IPAC2012 - List of Authors (Koeth, T.W.)

Paper	Title	Page
WEPPR013	Design of an Electrostatic Extraction Section for the University of Maryland Electron Ring	2964
	K.J. Ruisard Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA B.L. Beaudoin, I. Haber, R.A. Kishek, T.W. Koeth UMD, College Park, Maryland, USA
	Funding: This work is supported by the US Dept. of Energy Office of High Energy Physics. The University of Maryland Electron Ring (UMER) is a 11.5 meter circumference, 10 keV, electron storage ring dedicated to the study of the physics space-charge-dominated beams transported over long path lengths. The intensity of the space charge in UMER can be varied by aperturing the injected beam current from 0.6 mA to 100 mA. Recently, the electron beam has been transported over one thousand turns. To fully characterize the transverse and longitudinal evolution of the beam on a turn-by-turn basis, extraction and transport to a diagnostic station is required. We present the design of a pulsed electric extraction system that satisfies the challenging constraint of fitting the hardware within the dense magnet lattice. The extraction system must universally accommodate the range beam intensities and minimize any disruption to the circulating beam

WEPPR014	Recovering Measured Dynamics from a DC Circulating Space-Charge-Dominated Storage Ring	2967
	W.D. Stem, B.L. Beaudoin, I. Haber, T.W. Koeth UMD, College Park, Maryland, USA
	Funding: This work is supported by the US Dept. of Energy Offices of High Energy Physics and Fusion Energy Sciences, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office. Space-charge is increasingly significant at high beam intensities such as in FEL injectors and heavy ion inertial fusion drivers, where it dominates the beam dynamics. The University of Maryland Electron Ring (UMER) is a high intensity circular machine that is dedicated to the study of long path length space-charge-dominated beam physics on a small scale. Over multiple turns, longitudinal space charge effects cause the tail and head of an electron bunch to expand and interpenetrate, eventually resulting in a “DC beam”. This leads to complications when trying to measure the beam with UMER’s AC coupled diagnostics. Three techniques are developed to recover the information within the beam. Two “knockout” techniques implement invasive pulsed electric kicks to the beam in combination with either a fluorescent imaging screen or a current monitor. A third technique based on integration of the wall-current signal provides a non-invasive method to study the DC beam dynamics. Experimental results from all three methods are compared. The DC beam profile can then be studied over long trajectories and the existence of any loss mechanisms can be determined.

Paper

Title

Page

Design of an Electrostatic Extraction Section for the University of Maryland Electron Ring

2964

K.J. Ruisard
Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
B.L. Beaudoin, I. Haber, R.A. Kishek, T.W. Koeth
UMD, College Park, Maryland, USA

Funding: This work is supported by the US Dept. of Energy Office of High Energy Physics.
The University of Maryland Electron Ring (UMER) is a 11.5 meter circumference, 10 keV, electron storage ring dedicated to the study of the physics space-charge-dominated beams transported over long path lengths. The intensity of the space charge in UMER can be varied by aperturing the injected beam current from 0.6 mA to 100 mA. Recently, the electron beam has been transported over one thousand turns. To fully characterize the transverse and longitudinal evolution of the beam on a turn-by-turn basis, extraction and transport to a diagnostic station is required. We present the design of a pulsed electric extraction system that satisfies the challenging constraint of fitting the hardware within the dense magnet lattice. The extraction system must universally accommodate the range beam intensities and minimize any disruption to the circulating beam

WEPPR014

Recovering Measured Dynamics from a DC Circulating Space-Charge-Dominated Storage Ring

2967

W.D. Stem, B.L. Beaudoin, I. Haber, T.W. Koeth
UMD, College Park, Maryland, USA

Funding: This work is supported by the US Dept. of Energy Offices of High Energy Physics and Fusion Energy Sciences, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office.
Space-charge is increasingly significant at high beam intensities such as in FEL injectors and heavy ion inertial fusion drivers, where it dominates the beam dynamics. The University of Maryland Electron Ring (UMER) is a high intensity circular machine that is dedicated to the study of long path length space-charge-dominated beam physics on a small scale. Over multiple turns, longitudinal space charge effects cause the tail and head of an electron bunch to expand and interpenetrate, eventually resulting in a “DC beam”. This leads to complications when trying to measure the beam with UMER’s AC coupled diagnostics. Three techniques are developed to recover the information within the beam. Two “knockout” techniques implement invasive pulsed electric kicks to the beam in combination with either a fluorescent imaging screen or a current monitor. A third technique based on integration of the wall-current signal provides a non-invasive method to study the DC beam dynamics. Experimental results from all three methods are compared. The DC beam profile can then be studied over long trajectories and the existence of any loss mechanisms can be determined.