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Part II/Addendum Electron Beam Cooling between EBIS LINAC and Booster; Is Single Pass Cooling Possible?

Description: Due to some miscommunication, incomplete data was erroneously used in examining electron beam cooling for reducing momentum of gold ions exiting the EBIS LINAC before injection into the booster. Corrected calculations still indicate that single pass cooling is, in principle, feasible; momentum spread can be reduced by an order of magnitude in about one meter. Preliminary results suggest that this cooling deserves further consideration.
Date: July 1, 2008
Creator: Hershcovitch,A.
Partner: UNT Libraries Government Documents Department

Setup and performance of RHIC for the 2008 run with deuteron-gold collisions.

Description: This year (2008) deuterons and gold ions were collided in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) for the first time since 2003. The setup and performance of the collider for the 2008 run is reviewed with a focus on improvements that have led to an order of magnitude increase in luminosity over that achieved in the 2003 run.
Date: June 23, 2008
Creator: Gardner,C.; Abreu, N.P.; Ahren, L.; Alessi, J.; Bai, M. & al., et
Partner: UNT Libraries Government Documents Department

SETUP AND PERFORMANCE OF THE RHIC INJECTOR ACCELERATORS FOR THE 2007 RUN WITH GOLD IONS

Description: Gold ions for the 2007 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators is reviewed with a focus on improvements in the quality of beam delivered to RHIC. In particular, more uniform stripping foils between Booster and AGS7 and a new bunch merging scheme in AGS have provided beam bunches with reduced longitudinal emittance for RHIC.
Date: June 25, 2007
Creator: GARDNER,C.; AHRENS, L.; ALESSI, J.; BENJAMIN, J.; BLASKIEWICZ, M. & AL., ET
Partner: UNT Libraries Government Documents Department

Emittance Reduction between EBIS LINAC and Booster by Electron Beam Cooling; Is Single Pass Cooling Possible?

Description: Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in less than one meter.
Date: April 1, 2008
Creator: Hershcovitch,A.
Partner: UNT Libraries Government Documents Department

Experience with IBS-suppression lattice in RHIC

Description: An intra-beam scattering (IBS) is the limiting factor of the luminosity lifetime for RHIC operating with heavy ions. In order to suppress the IBS we designed and implemented new lattice with higher betatron tunes. This lattice had been developed during last three years and had been used for gold ions in yellow ring of the RHIC during d-Au part of the RHIC Run-8. The use of this lattice allowed both significant increases in the luminosity lifetime and the luminosity levels via reduction of beta-stars in the IPS. In this paper we report on the development, the tests and the performance of IBS-suppression lattice in RHIC, including the resulting increases in the peak and the average luminosity. We also report on our plans for future steps with the IBS suppression.
Date: June 23, 2008
Creator: Litvinenko,V.N.; Luo, Y.; Ptitsyn, V.; Satogata, T.; Tepikian, S.; Bai, M. et al.
Partner: UNT Libraries Government Documents Department

Energy loss of coasting gold ions and deuterons in RHIC.

Description: The total energy loss of coasting gold ion beams was measured at RHIC at two energies, corresponding to a gamma of 75.2 and 107.4. We describe the experiment and observations and compare the measured total energy loss with expectations from ionization losses at the residual gas, the energy loss due to impedance and synchrotron radiation. We find that the measured energy losses are below what is expected from free space synchrotron radiation. We believe that this shows evidence for suppression of synchrotron radiation which is cut off at long wavelength by the presence of the conducting beam pipe.
Date: June 23, 2008
Creator: Abreu,N.; Blaskiewicz, M.; Brown, K.A.; Butler, J.J.; FischW; Harvey, M. et al.
Partner: UNT Libraries Government Documents Department

Prominent Soft X-ray Lines of Sr-like Au41+ in Low-energy EBIT Spectrum

Description: Relativistic multireference M{o}ller-Plesset perturbation theory has been employed to calculate with high accuracy the energy levels and transition probabilities of Cu- to Sr-like gold ions. The many-body calculations were carried out to identify the unassigned blended lines in the 35-40 angstroms region of the low-energy EBIT spectrum of the gold ions. Most of the prominent lines in the 35-40 angstroms region were identified as the emission lines in Sr-like gold.
Date: March 27, 2007
Creator: Vilkas, M J; Ishikawa, Y & Trabert, E
Partner: UNT Libraries Government Documents Department

Issues concerning high current lower energy electron beams required for ion cooling between EBIS LINAC and booster

Description: Some issues, regarding a low energy high current electron beam that will be needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, are examined. Options for propagating such an electron beam, as well as the effect of neutralizing background plasma on electron and ion beam parameters are calculated. Computations and some experimental data indicate that none of these issues is a show stopper.
Date: March 1, 2009
Creator: Hershcovitch,A.
Partner: UNT Libraries Government Documents Department

RESULTS FROM BETATRON PHASE MEASUREMENTS IN RHIC DURING THE SEXTANT TEST.

Description: The Sextant Test of the Relativistic Heavy Ion Collider (RHIC) was an important step towards its completion. One sixth of the two RHIC accelerators was fully commissioned. Gold ion beam was injected and transported through one sextant of one of the two rings. The betatron phase advance per cell was measured by recording differences in the horizontal and vertical positions of the beam at the end of the sextant due to a sequence of correction dipole kicks along the beam line. Measurement results show excellent agreement with predicted values, confirming that production measurements of the integral functions of the quadrupoles were very accurate, and that the polarity of all elements (correction dipoles, quadrupoles, dipoles etc.) was correct.
Date: June 26, 1998
Creator: TRBOJEVIC, D.
Partner: UNT Libraries Government Documents Department

Scanning tunneling microscopy and atomic force microscopy of Au implanted in highly ordered pyrolytic graphite

Description: Surfaces of highly oriented pyrolytic graphite implanted with gold were studied by both constant current STM, constant force, and tapping mode AFM. Gold colloids were observed by both constant current STM and tapping mode AFM. The surfaces can be modified by applying currents of {plus_minus}4 V and 1 nA. In addition, pyramidal and faceted structures were observed on sample surfaces suggesting the presence of diamond microcrystals.
Date: January 1, 1996
Creator: Tung, Y.S.; Ueda, A.; Henderson, D.O.; Mu, R.; Gu, Z.; White, C.W. et al.
Partner: UNT Libraries Government Documents Department

Anomolous, intensity dependent losses in Au(32+) beams

Description: The AGS Booster is a rapid cycling proton and heavy ion synchrotron. Anomolous, intensity dependent losses in Au(32+) beams have been observed in the AGS Booster. No collective signal is expected, or observed, but increasing the number of injected ions decreases the beam lifetime. The loss rates for Au(32+) are compared with those for Au(15+).
Date: July 1, 1997
Creator: Blaskiewicz, M.; Ahrens, L. & Calvani, H.
Partner: UNT Libraries Government Documents Department

OPERATION OF THE RHIC AU ION SOURCE.

Description: The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is beginning its second year of operation. A cesium sputter ion source injecting into a tandem Van de Graaff provides the gold ions for RHIC. The ion source is operated in the pulsed beam mode and produces a 500{micro}sec long pulse of Au{sup -} with a peak intensity of 290pA at the entrance of the tandem. After acceleration in the tandem and post stripping, this results in a beam of Au{sup +32} with an intensity of 80e{micro}A and an energy of 182MeV. Over the last several years, a series of improvements have been made to increase the intensity of the pulsed beam from the ion source. Details of the source performance and improvements will be presented. In addition, an effort is under way to provide other beam species for RHIC collisions.
Date: September 2, 2001
Creator: STESKI,D.B.; ALESSI,J.; BENJAMIN,J.; CARLSON,C.; MANNI,M.; THIEBERGER,P. et al.
Partner: UNT Libraries Government Documents Department

THE TWO STAGE CRYSTAL COLLIMATOR FOR RHIC.

Description: The use of a two stage crystal collimation system in the RHIC yellow ring is examined. The system includes a copper beam scraper and a bent silicon crystal. While scrapers were installed in both of the RHIC rings before the year 2000 run, the crystal is installed for the 2001 run in one ring only, forming a two stage collimation system there. We present simulations of the expected channeling through the bent silicon crystal for both protons and gold ions with various beam parameters. This gives a picture of the particle losses around the ring, and the expected channeling efficiency. These results are then used to optimize the beam parameters in the area of the crystal to obtain maximum channeling efficiency, minimize out-scattering in the secondary collimator, and reduce beam halo.
Date: June 18, 2001
Creator: FLILLER, R.P. III; DREES, A.; GASSNER, D.; HAMMONS, L.; MCINTYRE, G.; TRBOJEVIC, D. et al.
Partner: UNT Libraries Government Documents Department

ELECTRON COOLING FOR RHIC.

Description: The Accelerator Collider Department (CAD) at Brookhaven National Laboratory is operating the Relativistic Heavy Ion Collider (RHIC), which includes the dual-ring, 3.834 km circumference superconducting collider and the venerable AGS as the last part of the RHIC injection chain. CAD is planning on a luminosity upgrade of the machine under the designation RHIC II. One important component of the RHIC II upgrade is electron cooling of RHIC gold ion beams. For this purpose, BNL and the Budker Institute of Nuclear Physics in Novosibirsk entered into a collaboration aimed initially at the development of the electron cooling conceptual design, resolution of technical issues, and finally extend the collaboration towards the construction and commissioning of the cooler. Many of the results presented in this paper are derived from the Electron Cooling for RHIC Design Report [1], produced by the, BINP team within the framework of this collaboration. BNL is also collaborating with Fermi National Laboratory, Thomas Jefferson National Accelerator Facility and the University of Indiana on various aspects of electron cooling.
Date: May 13, 2001
Creator: BEN-ZVI,I.
Partner: UNT Libraries Government Documents Department

THE PHENIX EXPERIMENT AT RHIC.

Description: PHENIX is a large detector at the Relativistic Heavy Ion Collider (RHIC) at BNL. RHIC and PHENIX have recently operated for the first time, producing and detecting collisions of gold ions at beam energies of 30 and 65 GeV per nucleon. The current performance and future plans of PHENIX and of RHIC are presented.
Date: July 27, 2000
Creator: ARONSON,S. FOR THE PHENIX COLLABORATION
Partner: UNT Libraries Government Documents Department

CHARGED PARTICLE MULTIPLICITIES AT BRAHMS.

Description: This report presents the measurement of charged particle multiplicity densities dN/d{eta} in ultrarelativistic heavy ion collisions as function of {eta} and the centrality of the collisions. This distributions were extracted from data collected by the BRAHMS collaboration during the first RHK run with gold ions at {radical}s{sub NN} = 130A {center_dot} GeV. The analysis method is described and, results are compared to some model predictions.
Date: July 30, 2001
Creator: DEBBE, R., FOR THE BRAHMS COLLABORATION
Partner: UNT Libraries Government Documents Department

Nondegenerate Four-Wave Mixing in Gold Nanocomposites Formed by Ion Implantation

Description: Nondegenerate four-wave mixing technique has been used to investigate the third-order nonlinear susceptibility for nanocomposite material with Au nanocrystals formed inside a SiO{sub 2} glass matrix. High concentrations of encapsulated Au nanocrystals are formed by implantation of Au ions into fused silica glass substrates and thermal annealing. The size distribution and the depth profiles of the Au nanoparticles can be controlled by the implantation dose, energy and annealing temperatures. The high value of the third-order susceptibility - (0.26--1.3)x10{sup -7} esu was found in the range of the frequency detunings near the surface plasmon resonance. Two characteristic relaxation times, 0.66 ps and 5.3 ps, have been extracted from the detuning curve of the third-order susceptibility as the probe-beam frequency changes and the pump-beam frequency fixed at the plasmon resonance. The first relaxation time was attributed to electron-phonon relaxation, and the second to thermal diffusion to the host medium. The efficient nondegenerate conversion is attractive for optical processing.
Date: July 1, 1999
Creator: Saonov, V.P.; Zhu, J.G.; Lepeshkin, N.N.; Armstrong, R.L.; Shalaev, V.M.; Ying, Z.C. et al.
Partner: UNT Libraries Government Documents Department

Formation of novel optical materials by ion implantation

Description: Ion implantation into glasses shows considerable promise as a technique for producing novel materials having unique optical properties. There is also significant commercial interest in the marketing of optical waveguides, high-performance polarizing glasses, and birefringent glasses. In this work, special glass compositions, including both two-phase and anisotropic materials, were prepared by bulk processing techniques and then implanted with Ag, Au, and Cu ions at different temperatures, energies, and doses. The composite materials produced showed strong resonant absorption at the surface plasmon resonance frequency. The plasmon frequency was consistent with the formation of spherical colloids of the implanted metals having diameters on the order of 10 nm. No anisotropic behavior of the implanted materials was observed. Possible applications for these materials, had such anisotropy been developed, would have included optical isolators, Faraday rotators, optical waveguides, and switching devices for use in optical communication and computing.
Date: October 1, 1995
Partner: UNT Libraries Government Documents Department

Study of bulk properties at high energy nuclear collisions - The search for the partonic equation of state at RHIC

Description: We discuss recent results from RHIC. Issues of energy loss and partonic collectivity from Au + Au collisions at {radical}s{sub NN} = 200 GeV are the focus of this paper. We propose a path toward the understanding of the partonic Equation of State in high energy nuclear collisions.
Date: January 1, 2004
Creator: Xu, Nu
Partner: UNT Libraries Government Documents Department

Partonic EoS in High-Energy Nuclear Collisions at RHIC

Description: The authors discuss the recent results on equation of state for partonic matter created at RHIC. Issues of partonic collectivity for multi-strange hadrons and J/{psi} from Au + Au collisions at {radical}Ss{sub NN} = 200 GeV are the focus of this paper.
Date: January 1, 2006
Creator: Xu, Nu
Partner: UNT Libraries Government Documents Department

Single pass electron beam cooling of gold ions between EBIS LINAC and booster is theoretically possible!

Description: Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Many issues, regarding a low energy high current electron beam that is needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, were examined. Computations and some experimental data indicate that none of these issues is a show stopper. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in about one meter. Hence, this option cooling deserves further more serious considerations.
Date: January 1, 2011
Creator: Hershcovitch, A.
Partner: UNT Libraries Government Documents Department

L-Shell Spectroscopy of Au as a Temperature Diagnostic Tool

Description: In order to develop plasma diagnostic for reduced-size hot hohlraums under laser irradiation, they have studied the L-shell emission from highly charged gold ions in the SuperEBIT electron beam ion trap. The resolving power necessary to identify emission features from individual charge states in a picket fence pattern has been estimated, and the observed radiation features have been compared with atomic structure calculations. They find that the strong 3d{sub 5/2} {yields} 2p{sub 3/2} emission features are particularly useful in determining the charge state distribution and average ion charge <Z>, which are strongly sensitive to the electron temperature.
Date: March 27, 2008
Creator: Trabert, E; Hansen, S B; Beiersdorfer, P; Brown, G V; Widmann, K & Chung, H K
Partner: UNT Libraries Government Documents Department