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Spherical Aberration Corrections for the Electrostatic Gridded Lens

Description: Two methods of spherical aberration corrections of an electrostatic gridded lens have been studied with ray tracing simulations. Both methods are based on modifying electrostatic field on the periphery of the lens. In a simplest case such modification is done by extending the part of the grid support on its radial periphery in axial direction. In alternative method the electric field on the radial periphery of the lens is modified by applying an optimum voltage on an electrically isolated correcting electrode. It was demonstrated, that for a given focal length the voltage on this lens can be optimized for minimum aberration The performance of lenses is presented as a lens contribution to the beam RMS normalized emittance.
Date: May 1, 2008
Creator: Pikin,A.
Partner: UNT Libraries Government Documents Department

SOME PHYSICAL AND ENGINEERING ASPECTS OF HIGH CURRENT EBIS.

Description: Some applications of an Electron Beam Ion Source (EBIS) require intensities of highly charged ions significantly greater than those which have been achieved in present EBIS sources. For example, the ion source for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) must be capable of generating 3x10{sup 9} ions of Au{sup 35+} or 2 x 10{sup 9} ions of U{sup 45+} per pulse [1]. In this case, if the fraction of ions of interest is 20% of the total ion space charge, the total extracted charge is {approx}{approx} 5 x 10{sup 11}. It is also desirable to extract these ions in a 10 ps pulse to allow single turn injection into the first synchrotron. Requirements for an EBIS which could meet the needs of the LHC at CERN are similar ({approx} 1.5 x 10{sup 9} ions of Pb{sup 54+} in 5.5 {micro}s). This charge yield is about an order of magnitude greater than that achieved in existing EBIS sources, and is what is meant here by ''high current''. This also implies, then, an EBIS with a high electron beam current. The scope of problems in a high current EBIS is broad, and includes generating a sufficient total charge of electrons in the volume of the ion trap, achieving a stable electron beam (without high frequency oscillations), preventing ions in the trap from acquiring too much energy (which can lead to a high rate of ion loss and increase in the emittance of the extracted ion beam), injection of metal ions into the ion trap, and achieving the appropriate vacuum in the ionization region. Development of the Electron Beam Test Stand (EBTS) at BNL addresses these problems, and is an attempt to develop the technologies relevant to a high current EBIS. The final goal of this development is ...
Date: May 10, 1999
Creator: Pikin, A.
Partner: UNT Libraries Government Documents Department

The effects of realistic pancake solenoids on particle transport

Description: Solenoids are widely used to transport or focus particle beams. Usually, they are assumed as being ideal solenoids with a high axial-symmetry magnetic field. Using the Vector Field Opera program, we modeled asymmetrical solenoids with realistic geometry defects, caused by finite conductor and current jumpers. Their multipole magnetic components were analyzed with the Fourier fit method; we present some possible optimized methods for them. We also discuss the effects of 'realistic' solenoids on low energy particle transport. The finding in this paper may be applicable to some lower energy particle transport system design.
Date: February 1, 2011
Creator: Gu, X.; Okamura, M.; Pikin, A.; Fischer, W. & Luo, Y.
Partner: UNT Libraries Government Documents Department

Optimizing the electron beam parameters for head-on beam-beam compensation in RHIC

Description: Head-on beam-beam compensation is adopted to compensate the large beam-beam tune spread from the protonproton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). Two e-lenses are being built and to be in stalled near IP10 in the end of 2011. In this article we perform numeric simulation to investigate the effect of the electron beam parameters on the proton dynamics. The electron beam parameters include its transverse profile, size, current, offset and random errors in them. In this article we studied the effect of the electron beam parameters on the proton dynamics. The electron beam parameters include its transverse shape, size, current, offset and their random errors. From the study, we require that the electron beam size can not be smaller than the proton beam's. And the random noise in the electron current should be better than 0.1%. The offset of electron beam w.r.t. the proton beam center is crucial to head-on beam-beam compensation. Its random errors should be below {+-}8{micro}m.
Date: March 28, 2011
Creator: Luo, Y.; Fischer, W.; Pikin, A. & Gu, X.
Partner: UNT Libraries Government Documents Department

Laser ion source for low charge heavy ion beams

Description: For heavy ion inertial fusion application, a combination of a laser ion source and direct plasma injection scheme into an RFQ is proposed. The combination might provide more than 100 mA of singly charged heavy ion beam from a single laser shot. A planned feasibility test with moderate current is also discussed.
Date: August 3, 2008
Creator: Okamura, M.; Pikin, A.; Zajic, V.; Kanesue, T. & Tamura, J.
Partner: UNT Libraries Government Documents Department

Some Physical and Engineering Aspects of High Current EBIS

Description: Some applications of an Electron Beam Ion Source (EBIS) require intensities of highly charged ions significantly greater than those which have been achieved in present EBIS sources. For example, the ion source for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) must be capable of generating 3 x 10{sup 9} ions of Au{sup 35+} or 2 x 10{sup 9} ions of U{sup 45+} per pulse. In this case, if the fraction of ions of interest is 20% of the total ion space charge, the total extracted charge is {approximately} 5 x 10{sup 11}. It is also desirable to extract these ions in a 10 {micro}s pulse to allow single turn injection into the first synchrotrons. Requirements for an EBIS which could meet the needs of the LHC at CERN are similar ({approximately} 1.5 x 10{sup 9} ions of Pb{sup 54+} in 5.5 {micro}s). This charge yield is about an order of magnitude greater than that achieved in existing EBIS sources, and is what is meant here by high current. This also implies, then, an EBIS with a high electron beam current.
Date: May 21, 1999
Creator: Pikin, A. & Prelec, K.
Partner: UNT Libraries Government Documents Department

ANALYSIS OF THE MAGNETIC FIELD MEASURED BY A ROTATING HALL PROBE IN A SOLENOID TO LOCATE ITS MAGNETIC AXIS.

Description: We have analyzed the motion of a Hall probe, which is rotated about an axis that is arbitrarily displaced and oriented with respect to the magnetic axis of a solenoid. We outline how the magnetic field measured by the rotating Hall probe can be calculated. We show how to compare theoretical results with actual measurements, to determine the displacement and orientation of the axis of rotation of the probe from the magnetic axis. If the center of rotation of the probe is known by surveying, the corresponding point on the magnetic axis of the solenoid can be located. This is applied to a solenoid that was built for BNL by Oxford Instruments.
Date: November 6, 2000
Creator: KPONOU,A.; PIKIN,A.; BEEBE,E. & ALESSI,J.
Partner: UNT Libraries Government Documents Department

Ionization of polarized 3He+ ions in EBIS trap with slanted electrostatic mirror.

Description: Methods of producing the nuclear polarized {sup 3}He{sup +} ions and their ionization to {sup 3}H{sup ++} in ion trap of the electron Beam Ion Source (EBIS) are discussed. Computer simulations show that injection and accumulation of {sup 3}He{sup +} ions in the EBIS trap with slanted electrostatic mirror can be very effective for injection times longer than the ion traversal time through the trap.
Date: September 10, 2007
Creator: Pikin, A.; Zelenski, A.; Kponou, A.; Alessi, J.; Beebe, E.; Prelee, K. et al.
Partner: UNT Libraries Government Documents Department

MODEL SIMULATIONS OF CONTINUOUS ION INTERJECTION INTO EBIS TRAP WITH SLANTED ELECTROSTATIC MIRROR.

Description: The efficiency of trapping ions in an EBIS is of primary importance for many applications requiring operations with externally produced ions: RIA breeders, ion sources, traps. At the present time, the most popular method of ion injection is pulsed injection, when short bunches of ions get trapped in a longitudinal trap while traversing the trap region. Continuous trapping is a challenge for EBIS devices because mechanisms which reduce the longitudinal ion energy per charge in a trap (cooling with residual gas, energy exchange with other ions, ionization) are not very effective, and accumulation of ions is slow. A possible approach to increase trapping efficiency is to slant the mirror at the end of the trap which is opposite to the injection end. A slanted mirror will convert longitudinal motion of ions into transverse motion, and, by reducing their longitudinal velocity, prevent these ions from escaping the trap on their way out. The trade off for the increased trapping efficiency this way is an increase in the initial transverse energy of the accumulated ions. The slanted mirror can be realized if the ends of two adjacent electrodes- drift tubes - which act as an electrostatic mirror, are machined to produce a slanted gap, rather than an upright one. Applying different voltages to these electrodes will produce a slanted mirror. The results are presented of 2D and 3D computer simulations of ion injection into a simplified model of EBIS with slanted mirror.
Date: August 26, 2007
Creator: PIKIN,A.; KPONOU, A.; ALESSI, J.G.; BEEBE, E.N.; PRELEC, K. & RAPARIA, D.
Partner: UNT Libraries Government Documents Department

HEAVY ION DRIVER WITH NON-SCALING FFAG.

Description: We explore the possibility of using two non-scaling FFAG accelerators for a high power heavy-ion driver as an alternative to a superconducting Linac. Ions of Uranium 238 are accelerated to a kinetic energy of 400 MeVIu and a total power of 400 kWatt. Different modes of acceleration have been studied: at 1 and 10 kHz repetition rate, and for Continuous Wave production. The following is a summary of the study. More details of the study can be found in reference 2.
Date: June 25, 2007
Creator: RUGGIERO,A.G.; ALESSI, J.; BEEBE, E.; PIKIN, A.; ROSER, T. & TRBOJEVIC
Partner: UNT Libraries Government Documents Department

EXPERIMENTAL STUDY OF ION INJECTION INTO AN EXTENDED TRAP OF THE BNL EBIS.

Description: Experiments on the BNL EBIS Test Stand (EBTS) with the ion trap extending beyond the edges of the superconducting solenoid had the main goal to study ion trap operation with a trap length exceeding that of the normal EBTS trap. Preliminary results indicate that the ion trap with length 107 cm is stable and controllable in the same fashion as our normal 70 cm trap with a multiampere electron beam. EBTS operation with ion trap 145 cm long and with electron current up to 3 A in earlier experiments also was stable and yielded more ions than from the basic ''short'' trap. These results increased our confidence in operation of the proposed RHIC in a stable mode and in the correctness of linear scaling of ion intensity with the length of the ion trap.
Date: September 2, 2001
Creator: Pikin, A.; Alessi, J.; Beebe, E.; Kponou, A. & Prelec, K.
Partner: UNT Libraries Government Documents Department

Simulation of 10 A electron beam formation and collection for a high current EBIS

Description: Development of an Electron Beam Ion Source (EBIS) for the Relativistic Heavy Ion Collider (RHIC) at BNL requires operating with a 10 A electron beam, which is approximately an order of magnitude higher current than in any existing EBIS device. A test stand is presently being designed and constructed where EBIS components will be twisted. It will be reported in a separate paper at this Conference. The design of the 10 A electron gun, drift tubes and electron collector requires extensive computer simulations. Calculations have been performed at Novosibirsk and BNL using two different programs, SAM and EGUN. Results of these simulations will be presented.
Date: November 1, 1997
Creator: Kponou, A.; Beebe, E.; Pikin, A.; Kuznetsov, G.; Batazova, M. & Tiunov, M.
Partner: UNT Libraries Government Documents Department

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

Description: 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.
Partner: UNT Libraries Government Documents Department

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

Description: 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.
Partner: UNT Libraries Government Documents Department

Ion optics of RHIC EBIS

Description: RHIC EBIS has been commissioned to operate as a versatile ion source on RHIC injection facility supplying ion species from He to Au for Booster. Except for light gaseous elements RHIC EBIS employs ion injection from several external primary ion sources. With electrostatic optics fast switching from one ion species to another can be done on a pulse to pulse mode. The design of an ion optical structure and the results of simulations for different ion species are presented. In the choice of optical elements special attention was paid to spherical aberrations for high-current space charge dominated ion beams. The combination of a gridded lens and a magnet lens in LEBT provides flexibility of optical control for a wide range of ion species to satisfy acceptance parameters of RFQ. The results of ion transmission measurements are presented.
Date: September 10, 2011
Creator: Pikin, A.; Alessi, J.; Beebe, E.; Kponou, A.; Okamura, M.; Raparia, D. et al.
Partner: UNT Libraries Government Documents Department

Designing a beam transport system for RHIC's electron lens

Description: 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.
Partner: UNT Libraries Government Documents Department

RHIC electron lens test bench diagnostics

Description: 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.
Partner: UNT Libraries Government Documents Department

HIGH PERFORMANCE EBIS FOR RHIC.

Description: An Electron Beam Ion Source (EBIS), capable of producing high charge states and high beam currents of any heavy ion species in short pulses, is ideally suited for injection into a synchrotron. An EBIS-based, high current, heavy ion preinjector is now being built at Brookhaven to provide increased capabilities for the Relativistic Heavy Ion Collider (RHIC), and the NASA Space Radiation Laboratory (NSRL). Benefits of the new preinjector include the ability to produce ions of any species, fast switching between species to serve the simultaneous needs of multiple programs, and lower operating and maintenance costs. A state-of-the-art EBIS, operating with an electron beam current of up to 10 A, and producing multi-milliamperes of high charge state heavy ions, has been developed at Brookhaven, and has been operating very successfully on a test bench for several years. The present performance of this high-current EBIS is presented, along with details of the design of the scaled-up EBIS for RHIC, and the status of its construction. Other aspects of the project, including design and construction of the heavy ion RFQ, Linac, and matching beamlines, are also mentioned.
Date: June 25, 2007
Creator: ALESSI,J.; BEEBE, E.; GOULD, O.; KPONOU, A.; LOCKEY, R.; PIKIN, A. et al.
Partner: UNT Libraries Government Documents Department

Head-on beam-beam compensation with electron lenses in the RHIC.

Description: The working point for the polarized proton run in the Relativistic Heavy Ion Collider is constrained between 2/3 and 7/10 in order to maintain good beam lifetime and polarization. To further increase the bunch intensity to improve the luminosity, a low energy Gaussian electron beam, or an electron lens is proposed to head-on collide with the proton beam to compensate the large tune shift and tune spread generated by the proton-proton beam-beam interactions at IP6 and IP8. In this article, we outline the scheme of head-on beam-beam compensation in the RHIC and give the layout of e-lens installation and the parameters of the proton and electron beams. The involved physics and engineering issues are shortly discussed.
Date: June 23, 2008
Creator: Luo,Y.; FischW; Abreu, N.; Beebe, E.; Montag, C.; Okamura, M. et al.
Partner: UNT Libraries Government Documents Department