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in creator/contributor: "Hock, J."

Comparing energy technology alternatives from an environmental perspective

A number of individuals and organizations advocate the use of comparative, formal analysis to determine which are the safest methods for producing and using energy. Some have suggested that the findings of such analyses should be the basis upon which final decisions are made about whether to actually deploy energy technologies. Some of those who support formal comparative analysis are in a position to shape the policy debate on energy and environment. An opposing viewpoint is presented, arguing that for technical reasons, analysis can provide no definitive or rationally credible answers to the question of overall safety. Analysis has not and cannot determine the sum total of damage to human welfare and ecological communities from energy technologies. Analysis has produced estimates of particular types of damage; however, it is impossible to make such estimates comparable and commensurate across different classes of technologies and environmental effects. As a result of the deficiencies, comparative analysis connot form the basis of a credible, viable energy policy. Yet, without formal comparative analysis, how can health, safety, and the natural environment be protected. This paper proposes a method for improving the Nation's approach to this problem. The proposal essentially is that health and the environment should be considered as constraints on the deployment of energy technologies, constraints that are embodied in Government regulations. Whichever technologies can function within these constraints should then compete among themselves. This competition should be based on market factors like cost and efficiency and on political factors like national security and the questions of equity.

Date: February 1, 1981

Creator: House, P W; Coleman, J A; Shull, R D; Matheny, R W & Hock, J C

Item Type: Report

Partner: UNT Libraries Government Documents Department

Effect of the electron lenses on the RHIC proton beam closed orbit

We are designing two electron lenses (E-lens) to compensate for the large beam-beam tune spread from proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). They will be installed at RHIC IR10. The transverse fields of the E-lenses bending solenoids and the fringe field of the main solenoids will shift the proton beam. We calculate the transverse kicks that the proton beam receives in the electron lens via Opera. Then, after incorporating the simplified E-lens lattice in the RHIC lattice, we obtain the closed orbit effect with the Simtrack Code.

Date: February 1, 2011

Creator: Gu, X.; Luo, Y.; Pikin, A.; Okamura, M.; Fischer, W.; Montag, C. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

The effects of the RHIC E-lenses magnetic structure layout on the proton beam trajectory

We are designing two electron lenses (E-lens) to compensate for the large beam-beam tune spread from proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). They will be installed in RHIC IR10. First, the layout of these two E-lenses is introduced. Then the effects of e-lenses on proton beam are discussed. For example, the transverse fields of the e-lens bending solenoids and the fringe field of the main solenoids will shift the proton beam. For the effects of the e-lens on proton beam trajectory, we calculate the transverse kicks that the proton beam receives in the electron lens via Opera at first. Then, after incorporating the simplified E-lens lattice in the RHIC lattice, we obtain the closed orbit effect with the Simtrack Code.

Date: March 28, 2011

Creator: Gu, X.; Pikin, A.; Luo, Y.; Okamura, M.; Fischer, W.; Gupta, R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

Designing a beam transport system for RHIC's electron lens

We designed two electron lenses to apply head-on beam-beam compensation for RHIC; they will be installed near IP10. The electron-beam transport system is an important subsystem of the entire electron-lens system. Electrons are transported from the electron gun to the main solenoid and further to the collector. The system must allow for changes of the electron beam size inside the superconducting magnet, and for changes of the electron position by 5 mm in the horizontal- and vertical-planes.

Date: March 28, 2011

Creator: Gu, X.; Pikin, A.; Okamura, M.; Fischer, W.; Luo, Y.; Gupta, R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

RHIC electron lens test bench diagnostics

An Electron Lens (E-Lens) system will be installed in RHIC to increase luminosity by counteracting the head-on beam-beam interaction. The proton beam collisions at the RHIC experimental locations will introduce a tune spread due to a difference of tune shifts between small and large amplitude particles. A low energy electron beam will be used to improve luminosity and lifetime of the colliding beams by reducing the betatron tune shift and spread. In preparation for the Electron Lens installation next year, a test bench facility will be used to gain experience with many sub-systems. This paper will discuss the diagnostics related to measuring the electron beam parameters.

Date: May 16, 2011

Creator: Gassner, D.; Beebe, E.; Fischer, W.; Gu, X.; Hamdi, K.; Hock, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons

The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide electron beams with the proton bunch trajectories over the {approx}2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.

Date: April 15, 2012

Creator: T., Thieberger; Beebe, E.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

A split-electrode for clearing scattered electrons in the RHIC e-lens

We are designing two electron lenses that will be installed at RHIC IR10 to compensate for the head-on beam-beam effect. To clear accumulated scattered electrons from 100 GeV proton-electron head-on collisions in the e-lens, a clearing split electrode may be constructed. The feasibility of this proposed electrode was demonstrated via the CST Particle Studio and Opera program simulations. By splitting one of the drift tubes in the e-lens and applying {approx} 380 V across the two parts, the scattered electrons can be cleared out within several hundred micro-seconds. At the same time we can restrict the unwanted shift of the primary electron-beam that already passed the 2-m interaction region in e-lens, to less than 15um.

Date: May 20, 2012

Creator: X., Gu; Pikin, A.; Thieberger, P.; Fischer, W.; Hock, J.; Hamdi, K. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

RHIC electron lens beam transport system design considerations

To apply head-on beam-beam compensation for RHIC, two electron lenses are designed and will be installed at IP10. Electron beam transport system is one of important subsystem, which is used to transport electron beam from electron gun side to collector side. This system should be able to change beam size inside superconducting magnet and control beam position with 5 mm in horizontal and vertical plane. Some other design considerations for this beam transport system are also reported in this paper. The head-on beam-beam effect is one of important nonlinear source in storage ring and linear colliders, which have limited the luminosity improvement of many colliders, such as SppS, Tevatron and RHIC. In order to enhance the performance of colliders, beam-beam effects can be compensated with direct space charge compensation, indirect space charge compensation or betatron phase cancellation scheme. Like other colliders, indirect space charge compensation scheme (Electron Lens) was also proposed for Relativistic Heavy Ion Collider (RHIC) beam-beam compensation at Brookhaven National Laboratory. The two similar electron lenses are located in IR10 between the DX magnets. One RHIC electron lens consists of one DC electron gun, one superconducting magnet, one electron collector and beam transport system.

Date: October 1, 2010

Creator: Gu, X.; Pikin, A.; Okamura, M.; Fischer, W.; Luo, Y.; Gupta, R. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

Structure and design of the electron lens for RHIC

Two electron lenses for a head-on beam-beam compensation are being planned for RHIC; one for each circulating proton beam. The transverse profile of the electron beam will be Gaussian up to a maximum radius of r{sub e} = 3{sigma}. Simulations and design of the electron gun with Gaussian radial emission current density profile and of the electron collector are presented. Ions of the residual gas generated in the interaction region by electron and proton beams will be removed by an axial gradient of the electric field towards the electron collector. A method for the optical observation of the transverse profile of the electron beam is described.

Date: March 28, 2011

Creator: Pikin, A.; Fischer, W.; Alessi, J.; Anerella, M.; Beebe, E. Gassner, D.; Gu, X. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

Proposed electron halo detector system as one of the beam overlap diagnostic tools for the new RHIC electron lens

An electron lens for head-on beam-beam compensation planned for RHIC requires precise overlap of the electron and proton beams which both can have down to 0.3 mm rms transverse radial widths along the 2m long interaction region. Here we describe a new diagnostic tool that is being considered to aid in the tuning and verification of this overlap. Some of ultra relativistic protons (100 or 250 GeV) colliding with low energy electrons (2 to 10 keV) will transfer sufficient transverse momentum to cause the electrons to spiral around the magnetic guiding field in a way that will make them detectable outside of the main solenoid. Time-of-flight of the halo electron signals will provide position-sensitive information along the overlap region. Scattering cross sections are calculated and counting rate estimates are presented as function of electron energy and detector position.

Date: March 28, 2011

Creator: Thieberger, P.; Alessi, J.; Beebe, E.; Chasman, C.; Fischer, W.; Gassner, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

Status of RHIC head-on beam-beam compensation project

Two electron lenses are under construction for RHIC to partially compensate the head-on beam-beam effect in order to increase both the peak and average luminosities. The final design of the overall system is reported as well as the status of the component design, acquisition, and manufacturing. An overview of the RHIC head-on beam-beam compensation project is given in [1], and more details in [2]. With 2 head-on beam-beam interactions in IP6 and IP8, a third interaction with a low-energy electron beam is added near IP10 to partially compensate the the head-on beam-beam effect. Two electron lenses are under construction, one for each ring. Both will be located in a region common to both beams, but each lens will act only on one beam. With head-on beam-beam compensation up to a factor of two improvement in luminosity is expected together with a polarized source upgrade. The current RHIC polarized proton performance is documented in Ref. [4]. An electron lens (Fig. 1) consists of an DC electron gun, warm solenoids to focus the electron beam during transport, a superconducting main solenoid in which the interaction with the proton beam occurs, steering magnets, a collector, and instrumentation. The main developments in the last year are given below. The experimental program for polarized program at 100 GeV was expected to be finished by the time the electron lenses are commissioned. However, decadal plans by the RHIC experiments STAR and PHENIX show a continuing interest at both 100 GeV and 250 GeV, and a larger proton beam size has been accommodated in the design (Tab. 1). Over the last year beam and lattice parameters were optimized, and RHIC proton lattices are under development for optimized electron lens performance. The effect of the electron lens magnetic structure on the proton beam was evaluated, and found to ...

Date: March 28, 2011

Creator: Fischer, W.; Anerella, M.; Beebe, E.; Bruno, D.; Gassner, D.M.; Gu, X. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department