Engineering topics

DeBarger, S

Publications and source records attributed to DeBarger, S.

4 records

DOE OSTI2011

Parameters for the PEP-II B-Factory at SLAC in 2008

The PEP-II B-Factory at SLAC (3.1 GeV e{sup +} x 9.0 GeV e{sup -}) operated from 1999 to 2008, delivering luminosity to the BaBar experiment. The design luminosity was reached after one and a half years of operation. In the end PEP-II surpassed, by four times, its design luminosity reaching 1.21 x 10{sup 34} cm{sup -2}s{sup -1}. It also set world stored beam current records of 2.1 A e{sup -} and 3.2 A e{sup +}. Continuous injection was implemented with BaBar successfully taking data. The total delivered luminosity to the BaBar detector was 557.4 fb{sup -1} spanning five upsilon resonances. PEP-II was constructed by SLAC, LBNL, and LLNL with help from BINP, IHEP, the BaBar collaboration, and the US DOE OHEP.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

The Interaction Region of PEP-II

The PEP-II e{sup +}e{sup -} collider turned off last year after a very successful 9 years of running. The accelerator achieved a peak luminosity of 12 x 10{sup 33} cm{sup -2} s{sup -1}, 4 times over the design of 3 x 10{sup 33} cm{sup -2} s{sup -1}. The peak beam currents were quite high; over 3 A for the positron beam and over 2 A for the electron beam. The beams were stored in separate storage rings. The PEP-II design called for a head-on collision at the interaction point (IP). This was possible because of the asymmetric beam energies (9 on 3.1 GeV) and was achieved using permanent magnet (PM) dipoles. I describe the actual interaction region (IR) layout including some of the design constraints that led to the final design and discuss operation issues related to the IR design.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

High-Current Effects in the PEP-II Storage Ring

The PEP-II B-Factory operated at peak and integrated luminosity several times the original design values. Its storage rings operated at world-record beam currents with bunch lengths of about 10 mm. Correspondingly significant heat load was imposed on the vacuum system, both due to synchrotron radiation and by energy loss into higher-order modes. The latter in turn would lead to local heating or discharges wherever such energy got absorbed. Over the course of PEP-II running we experienced numerous such effects, which lead to upgrade programs of significant scope. In the following we will describe the most significant of such effects and their mitigation: (1) Upgrades and repairs of RF seals and shields in both rings; (2) Redesign of overheating stripline kicker electrodes to withstand higher powers; and (3) Redesign and replacement of BPM buttons following failure.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

Ideas for a Future PEP-X Light Source

SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing synchrotron source -- PEP-X -- a new storage ring that would occupy the existing PEP-II tunnel and support two experimental halls, each containing 16 x-ray beam lines. Operating at 4.5 GeV and 1.5 A with a horizontal emittance of 0.14 nm-rad, reached using 90 m of damping wigglers, PEP-X would have an order of magnitude higher average brightness and flux in the 1-{angstrom} x-ray range than any existing or planned future storage ring sources. Higher brightness in the soft x-ray regime might be reached with partial lasing in long undulators, and high peak brightness could be reached with seeded FEL emission. The status of preliminary studies of PEP-X is presented.

43 PARTICLE ACCELERATORS↗