NAPAC2016 - List of Authors (Sun, Y.)

Paper	Title	Page
TUPOA14	An Internet Rack Monitor-Controller for APS LINAC RF Electronics Upgrade	314
	H. Ma, A. Nassiri, T.L. Smith, Y. Sun ANL, Argonne, Illinois, USA L.R. Doolittle, A. Ratti LBNL, Berkeley, California, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences To support the current research and development in APS LINAC area, the existing LINAC rf control performance needs to be much improved, and thus an upgrade of the legacy LINAC rf electronics becomes necessary. The proposed upgrade plan centers on the concept of using a modern, network-attached, rack-mount digital electronics platform 'Internet Rack Monitor-Controller (or IRMC) to replace the existing analog ones on the legacy crate/backplane-based hardware. The system model of the envisioned IRMC is basically a 3-tier stack with a high-performance processor in the mid- layer to handle the general digital signal processing (DSP). The custom FPGA IP's in the bottom layer handle the high-speed, real-time, low-latency DSP tasks, and provide the interface ports. A network communication gateway, in conjunction with an embedded event receiver (EVR), in the top layer merges the Internet Rack Monitor-Controller device into the networks of the accelerator controls infrastructure. Although the concept is very much in trend with today's Internet-of-Things (IoT), this implementation has actually been used in accelerators for over two decades.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA14
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TUB3CO04	A New Thermionic RF Electron Gun for Synchrotron Light Sources	453
	S.V. Kutsaev, A.Y. Murokh, E.A. Savin, A.Yu. Smirnov, A.V. Smirnov RadiaBeam Systems, Santa Monica, California, USA R.B. Agustsson, J.J. Hartzell, A. Verma RadiaBeam, Santa Monica, California, USA A. Nassiri, Y. Sun, G.J. Waldschmidt, A. Zholents ANL, Argonne, Illinois, USA E.A. Savin MEPhI, Moscow, Russia
	Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Science, under contract DE-SC0015191 and contract No. DE-AC02-06CH11357. A thermionic RF gun is a compact and efficient source of electrons used in many practical applications. RadiaBeam Systems and the Advanced Photon Source of Argonne National Laboratory collaborate in developing of a reliable and robust thermionic RF gun for synchrotron light sources which would offer substantial improvements over existing thermionic RF guns and allow stable operation with up to 1A of beam peak current at a 100 Hz pulse repetition rate and a 1.5 μs RF pulse length. In this paper, we discuss the electromagnetic and engineering design of the cavity, and report the progress towards high power tests of the cathode assembly of the new gun.
	Slides TUB3CO04 [2.661 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB3CO04
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WEPOA12	Interleaving Lattice Design for APS Linac	713
	S. Shin, Y. Sun, A. Zholents ANL, Argonne, Illinois, USA
	In order to realize and test advanced accelerator concepts and hardware, the existing beamline with both old and new components are being reconfigured in Linac Extension Area (LEA) of APS linac. Photo injector, which had been installed in the beginning of APS linac, will provide low emittance electron beam into the LEA. The thermionic RF gun beam for storage ring and photo-cathode RF gun beam for LEA will be operated though the LINAC in an interleaved fashion. In this presentation, technical issues as well as beam dynamics on the design for interleaving operation will be described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA12
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WEPOB25	Analytical Modeling of Electron Back-Bombardment Induced Current Increase in Un-Gated Thermionic Cathode Rf Guns	953
	J.P. Edelen Fermilab, Batavia, Illinois, USA J.R. Harris Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA Y. Sun ANL, Argonne, Illinois, USA
	In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, field-enhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB25
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WEPOB26	Observation of Repetition-Rate Dependent Emission From an Un-Gated Thermionic Cathode Rf Gun	956
	J.P. Edelen Fermilab, Batavia, Illinois, USA J.R. Harris Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA Y. Sun ANL, Argonne, Illinois, USA
	Recent work at Fermilab in collaboration with the Advanced Photon Source and members of other national labs, designed an experiment to study the relationship between the RF repetition rate and the average current per RF pulse. While existing models anticipate a direct relationship between these two parameters we observed an inverse relationship. We believe this is a result of damage to the barium coating on the cathode surface caused by a change in back-bombardment power that is unaccounted for in the existing theories. These observations shed new light on the challenges and fundamental limitations associated with scaling an un-gated thermionic cathode RF gun to high average current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB26
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WEPOB48	THz and Sub-THz Capabilities of a Table-Top Radiation Source Driven by an RF Thermionic Electron Gun	998
	A.V. Smirnov, R.B. Agustsson, S. Boucher, T.J. Campese, Y.C. Chen, J.J. Hartzell, B.T. Jacobson, A.Y. Murokh, F.H. O'Shea, E. Spranza RadiaBeam, Santa Monica, California, USA W. Berg, M. Borland, J.C. Dooling, L. Erwin, R.R. Lindberg, S.J. Pasky, N. Sereno, Y. Sun, A. Zholents ANL, Argonne, Illinois, USA W. Bruns WBFB, Berlin, Germany M.J. de Loos, S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC-FOA-0007702). Design features and experimental results are presented for a sub-mm wave source [1] based on APS RF thermionic electron gun. The setup includes compact alpha-magnet, quadrupoles, sub-mm-wave radiators, and THz optics. The sub-THz radiator is a planar, oversized structure with gratings. Source upgrade for generation frequencies above 1 THz is discussed. The THz radiator will use a short-period undulator having 1 T field amplitude, ~20 cm length, and integrated with a low-loss oversized waveguide. Both radiators are integrated with a miniature horn antenna and a small ~90°-degree in-vacuum bending magnet. The electron beamline is designed to operate different modes including conversion to a flat beam interacting efficiently with the radiator. The source can be used for cancer diagnostics, surface defectoscopy, and non-destructive testing. Sub-THz experiment demonstrated a good potential of a robust, table-top system for generation of a narrow bandwidth THz radiation. This setup can be considered as a prototype of a compact, laser-free, flexible source capable of generation of long trains of Sub-THz and THz pulses with repetition rates not available with laser-driven sources. [1] A. V. Smirnov, R. Agustsson, W. J. Berg et al., Phys. Rev. ST Accel. Beams 18, 090703(2015)
	Poster WEPOB48 [1.335 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB48
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Paper

Title

Page

An Internet Rack Monitor-Controller for APS LINAC RF Electronics Upgrade

314

H. Ma, A. Nassiri, T.L. Smith, Y. Sun
ANL, Argonne, Illinois, USA
L.R. Doolittle, A. Ratti
LBNL, Berkeley, California, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences
To support the current research and development in APS LINAC area, the existing LINAC rf control performance needs to be much improved, and thus an upgrade of the legacy LINAC rf electronics becomes necessary. The proposed upgrade plan centers on the concept of using a modern, network-attached, rack-mount digital electronics platform 'Internet Rack Monitor-Controller (or IRMC) to replace the existing analog ones on the legacy crate/backplane-based hardware. The system model of the envisioned IRMC is basically a 3-tier stack with a high-performance processor in the mid- layer to handle the general digital signal processing (DSP). The custom FPGA IP's in the bottom layer handle the high-speed, real-time, low-latency DSP tasks, and provide the interface ports. A network communication gateway, in conjunction with an embedded event receiver (EVR), in the top layer merges the Internet Rack Monitor-Controller device into the networks of the accelerator controls infrastructure. Although the concept is very much in trend with today's Internet-of-Things (IoT), this implementation has actually been used in accelerators for over two decades.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA14

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TUB3CO04

A New Thermionic RF Electron Gun for Synchrotron Light Sources

453

S.V. Kutsaev, A.Y. Murokh, E.A. Savin, A.Yu. Smirnov, A.V. Smirnov
RadiaBeam Systems, Santa Monica, California, USA
R.B. Agustsson, J.J. Hartzell, A. Verma
RadiaBeam, Santa Monica, California, USA
A. Nassiri, Y. Sun, G.J. Waldschmidt, A. Zholents
ANL, Argonne, Illinois, USA
E.A. Savin
MEPhI, Moscow, Russia

Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Science, under contract DE-SC0015191 and contract No. DE-AC02-06CH11357.
A thermionic RF gun is a compact and efficient source of electrons used in many practical applications. RadiaBeam Systems and the Advanced Photon Source of Argonne National Laboratory collaborate in developing of a reliable and robust thermionic RF gun for synchrotron light sources which would offer substantial improvements over existing thermionic RF guns and allow stable operation with up to 1A of beam peak current at a 100 Hz pulse repetition rate and a 1.5 μs RF pulse length. In this paper, we discuss the electromagnetic and engineering design of the cavity, and report the progress towards high power tests of the cathode assembly of the new gun.

Slides TUB3CO04 [2.661 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB3CO04

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WEPOA12

Interleaving Lattice Design for APS Linac

713

S. Shin, Y. Sun, A. Zholents
ANL, Argonne, Illinois, USA

In order to realize and test advanced accelerator concepts and hardware, the existing beamline with both old and new components are being reconfigured in Linac Extension Area (LEA) of APS linac. Photo injector, which had been installed in the beginning of APS linac, will provide low emittance electron beam into the LEA. The thermionic RF gun beam for storage ring and photo-cathode RF gun beam for LEA will be operated though the LINAC in an interleaved fashion. In this presentation, technical issues as well as beam dynamics on the design for interleaving operation will be described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA12

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WEPOB25

Analytical Modeling of Electron Back-Bombardment Induced Current Increase in Un-Gated Thermionic Cathode Rf Guns

953

J.P. Edelen
Fermilab, Batavia, Illinois, USA
J.R. Harris
Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA
Y. Sun
ANL, Argonne, Illinois, USA

In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, field-enhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB25

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WEPOB26

Observation of Repetition-Rate Dependent Emission From an Un-Gated Thermionic Cathode Rf Gun

956

J.P. Edelen
Fermilab, Batavia, Illinois, USA
J.R. Harris
Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA
Y. Sun
ANL, Argonne, Illinois, USA

Recent work at Fermilab in collaboration with the Advanced Photon Source and members of other national labs, designed an experiment to study the relationship between the RF repetition rate and the average current per RF pulse. While existing models anticipate a direct relationship between these two parameters we observed an inverse relationship. We believe this is a result of damage to the barium coating on the cathode surface caused by a change in back-bombardment power that is unaccounted for in the existing theories. These observations shed new light on the challenges and fundamental limitations associated with scaling an un-gated thermionic cathode RF gun to high average current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB26

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB48

THz and Sub-THz Capabilities of a Table-Top Radiation Source Driven by an RF Thermionic Electron Gun

998

A.V. Smirnov, R.B. Agustsson, S. Boucher, T.J. Campese, Y.C. Chen, J.J. Hartzell, B.T. Jacobson, A.Y. Murokh, F.H. O'Shea, E. Spranza
RadiaBeam, Santa Monica, California, USA
W. Berg, M. Borland, J.C. Dooling, L. Erwin, R.R. Lindberg, S.J. Pasky, N. Sereno, Y. Sun, A. Zholents
ANL, Argonne, Illinois, USA
W. Bruns
WBFB, Berlin, Germany
M.J. de Loos, S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC-FOA-0007702).
Design features and experimental results are presented for a sub-mm wave source [1] based on APS RF thermionic electron gun. The setup includes compact alpha-magnet, quadrupoles, sub-mm-wave radiators, and THz optics. The sub-THz radiator is a planar, oversized structure with gratings. Source upgrade for generation frequencies above 1 THz is discussed. The THz radiator will use a short-period undulator having 1 T field amplitude, ~20 cm length, and integrated with a low-loss oversized waveguide. Both radiators are integrated with a miniature horn antenna and a small ~90°-degree in-vacuum bending magnet. The electron beamline is designed to operate different modes including conversion to a flat beam interacting efficiently with the radiator. The source can be used for cancer diagnostics, surface defectoscopy, and non-destructive testing. Sub-THz experiment demonstrated a good potential of a robust, table-top system for generation of a narrow bandwidth THz radiation. This setup can be considered as a prototype of a compact, laser-free, flexible source capable of generation of long trains of Sub-THz and THz pulses with repetition rates not available with laser-driven sources.
[1] A. V. Smirnov, R. Agustsson, W. J. Berg et al., Phys. Rev. ST Accel. Beams 18, 090703(2015)

Poster WEPOB48 [1.335 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB48

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