IPAC2015 - List of Authors (Green, A.T.)

Paper	Title	Page
MOPMA051	Generation of Modulated Bunch Using a Masked Chicane for Beam-Driven Acceleration Experiments at ASTA	666
	Y.-M. Shin, P. Piot Northern Illinois University, DeKalb, Illinois, USA D.R. Broemmelsiek, D.J. Crawford, A.H. Lumpkin Fermilab, Batavia, Illinois, USA A.T. Green Northern Illinois Univerity, Dekalb, Illinois, USA
	Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC. Longitudinal density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling . The sub-ps beam modulation has been studied with a masked chicane * *** by the analytic model and simulations with the beam parameters of the Advanced Superconducting Test Accelerator (ASTA) in Fermilab. With the nominal 50 MeV chicane parameters and 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 um and aperture width 300 μm generates about 100-um modulation periodicity with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell simulations (CST-PS), including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in ~ 100 um of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 0.25, 1 , and 3.2 nC, by extended 3D tracking simulations (Elegant). The modulated bunch generation will be tested by a slit-mask installed at the chicane of the ASTA 50-MeV-injector beamline for beam-driven acceleration experiments. * E. Kallos, Southern California 2008 D. C. Nguyen, B. E. Carlston, NIMA 375, 597 (1996) * P. Muggli, V. Yakimenko, M. Babzien, E. Kallos, and K. P. Kusche, PRL 101, 054801 (2008)
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MOPMA052	Implementation of Quadrupole-scan Emittance Measurement at Fermilab's Advanced Superconducting Test Accelerator (ASTA)	669
	A.T. Green Northern Illinois Univerity, Dekalb, Illinois, USA Y.-M. Shin Fermilab, Batavia, Illinois, USA Y.-M. Shin Northern Illinois University, DeKalb, Illinois, USA
	Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC. Transverse-emittance measurements based on the quadrupole-scan technique * , have been widely used to characterize the beam phase-space parameters in linear accelerators. This paper discusses the implementation of the technique at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. We plan on deploying a flexible implementation that permits an operator to select the quadrupole associated analysing screen to measure the beam emittance. Our implementation utilizes Python scripts combined with Fermilab’s control system ACNet and ELEGANT quadrupole-scan method at 50 MeV given the range of operating charge (20 pC to 3.2 nC) available at ASTA. Some preliminary measurements will also be presented. B.E. Carlsten, et al, Nucl. Instrum. Methods Phys. Res. Sect. A 331, 791 (1993) C. Eckman et al, IPAC 2012 * K. Poorrezaei, et al, Phys. Rev. ST-AB 16, 082801 (2013)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA052
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TUPMA010	Development of a Field-Emission Type S-band RF-Gun System for High Brightness Electron Source Applications	1856
	Y.-M. Shin Northern Illinois University, DeKalb, Illinois, USA N. Barov Far-Tech, Inc., San Diego, California, USA A.T. Green Northern Illinois Univerity, Dekalb, Illinois, USA
	Electron beams emitted from a cold cathode are thermally stable and mono-energetic with a small phase-space volume. We have been developing a field-emission type RF-gun system for high brightness electron source applications, including electron scattering/diffraction and tunable coherent X-ray/THz generation. The system consists of a single-gap gun-cavity and an S-band klystron/modulator capable of powering the gun with up to 5.5 MW peak (PRR = 1 Hz, duration = 2.5 μs). The designed gun built with the symmetrised side-couplers has surface field on the cathode ranging 50 – 100 MV/m with 1.3 – 1.7 MW klystron-power and 1.2 field ratio (HFSS). ASTRA simulations also indicate that the gun produces the beam with transverse emittances of less than 1 mm-mrad with 10 – 20 pC bunch charge at 500 keV beam energy. Under the gun operating condition, particle tracking/PIC simulations (CST) show that a single-tip CNT field-emitter* produces short pulsed bunches (~ 1/10 RF-cycle) with small emittance ( 0.01 mm-mrad) and high peak current density ( 10,000 kA/cm²). After the gun is fully installed and commissioned, a CNT-tip cathode will be tested with RF-field emission. * N. De Jonge, J.-M. Bonard, Phil. Trans. R. Soc. Lond. A 362, 2239 (2004) ** G. S. Bocharov, and A. V. Eletskii, Nanomaterials 3, 393 (2013)
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Paper

Title

Page

Generation of Modulated Bunch Using a Masked Chicane for Beam-Driven Acceleration Experiments at ASTA

666

Y.-M. Shin, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Broemmelsiek, D.J. Crawford, A.H. Lumpkin
Fermilab, Batavia, Illinois, USA
A.T. Green
Northern Illinois Univerity, Dekalb, Illinois, USA

Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Longitudinal density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling *. The sub-ps beam modulation has been studied with a masked chicane ** *** by the analytic model and simulations with the beam parameters of the Advanced Superconducting Test Accelerator (ASTA) in Fermilab. With the nominal 50 MeV chicane parameters and 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 um and aperture width 300 μm generates about 100-um modulation periodicity with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell simulations (CST-PS), including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in ~ 100 um of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 0.25, 1 , and 3.2 nC, by extended 3D tracking simulations (Elegant). The modulated bunch generation will be tested by a slit-mask installed at the chicane of the ASTA 50-MeV-injector beamline for beam-driven acceleration experiments.
* E. Kallos, Southern California 2008
** D. C. Nguyen, B. E. Carlston, NIMA 375, 597 (1996)
*** P. Muggli, V. Yakimenko, M. Babzien, E. Kallos, and K. P. Kusche, PRL 101, 054801 (2008)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA051

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MOPMA052

Implementation of Quadrupole-scan Emittance Measurement at Fermilab's Advanced Superconducting Test Accelerator (ASTA)

669

A.T. Green
Northern Illinois Univerity, Dekalb, Illinois, USA
Y.-M. Shin
Fermilab, Batavia, Illinois, USA
Y.-M. Shin
Northern Illinois University, DeKalb, Illinois, USA

Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Transverse-emittance measurements based on the quadrupole-scan technique * ** ***, have been widely used to characterize the beam phase-space parameters in linear accelerators. This paper discusses the implementation of the technique at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. We plan on deploying a flexible implementation that permits an operator to select the quadrupole associated analysing screen to measure the beam emittance. Our implementation utilizes Python scripts combined with Fermilab’s control system ACNet and ELEGANT quadrupole-scan method at 50 MeV given the range of operating charge (20 pC to 3.2 nC) available at ASTA. Some preliminary measurements will also be presented.
* B.E. Carlsten, et al, Nucl. Instrum. Methods Phys. Res. Sect. A 331, 791 (1993)
** C. Eckman et al, IPAC 2012
*** K. Poorrezaei, et al, Phys. Rev. ST-AB 16, 082801 (2013)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA052

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TUPMA010

Development of a Field-Emission Type S-band RF-Gun System for High Brightness Electron Source Applications

1856

Y.-M. Shin
Northern Illinois University, DeKalb, Illinois, USA
N. Barov
Far-Tech, Inc., San Diego, California, USA
A.T. Green
Northern Illinois Univerity, Dekalb, Illinois, USA

Electron beams emitted from a cold cathode are thermally stable and mono-energetic with a small phase-space volume*. We have been developing a field-emission type RF-gun system for high brightness electron source applications, including electron scattering/diffraction and tunable coherent X-ray/THz generation. The system consists of a single-gap gun-cavity and an S-band klystron/modulator capable of powering the gun with up to 5.5 MW peak (PRR = 1 Hz, duration = 2.5 μs). The designed gun built with the symmetrised side-couplers has surface field on the cathode ranging 50 – 100 MV/m with 1.3 – 1.7 MW klystron-power and 1.2 field ratio (HFSS). ASTRA simulations also indicate that the gun produces the beam with transverse emittances of less than 1 mm-mrad with 10 – 20 pC bunch charge at 500 keV beam energy. Under the gun operating condition, particle tracking/PIC simulations (CST) show that a single-tip CNT field-emitter** produces short pulsed bunches (~ 1/10 RF-cycle) with small emittance ( 0.01 mm-mrad) and high peak current density ( 10,000 kA/cm²). After the gun is fully installed and commissioned, a CNT-tip cathode will be tested with RF-field emission.
* N. De Jonge, J.-M. Bonard, Phil. Trans. R. Soc. Lond. A 362, 2239 (2004)
** G. S. Bocharov, and A. V. Eletskii, Nanomaterials 3, 393 (2013)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA010

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