2011 Particle Accelerator Conference - List of Authors (Piller, M.F.)

Paper

Title

Page

Broadband Antenna Matching Network Design and Application for RF Plasma Ion Source

1990

K.R. Shin
ORNL RAD, Oak Ridge, Tennessee, USA
A.E. Fathy
University of Tennessee, Knoxville, Tennessee, USA
Y.W. Kang, M.F. Piller
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 RF ion source at Spallation Neutron Source has been upgraded to meet higher beam power requirement. One important subsystem for efficient operation of the ion source is the 2MHz RF impedance matching network. The real part of the antenna impedance is very small and is affected by plasma density for 2MHz operating frequency. Previous impedance matching network for the antenna has limited tuning capability to cover this potential variation of the antenna impedance since it employed a single tuning element and an impedance transformer. A new matching network with two tunable capacitors has been built and tested. This network can allow precision matching and increase the tunable range without using a transformer. A 5-element broadband matching network also has been designed, built and tested. The 5-element network allows wide band matching up to 50 kHz bandwidth from the resonance center of 2 MHz. The design procedure, simulation and test results are presented.

WEP275

Highly-Persistent SNS H⁻ Source Fueling 1-MW Beams with 7-9 kC Service Cycles

1993

M.P. Stockli, T.W. Hardek, Y.W. Kang, S.N. Murray, T.R. Pennisi, M.F. Piller, M. Santana, R.F. Welton
ORNL, Oak Ridge, Tennessee, USA
B. Han
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
Running routinely with ~40-mA, 1-MW beams, the SNS linac is fed from the ion source with ~1ms long, ~50-mA H⁻ beam pulses at 60 Hz. This requires the daily extraction of ~230 C of H⁻ ions, which exceeds the routine daily production of other H⁻ accelerator sources by almost an order of magnitude. The source service cycle has been extended from 2, to 3, to 4, and up to 5.6 weeks without age-related failures. The 7-9 kC of H⁻ ions delivered in single service cycles exceed the service cycle yields of other accelerator sources. The paper discusses the findings as well as the issues and their mitigations, which enabled the simultaneous increase of the beam current, the duty factor, the availability, and the service cycle.

THOAS3

Status of the Oak Ridge Spallation Neutron Source (SNS) RF Systems

2050

T.W. Hardek, M.T. Crofford, Y.W. Kang, M.F. Piller, A.V. Vassioutchenko
ORNL, Oak Ridge, Tennessee, USA
S.W. Lee, M.E. Middendorf
ORNL RAD, Oak Ridge, Tennessee, USA

The SNS has been delivering production neutrons for five years with first beam delivered to the neutron target at the end of April 2006. On September 18, 2009 SNS officially reached 1 megawatt of beam on target marking the achievement of a decades-old dream of providing a U.S. megawatt class pulsed spallation source. The SNS is now routinely delivering 1 megawatt of beam power to the neutron target at over 85 percent of the scheduled beam time. The present effort is aimed at increasing availability eventually to 95 percent and gradually increasing the intensity to the 1.4 megawatt design level. While the RF systems have performed well since initial installation some improvements have been implemented. This paper provides a review of the SNS RF Systems, an overview of the performance of the various components and a detailed review of RF related issues addressed over the past several years.

Slides THOAS3 [2.759 MB]

Paper	Title	Page
WEP274	Broadband Antenna Matching Network Design and Application for RF Plasma Ion Source	1990
	K.R. Shin ORNL RAD, Oak Ridge, Tennessee, USA A.E. Fathy University of Tennessee, Knoxville, Tennessee, USA Y.W. Kang, M.F. Piller 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 RF ion source at Spallation Neutron Source has been upgraded to meet higher beam power requirement. One important subsystem for efficient operation of the ion source is the 2MHz RF impedance matching network. The real part of the antenna impedance is very small and is affected by plasma density for 2MHz operating frequency. Previous impedance matching network for the antenna has limited tuning capability to cover this potential variation of the antenna impedance since it employed a single tuning element and an impedance transformer. A new matching network with two tunable capacitors has been built and tested. This network can allow precision matching and increase the tunable range without using a transformer. A 5-element broadband matching network also has been designed, built and tested. The 5-element network allows wide band matching up to 50 kHz bandwidth from the resonance center of 2 MHz. The design procedure, simulation and test results are presented.

WEP275	Highly-Persistent SNS H⁻ Source Fueling 1-MW Beams with 7-9 kC Service Cycles	1993
	M.P. Stockli, T.W. Hardek, Y.W. Kang, S.N. Murray, T.R. Pennisi, M.F. Piller, M. Santana, R.F. Welton ORNL, Oak Ridge, Tennessee, USA B. Han ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. Running routinely with ~40-mA, 1-MW beams, the SNS linac is fed from the ion source with ~1ms long, ~50-mA H⁻ beam pulses at 60 Hz. This requires the daily extraction of ~230 C of H⁻ ions, which exceeds the routine daily production of other H⁻ accelerator sources by almost an order of magnitude. The source service cycle has been extended from 2, to 3, to 4, and up to 5.6 weeks without age-related failures. The 7-9 kC of H⁻ ions delivered in single service cycles exceed the service cycle yields of other accelerator sources. The paper discusses the findings as well as the issues and their mitigations, which enabled the simultaneous increase of the beam current, the duty factor, the availability, and the service cycle.

THOAS3	Status of the Oak Ridge Spallation Neutron Source (SNS) RF Systems	2050
	T.W. Hardek, M.T. Crofford, Y.W. Kang, M.F. Piller, A.V. Vassioutchenko ORNL, Oak Ridge, Tennessee, USA S.W. Lee, M.E. Middendorf ORNL RAD, Oak Ridge, Tennessee, USA
	The SNS has been delivering production neutrons for five years with first beam delivered to the neutron target at the end of April 2006. On September 18, 2009 SNS officially reached 1 megawatt of beam on target marking the achievement of a decades-old dream of providing a U.S. megawatt class pulsed spallation source. The SNS is now routinely delivering 1 megawatt of beam power to the neutron target at over 85 percent of the scheduled beam time. The present effort is aimed at increasing availability eventually to 95 percent and gradually increasing the intensity to the 1.4 megawatt design level. While the RF systems have performed well since initial installation some improvements have been implemented. This paper provides a review of the SNS RF Systems, an overview of the performance of the various components and a detailed review of RF related issues addressed over the past several years.
	Slides THOAS3 [2.759 MB]