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Wang, P.

Paper Title Page
MOPAS037 New Generation Digital Longitudinal Feedback System for Duke FEL and HIGS Facilities 518
  • Y. Kim, M. D. Busch, P. Wang, W. Wu, Y. K. Wu
    FEL/Duke University, Durham, North Carolina
  • J. Choi, I. S. Ko, I. S. Park
    PAL, Pohang, Kyungbuk
  • D. Teytelman
    Dimtel, Redwood City, California
  To increase intensity of the High Intensity Gamma-ray Source (HIGS) which is driven by the Duke storage ring FEL via Compton scattering, stored beam current should be increased. However, high-current multi-bunch operation in the Duke storage ring is limited by strong longitudinal coupled-bunch beam instabilities. To control those instabilities, we have been developing an active longitudinal feedback system which is based on the Integrated Gigasample Processor (iGP) through collaboration with Dimtel, Inc. and Pohang Accelerator Laboratory. In this paper, we report the present status of our longitudinal feedback system.  
TUPMS014 Commissioning of the Booster Injector Synchrotron for the HIGS Facility at Duke University 1209
  • S. F. Mikhailov, M. D. Busch, M. Emamian, S. M. Hartman, Y. Kim, J. Li, V. Popov, G. Swift, P. W. Wallace, P. Wang, Y. K. Wu
    FEL/Duke University, Durham, North Carolina
  • O. Anchugov, N. Gavrilov, G. Y. Kurkin, Yu. Matveev, D. Shvedov, N. Vinokurov
    BINP SB RAS, Novosibirsk
  • C. R. Howell
    TUNL, Durham, North Carolina
  Funding: This work is supported by the US DoE grant #DE-FG02-01ER41175

A booster synchrotron has been built and recently commissioned at Duke University Free Electron Laser Laboratory (DFELL) as part of the High Intensity Gamma-ray Source (HIGS) facility upgrade. HIGS is developed collaboratively by the DFELL and Triangular Universities Nuclear Laboratory (TUNL). The booster will provide top-off injection into the Duke FEL storage ring in the energy range of 0.27 - 1.2 GeV. When operating the Duke storage ring to produce high energy Compton gamma ray beams above 20 MeV, continuous electron beam loss occurs. The lost electrons will be replenished by the booster injector operating in the top-off mode. The compactness of the booster posed a challenge for its development and commissioning. The booster has been successfully commissioned in 2006. This paper reports experience of commissioning and initial operation of the booster.

FRPMS040 BPM signal conditioning for a wide range of single bunch current operation in Duke storage ring 4042
  • J. Li, P. Wang, Y. K. Wu
    FEL/Duke University, Durham, North Carolina
  Funding: Supported by US DoE grant #DE-FG02-01ER41175.

The beam position monitor system of the Duke storage ring has been in operation since 1998. Recently, by injecting at higher energy with a booster synchrotron, the single bunch current threshold is much more increased. This makes the BPM system do not work properly and rises the risk to damaged the BPM signal processing modules. To get reliable orbit data and protect the BPM modules, we carefully studied the BPM signal, and then found a way to overcome this problem. This paper will report the study results and the solution method.

FRPMS042 Electron Beam Diagnostics for Compact 1.2 GeV Booster Synchrotron 4051
  • V. Popov, M. D. Busch, S. M. Hartman, J. Li, S. F. Mikhailov, P. W. Wallace, P. Wang, Y. K. Wu
    FEL/Duke University, Durham, North Carolina
  • G. Y. Kurkin
    BINP SB RAS, Novosibirsk
  Funding: Supported by US DoE grant #DE-FG02-01ER41175.

First operational experience has been gained with the linac and booster diagnostic system during the commissioning of the booster synchrotron at Duke University. Beam charge measurements are provided by Faraday cups, Integrated Current Transformers (ICT) and Modular Parametric Current Transformer (MPCT). Beam position monitoring is based on BPM system delivered from Bergoz company. Betatron tune measurements use synchrotron radiation (SR) and are different for two modes of operation: stored beam and energy ramping. Transverse profile and temporal beam structure monitoring employ insertable screens, CCD cameras, striplines and dissector. The diagnostics provided good understanding of electron beam behavior and allowed to adjust important beam parameters within design specifications. An overview of the diagnostic instrumentation of the Duke linac and booster synchrotron is given along with measurement examples and discussion of operational experience.

FRPMS044 A Tune Measurement System for Low Current and Energy Ramping Operation of a Booster Synchrotron 4063
  • Y. K. Wu, J. Li, S. F. Mikhailov, V. Popov, P. Wang
    FEL/Duke University, Durham, North Carolina
  Funding: This work is supported by the US AFOSR MFEL grant #FA9550-04-01-0086 and by U. S. DOE grant DE-FG05-91ER40665.

The betatron tune measurement system is one of the most important diagnostics for any circular accelerator. During the commissioning of a booster synchrotron newly developed for top-off injection into the Duke storage ring, a versatile tune measurement system employing a photomultiplier tube (PMT) and a space filter has been developed to provide reliable measurements for low current operation at a few micro-amperes of beam-current. Using the turn-by-turn technique, this tune measurement system is being used as a live tune monitor during the booster energy ramping. This system has also be used to measure chromaticity and other important beam parameters. In this paper, we describe the tune measurement system in detail and report our most recent experimental results using this system.