2011 Particle Accelerator Conference - List of Authors (Keister, J.W.)

Paper	Title	Page
MOP207	Diamond X-ray Beam Position Monitors	483
	J. Smedley, A. Heroux, J.W. Keister BNL, Upton, Long Island, New York, USA K. Attenkofer ANL, Argonne, USA J. Bohon Case Western Reserve University, Center for Synchrotron Biosciences, Upton, New York, USA J. Distel LANL, Los Alamos, New Mexico, USA M. Gaowei SBU, Stony Brook, New York, USA E.M. Muller Stony Brook University, Stony Brook, USA
	Funding: The authors wish to acknowledge the support of the U.S. Department of Energy (DOE) under grant DE-FG02-08ER41547. Modern synchrotrons are capable of significant per-pulse x-ray flux, and time resolved pulse-probe experiments have become feasible. These experiments provide unique demands on x-ray monitors, as the beam position, flux and arrival time all potentially need to be recorded for each x-ray pulse. Further, monitoring of “white” x-ray beam position and flux upstream of beamline optics is desirable as a diagnostic of the electron source. We report on a diamond quadrant monitors which provide beam monitoring for a variety of applications, for both white and monochromatic beams. These monitors have a position resolution of 20 nm for a stable beam, are linear in flux over at least 11 orders of magnitude, and can resolve beam motion shot-by-shot at repetition rates up to 6.5 MHz.

WEP162	Modeling of Diamond Based Devices for Beam Diagnostics	1794
	D.A. Dimitrov, R. Busby Tech-X, Boulder, Colorado, USA I. Ben-Zvi, J.W. Keister, T. Rao, J. Smedley BNL, Upton, Long Island, New York, USA E.M. Muller Stony Brook University, Stony Brook, USA
	Funding: The authors wish to acknowledge the support of the U.S. Department of Energy (DOE) under grants DE-SC0004584 (Tech-X Corp.) and DE-FG02-08ER41547 (BNL). Beamlines at new light sources, such as the National Synchrotron Light Source II will operate at flux levels beyond the saturation level of existing diagnostics, necessitating the development of new devices. Currently, there is no detector which can span the entire flux range that is possible even in a second generation light source and will become crucial for next generation light sources. One new approach* is a diamond-based detector that will be able to monitor beam position, flux and timing to much better resolution. Furthermore, this detector also has linear response to flux over 11 orders of magnitude. However, the successful development of the detector requires thorough understanding and optimization of the physical processes involved. We will discuss the new modeling capabilities we have been implementing in the VORPAL 3D code to investigate the effects of charge generation due to absorption of x-ray photons, transport, and charge trapping. We will report results from VORPAL simulations on charge collection and how it depends on applied field, charge trapping, and the energy of absorbed photons. *J. W. Keister, J. Smedley, D. A. Dimitrov, and R. Busby, Charge Collection and Propagation in Diamond X-ray Detectors, IEEE Transactions on Nuclear Science, 57, 2400 (2010).

Paper

Title

Page

Diamond X-ray Beam Position Monitors

483

J. Smedley, A. Heroux, J.W. Keister
BNL, Upton, Long Island, New York, USA
K. Attenkofer
ANL, Argonne, USA
J. Bohon
Case Western Reserve University, Center for Synchrotron Biosciences, Upton, New York, USA
J. Distel
LANL, Los Alamos, New Mexico, USA
M. Gaowei
SBU, Stony Brook, New York, USA
E.M. Muller
Stony Brook University, Stony Brook, USA

Funding: The authors wish to acknowledge the support of the U.S. Department of Energy (DOE) under grant DE-FG02-08ER41547.
Modern synchrotrons are capable of significant per-pulse x-ray flux, and time resolved pulse-probe experiments have become feasible. These experiments provide unique demands on x-ray monitors, as the beam position, flux and arrival time all potentially need to be recorded for each x-ray pulse. Further, monitoring of “white” x-ray beam position and flux upstream of beamline optics is desirable as a diagnostic of the electron source. We report on a diamond quadrant monitors which provide beam monitoring for a variety of applications, for both white and monochromatic beams. These monitors have a position resolution of 20 nm for a stable beam, are linear in flux over at least 11 orders of magnitude, and can resolve beam motion shot-by-shot at repetition rates up to 6.5 MHz.

WEP162

Modeling of Diamond Based Devices for Beam Diagnostics

1794

D.A. Dimitrov, R. Busby
Tech-X, Boulder, Colorado, USA
I. Ben-Zvi, J.W. Keister, T. Rao, J. Smedley
BNL, Upton, Long Island, New York, USA
E.M. Muller
Stony Brook University, Stony Brook, USA

Funding: The authors wish to acknowledge the support of the U.S. Department of Energy (DOE) under grants DE-SC0004584 (Tech-X Corp.) and DE-FG02-08ER41547 (BNL).
Beamlines at new light sources, such as the National Synchrotron Light Source II will operate at flux levels beyond the saturation level of existing diagnostics, necessitating the development of new devices. Currently, there is no detector which can span the entire flux range that is possible even in a second generation light source and will become crucial for next generation light sources. One new approach* is a diamond-based detector that will be able to monitor beam position, flux and timing to much better resolution. Furthermore, this detector also has linear response to flux over 11 orders of magnitude. However, the successful development of the detector requires thorough understanding and optimization of the physical processes involved. We will discuss the new modeling capabilities we have been implementing in the VORPAL 3D code to investigate the effects of charge generation due to absorption of x-ray photons, transport, and charge trapping. We will report results from VORPAL simulations on charge collection and how it depends on applied field, charge trapping, and the energy of absorbed photons.
*J. W. Keister, J. Smedley, D. A. Dimitrov, and R. Busby, Charge Collection and Propagation in Diamond X-ray Detectors, IEEE Transactions on Nuclear Science, 57, 2400 (2010).