ENGINEERING OF THE AGS SNAKE COIL ASSEMBLY. (open access)

ENGINEERING OF THE AGS SNAKE COIL ASSEMBLY.

A 30% Snake superconducting magnet is proposed to maintain polarization in the AGS proton beam, the magnetic design of which is described elsewhere. The required helical coils for this magnet push the limits of the technology developed for the RHIC Snake coils. First, fields must be provided with differing pitch along the length of the magnet. To accomplish this, a new 3-D CAD system (''Pro/Engineer'' from PTC), which uses parametric techniques to enable fast iterations, has been employed. Revised magnetic field calculations are then based on the output of the mechanical model. Changes are made in turn to the model on the basis of those field calculations. To ensure that accuracy is maintained, the final solid model is imported directly into the CNC machine programming software, rather than by the use of graphics translating software. Next, due to the large coil size and magnetic field, there was concern whether the structure could contain the coil forces. A finite element analysis was performed, using the 3-D model, to ensure that the stresses and deflections were acceptable. Finally, a method was developed using ultrasonic energy to improve conductor placement during coil winding, in an effort to minimize electrical shorts due to conductor …
Date: May 12, 2003
Creator: ANERELLA,M. GUPTA,R. KOVACH,P. MARONE,A. PLATE,S. POWER,K. SCHMALZLE,J. WILLEN,E.
Object Type: Article
System: The UNT Digital Library
Trade and the Americas (open access)

Trade and the Americas

None
Date: May 12, 2003
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges (open access)

U.S.-European Union Trade Relations: Issues and Policy Challenges

None
Date: May 12, 2003
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
Development and testing of a method for efficient simulation of evaporation from a seepage face (open access)

Development and testing of a method for efficient simulation of evaporation from a seepage face

Evaporation from the surface of a porous medium is a complex process, governed by interplay between (1) coupled liquid and vapor flow in the porous medium, and (2) relative humidity, temperature, and aerodynamic conditions in the surrounding air. In order to avoid the computational expense of explicitly simulating liquid, gas, and heat flow in the porous medium (and the possible further expense of simulating the flow of water vapor in the atmosphere), evaporative potentials can be treated in a simplified manner within a model where liquid is the only active phase. In the case of limited air mixing, evaporation can be approximated as a diffusion process with a linear vapor-concentration gradient. We have incorporated a simplified scheme into the EOS9 module of iTOUGH2 to represent evaporation as isothermal Fickian diffusion. This is notable because the EOS9 module solves a single equation describing saturated and unsaturated flow, i.e., phase transitions and vapor flow are not explicitly simulated. The new approach was applied to three simple problems and the results were compared to those obtained with analytical solutions or the EOS4 module, which explicitly considers advective and diffusive vapor flow. Where vapor flow within the porous medium can be neglected, this new …
Date: May 12, 2003
Creator: Ahlers, C. Fredrik; Ghezzehei, Teamrat & Finsterle, Stefan
Object Type: Article
System: The UNT Digital Library
Vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters (open access)

Vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters

In this work we report on thevacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters. Clusters of methanol with water are generated via co-expansion of the gas phase constituents in a continuous supersonic jet expansion of methanol and water seeded in Ar. The resulting clusters are investigated by single photon ionization with tunable vacuumultraviolet synchrotron radiation and mass analyzed using reflectron mass spectrometry. Protonated methanol clusters of the form (CH3OH)nH + (n=1-12) dominate the mass spectrum below the ionization energy of the methanol monomer. With an increase in water concentration, small amounts of mixed clusters of the form (CH3OH)n(H2O)H + (n=2-11) are detected. The only unprotonated species observed in this work are the methanol monomer and dimer. Appearance energies are obtained from the photoionization efficiency (PIE) curves for CH3OH +, (CH 3OH)2 +, (CH3OH)nH + (n=1-9), and (CH 3OH)n(H2O)H + (n=2-9 ) as a function of photon energy. With an increase in the water content in the molecular beam, there is an enhancement of photoionization intensity for methanol dimer and protonated methanol monomer at threshold. These results are compared and contrasted to previous experimental observations.
Date: May 12, 2008
Creator: Ahmed, Musahid; Ahmed, Musahid; Wilson, Kevin R.; Belau, Leonid & Kostko, Oleg
Object Type: Article
System: The UNT Digital Library
The RHIC Injector Accelerators Configurations, and Performance for the RHIC 2003 Au-D Physics Run. (open access)

The RHIC Injector Accelerators Configurations, and Performance for the RHIC 2003 Au-D Physics Run.

The RHIC 2003 Physics Run [1] required collisions between gold ions and deuterons. The injector necessarily had to deliver adequate quality (transverse and longitudinal emittance) and quantity of both species. For gold this was a continuing evolution from past work [2]. For deuterons it was new territory. For the filling of the RHIC the injector not only had to deliver quality beams but also had to switch between these species quickly. This paper details the collider requirements and our success in meeting these. Some details of the configurations employed are given.
Date: May 12, 2003
Creator: Ahrens, L.; Benjamin, J.; Blaskiewicz, M.; Brennan, J. M.; Brown, K. A.; Carlson, K. A. et al.
Object Type: Article
System: The UNT Digital Library
Supernova/Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy (open access)

Supernova/Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

The Supernova/Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universes expansion by performing a series of complementary systematics-controlled astrophysical measurements. We here describe a self-consistent reference mission design that can accomplish this goal with the two leading measurement approaches being the Type Ia supernova Hubble diagram and a wide-area weak gravitational lensing survey. This design has been optimized to first order and is now under study for further modification and optimization. A 2-m three-mirror anastigmat wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high efficiency low-resolution integral field spectrograph. The instrumentation suite provides simultaneous discovery and light-curve measurements of supernovae and then can target individual objects for detailed spectral characterization. The SNAP mission will discover thousands of Type Ia supernovae out to z = 3 and will obtain high-signal-to-noise calibrated light-curves and spectra for a subset of > 2000 supernovae at redshifts between z = 0.1 and 1.7 in a northern field and in a southern field. A wide-field survey covering one thousand square degrees in both northern and …
Date: May 12, 2004
Creator: Aldering, G.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Baltay, C. et al.
Object Type: Article
System: The UNT Digital Library
On the Significance of the Contribution of Multiple-Electron Capture Processes to Cometary X-Ray Emission (open access)

On the Significance of the Contribution of Multiple-Electron Capture Processes to Cometary X-Ray Emission

We report laboratory studies of the role played by multiple-electron capture (MEC) in solar wind induced cometary X-ray emission. Collisions of Ne{sup 10+} with He, Ne, Ar, CO, and CO{sub 2} have been investigated by means of the traditional singles X-ray spectroscopy in addition to the triple-coincidence measurements of X-rays, scattered projectile, and target recoil ions for the atomic targets. The coincidence measurements enable the reduction of the singles X-ray spectra into partial spectra originating in single-electron capture (SEC) and MEC collisions. The measurements provide unequivocal evidence for a significant role played by MEC, and strongly suggest that models based solely on SEC are bound to yield erroneous conclusions on the solar wind composition and velocities and on cometary atmospheres. The experimental relative importance of MEC collisions is compared with molecular classical-over-the-barrier model (MCBM), classical trajectory Monte Carlo (CTMC), and multi-channel Landau-Zener (MCLZ), calculations which can qualitatively reproduce the experimental trends.
Date: May 12, 2005
Creator: Ali, R.; Neill, P. A.; Beiersdorfer, P.; Harris, C. L.; Rakovi?, M. J.; Wang, J. G. et al.
Object Type: Article
System: The UNT Digital Library
Congressional Gifts and Travel: Proposals for the 109th Congress (open access)

Congressional Gifts and Travel: Proposals for the 109th Congress

This report provides a brief analysis of the proposal for change introduced or discussed in the 109th Congress and will be updated as events warrant.
Date: May 12, 2006
Creator: Amer, Mildred
Object Type: Report
System: The UNT Digital Library
NATO and the European Union (open access)

NATO and the European Union

Report which discusses issues related to the North Atlantic Trade Organization (NATO) and the European Union (EU) including the level of involvement of the entities in using political and military actions to defend against terrorism and proliferation, the types of military forces necessary, the role of the EU in crisis management, the appropriateness of decision-making procedures to respond to emerging threats, and the role of other international institutions.
Date: May 12, 2005
Creator: Archick, Kristin & Gallis, Paul E.
Object Type: Report
System: The UNT Digital Library
MEASURING BETA FUNCTION AND PHASE ADVANCE IN RHIC WITH AN AC DIPOLE. (open access)

MEASURING BETA FUNCTION AND PHASE ADVANCE IN RHIC WITH AN AC DIPOLE.

High energy hadron collider operation requires accurate measurements of the beta functions and phase advances, to check the linear optics and to locate gradient errors. During the RHIC 2003 run, two AC dipoles with vertical and horizontal magnetic field [1] were used to measure the linear optics at storage and at injection energies. The two AC dipoles are set up to adiabatically induce sizable coherent oscillations at a frequency close to the betatron frequencies. The beta functions and phase advances are then calculated from the 1024 turn-by-turn measurements available from all the RHIC BPMs (Beam Position Monitors). Because the coherent excitation is adiabatic, the beam emittance is preserved after the measurement. The algorithm is discussed in this paper, and experimental results are presented.
Date: May 12, 2003
Creator: BAI,M. PEGGS,S. ROSER,T. SATOGATA,T.
Object Type: Article
System: The UNT Digital Library
MEASUREMENT OF LINEAR COUPLING RESONANCE IN RHIC. (open access)

MEASUREMENT OF LINEAR COUPLING RESONANCE IN RHIC.

Linear coupling is one of the factors that determine beam lifetime in RHIC. The traditional method of measuring the minimum tune separation requires a tune scan and can't be done parasitically or during the acceleration ramp. A new technique of using ac dipoles to measure linear coupling resonance has been developed at RHIC. This method measures the degree of coupling by comparing the amplitude of the horizontal coherent excitation with the amplitude of the vertical coherent excitation if the beam is excited by the vertical AC dipole and vice versa. One advantage of this method is that it can be done without changing tunes from the normal machine working points. In principle, this method can also localize the coupling source by mapping out the coupling driving terms throughout the ring. This is very useful for local decoupling the interaction regions in RHIC. A beam experiment of measuring linear coupling has been performed in RHIC during its 2003 run, and the analysis of the experimental data is discussed in this paper.
Date: May 12, 2002
Creator: BAI,M. PILAT,F. SATOGATA,T. TOMAS,R.
Object Type: Article
System: The UNT Digital Library
STOCHASTIC COOLING FOR RHIC. (open access)

STOCHASTIC COOLING FOR RHIC.

Emittance growth due to Intra-Beam Scattering significantly reduces the heavy ion luminosity lifetime in RHIC. Stochastic cooling of the stored beam could improve things considerably by counteracting IBS and preventing particles from escaping the rf bucket [1]. High frequency bunched-beam stochastic cooling is especially challenging but observations of Schottky signals in the 4-8 GHz band indicate that conditions are favorable in RHIC [2]. We report here on measurements of the longitudinal beam transfer function carried out with a pickup kicker pair on loan from FNAL TEVATRON. Results imply that for ions a coasting beam description is applicable and we outline some general features of a viable momentum cooling system for RHIC.
Date: May 12, 2003
Creator: BLASKIEWICZ,M. BRENNAN,J. M. CAMERON,P. WEI,J.
Object Type: Article
System: The UNT Digital Library
LONGITUDINAL SOLUTIONS IN RHIC. (open access)

LONGITUDINAL SOLUTIONS IN RHIC.

Stable, coherent, longitudinal oscillations have been observed in the RHIC accelerator. Within the context of perturbation theory, the beam parameters and machine impedance suggest these oscillations should be Landau damped. When nonlinear effects are included, long lived, stable oscillations become possible for low intensity beams. Simulations and theory are compared with data.
Date: May 12, 2003
Creator: BLASKIEWICZ,M. BRENNAN,J. M. FISCHER,W. CAMERON,P. WEI,J. LUQUE,A. SCHAMEL,H.
Object Type: Article
System: The UNT Digital Library
STATUS OF SLOW EXTRACTION OF HIGH INTENSITY PROTONS FROM BROOKHAVEN'S AGS. (open access)

STATUS OF SLOW EXTRACTION OF HIGH INTENSITY PROTONS FROM BROOKHAVEN'S AGS.

The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams. We have an active program of high energy physics experiments, including the high precision measurement of the muons magnetic moment [1] and the discovery of the rare Kaon decay, K+ {yields} {pi} + {nu}{bar {nu}} [2]. This program is continuing into the future with the rare symmetry violating process experiments [3] currently being designed to operate at the AGS. In this paper, we will present results from operation of high intensity slow extraction, the problems we encounter, and our solutions to those problems.
Date: May 12, 2003
Creator: BROWN,K. A. AHRENS,L. BRENNAN,J. M. GLENN,J. W. ROSER,T. RUSSO,T. TSOUPAS,N. SMITH,K. ZENO,K.
Object Type: Article
System: The UNT Digital Library
RHIC POWER SUPPLIES - LESSONS LEARNED FROM THE 1999 - 2001 RHIC RUNS. (open access)

RHIC POWER SUPPLIES - LESSONS LEARNED FROM THE 1999 - 2001 RHIC RUNS.

The Relativistic Heavy Ion Collider (RHIC) was commissioned in 1999 and 2000. The two RHIC rings require a total of 933 power supplies (PSs) to supply currents to highly inductive superconducting magnets. These units function as 4 main PSs, 237 insertion region (02) PSs, 24 sextupole PSs, 24 Gamma-T PSs, 8 snake PSs, 16 spin rotator PSs, and 620 correction PSs. PS reliability in this type of machine is of utmost importance because the IR PSs are nested within other IR PSs, and these are all nested within the main PSs. This means if any main or IR PS trips off due to a PS fault or quench indication, then all the IR and main PSs in that ring must follow. When this happens, the Quench Protection Assemblies (QPA's) for each unit disconnects the PSs from the circuit and absorb the stored energy in the magnets. Commissioning these power supplies and QPA's was and still is a learning experience. A summary of the major problems encountered during these first three RHIC runs will be presented along with solutions.
Date: May 12, 2003
Creator: BRUNO,D. ENG,W. GANETIS,G. LAMBIASE,R. F. LOUIE,W. SANDBERG,J. SCHULTHEISS,C.
Object Type: Article
System: The UNT Digital Library
Liquid phase epitaxial growth and characterization of germanium far infrared blocked impurity band detectors (open access)

Liquid phase epitaxial growth and characterization of germanium far infrared blocked impurity band detectors

Germanium Blocked Impurity Band (BIB) detectors require a high purity blocking layer (< 10{sup 13} cm{sup -3}) approximately 1 mm thick grown on a heavily doped active layer ({approx} 10{sup 16} cm{sup -3}) approximately 20 mm thick. Epilayers were grown using liquid phase epitaxy (LPE) of germanium out of lead solution. The effects of the crystallographic orientation of the germanium substrate on LPE growth modes were explored. Growth was studied on substrates oriented by Laue x-ray diffraction between 0.02{sup o} and 10{sup o} from the {l_brace}111{r_brace} toward the {l_brace}100{r_brace}. Terrace growth was observed, with increasing terrace height for larger misorientation angles. It was found that the purity of the blocking layer was limited by the presence of phosphorus in the lead solvent. Unintentionally doped Ge layers contained {approx}10{sup 15} cm{sup -3} phosphorus as determined by Hall effect measurements and Photothermal Ionization Spectroscopy (PTIS). Lead purification by vacuum distillation and dilution reduced the phosphorus concentration in the layers to {approx} 10{sup 14} cm{sup -3} but further reduction was not observed with successive distillation runs. The graphite distillation and growth components as an additional phosphorus source cannot be ruled out. Antimony ({approx}10{sup 16} cm{sup -3}) was used as a dopant for the …
Date: May 12, 2001
Creator: Bandaru, Jordana
Object Type: Thesis or Dissertation
System: The UNT Digital Library
FY2005 Supplemental Appropriations for Iraq and Afghanistan, Tsunami Relief, and Other Activities (open access)

FY2005 Supplemental Appropriations for Iraq and Afghanistan, Tsunami Relief, and Other Activities

None
Date: May 12, 2005
Creator: Belasco, Amy & Nowels, Larry
Object Type: Report
System: The UNT Digital Library
Boron-Loaded Silicone Rubber Scintillators (open access)

Boron-Loaded Silicone Rubber Scintillators

Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.
Date: May 12, 2003
Creator: Bell, Z. W.; Maya, L.; Brown, G. M. & Sloop, F. V. Jr
Object Type: Report
System: The UNT Digital Library
R&D Towards Cooling of the RHIC Collider. (open access)

R&D Towards Cooling of the RHIC Collider.

We introduce the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon bunched-beam ion collider at storage energy using 54 MeV electrons. The electron source will be an RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum bunch frequency is 28.15 MHz, with bunch charge of 10 nC. The R&D program has the following components: The photoinjector, the superconducting linac, start-to-end beam dynamics with magnetized electrons, electron cooling calculations and development of a large superconducting solenoid.
Date: May 12, 2003
Creator: Ben-Zvi, Ilan; Brennan, Joseph; Burrill, Andrew; Calega, Rama; Chang, Xiangyun; Citver, Gregory et al.
Object Type: Article
System: The UNT Digital Library
Linear Model for Non Isosceles Absorbers. (open access)

Linear Model for Non Isosceles Absorbers.

Previous analyses have assumed that wedge absorbers are triangularly shaped with equal angles for the two faces. In this case, to linear order, the energy loss depends only on the position in the direction of the face tilt, and is independent of the incoming angle. One can instead construct an absorber with entrance and exit faces facing rather general directions. In this case, the energy loss can depend on both the position and the angle of the particle in question. This paper demonstrates that and computes the effect to linear order.
Date: May 12, 2003
Creator: Berg, J. S.
Object Type: Article
System: The UNT Digital Library
Conceptual Design of a Simplified Skid-Mounted Caustic-Side Solvent Extraction Process for Removal of Cesium from Savannah Rive Site High-Level Waste (open access)

Conceptual Design of a Simplified Skid-Mounted Caustic-Side Solvent Extraction Process for Removal of Cesium from Savannah Rive Site High-Level Waste

This report presents the results of a conceptual design of a solvent extraction process for the selective removal of {sup 137}Cs from high-level radioactive waste currently stored in underground tanks at the U.S. Department of Energy's Savannah River Site (SRS). This study establishes the need for and feasibility of deploying a simplified version of the Caustic-Side Solvent Extraction (CSSX) process; cost/benefit ratios ranging from 33 to 55 strongly support the considered deployment. Based on projected compositions, 18 million gallons of dissolved salt cake waste has been identified as having {sup 137}Cs concentrations that are substantially lower than the worst-case design basis for the CSSX system that is to be deployed as part of the Salt Waste Processing Facility (SWPF) but that does not meet the waste acceptance criteria for immobilization as grout in the Saltstone Manufacturing and Disposal Facility at SRS. Absent deployment of an alternative cesium removal process, this material will require treatment in the SWPF CSSX system, even though the cesium decontamination factor required is far less than that provided by that system. A conceptual design of a CSSX processing system designed for rapid deployment and having reduced cesium decontamination factor capability has been performed. The proposed accelerated-deployment …
Date: May 12, 2004
Creator: Birdwell, JR.J.F.
Object Type: Report
System: The UNT Digital Library
The United Nations Convention on the Rights of the Child: Background and Policy Issues (open access)

The United Nations Convention on the Rights of the Child: Background and Policy Issues

This report provides an overview of the United Nations Convention of the Rights of the Child's (CRC) background and structure and examines evolving U.S. policy toward the Convention, including past and current Administration positions and congressional perspectives. It also highlights issues for the 112th Congress, including the Convention's possible impact on federal and state laws, U.S. sovereignty, parental rights, and U.S. family planning and abortion policy.
Date: May 12, 2009
Creator: Blanchfield, Luisa
Object Type: Report
System: The UNT Digital Library
Transverse Instabilities in Rhic. (open access)

Transverse Instabilities in Rhic.

The beam quality in RHIC can be significantly impacted by a transverse instability which can occur just after transition [1]. Data characterizing the instability are presented and analyzed. Techniques for ameliorating the situation are considered.
Date: May 12, 2003
Creator: Blaskiewicz, M.; Cameron, P.; Catalan-Lasheras, N.; Dawson, C.; Degen, C.; Drees, K. et al.
Object Type: Article
System: The UNT Digital Library