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| MOAA003 | PEP-II and KEKB Operational Status | luminosity, injection, beam-beam-effects, collider | 276 | ||
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Funding: Work supported by DOE contract DE-AC02-76SF00515. |
The present two B-Factories, KEKB at Tsukuba in Japan and PEP-II at SLAC in California, operate at the Upsilon 4S and have reached parameter levels unprecedented for e+e- colliders. They have provided very large data samples for their respective particle detectors, BELLE and BaBar. Luminosities are approaching 1 x 1034/cm2/s and beyond. Beam currents have reached over 2.5 A with 1600 positron bunches spaced by 4 nsec. Continuous injection with the detectors taking data has added significantly to data collection rates. Bunch-by-bunch feedback systems damp strong longitudinal and transverse coupled bunch instabilities. The beam-beam interaction has allowed high tune shift levels even in the presence of parasitic crossing and crossing angle effects. Both B-Factory colliders have significant near term luminosity improvement programs. |
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| MPPE028 | Non Linear Error Analysis from Orbit Measurements in SPS and RHIC | sextupole, simulation, scattering, resonance | 2012 | ||
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Funding: U.S. Department of Energy and Colciencias. |
Recently, an "action and phase" analysis of SPS orbits measurements proved to be sensitive to sextupole components intentionally activated at specific locations in the ring. In this paper we attempt to determine the strenght of such sextupoles from the measured orbits and compare them with the set values. Action and phase analysis of orbit trayectories generated by RHIC models with non linearities will also be presented and compare with RHIC experiments. |
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| MPPE030 | Comparison of Off-Line IR Bump and Action-Angle Kick Minimization | sextupole, octupole, simulation, resonance | 2116 | ||
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Funding: Work supported by U.S. DOE under contract No. DE-AC02-98CH10886. |
The interaction region bump (IR bump) nonlinear correction method has been used for the sextupole and octupole field error on-line corrections in the Relativistic Heavy Ion Collider (RHIC). Some differences were found for the sextupole and octupole corrector strengths between the on-line IR bump correction and the predictions from the action-angle kick minimization. In this report we compare the corrector strengths from these two methods based on the RHIC Blue ring lattice with the IR nonlinear modeling. The comparison confirms the differences between resulting corrector strengths. And the reason for the differences is found and discussed. It is followed by a further discussion of the operational IR bump applications to the octupole, and skew sextupole and skew quadrupole field error corrections. |
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| MPPE080 | Transversal Deflection of Electrons Moving in Parallel with Linearly Polarized Laser Beam and its Application | electron, laser, photon, polarization | 4054 | ||
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The motion of electrons in linearly polarized laser beams in a finite length interaction region and after in a field free drift length is investigated. It is shown that in the interaction region the trajectory of the electrons is almost straight lines with very small oscillation weakly depending on the laser intensity. In the drift region the electrons acquire significant transversal deflection that allows to carry out the measurement of the length and longitudinal particle distribution of femtosecond bunches. The dependence of this deflection upon the electron energy, interaction region length, etc is studied. The principles of the construction of femtosecond oscilloscopes are discussed.
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| MPPT002 | Design and Experiment of the BEPCII IR Conventional Dual Aperture Quadrupole | quadrupole, multipole, septum, magnet-design | |||
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The quadrupole magnet Q1a is one of the final horizontal focus quadrupoles for the Beijing Electron-Positron Collider Interaction Region (BEPCII IR). The BEPCII IR lattice design specification calls for a very high field quality for the quadrupole magnet. The Q1a is a conventional dual apertures quadrupole magnet. The required integral quadrupole strengths in two apertures are the same. This magnet is a septum quadrupole with high current density and solid core. 2D pole contour optimization and pole end chamfers are used to minimize harmonic error. The design methods, experiment results and magnet performances are described in this paper.
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| MPPT009 | HTS Power Leads for the BTeV Interaction Region | quadrupole, magnet-design, power-supply, accumulation | 1147 | ||
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Funding: DOE |
A new Interaction Region for the BTEV experiment is planned to be built soon at Fermilab. This IR will require new superconducting quadrupole magnets and many additional power circuits for their operation. The new "low beta" quadupole magnet design is based upon the Fermilab LHC quadrupole design, and will operate at 9.56 kA in 4.5 K liquid helium. The use of conventional power leads for these circuits would require substantially more helium for cooling than is available from the cryogenic plant, which is already operating close to its limit. To decrease the heat load and helium cooling demands, the use of HTS power leads is necessary. Fermilab is in the process of procuring HTS leads for this new interaction region. Several 6 kA HTS leads produced by American Superconductor Corporation have been tested at over-current conditions. Based on the test results, design requirements are being developed for procuring the HTS current leads. This paper summarizes the test results and describes the design requirements for the 9.65 kA HTS power leads. |
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| MPPT037 | Design Study of Superconducting Magnets for the Super-KEKB Interaction Region | quadrupole, superconducting-magnet, multipole, luminosity | 2470 | ||
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The KEKB accelerator has achieved the highest luminosity of 1.39E1034cm-2s-1 at June-03-2004. For getting the higher luminosity over 1E1035cm-2s-1, the KEKB accelerator group continues to study the upgraded machine of the KEKB, that is the Super-KEKB. The designed machine parameters for this Super-KEKB are the vertical beta of 3 mm at the interaction point (IP), the LER and HER currents of 9.4 A and 4.1 A, and the half crossing angle of 15 mrad for the target luminosity of 1-5E1035cm-2s-1. For achieving these beam parameters, the superconducting magnets (final focus quadrupoles and compensation solenoids) are newly required to design. The magnet-cryostats have very tight spatial constraints against the Belle particle detector and the beam pipe so that the beam and the synchrotron light do not have any interference with the beam pipe. In this design, the final focus quadrupoles generate the field gradient of 42.3 T/m and their effective magnetic lengths are 0.30m and 0.36m in each side with respect to the IP, respectively. The compensation solenoids are overlaid with the quadrupoles. We will report the design of these magnets in detail and show the difficulties for the Super-KEKB-IR.
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| TOAA002 | U.S. Accelerator Contribution to the LHC | quadrupole, alignment, dipole, luminosity | 184 | ||
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In 1998, the United States entered into an agreement with CERN to help build the Large Hadron Collider (LHC), with contributions to the accelerator and to the large HEP detectors. To accomplish this, the US LHC Accelerator Project was formed, encompassing expertise from Brookhaven National Laboratory, Fermi National Accelerator Laboratory and the Lawrence Berkeley National Laboratory. Contributions from the US LHC Accelerator project included superconducting high gradient quadrupoles and beam separation dipoles for the four interaction regions and the RF section; feedboxes for cryogenic, power and instrumentation distribution; neutral and hadron beam absorbers in the high luminosity regions; design of the inner triplet cryogenic system; beam tracking studies utilizing the design IR magnet field quality and magnet alignment; particle heat deposition studies in the IR’s; and short sample characterization of superconducting cables used in the arc dipoles and quadrupoles. This report is a summary of these contributions including the progress towards project completion, as well as a discussion of future plans for US participation in the LHC accelerator.
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| TPAE037 | Simulation of the Laser Acceleration Experiment at the Femilab/NICADD Photoinjector Laboratory | laser, acceleration, electron, vacuum | 2503 | ||
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The possibility of using a laser to accelerate electrons in a waveguide structure with dimension much larger than the laser wavelength was first proposed by Pantell [NIM A 393 pg 1-5 (1997)] and investigated analytically by M. Xie [reports LBNL-40558 (1997) and LBNL-42055 (1998) available from LBNL Berkeley]. In the present paper we present the status of our experimental plan to demonstrate the laser interaction on an electron beam with initial momentum of 40-50 MeV/c. A laser (λ=1.06 micron) operating on the TM*01 mode has been developed. The large wavenumber (k~6x106 m-1) together with the initial low electron momentum poses a serious problem for efficient acceleration. In the present paper, we present start-to-end simulations of the laser acceleration experiment as foreseen to be installed in the upgraded Femilab/NICADD photoinjector laboratory.
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| TPPP029 | A Preliminary Interaction Region Design for a Super B-Factory | background, luminosity, radiation, synchrotron | 2077 | ||
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Funding: work supportted by the Department of Energy under contract number DE-AC03-76SF00515. |
The success of the two B-Factories (PEP-II and KEKB) has encouraged us to look at design parameters for a B-Factory with a 30-50 times increase in the luminosity of the present machines (L~1e36). In order to achieve this high luminosity, the beta y* values are reduced to 3-2 mm, the bunch spacing is minimized (0.6-0.3 m) and the bunch currents are increased. Total beam currents range from 5-25 A. The interaction region (IR) of these "SuperB" designs presents special challenges. Synchrotron radiation fans from local bending in shared magnets and from upstream sources pose difficulties due to the high power levels in these fans. High-order-mode(HOM)heating, effects that have been seen in the present B-factories, will become much more pronounced with the very short bunches and high beam currents. Masking the detector beam pipe from synchrotron radiation must take into account effects of HOM power generation. Backgrounds that are a function of the luminosity will become very important. We present an initial design of an IR with a crossing angle of ± 14 mrad and include a discussion of the constraints, requirements and concerns that go into designing an IR for these very high luminosity e+e- machines. |
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| TPPP034 | Parameters of a Super-B-Factory Design | luminosity, factory, collider, linac | 2333 | ||
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Funding: Work supported by DOE contract DE-AC02-76SF00515. |
Submitted for the High Luminosity Study Group: Parameters are being studied for a high luminosity e+e- collider operating at the Upsilon 4S that would deliver a luminosity in the range of 7 to 10 x 1035/cm2/s. Particle physics studies dictate that a much higher luminosity collider is needed to answer new key physics questions. A Super-B-Factory with 20 to 100 times the performance of the present PEP-II accelerator would incorporate a higher frequency RF system, lower impedance vacuum chambers, higher power synchrotron radiation absorbers, and stronger bunch-by-bunch feedback systems. Parameter optimizations are discussed. |
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| TPPP042 | Synchrotron Radiation in eRHIC Interaction Region | radiation, photon, synchrotron, synchrotron-radiation | 2729 | ||
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Funding: Work performed under the auspices of the US DOE. |
The eRHIC currently under study at BNL consists of an electron storage ring added to the existing RHIC complex. The interaction region of this facility has to provide the required low-beta focusing while accommodating the synchrotron radiation generated by beam separation close to the interaction point. In the current design, the synchrotron radiation caused by 10GeV electrons bent by low-beta triplet magnets will be guided through the interaction region and dumped 5m downstream. However, it is unavoidable to stop a fraction of the photons at the septum where the electron and ion vacuum system are separated. In order to protect the septum and minimize the backward scattering of the synchrotron radiation, an absorber and collimation system will be employed. In this paper, we first present the overview of the current design of the eRHIC interaction region with special emphasis on the synchrotron radiation. Then the initial design of the absorber and collimation system, including their geometrical and physical properties, will be described. Finally, our initial investigation of synchrotron radiation in the eRHIC interaction region, especially a simulation of the backward scattering from the absorber, will be presented. |
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| TPPP045 | Interaction Region Design for the Electron-Ion Collider eRHIC | electron, radiation, synchrotron, synchrotron-radiation | 2893 | ||
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Funding: Work performed under the auspices of the U.S. Department of Energy. |
To facilitate the study of collisions between 10 GeV polarized electrons and 100 GeV/u heavy ions or 250 GeV polarized protons at high luminosities, adding a 10 GeV electron storage ring to the existing RHIC complex has been proposed. The interaction region of this electron-ion collider eRHIC has to provide the required low-beta focusing, while simultaneously accomodating the synchrotron radiation fan generated by beam separation close to the interaction point, which is particularly challenging. The latest design status of the eRHIC interaction region is presented. |
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| TPPP049 | eRHIC Detector Design Studies - Implications and Constraints on the ep(A) Interaction-Region Design | electron, proton, scattering, luminosity | 3043 | ||
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An electron-proton/ion collider facility (eRHIC) is under consideration at Brookhaven National Laboratory. This high energy, high intensity polarized electron/positron beam facility to collide with the existing RHIC heavy ion and polarized proton beam would significantly enhance the exploration of fundamental aspects of Quantum Chromodynamics (QCD), the underlying quantum field theory of strong interactions. The design of a new optimized detector is closely coupled to the design of the interaction region and thus to the machine development work in general. A GEANT-based detector simulation framework has been developed to study various processes at eRHIC taking into consideration the impact of machine elements inside the detector volume and the synchrotron radiation fan generated by the electron/positron beam. The GEANT-based detector simulation framework called ELECTRA will be presented followed by a discussion of constraints and implications on the interaction region design.
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| WOAD005 | BEPCII Interaction Region Design and Construction Status | quadrupole, vacuum, superconducting-magnet, septum | 478 | ||
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BEPC (Beijing Electron Positron Collider) is now upgrading to a double-ring collider with a new and compact interaction region. The multi-purpose superconducting magnets and conventional dual aperture quadrupole magnets are used as final focusing quadrupole in the interaction region .The two beams collide at the interaction point with a cross angle of ±11 mrad and further beams separation is enhanced with the help of a septum bending magnet which locates just beyond the vertically focusing quadrupole and acts on the outgoing beam lines only. This paper will describe the IR design and its construction status.
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| RPAT047 | Preliminary Design of a Femtosecond Oscilloscope | electron, laser, photon, electromagnetic-fields | 2944 | ||
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The calculations on motion of electrons in a finite length electromagnetic field of linearly and circularly polarized laser beams have shown that one can use the transversal deflection of electrons on a screen at a certain distance after the interaction region for the measurement of the length and longitudinal particle distribution of femtosecond bunches. In this work the construction and preliminary parameters of various parts of a device that may be called femtosecond oscilloscope are considered. The influence of various factors, such as the energy spread and size of the electron bunches, are taken into account. For CO2 laser intensity 1016 W/cm2 and field free drift length 1m the deflection is 5.3 and 0.06 cm, while the few centimeters long interaction length between 2 mirrors requires assembling accuracy 6 mm and 1.3 micron for 20 MeV to 50 keV, respectively.
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| RPPT067 | A High-Power Target Experiment | target, proton, factory, synchrotron | 3745 | ||
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Funding: U.S. Department of Energy. |
We describe an experiment designed as a proof-of-principle test for a target system capable of converting a 4 MW proton beam into a high-intensity muon beam suitable for incorporation into either a neutrino factory complex or a muon collider. The target system is based on exposing a free mercury jet to an intense proton beam in the presence of a high strength solenoidal field. |
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| FPAT060 | An FPGA-Based Quench Detection and Protection System for Superconducting Accelerator Magnets | superconducting-magnet, power-supply, extraction, quadrupole | 3502 | ||
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A new quench detection and protection system for superconducting accelerator magnets was developed at the Fermilab's Magnet Test Facility (MTF). This system is based on a Field-Programmable Gate Array (FPGA) module, and it is made of mostly commerically available, integrated hardware and software components. It provides most of the functionality of our existing VME-based quench detection and protection system, but in addition the new system is easily scalable to protect multiple magnets powered independently and has a more powerful user interface and analysis tools. First applications of the new system will be for testing corrector coil packages. In this paper we describe the new system and present results of testing LHC Interaction Region Quadrupole (IRQ) correctors.
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