outer planets. A design for the sampling geometry of a pulsed Laval nozzle expansion has beendeveloped that operates successfully for the determination of rate coefficients by time-resolved mass spectrometry. The new concept employs airfoil sampling of the collimated expansion withexcellent sampling throughput. Time-resolved profiles of the high Mach number gas flow obtained by photoionization signals show that perturbation of the collimated expansion by theairfoil is negligible. The reaction of C2H with C2H2 is studied at 70 K as a proof-of-principle result for both low-temperature rate coefficient measurements and product identification basedon the photoionization spectrum of the reaction product versus VUV photon energy. This approach can be used to provide new insights into reaction mechanisms occurring at kinetic ratesclose to the collision-determined limit.
Date: October 12, 2011
Creator: Soorkia, Satchin; Liu, Chen-Lin; Savee, John D.; Ferrell, Sarah J.; Leone, Stephen R. & Wilson, Kevin R.
System: The UNT Digital Library
ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity (open access)

ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity

Nanoporous metals have many technologically promising applications but their tendency to coarsen limits their long-term stability and excludes high temperature applications. Here, we demonstrate that atomic layer deposition (ALD) can be used to stabilize and functionalize nanoporous metals. Specifically, we studied the effect of nanometer-thick alumina and titania ALD films on thermal stability, mechanical properties, and catalytic activity of nanoporous gold (np-Au). Our results demonstrate that even only one-nm-thick oxide films can stabilize the nanoscale morphology of np-Au up to 1000 C, while simultaneously making the material stronger and stiffer. The catalytic activity of np-Au can be drastically increased by TiO{sub 2} ALD coatings. Our results open the door to high temperature sensor, actuator, and catalysis applications and functionalized electrodes for energy storage and harvesting applications.
Date: March 24, 2011
Creator: Biener, M M; Biener, J; Wichmann, A; Wittstock, A; Baumann, T F; Baeumer, M et al.
System: The UNT Digital Library
AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics (open access)

AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics

This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.
Date: May 31, 2011
Creator: Sun, K. X.
System: The UNT Digital Library
ALLOYING-DRIVEN PHASE STABILITY IN GROUP-VB TRANSITION METALS UNDER COMPRESSION (open access)

ALLOYING-DRIVEN PHASE STABILITY IN GROUP-VB TRANSITION METALS UNDER COMPRESSION

The change in phase stability of Group-VB (V, Nb, and Ta) transition metals due to pressure and alloying is explored by means of first-principles electronic-structure calculations. It is shown that under compression stabilization or destabilization of the ground-state body-centered cubic (bcc) phase of the metal is mainly dictated by the band-structure energy that correlates well with the position of the Kohn anomaly in the transverse acoustic phonon mode. The predicted position of the Kohn anomaly in V, Nb, and Ta is found to be in a good agreement with data from the inelastic x-ray or neutron scattering measurements. In the case of alloying the change in phase stability is defined by the interplay between the band-structure and Madelung energies. We show that band-structure effects determine phase stability when a particular Group-VB metal is alloyed with its nearest neighbors within the same d-transition series: the neighbor with less and more d electrons destabilize and stabilize the bcc phase, respectively. When V is alloyed with neighbors of a higher (4d- or 5d-) transition series, both electrostatic Madelung and band-structure energies stabilize the body-centered-cubic phase. The opposite effect (destabilization) happens when Nb or Ta is alloyed with neighbors of the 3d-transition series.
Date: April 11, 2011
Creator: Landa, A & Soderlind, P
System: The UNT Digital Library
Alpha Heating in ITER L-mode and H-mode Plasma (open access)

Alpha Heating in ITER L-mode and H-mode Plasma

There are many uses of predictions of ITER plasma performance. One is assessing requirements of different plasma regimes. For instance, what current drive and control are needed for steady state. The heating, current drive, and torque systems planned for initial DT operation are negative ion neutral beam injection (NB), ion cyclotron resonance (IC), and electron cyclotron resonance (EC). Which combinations of heating are optimal. What are benefits of the torques, current drive, and fueling using NB. What are the shine-through power and optimum voltage for the NB? What are optimal locations and aiming of the EC launchers? Another application is nuclear licensing (e.g. System integrity, how many neutrons).
Date: July 18, 2011
Creator: Budny, R.V.
System: The UNT Digital Library
ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS (open access)

ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS

Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.
Date: December 6, 2011
Creator: Beals, D.
System: The UNT Digital Library
ALTERED STRUCTURE OF THE MN4CA CLUSTER IN THE OXYGEN EVOLVING COMPLEX OF PHOTOSYSTEM II BY A HISTIDINE LIGAND MUTATION (open access)

ALTERED STRUCTURE OF THE MN4CA CLUSTER IN THE OXYGEN EVOLVING COMPLEX OF PHOTOSYSTEM II BY A HISTIDINE LIGAND MUTATION

None
Date: January 20, 2011
Creator: Yano, Junko; Walker, Lee; Service, Rachel; Yachandra, Vittal & Debus, Richard
System: The UNT Digital Library
Aluminum Stabilized NbTi Conductor Test Coil Design, Fabrication, and Test Results (open access)

Aluminum Stabilized NbTi Conductor Test Coil Design, Fabrication, and Test Results

A new generation of precision muon conversion experiments is planned at both Fermilab and KEK. These experiments will depend upon a complex set of solenoid magnets for the production, momentum selection and transport of a muon beam to a stopping target, and for tracking detector momentum analysis of candidate conversion electrons from the target. Baseline designs for the production and detector solenoids use NbTi cable that is heavily stabilized by an extruded high RRR aluminum jacket. A U.S.-Japan research collaboration has begun whose goal is to advance the development of optimized Al-NbTi conductors, gain experience with the technology of winding coils from this material, and test the conductor performance as modest length samples become available. For this purpose, a 'conductor test' solenoid with three coils was designed and built at Fermilab. A sample of the RIKEN Al-NbTi conductor from KEK was wound into a 'test' coil; this was sandwiched between two 'field' coils wound from doubled SSC cable, to increase the peak field on the RIKEN test coil. All three solenoid coils were epoxy impregnated, and utilized aluminum outer bandage rings to apply preload to the coils when cold. The design and fabrication details, and results of the magnet quench …
Date: September 1, 2011
Creator: Andreev, N.; Chlachidze, G.; Evbota, D.; Kashikhin, V. S.; Lamm, M.; Makarov, A. et al.
System: The UNT Digital Library
Ambient beam motion and its excitation by ghost lines in the Tevatron (open access)

Ambient beam motion and its excitation by ghost lines in the Tevatron

Transverse betatron motion of the Tevatron proton beam is measured and analyzed. It is shown that the motion is coherent and excited by external sources of unknown origins. Observations of the time-varying 'ghost lines' in the betatron spectrum are reported. The direct measurement of the rms betatron oscillations amplitude estimates it at about 110 nm at {beta}{sub y} {approx} 900 m. Correspondingly, at the amplitudes at the average beta function location with {beta}{sub y} {approx} 50 m is about 25 nm. Given that such direct measurements with clearly observable betatron peak were not repeatedly reproducible, one can conclude that well know 'ghost lines' are the reason for that - as they are come and go without any obvious regularity. Our analysis of these 'ghost lines' shows that (a) besides slow motion across frequencies, they also exhibit oscillatory movements with period varying from 15-20 min to few hours; (b) for the stores analysed, the lines add about factor of 2 to average - over colliding store duration - Schottky power in the betatron bands. The latter allows to estimate that they contribute about half to the previously determined the rms normalized emittance growth rate of some 0.06 {pi} mm mrad/hr. The …
Date: March 1, 2011
Creator: Shiltsev, V.
System: The UNT Digital Library
Amorphous Diamond - A High-pressure Superhard Carbon Allotrope (open access)

Amorphous Diamond - A High-pressure Superhard Carbon Allotrope

This report is about the Amorphous Diamond - A High-pressure Superhard Carbon Allotrope
Date: November 4, 2011
Creator: Lin, Yu
System: The UNT Digital Library
Amorphous Indium-Zinc-Oxide Transparent Conductors for Thin Film PV: Preprint (open access)

Amorphous Indium-Zinc-Oxide Transparent Conductors for Thin Film PV: Preprint

Amorphous InZnO's (a-IZO) basic PV applicability has now been demonstrated in prototype CIGS, Si Heterojunction (SiHJ) and organic photovoltaics (OPV). However, to move beyond initial demonstration devices, improved TCO properties and processibility of the a-IZO films are needed. Here, RF-superimposed DC sputtering was used to improve the reliable deposition of a-IZO with conductivity > 3000 S/cm.
Date: July 1, 2011
Creator: Perkins, J.; Gennett, T.; Galante, M.; Gillaspie, D. & Ginley, D.
System: The UNT Digital Library
Amplification of current density modulation in a FEL with an infinite electron beam (open access)

Amplification of current density modulation in a FEL with an infinite electron beam

We show that the paraxial field equation for a free electron laser (FEL) in an infinitely wide electron beam with {kappa}-2 energy distribution can be reduced to a fourth ordinary differential equation (ODE). Its solution for arbitrary initial phase space density modulation has been derived in the wave-vector domain. For initial current modulation with Gaussian profile, close form solutions are obtained in space-time domain. In developing an analytical model for a FEL-based coherent electron cooling system, an infinite electron beam has been assumed for the modulation and correction processes. While the assumption has its limitation, it allows for an analytical close form solution to be obtained, which is essential for investigating the underlying scaling law, benchmarking the simulation codes and understanding the fundamental physics. 1D theory was previously applied to model a CeC FEL amplifier. However, the theory ignores diffraction effects and does not provide the transverse profile of the amplified electron density modulation. On the other hand, 3D theories developed for a finite electron beam usually have solutions expanded over infinite number of modes determined by the specific transverse boundary conditions. Unless the mode with the largest growth rate substantially dominates other modes, both evaluation and extracting scaling laws …
Date: March 28, 2011
Creator: Wang, G.; Litvinenko, V. N. & Webb, S. D.
System: The UNT Digital Library
Amplitude Analysis of B0 to K^ pi^-pi^0 and Evidence of Direct CP Violation in B to K^* pi decays (open access)

Amplitude Analysis of B0 to K^ pi^-pi^0 and Evidence of Direct CP Violation in B to K^* pi decays

We analyze the decay B{sup 0} {yields} K{sup +} {pi}{sup -} {pi}{sup 0} with a sample of 454 million B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, and extract the complex amplitudes of seven interfering resonances over the Dalitz plot. These results are combined with amplitudes measured in B{sup 0} {yields} K{sup 0}{sub s}{pi}{sup +}{pi}{sup -} decays to construct isospin amplitudes from B{sup 0} {yields} K{sup *}{pi} and B{sup 0} {yields} {rho}K decays. We measure the phase of the isospin amplitude {Phi}{sub 3/2}, useful in constraining the CKM unitarity triangle angle {gamma} and evaluate a CP rate asymmetry sum rule sensitive to the presence of new physics operators. We measure direct CP violation in B{sup 0} {yields} K{sup *+}{pi}{sup -} decays at the level of 3 {sigma} when measurements from both B{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0} and B{sup 0} {yields} K{sup 0}{sub s}{pi}{sup +}{pi}{sup -} decays are combined.
Date: November 4, 2011
Creator: Lees, J. P.
System: The UNT Digital Library
Amplitudes and Ultraviolet Behavior of N = 8 Supergravity (open access)

Amplitudes and Ultraviolet Behavior of N = 8 Supergravity

In this contribution we describe computational tools that permit the evaluation of multi-loop scattering amplitudes in N = 8 supergravity, in terms of amplitudes in N = 4 super-Yang-Mills theory. We also discuss the remarkable ultraviolet behavior of N = 8 supergravity, which follows from these amplitudes, and is as good as that of N = 4 super-Yang-Mills theory through at least four loops.
Date: May 20, 2011
Creator: Bern, Zvi; Carrasco, John Joseph; Dixon, Lance J.; Johansson, Henrik & Roiban, Radu
System: The UNT Digital Library
Analysis and Mitigation of X-Ray Hazard Generated From High Intensity Laser-Target Interactions (open access)

Analysis and Mitigation of X-Ray Hazard Generated From High Intensity Laser-Target Interactions

Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.
Date: March 21, 2011
Creator: Qiu, R.; Liu, J. C.; Prinz, A. A.; Rokni, S. H.; Woods, M. & Xia, Z.
System: The UNT Digital Library
Analysis and Modeling of Laser Ramps and Shocks in Tiitatium and Zirconium With Phase Transitions (open access)

Analysis and Modeling of Laser Ramps and Shocks in Tiitatium and Zirconium With Phase Transitions

None
Date: August 5, 2011
Creator: Heuze, O. & Swift, D. C.
System: The UNT Digital Library
Analysis Model for Domestic Hot Water Distribution Systems: Preprint (open access)

Analysis Model for Domestic Hot Water Distribution Systems: Preprint

A thermal model was developed to estimate the energy losses from prototypical domestic hot water (DHW) distribution systems for homes. The developed model, using the TRNSYS simulation software, allows researchers and designers to better evaluate the performance of hot water distribution systems in homes. Modeling results were compared with past experimental study results and showed good agreement.
Date: November 1, 2011
Creator: Maguire, J.; Krarti, M. & Fang, X.
System: The UNT Digital Library
Analysis of 1w Bulk Laser Damage in KDP (open access)

Analysis of 1w Bulk Laser Damage in KDP

The influence of laser parameters on laser-induced damage in the bulk of KDP is difficult to determine because the damage manifests as discrete sites a few microns in diameter distributed throughout a relatively large volume of material. Here, they present a method to directly measure the size and location of many thousands of such sites and correlate them to the laser conditions which produced them. This technique is used to characterize the effects of pulse duration on damage initiated by 1053 nm light in the bulk of KDP crystals. They find that the density of damage sites produced by 1053 nm light is less sensitive to pulse duration than was previously reported for 526 nm and 351 nm light. In addition, the effect of pulse duration on the size of the damage sites produced appears insensitive to wavelength.
Date: April 11, 2011
Creator: Cross, D A & Carr, C W
System: The UNT Digital Library
Analysis of a Small Loop Antenna with Inductive Coupling to Nearby Loops (open access)

Analysis of a Small Loop Antenna with Inductive Coupling to Nearby Loops

None
Date: April 1, 2011
Creator: Perkins, M. P.; Ong, M. M.; Speer, R. D. & Brown, C. G.
System: The UNT Digital Library
Analysis of beam loss mechanism in the Project X linac (open access)

Analysis of beam loss mechanism in the Project X linac

Minimization of the beam losses in a multi-MW H{sup -} linac such as ProjectX to a level below 1 W/m is a challenging task. The impact of different mechanism of beam stripping, including stripping in electric and magnetic fields, residual gas, blackbody radiation and intra-beam stripping, is analyzed. Other sources of beam losses are misalignements of beamline elements and errors in RF fields and phases. We present in this paper requirements for dynamic errors and correction schemes to keep beam losses under control.
Date: March 1, 2011
Creator: Carneiro, J. P.; Lebedev, V.; Nagaitsev, S.; Ostiguy, J. F. & Solyak, N.
System: The UNT Digital Library
Analysis of Conductor Impedances Accounting for Skin Effect and Nonlinear Permeability (open access)

Analysis of Conductor Impedances Accounting for Skin Effect and Nonlinear Permeability

It is often necessary to protect sensitive electrical equipment from pulsed electric and magnetic fields. To accomplish this electromagnetic shielding structures similar to Faraday Cages are often implemented. If the equipment is inside a facility that has been reinforced with rebar, the rebar can be used as part of a lighting protection system. Unfortunately, such shields are not perfect and allow electromagnetic fields to be created inside due to discontinuities in the structure, penetrations, and finite conductivity of the shield. In order to perform an analysis of such a structure it is important to first determine the effect of the finite impedance of the conductors used in the shield. In this paper we will discuss the impedances of different cylindrical conductors in the time domain. For a time varying pulse the currents created in the conductor will have different spectral components, which will affect the current density due to skin effects. Many construction materials use iron and different types of steels that have a nonlinear permeability. The nonlinear material can have an effect on the impedance of the conductor depending on the B-H curve. Although closed form solutions exist for the impedances of cylindrical conductors made of linear materials, computational …
Date: July 20, 2011
Creator: Perkins, M. P.; Ong, M. M.; Brown, C. G. & Speer, R. D.
System: The UNT Digital Library
Analysis of electric vehicle interconnection with commercial building microgrids (open access)

Analysis of electric vehicle interconnection with commercial building microgrids

The outline of this presentation is: (1) global concept of microgrid and electric vehicle (EV) modeling; (2) Lawrence Berkeley National Laboratory's Distributed Energy Resources Customer Adoption Model (DER-CAM); (3) presentation summary - how does the number of EVs connected to the building change with different optimization goals (cost versus CO{sub 2}); (3) ongoing EV modeling for California: the California commercial end-use survey (CEUS) database, objective: 138 different typical building - EV connections and benefits; (4) detailed analysis for healthcare facility: optimal EV connection at a healthcare facility in southern California; and (5) conclusions. Conclusions are: (1) EV Charging/discharging pattern mainly depends on the objective of the building (cost versus CO{sub 2}); (2) performed optimization runs show that stationary batteries are more attractive than mobile storage when putting more focus on CO{sub 2} emissions. Why? Stationary storage is available 24 hours a day for energy management - more effective; (3) stationary storage will be charged by PV, mobile only marginally; (4) results will depend on the considered region and tariff - final work will show the results for 138 different buildings in nine different climate zones and three major utility service territories.
Date: April 1, 2011
Creator: Stadler, Michael; Mendes, Goncalo; Marnay, Chris; Mé gel, Olivier & Lai, Judy
System: The UNT Digital Library