CEBAF Photo Gun RF System

Conference · Tue Jan 01 04:00:00 EST 2019

DOI:https://doi.org/10.18429/JACoW-LINAC2018-MOPO115· OSTI ID:1542088

Plawski, Tomasz ^[1]; Bachimanchi, Ramakrishna ^[1]; Diaz, Manuel ^[1]; Higgins, C. Scott ^[1]; Hovater, J. Curt ^[1]; Mounts, Clyde I. ^[1]; Seidman, David J. ^[1]

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1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

During the CEBAF 12 GeV Upgrade at Jefferson Lab, a fourth experimental hall, ?D?, was added to the existing three halls. To produce four beams and deliver them to all halls concurrently requires new frequencies and a new timing pattern of the electron bunches. Since a photo-gun is used to produce electron bunches, the gun?s drive laser pulses need to be synchronized with the required bunch rate frequencies of 499 MHz or 249.5 MHz. To meet these new operational requirements, the new LLRF system has been proposed. Very specific requirements (dual frequency operation) on one side and the simple RF drive mode operation on the other imply the use of a commercial off-the-shelf digital platform rather than a system typical for RF cavity field control. We have chosen the Texas Instruments FPGA board along with a high-speed 8-Channel, 14-Bit board, and a 4-Channel, 16-Bit board. The DAC board includes the clock generator for clocking ADCs, DACs and the FPGA. The only custom design section of the system is the RF Front End board. The complete Gun Laser LLRF system has been designed, built, and recently commissioned in the CEBAF Injector. This paper will detail the design and report on commissioning activities.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
• DOE Contract Number: AC05-06OR23177; SC0005264
• OSTI ID: 1542088
• Report Number(s): JLAB-ACE-18-2840; DOE/OR/23177-4565; MOPO115
• Country of Publication: United States
• Language: English