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Carbon foils as heavy ion strippers

Description: A discussion is given of the advantages and disadvantages of thin carbon foil strippers for heavy ion beams from tandem electrostatic accelerators. Foil lifetimes were increased by radiative heating and by the evaporation of a thin layer of gold on the foil. (PMA)
Date: January 1, 1975
Creator: Yntema, J.L.
Partner: UNT Libraries Government Documents Department

Lifetimes of carbon stripping foils

Description: In an effort to produce a coherent picture of foil lifetimes, a review is given of results of various authors on the use of carbon foil beam strippers for heavy ion facilities. Foil heating in the tandem terminal during heavy ion bombardment, combined with oscillation of the foil, should produce acceptable foil lifetimes and improve the beam quality by reduction of the foil thickening effect and the accompanying inhomogeneity. The installation and operation of such a system does not present insurmountable problems. (PMA)
Date: October 1, 1975
Creator: Yntema, J.L.
Partner: UNT Libraries Government Documents Department

Stripping foils at RHIC

Description: There are two major science programs at the Relativistic Heavy Ion Collider (RHIC). These are the heavy ion program, which collides beams of fully stripped ions, and the polarized proton program. A wide variety of stripper foils and carbon targets are used throughout the RHIC accelerator chain to facilitate these collisions. Each stripper and target has unique properties and functions. Those characteristics will be discussed, as well as recent efforts to improve their performance.
Date: September 15, 2008
Creator: Steski,D.B. & Thieberger, P.
Partner: UNT Libraries Government Documents Department

Intrabeam stripping in H- Linacs

Description: A beam loss in the superconducting part of the SNS linac has been observed during its commissioning and operation. Although the loss does not prevent the SNS high power operation, it results in an almost uniform irradiation of linac components and increased radiation levels in the tunnel. Multi-particle tracking could neither account for the magnitude of the observed loss nor its dependence on machine parameters. It was recently found that the loss is consistent with the intrabeam particle collisions resulting in stripping of H{sup -} ions. The paper describes experimental observations and corresponding analytical estimates of the intrabeam stripping.
Date: September 1, 2010
Creator: Lebedev, V.; Solyak, N.; Ostigy, J.-F.; /Fermilab; Alexandrov, A.; Shishlo, A. et al.
Partner: UNT Libraries Government Documents Department

Carbon stripper foils used in the Los Alamos PSR

Description: Carbon stripper foils produced by the modified controlled ACDC arc discharge method (mCADAD) at the Institute for Nuclear Study have been tested and used for high current 800-MeV beam production in the Proton Storage Ring (PSR) since 1993. Two foils approximately 110 {mu}g/cm{sup 2} each are sandwiched together to produce an equivalent 220 {mu}g/cm{sup 2} foil. The foil sandwitch is supported by 4-5 {mu}m diameter carbon filters attached to an aluminum frame. These foils have survived as long as five months during PSR normal beam production of near 70 {mu}A average current on target. Typical life-times of other foils vary from seven to fourteen days with lower on-target average current. Beam loss data also indicate that these foils have slower shrinkage rates than standard foils. Equipment has been assembled and used to produce foils by the mCADAD method at Los Alamos. These foils will be tested during 1997 operation.
Date: December 1, 1997
Creator: Borden, M.J.; Plum, M.A. & Sugai, I.
Partner: UNT Libraries Government Documents Department

The Effects of Labeling and Stigma on the Social Rejection of Striptease Performers

Description: This study uses survey data collected from a convenience sample of undergraduate students (N=89). A vignette survey design is employed to measure social rejection of striptease performers compared to a control group. Data is also collected on negative stereotypes held about striptease performers, which are correlated with social rejection. Link and Phelan's conceptualization of the stigma process provides the theoretical framework for this analysis. Findings suggest that striptease performers experience higher levels of social rejection and are perceived more negatively than the control group and that endorsement of negative stereotypes is associated with social rejection.
Date: December 2006
Creator: Ebeid, Omar Randi
Partner: UNT Libraries

UPGRADING THE SNS COMPRESSOR RING TO 3 MW.

Description: The initial performance goal for the SNS compressor ring is 1.4 MW with 1.0 GeV linac beam. During the design phase many considerations and provisions have been made to allow progressive increase in power level of the ring, ultimately to 3.0 MW and beyond after years of improvements. The most important provision for future higher power operation is an increase in beam energy from 1.0 to 1.3 GeV. Other possible upgrades covered in this report include ion source current, new stripper foil material, injection and extraction systems, transverse damper, barrier cavity, and electron clearing to avoid e-p instability.
Date: June 3, 2002
Creator: WENG,W.T.; BLASKIEWICZ,M.; FEDOTOV,A.; LEE,Y.Y.; RAPARIA,D.; WEI,J. et al.
Partner: UNT Libraries Government Documents Department

Electronic excitation in transmission of relativistic H{sup {minus}} ions through thin foils

Description: The authors describe a theoretical model to study the transmission of relativistic H{sup {minus}} ions through thin carbon foils. The approach is based on a Monte Carlo solution of the Langevin equation describing electronic excitations of the atoms during the transport through the foil. Calculations for the subshell populations of outgoing hydrogen atoms are found to be in good agreement with recent experimental data on an absolute scale and show that there exists a propensity for populating extreme Stark states.
Date: May 7, 1998
Creator: Reinhold, C.O.; Kuerpick, P.; Burgdoerfer, J.; Yoshida, S. & Gervais, B.
Partner: UNT Libraries Government Documents Department

THE COLLIMATION SYSTEM OF THE SNS TRANSFER LINES.

Description: The High Energy Beam Transport (HEBT) and Ring to Target Beam Transport (RTBT) lines of the Spallation Neutron Source (SNS) include collimation systems that protect the line itself, as well as the systems downstream. Due to the one-pass mechanism in a transfer line, collimation can only provide protection against accidental losses while shaping the beam is reserved for multi-pass systems as rings. Efficiency has to be improved by increasing the impact parameter in the collimator in the first passage. In the HEBT line the use of stripers for collimation of the H-beam enhances the final capture efficiency but introduces some limitations in the layout geometry. In the RTBT, protection is provided by the optics of the line and collimator optimization is reduced to considerations of length and the amount of free space available. We revisited the design of the collimation systems for both transfer lines attending to various criteria including loss scenarios and flexibility. With the revised design, we estimated the final performance and cleaning efficiency under nominal conditions for both systems.
Date: June 18, 2001
Creator: CATALAN-LASHERAS,N. & RAPARIA,D.
Partner: UNT Libraries Government Documents Department

Safety evaluation of the ITP filter/stripper test runs and quiet time runs using simulant solution. Revision 3

Description: The purpose is to provide the technical bases for the evaluation of Unreviewed Safety Question for the In-Tank Precipitation (ITP) Filter/Stripper Test Runs (Ref. 7) and Quiet Time Runs Program (described in Section 3.6). The Filter/Stripper Test Runs and Quiet Time Runs program involves a 12,000 gallon feed tank containing an agitator, a 4,000 gallon flush tank, a variable speed pump, associated piping and controls, and equipment within both the Filter and the Stripper Building.
Date: June 1, 1994
Creator: Gupta, M.K.
Partner: UNT Libraries Government Documents Department

Possibilities for Beam Stripping Solutions at a Rare Isotope Accelerator (RIA)

Description: As part of the DOE RIA R&D effort we investigated the possibilities and problems of beam strippers in the different heavy ion accelerator components of a possible Rare Isotope Accelerator (RIA) facility. We focused on two beam stripping positions in the RIA heavy ion driver where benchmark currents of up to 5 particle μA 238-U were projected at energies of 10.5 MeV/u and 85 MeV/u respectively. In order to select feasible stripper materials, data from experiments with Uranium beams at Texas A&M and GSI were evaluated. Based on these results thermal estimates for a possible design were calculated and cooling simulations with commercially available software performed. Additionally, we performed simulations with the GEANT4 code on evaluating the radiation environment for our beam stripping solution at the 85 MeV/u position in the RIA driver.
Date: August 29, 2006
Creator: Greife, Uwe
Partner: UNT Libraries Government Documents Department

Status of the 25URC accelerator

Description: This paper discusses the operation of the 25URC accelerator. Shaft and charging chain life, new corona point holder, recirculating gas stripper, an air-SF/sub 6/ separator, and replication of chopped beam pulse are discussed. Seven new ion species were provided for experiment. 2 refs., 2 figs., 2 tabs. (LSP)
Date: January 1, 1987
Creator: Ziegler, N.F.; Mills, G.D.; Meigs, M.J.; McPherson, R.L.; Juras, R.C.; Jones, C.M. et al.
Partner: UNT Libraries Government Documents Department

Electron beam charge state amplifier (EBQA)--a conceptual evaluation.

Description: A concept is presented for stripping low-energy, radioactive ions from 1+ to higher charge states. Referred to as an Electron Beam Charge State Amplifier (EBQA), this device accepts a continuous beam of singly-charged, radioactive ions and passes them through a high-density electron beam confined by a solenoidal magnetic field. Singly-charged ions may be extracted from standard Isotope-Separator-Online (ISOL) sources. An EBQA is potentially useful for increasing the charge state of ions prior to injection into post-acceleration stages at ISOL radioactive beam facilities. The stripping efficiency from q=1+ to 2+ ({eta}{sub 12}) is evaluated as a function of electron beam radius at constant current with solenoid field, injected ion energy, and ion beam emittance used as parameters. Assuming a 5 keV, 1 A electron beam, {eta}{sub 12} = 0.38 for 0.1 keV, {sup 132}Xe ions passing through an 8 Tesla solenoid, 1 m in length. Multi-pass configurations to achieve 3+ or 4+ charge states are also conceivable. The calculated efficiencies depend inversely on the initial ion beam emittances. The use of a helium-buffer-gas, ion-guide stage to improve the brightness of the 1+ beams [1] may enhance the performance of an EBQA.
Date: October 12, 1998
Creator: Dooling, J. C.
Partner: UNT Libraries Government Documents Department

Laser stripping of relativistic H{sup {minus}} ions with practical considerations

Description: This paper describes laser stripping of H{sup {minus}} ions. Some applications are suggested for HEP including stripping 2GeV ions circulating in an accelerator with radius 75 meters where laser meets ion head on in a three meter interaction region. The paper describes photoionizaton cross section, laser power calculation, and how to generate the 5 micrometer light.
Date: December 1, 1995
Creator: Tomlin, R.
Partner: UNT Libraries Government Documents Department

Physics with Heavy Neutron-Rich RIBs at the HRIBF*

Description: The Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge is the first ISOL-type facility to provide beams of accelerated radioactive fission products. To generate these beams, products of fission induced by proton bombardment of a uranium carbide target are ionized, charge-exchanged in Cs vapor, and injected into the HRIBF tandem. Using a single stripper foil in the terminal, they can be accelerated to about 3 MeV per nucleon, ideal for Coulomb Excitation studies. Alternatively, they can be accelerated to energies above the Coulomb barrier by means of double-stripping, at the expense of a factor of about five in lost beam intensity. This paper reports on recent experiments using neutron-rich radioactive ion beams (RIBs) from the HRIBF facility. They have performed Coulomb excitation measurements of B(E2; 0{sup +} {yields} 2{sup +}) in {sup 126,128}Sn and {sup 132,134,136}Te, neutron transfer to single-particle states in {sup 135}Te, and fusion-evaporation reactions on light targets to study evaporation residues with {gamma}-{gamma}-recoil coincidence spectroscopy.
Date: August 14, 2001
Creator: Radford, D.C.
Partner: UNT Libraries Government Documents Department

Production of optically thin free-standing oil films from the edge of a rotating disc

Description: A method is described for forming thin free-standing oil films which are spun from the edge of a sharp-edged rotating disc. The films can be made thin enough to show strong optical interference colors when viewed in white light. The thinnest films have areal densities down to about 10 to 20 ..mu..gm/cm/sup 2/. A stable roughly triangular film with an area of about 10 cm/sup 2/ and fairly uniform thickness can be readily produced. Much larger films having either greater thickness or less stability are also possible. Films have been produced both in air and in vacuum.
Date: January 1, 1980
Creator: Cramer, J.G.; Burch, D.F.; Rodenberg, R. & Cramer, P.B.
Partner: UNT Libraries Government Documents Department

The SSC beam scraper system

Description: In this paper we present the results of a full-scale study of a beam scraping system that is designed to guarantee reliable operation of the SSC throughout the whole cycle and for minimum background for experiments at the interaction regions. The machine aperture limits and beam loss formation are analyzed. Simulation programs and a calculational model are described. The physics of beam scraping is explored, and measures to increase significantly the system efficiency are determined. A tolerable scraping rate, taking into account scraper material integrity, quench limits in downstream superconducting magnets, radiation shielding requirements, and minimal beam halo levels at the IPs are also determined. Finally, a complete multi-component scraper system in the SSC East Cluster is proposed. Throughout the paper we define a scraper as a primary absorber consisting of precise movable jaws that have a flat inner edge along the circulation beam and which may be forced to touch the beam halo in horizontal or vertical planes. Secondary absorbers -- collimators -- are destined to intercept outscattered protons and other particles produced in scraper material. All these are surrounded with a radiation shielding. 15 refs., 50 figs., 13 tabs.
Date: June 1, 1991
Creator: Maslov, M.A.; Mokhov, N.V. & Yazynin (Superconducting Super Collider Lab., Dallas, TX (United States) Institut Fiziki Vysokikh Ehnergij, Protvino (USSR))
Partner: UNT Libraries Government Documents Department

Influence of a biased beam dump on H/sup /minus// beam neutralization measurements with a four-grid energy analyzer

Description: A four-grid energy analyzer (FGA) diagnostic has been developed for the study of H/sup /minus// beam space-charge compensation, and first measurements have been reported previously. Biased beam-dump measurements were undertaken to clarify the origin of electron currents measured in the FGA because they far exceeded predictions based on H/sup /minus// beam ionization and stripping processes. This experiment partially explains the anomalously large radial electron current. The FGA observations for beam-dump bias <0 suggest electron ionization of the background gas is an additional mechanism for producing positive ions, where the electron kinetic energy is derived form the beam-dump voltage. 6 refs., 4 figs.
Date: January 1, 1989
Creator: Sherman, J.; Pitcher, E. & Allison, P.
Partner: UNT Libraries Government Documents Department

ORIC stripping foil positioner for tandem beam injection

Description: The Oak Ridge Isochronous Cyclotron (ORIC) is used as an energy booster for heavy ions from a 25 MV tandem accelerator. This operation requires precise placement of a stripping foil in the cyclotron for capture of the injected ions into an acceleration orbit. The mechanical design and control of the foil positioning device are described.
Date: January 1, 1981
Creator: Ludemann, C.A.; Lord, R.S.; Hudson, E.D.; Irwin, F.; Beckers, R.M.; Haynes, D.L. et al.
Partner: UNT Libraries Government Documents Department