IPAC2012 - List of Authors (Han, B.)

Paper	Title	Page
MOPPC091	Parallel 3D Simulations to Support Commissioning of a Solenoid-based LEBT Test Stand	349
	B.T. Schwartz, D.T. Abell, D.L. Bruhwiler, Y. Choi, S. Mahalingam, P. Stoltz, J. von Stecher Tech-X, Boulder, Colorado, USA B. Han, M.P. Stockli ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844. A solenoid-based low-energy beam transport (LEBT) test stand is under development for the Spallation Neutron Source (SNS). To support commissioning of the test stand, the parallel Vorpal framework is being used for 3D electrostatic particle-in-cell (PIC) simulations of H⁻ beam dynamics in the LEBT, including impact ionization physics and MHz chopping of the partially-neutralized \Hm beam. Here we describe the process of creating a partially-neutralized beam and examine the effects of a single chopping event on the beam's emittance.

TUPPD048	Optical Emission Spectroscopy Studies of the Spallation Netron Source (SNS) H⁻ Ion Source	1512
	B. Han, S.N. Murray ORNL RAD, Oak Ridge, Tennessee, USA T.R. Pennisi, M. Santana, M.P. Stockli, R.F. Welton ORNL, Oak Ridge, Tennessee, USA
	A Cs enhanced, RF-driven H⁻ ion source feeds the SNS accelerator with a 65 keV H⁻ beam at 60 Hz with a pulse length of up to 1.0 ms. The ion source beam intensity and reliability are critical to the SNS operational power level and availability. The 1-MW level routine operation of the SNS requires ~38 mA beam in the linac. This requirement is normally met by the ion source in a persistent manner for a 4-5 weeks service-cycle of the ion source. But, in some occasions, the ion source either falls short of the beam current or fails to keep the beam current persistent. The key factor in achieving high current, persistent H⁻ beam is to have a proper coverage of Cs on the ion converter surface near the source outlet. To quantify the amount of Cs put into the system during cesiation(s) and to monitor the Cs migration during the source operation, an experimental study is under way with an optical spectrometer monitoring the emission lights from the ion source plasma. Another possible use of this emission spectroscopy study is to detect the indication of the ion source antenna deterioration before it develops into a total failure. The progress and some preliminary results are presented.

Paper

Title

Page

Parallel 3D Simulations to Support Commissioning of a Solenoid-based LEBT Test Stand

349

B.T. Schwartz, D.T. Abell, D.L. Bruhwiler, Y. Choi, S. Mahalingam, P. Stoltz, J. von Stecher
Tech-X, Boulder, Colorado, USA
B. Han, M.P. Stockli
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844.
A solenoid-based low-energy beam transport (LEBT) test stand is under development for the Spallation Neutron Source (SNS). To support commissioning of the test stand, the parallel Vorpal framework is being used for 3D electrostatic particle-in-cell (PIC) simulations of H⁻ beam dynamics in the LEBT, including impact ionization physics and MHz chopping of the partially-neutralized \Hm beam. Here we describe the process of creating a partially-neutralized beam and examine the effects of a single chopping event on the beam's emittance.

TUPPD048

Optical Emission Spectroscopy Studies of the Spallation Netron Source (SNS) H⁻ Ion Source

1512

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

A Cs enhanced, RF-driven H⁻ ion source feeds the SNS accelerator with a 65 keV H⁻ beam at 60 Hz with a pulse length of up to 1.0 ms. The ion source beam intensity and reliability are critical to the SNS operational power level and availability. The 1-MW level routine operation of the SNS requires ~38 mA beam in the linac. This requirement is normally met by the ion source in a persistent manner for a 4-5 weeks service-cycle of the ion source. But, in some occasions, the ion source either falls short of the beam current or fails to keep the beam current persistent. The key factor in achieving high current, persistent H⁻ beam is to have a proper coverage of Cs on the ion converter surface near the source outlet. To quantify the amount of Cs put into the system during cesiation(s) and to monitor the Cs migration during the source operation, an experimental study is under way with an optical spectrometer monitoring the emission lights from the ion source plasma. Another possible use of this emission spectroscopy study is to detect the indication of the ion source antenna deterioration before it develops into a total failure. The progress and some preliminary results are presented.