| Paper | Title | Page |
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| MOPA007 | Polarized Proton Collisions at RHIC | 600 |
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Funding: The work was performed under the auspices of the U.S. Department of Energy and RIKEN Japan. The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limited conditions are reported. |
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| WPAT019 | Beam Tests of a New Digital Beam Control System for the CERN LEIR Accelerator | 1649 |
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| We are developing a digital beam control and cavity servo system for controlling the RF acceleration in CERN’s Low Energy Ion Ring (LEIR), a major component in the LHC lead ion injector chain. As the LEIR ring will only start during summer 2005, we have tested a simplified prototype of the system with low intensity beams on the CERN PS Booster (PSB). The hardware and software have been developed within the framework of a CERN-BNL collaboration. This fully digital beam control system is contained in VME mother boards which can accommodate several daughter boards. The fast signal processing is implemented in Field Programmable Gate Arrays (FPGAs), while the slower signal processing and communication with the software layer above is implemented in programmable Digital Signal Processors (DSPs). The objectives of the tests with beam in the PSB are to verify the multiple DSP and FPGA architecture, the sampling rates and data flows and the feedback loop dynamics. An additional goal is to integrate a number of highly complex intelligent VME modules with many sub-functions in the CERN controls environment to provide adequate signal acquisition, control and diagnostics to operate the system. | ||
| TPAT093 | Operations and Performance of RHIC as a Cu-Cu Collider | 4281 |
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Funding: Work performed under the auspices of the U.S. Department of Energy. The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons at 100 GeV. We will address here overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a ?* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements and machine performance limitations, such as vacuum pressure rise, intra-beam scattering, and beam beam interaction. |
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| FPAE029 | Setup and Performance of the RHIC Injector Accelerators for the 2005 Run with Copper Ions | 2068 |
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Funding: Work performed under the auspices of the U.S. Department of Energy. Copper ions for the 2005 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators will be reviewed. |