PAC2013 - List of Authors (Milton, S.V.)

Paper	Title	Page
MOPAC07	Photonic Crystal as a Passively Driven Structure to Boost Beam Energy	87
	B.R. Poole LLNL, Livermore, California, USA J.R. Harris, S.V. Milton CSU, Fort Collins, Colorado, USA
	Funding: Parts of this work were performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The use of electromagnetic structures to couple energy to a charged particle beam is well known. These structures are usually driven by an external source of electromagnetic energy and the structure distributes that energy is such a way as being favorable to accelerate charged particles. Photonic crystals typically consist of periodic arrays of metal and/or dielectric structures spaced on a scale comparable to the wavelength of interest, have been investigated for use both as sources of microwave radiation and particle accelerators. In this case we consider driving a photonic crystal structure using a repetitive sequence of charge bunches driven from a photo-injector to resonantly excite the structure to produce an acceleration field to accelerate a suitably-delayed witness charge bunch to high energy. We examine the generation of the acceleration field as well as spurious modes. The dynamics of the witness bunch are examined to determine the longitudinal dynamics of the bunch and the energy spectra.

TUPSM09	A Two Frequency Gun for High Current Thermionic Cathode Electron Injector Systems	649
	J.P. Edelen, S. Biedron, J.R. Harris, S.V. Milton CSU, Fort Collins, Colorado, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA
	Funding: Office of Naval Research This paper discusses work done on designing a Radio Frequency, thermionic cathode electron gun for high current injection systems. The background and previous work on the subject is overviewed as well as an introduction to other facilities operating thermionic cathodes and their particular configuration. We discuss using a two frequency TM010 electron gun at the Colorado State University accelerator facility and we discuss theory and simulation of exotic mode electron guns. Results are compared using both PARMELA and SPIFFE and for high current electron beams we have simulated CW operation with very-low back-bombardment levels.

WEPHO10	X-Band RF Power Generation via an L-Band Accelerator System and Uses	951
	N. Sipahi, S. Biedron, S.V. Milton, T. Sipahi CSU, Fort Collins, Colorado, USA C. Adolphsen SLAC, Menlo Park, California, USA
	The development of compact, cost effective sources of high-energy electron beams is a major thrust of the Colorado State University Accelerator Laboratory team. In this paper we describe a way to generate usable X-Band RF power suitable for powering an X-Band accelerating structure to overall potentials significantly higher than what we are presently able to obtain from our L-Band photocathode RF gun system. The concept relies on the use of the L-band accelerator beam to generate the X-band power that is then delivered to a suitable X-band structure. Once powered this X-band structure can be used to accelerate an electron bunch to high beam energies.

WEPMA10	Passively Driven X-band RF Linac Structure	1001
	T. Sipahi, S. Biedron, S.V. Milton, N. Sipahi CSU, Fort Collins, Colorado, USA C. Adolphsen SLAC, Menlo Park, California, USA
	Accelerating structures operated at X-band frequencies have been shown to regularly achieve gradients of around 100 MV/m or better. Obviously, use of such technology can lead to more compact particle accelerators. At the Colorado State University Accelerator Laboratory we would like to adapt this technology to our L-band (1.3 GHz) accelerator system via a 2-beam configuration that capitalizes on the high gradients achievable in X-band accelerating structures in order to increase our overall beam energy in a manner that does not require investment in an expensive, custom, high-power X-band klystron system. A novel configuration has been proposed. Here we provide the design details of the X-band accelerator system that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structure.

WEPSM17	Non-Invasive Beam Detection in a High-Average Power Electron Accelerator	1082
	J.E. Williams, S. Biedron, J.R. Harris, S.V. Milton CSU, Fort Collins, Colorado, USA S.V. Benson, P.E. Evtushenko, G. Neil, S. Zhang JLAB, Newport News, Virginia, USA
	For a free-electron laser (FEL) to work effectively the electron beam quality must meet exceptional standards. In the case of an FEL operating at infrared wavelengths in an amplifier configuration the critical phase space tends to be in the longitudinal direction. Achieving high enough longitudinal phase space density directly from the electron injector system of such an FEL is difficult due to space charge effects, thus one needs to manipulate the longitudinal phase space once the beam energy reaches a sufficiently high value. However, this is fraught with problems. Longitudinal space charge and coherent synchrotron radiation can both disrupt the overall phase space, furthermore, the phase space disruption is exacerbated by the longitudinal phase space manipulation process required to achieve high peak current. To achieve and maintain good FEL performance one needs to investigate the longitudinal emittance and be able to measure it during operation preferably in a non-invasive manner. Using the electro-optical sampling (EOS) method, we plan to measure the bunch longitudinal profile of a high-energy (~120-MeV), high-power (~10kW or more FEL output power) beam.

Paper

Title

Page

Photonic Crystal as a Passively Driven Structure to Boost Beam Energy

87

B.R. Poole
LLNL, Livermore, California, USA
J.R. Harris, S.V. Milton
CSU, Fort Collins, Colorado, USA

Funding: Parts of this work were performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
The use of electromagnetic structures to couple energy to a charged particle beam is well known. These structures are usually driven by an external source of electromagnetic energy and the structure distributes that energy is such a way as being favorable to accelerate charged particles. Photonic crystals typically consist of periodic arrays of metal and/or dielectric structures spaced on a scale comparable to the wavelength of interest, have been investigated for use both as sources of microwave radiation and particle accelerators. In this case we consider driving a photonic crystal structure using a repetitive sequence of charge bunches driven from a photo-injector to resonantly excite the structure to produce an acceleration field to accelerate a suitably-delayed witness charge bunch to high energy. We examine the generation of the acceleration field as well as spurious modes. The dynamics of the witness bunch are examined to determine the longitudinal dynamics of the bunch and the energy spectra.

TUPSM09

A Two Frequency Gun for High Current Thermionic Cathode Electron Injector Systems

649

J.P. Edelen, S. Biedron, J.R. Harris, S.V. Milton
CSU, Fort Collins, Colorado, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA

Funding: Office of Naval Research
This paper discusses work done on designing a Radio Frequency, thermionic cathode electron gun for high current injection systems. The background and previous work on the subject is overviewed as well as an introduction to other facilities operating thermionic cathodes and their particular configuration. We discuss using a two frequency TM010 electron gun at the Colorado State University accelerator facility and we discuss theory and simulation of exotic mode electron guns. Results are compared using both PARMELA and SPIFFE and for high current electron beams we have simulated CW operation with very-low back-bombardment levels.

WEPHO10

X-Band RF Power Generation via an L-Band Accelerator System and Uses

951

N. Sipahi, S. Biedron, S.V. Milton, T. Sipahi
CSU, Fort Collins, Colorado, USA
C. Adolphsen
SLAC, Menlo Park, California, USA

The development of compact, cost effective sources of high-energy electron beams is a major thrust of the Colorado State University Accelerator Laboratory team. In this paper we describe a way to generate usable X-Band RF power suitable for powering an X-Band accelerating structure to overall potentials significantly higher than what we are presently able to obtain from our L-Band photocathode RF gun system. The concept relies on the use of the L-band accelerator beam to generate the X-band power that is then delivered to a suitable X-band structure. Once powered this X-band structure can be used to accelerate an electron bunch to high beam energies.

WEPMA10

Passively Driven X-band RF Linac Structure

1001

T. Sipahi, S. Biedron, S.V. Milton, N. Sipahi
CSU, Fort Collins, Colorado, USA
C. Adolphsen
SLAC, Menlo Park, California, USA

Accelerating structures operated at X-band frequencies have been shown to regularly achieve gradients of around 100 MV/m or better. Obviously, use of such technology can lead to more compact particle accelerators. At the Colorado State University Accelerator Laboratory we would like to adapt this technology to our L-band (1.3 GHz) accelerator system via a 2-beam configuration that capitalizes on the high gradients achievable in X-band accelerating structures in order to increase our overall beam energy in a manner that does not require investment in an expensive, custom, high-power X-band klystron system. A novel configuration has been proposed. Here we provide the design details of the X-band accelerator system that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structure.

WEPSM17

Non-Invasive Beam Detection in a High-Average Power Electron Accelerator

1082

J.E. Williams, S. Biedron, J.R. Harris, S.V. Milton
CSU, Fort Collins, Colorado, USA
S.V. Benson, P.E. Evtushenko, G. Neil, S. Zhang
JLAB, Newport News, Virginia, USA

For a free-electron laser (FEL) to work effectively the electron beam quality must meet exceptional standards. In the case of an FEL operating at infrared wavelengths in an amplifier configuration the critical phase space tends to be in the longitudinal direction. Achieving high enough longitudinal phase space density directly from the electron injector system of such an FEL is difficult due to space charge effects, thus one needs to manipulate the longitudinal phase space once the beam energy reaches a sufficiently high value. However, this is fraught with problems. Longitudinal space charge and coherent synchrotron radiation can both disrupt the overall phase space, furthermore, the phase space disruption is exacerbated by the longitudinal phase space manipulation process required to achieve high peak current. To achieve and maintain good FEL performance one needs to investigate the longitudinal emittance and be able to measure it during operation preferably in a non-invasive manner. Using the electro-optical sampling (EOS) method, we plan to measure the bunch longitudinal profile of a high-energy (~120-MeV), high-power (~10kW or more FEL output power) beam.