2011 Particle Accelerator Conference - List of Authors (Geng, X.)

Paper	Title	Page
MOP257	High Power RF Distribution and Control for Multi-Cavity Cryomodule Testing	591
	Y.W. Kang, M. Broyles, M.T. Crofford, X. Geng, S.-H. Kim, S.W. Lee, C.L. Phibbs, K.R. Shin, W.H. Strong ORNL, Oak Ridge, Tennessee, USA
	Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS has been successfully operating 81 superconducting six-cell cavities in 23 cryomodules in its linac to achieve the goals in beam power and energy. For near-term production of spare cryomodules and the upcoming power upgrade project that will need 36 additional cavities in 9 cryomodules, high RF power testing and qualification of the cavities is required in the RF test facility. Simultaneously powering all the cavities in a cryomodule is considered desirable for robust conditioning and studying of cavity field emission since certain cavities exhibit field emissions that could be mutually coupled. A four-way variable output power waveguide splitting system is being prepared for testing cryomodules with up to four cavities. The splitting system is fed by an 805 MHz, 5 MW peak power pulsed klystron. The power output at each arm can be adjusted in both amplitude and phase to wide ranges of values using two mechanical waveguide phase shifters that form a vector modulator. The system control is implemented in the EPICS environment similar to the main accelerator controls. The work performed on the design, integration, operation, and test of the system are presented.

MOP300	The Spallation Neutron Source Eight-Channel Pulsed Power Meter	684
	M.T. Crofford, X. Geng, T.W. Hardek ORNL, Oak Ridge, Tennessee, USA T.L. Davidson ORNL RAD, Oak Ridge, Tennessee, USA
	The Spallation Neutron Source (SNS) Low Level Radio Frequency (LLRF) Control System currently utilizes the High-Power Protection Module (HPM) to monitor RF power levels, arc faults, and associated signals for the protection of the RF systems and accelerating cavities. The HPM is limited to seven RF channels for monitoring signals which in some instances leaves some signals of interest unmonitored. In addition, the HPM does not support monitoring of RF frequencies below 100 MHz which makes it unusable for our Ring and Ion Source systems that operate at 1 and 2 MHz respectively. To alleviate this problem, we have developed a microprocessor based eight channel pulsed RF power meter that allows us to monitor additional channels between the frequency range of 1 MHz to 2.5 GHz. This meter has been field tested in several locations with good results and plans are in place for a wider deployment.

Paper

Title

Page

High Power RF Distribution and Control for Multi-Cavity Cryomodule Testing

591

Y.W. Kang, M. Broyles, M.T. Crofford, X. Geng, S.-H. Kim, S.W. Lee, C.L. Phibbs, K.R. Shin, W.H. Strong
ORNL, Oak Ridge, Tennessee, USA

Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
The SNS has been successfully operating 81 superconducting six-cell cavities in 23 cryomodules in its linac to achieve the goals in beam power and energy. For near-term production of spare cryomodules and the upcoming power upgrade project that will need 36 additional cavities in 9 cryomodules, high RF power testing and qualification of the cavities is required in the RF test facility. Simultaneously powering all the cavities in a cryomodule is considered desirable for robust conditioning and studying of cavity field emission since certain cavities exhibit field emissions that could be mutually coupled. A four-way variable output power waveguide splitting system is being prepared for testing cryomodules with up to four cavities. The splitting system is fed by an 805 MHz, 5 MW peak power pulsed klystron. The power output at each arm can be adjusted in both amplitude and phase to wide ranges of values using two mechanical waveguide phase shifters that form a vector modulator. The system control is implemented in the EPICS environment similar to the main accelerator controls. The work performed on the design, integration, operation, and test of the system are presented.

MOP300

The Spallation Neutron Source Eight-Channel Pulsed Power Meter

684

M.T. Crofford, X. Geng, T.W. Hardek
ORNL, Oak Ridge, Tennessee, USA
T.L. Davidson
ORNL RAD, Oak Ridge, Tennessee, USA

The Spallation Neutron Source (SNS) Low Level Radio Frequency (LLRF) Control System currently utilizes the High-Power Protection Module (HPM) to monitor RF power levels, arc faults, and associated signals for the protection of the RF systems and accelerating cavities. The HPM is limited to seven RF channels for monitoring signals which in some instances leaves some signals of interest unmonitored. In addition, the HPM does not support monitoring of RF frequencies below 100 MHz which makes it unusable for our Ring and Ion Source systems that operate at 1 and 2 MHz respectively. To alleviate this problem, we have developed a microprocessor based eight channel pulsed RF power meter that allows us to monitor additional channels between the frequency range of 1 MHz to 2.5 GHz. This meter has been field tested in several locations with good results and plans are in place for a wider deployment.