2011 Particle Accelerator Conference - List of Authors (Efthimion, P.)

Paper	Title	Page
WEP076	Masking the Paul Trap Simulator Experiment (PTSX) Ion Source to Modify the Transverse Distribution Function and Study Beam Stability and Collective Oscillations	1618
	E.P. Gilson, R.C. Davidson, P. Efthimion, R. M. Majeski, E. Startsev, H. Wang PPPL, Princeton, New Jersey, USA M. Dorf LLNL, Livermore, California, USA
	Funding: Research supported by the U.S. Department of Energy. A variety of masks were installed on the Paul Trap Simulator Experiment (PTSX) cesium ion source in order to perform experiments with modified transverse distribution functions. Masks were used to block injection of ions into the PTSX chamber, thereby creating injected transverse beam distributions that were either hollow, apertured and centered, apertured and off-center, or comprising five beamlets. Experiments were performed using either trapped plasmas or the single-pass, streaming, mode of PTSX. The transverse streaming current profiles clearly demonstrated centroid oscillations. Further analysis of these profiles also shows the presence of certain collective beam modes, such as azimuthally symmetric radial modes. When these plasmas are trapped for thousands of lattice periods, the plasma quickly relaxes to a state with an elevated effective transverse temperature and is subsequently stable. Both sinusoidal and periodic step function waveforms were used and the resulting difference in the measured transverse profiles will be discussed.

WEP276	Development of an Advanced Barium Ion Source for a Laser-Induced-Fluorescence (LIF) Diagnostic on the Paul Trap Simulator Experiment (PTSX)	1996
	H. Wang, R.C. Davidson, P. Efthimion, E.P. Gilson, R. M. Majeski PPPL, Princeton, New Jersey, USA
	The Paul Trap Simulator Experiment (PTSX) is a cylindrical Paul trap that simulates the nonlinear transverse dynamics of intense charged particle beam propagation through an equivalent kilometers-long magnetic alternating-gradient (AG) focusing system. Understanding the collective dynamics and instability excitations of intense charged particle beam is of great importance for a wide variety of accelerator applications. Since the optical spectrum of barium ions is better-suited to the Laser-Induced-Fluorescence (LIF) diagnostic than cesium ions, a barium ion source is being developed to replace the cesium ion source. A Laser-Induced-Fluorescence diagnostic will be able to provide in situ measurement of the radial density profile and, ultimately, the velocity distribution function of the intense charged particle beam. The new barium ion source is expected to increase the ion density as well as minimize the number of neutral barium atoms which enter the PTSX vacuum chamber. The design includes an ionizer, an extractor, and a neutral gas filter scheme. Initial test results of this new barium ion source will be presented.

Paper

Title

Page

Masking the Paul Trap Simulator Experiment (PTSX) Ion Source to Modify the Transverse Distribution Function and Study Beam Stability and Collective Oscillations

1618

E.P. Gilson, R.C. Davidson, P. Efthimion, R. M. Majeski, E. Startsev, H. Wang
PPPL, Princeton, New Jersey, USA
M. Dorf
LLNL, Livermore, California, USA

Funding: Research supported by the U.S. Department of Energy.
A variety of masks were installed on the Paul Trap Simulator Experiment (PTSX) cesium ion source in order to perform experiments with modified transverse distribution functions. Masks were used to block injection of ions into the PTSX chamber, thereby creating injected transverse beam distributions that were either hollow, apertured and centered, apertured and off-center, or comprising five beamlets. Experiments were performed using either trapped plasmas or the single-pass, streaming, mode of PTSX. The transverse streaming current profiles clearly demonstrated centroid oscillations. Further analysis of these profiles also shows the presence of certain collective beam modes, such as azimuthally symmetric radial modes. When these plasmas are trapped for thousands of lattice periods, the plasma quickly relaxes to a state with an elevated effective transverse temperature and is subsequently stable. Both sinusoidal and periodic step function waveforms were used and the resulting difference in the measured transverse profiles will be discussed.

WEP276

Development of an Advanced Barium Ion Source for a Laser-Induced-Fluorescence (LIF) Diagnostic on the Paul Trap Simulator Experiment (PTSX)

1996

H. Wang, R.C. Davidson, P. Efthimion, E.P. Gilson, R. M. Majeski
PPPL, Princeton, New Jersey, USA

The Paul Trap Simulator Experiment (PTSX) is a cylindrical Paul trap that simulates the nonlinear transverse dynamics of intense charged particle beam propagation through an equivalent kilometers-long magnetic alternating-gradient (AG) focusing system. Understanding the collective dynamics and instability excitations of intense charged particle beam is of great importance for a wide variety of accelerator applications. Since the optical spectrum of barium ions is better-suited to the Laser-Induced-Fluorescence (LIF) diagnostic than cesium ions, a barium ion source is being developed to replace the cesium ion source. A Laser-Induced-Fluorescence diagnostic will be able to provide in situ measurement of the radial density profile and, ultimately, the velocity distribution function of the intense charged particle beam. The new barium ion source is expected to increase the ion density as well as minimize the number of neutral barium atoms which enter the PTSX vacuum chamber. The design includes an ionizer, an extractor, and a neutral gas filter scheme. Initial test results of this new barium ion source will be presented.