NAPAC2016 - List of Authors (Milton, S.V.)

Paper	Title	Page
MOPOB17	Resonant Frequency Control for the PIP-II Injector Test RFQ: Control Framework and Initial Results	109
	A.L. Edelen, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA D.L. Bowring, B.E. Chase, J.P. Edelen, D.J. Nicklaus, J. Steimel Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359. For the PIP-II Injector Test (PI-Test) at Fermilab, a four-vane radio frequency quadrupole (RFQ) is designed to accelerate a 30-keV, 1-mA to 10-mA H' beam to 2.1 MeV under both pulsed and continuous wave (CW) RF operation. The available headroom of the RF amplifiers limit the maximum allowable detuning to 3 kHz, and the detuning is controlled entirely via thermal regulation. Fine control over the detuning, minimal manual intervention, and fast trip recovery is desired. In addition, having active control over both the walls and vanes provides a wider tuning range. For this, we intend to use model predictive control (MPC). To facilitate these objectives, we developed a dedicated control framework that handles higher-level system decisions as well as executes control calculations. It is written in Python in a modular fashion for easy adjustments, readability, and portability. Here we describe the framework and present the first control results for the PI-Test RFQ under pulsed and CW operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB17
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MOPOB56	Frequency Domain Simulations of Rf Cavity Structures and Coupler Designs for Co-Linear X-Band Energy Booster (CXEB) with ACE3P	191
	T. Sipahi, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	Due to their higher intrinsic shunt impedance X-band accelerating structures offer significant gradients with relatively modest input powers, and this can lead to more compact light sources. At the Colorado State University Accelerator Laboratory (CSUAL) we would like to adapt this technology to our 1.3-GHz, L-band accelerator system using a passively driven 11.7 GHz traveling wave X-band configuration that capitalizes on the high shunt impedances 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. Here we provide the frequency domain simulation results using the ACE3P Electromagnetic Suite's OMEGA3P and S3P for our proposed Co-linear X-band Energy Booster (CXEB) system that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structures while driven solely by the beam from the L-band system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB56
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MOPOB57	Wakefield Excitation in Power Extraction Cavity of Co-Linear X-Band Energy Booster in Time Domain With ACE3P	195
SUPO43	use link to see paper's listing under its alternate paper code
	T. Sipahi, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	We provide the general concept and the design details of our proposed Co-linear X-band Energy Booster (CXEB). Here, using the time domain solver T3P of the ACE3P Suite we provide the single bunch and multiple bunch wakefield excitation mechanism for the power build up when using a symmetric Gaussian bunch distribution in our traveling wave (TW) X-band power extraction cavity (PEC). Finally, we determine the achievable X-band power at the end of the PEC structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB57
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TUPOA51	First Steps Toward Incorporating Image Based Diagnostics into Particle Accelerator Control Systems Using Convolutional Neural Networks	390
SUPO10	use link to see paper's listing under its alternate paper code
	A.L. Edelen, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA J.P. Edelen Fermilab, Batavia, Illinois, USA
	At present, a variety of image-based diagnostics are used in particle accelerator systems. Often times, these are viewed by a human operator who then makes appropriate adjustments to the machine. Given recent advances in using convolutional neural networks (CNNs) for image processing, it should be possible to use image diagnostics directly in control routines (NN-based or otherwise). This is especially appealing for non-intercepting diagnostics that could run continuously during beam operation. Here, we show results of a first step toward implementing such a controller: our trained CNN can predict multiple simulated downstream beam parameters at the Fermilab Accelerator Science and Technology (FAST) facility's low energy beamline using simulated virtual cathode laser images, gun phases, and solenoid strengths.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA51
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TUPOA52	Updates to the Low-Level RF Architecture for Fermilab	394
	J. Einstein, B.E. Chase, E. Cullerton, P. Varghese Fermilab, Batavia, Illinois, USA S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA D. Sharma RRCAT, Indore (M.P.), India
	Fermilab has teamed with Colorado State University on several projects in LLRF controls and architecture. These projects include new LLRF hardware, updated controls techniques, and new system architectures. Here we present a summary of our work to date.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA52
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WEPOA42	RF Design of a 1.3-GHz High Average Beam Power SRF Electron Source	789
SUPO42	use link to see paper's listing under its alternate paper code
	N. Sipahi, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA I.V. Gonin, R.D. Kephart, T.N. Khabiboulline, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	There is a significant interest in developing high-average power electron sources, particularly those integrated with Superconducting Radio Frequency (SRF) accelerator systems. Even though there are examples of high-average-power electron sources, they are not compact, highly efficient, or available at a reasonable cost. Adapting the recent advances in SRF cavities, RF power sources, and innovative solutions for an SRF gun and cathode system, we have developed a design concept for a compact SRF high-average power electron linac. This design will produce electron beams with energies up to 10 MeV. In this paper, we present the design results of our cathode structure integrated with modified 9-cell accelerating structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA42
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WEPOA43	Simulations of High Current Magnetic Horn Striplines at Fermilab	792
	T. Sipahi, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA J. Hylen, R.M. Zwaska Fermilab, Batavia, Illinois, USA
	Both the NuMI (Neutrinos and the Main Injector) beam line, that has been providing intense neutrino beams for several Fermilab experiments (MINOS, MINERVA, NOVA), and the newly proposed LBNF (Long Baseline Neutrino Facility) beam line, which plans to produce the highest power neutrino beam in the world for DUNE (the Deep Underground Neutrino Experiment), need pulsed magnetic horns to focus the mesons that decay to produce the neutrinos. The high-current horn and stripline design has been evolving as NuMI reconfigures for higher beam power and to meet the needs of the future LBNF program. We evaluated the two existing high-current striplines for NuMI and NOvA at Fermilab by producing Electromagnetic simulations of the magnetic horns and the required high-current striplines. In this paper, we present the comparison of these two designs using the ANSYS Electric and ANSYS Maxwell 3D codes with special attention on the critical stress points. These results are being used to support the development of evolving horn stripline designs to handle increased electrical current and higher beam power for NuMI upgrades and for the LBNF experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA43
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THPOA37	Study of 2D CSR Effects in a Compression Chicane	1181
	C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	The study of coherent synchrotron radiation (CSR) has been an area of great interest because of its negative impact on FEL performance. The modeling of CSR is frequently performed using a 1D approximation, as 2D and 3D models can become extremely computational intensive. While experimental evidence is lacking in this area most studies show reasonable agreement between 1D and 2D CSR models for beam parameters in existing accelerators. In this work we focus on 2D modeling of CSR in a four-dipole chicane lattice based on the Jefferson Lab FEL. Comparison is shown between several models and measurement for energy loss due to CSR in the chicane. While good agreement is generally observed we also present investigation of several key differences observed in simulation. In particular, showing how the 1D and 2D CSR models deviate in regards to CSR and beam interaction within the drift spaces of the chicane and the downstream drift at the chicane end. E. Saldin, E. Schneidmiller, and M. Yurkov, Nucl. Instr. Meth. A398, 373 (1997).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA37
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FRA1CO03	An Ultra-High Resolution Pulsed-Wire Magnet Measurement System	1268
	A. D'Audney, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	The performance of a Free-Electron Laser (FEL) depends in part on the quality of the magnetic field in the undulator. Imperfections in the magnetic field of an undulator lead to an imperfect electron trajectory, both offset and angle, as well as a relative phase error between the oscillation phase of the electrons and the generated electromagnetic field. The result of such errors is a reduction of laser gain impacting overall FEL performance. A pulsed-wire method can be used to determine the profile of the magnetic field. This is achieved by sending a square-current pulse through a wire placed along the length of the axis that will induce a Lorentz-force interaction with the magnetic field. Measurement of the resulting displacement in the wire over time using a motion detector yields the first or second integrals of the magnetic field and so provides a measure of the local magnetic field strength. Dispersion in the wire can be corrected using algorithms, with a resulting increase in overall accuracy of the measurement. We have designed, constructed and tested a pulsed-wire magnetic measurement system and used this system to characterize the CSU FEL undulator.
	Slides FRA1CO03 [4.318 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-FRA1CO03
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Paper

Title

Page

Resonant Frequency Control for the PIP-II Injector Test RFQ: Control Framework and Initial Results

109

A.L. Edelen, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
D.L. Bowring, B.E. Chase, J.P. Edelen, D.J. Nicklaus, J. Steimel
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359.
For the PIP-II Injector Test (PI-Test) at Fermilab, a four-vane radio frequency quadrupole (RFQ) is designed to accelerate a 30-keV, 1-mA to 10-mA H' beam to 2.1 MeV under both pulsed and continuous wave (CW) RF operation. The available headroom of the RF amplifiers limit the maximum allowable detuning to 3 kHz, and the detuning is controlled entirely via thermal regulation. Fine control over the detuning, minimal manual intervention, and fast trip recovery is desired. In addition, having active control over both the walls and vanes provides a wider tuning range. For this, we intend to use model predictive control (MPC). To facilitate these objectives, we developed a dedicated control framework that handles higher-level system decisions as well as executes control calculations. It is written in Python in a modular fashion for easy adjustments, readability, and portability. Here we describe the framework and present the first control results for the PI-Test RFQ under pulsed and CW operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB17

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MOPOB56

Frequency Domain Simulations of Rf Cavity Structures and Coupler Designs for Co-Linear X-Band Energy Booster (CXEB) with ACE3P

191

T. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

Due to their higher intrinsic shunt impedance X-band accelerating structures offer significant gradients with relatively modest input powers, and this can lead to more compact light sources. At the Colorado State University Accelerator Laboratory (CSUAL) we would like to adapt this technology to our 1.3-GHz, L-band accelerator system using a passively driven 11.7 GHz traveling wave X-band configuration that capitalizes on the high shunt impedances 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. Here we provide the frequency domain simulation results using the ACE3P Electromagnetic Suite's OMEGA3P and S3P for our proposed Co-linear X-band Energy Booster (CXEB) system that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structures while driven solely by the beam from the L-band system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB56

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MOPOB57

Wakefield Excitation in Power Extraction Cavity of Co-Linear X-Band Energy Booster in Time Domain With ACE3P

195

SUPO43

use link to see paper's listing under its alternate paper code

T. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

We provide the general concept and the design details of our proposed Co-linear X-band Energy Booster (CXEB). Here, using the time domain solver T3P of the ACE3P Suite we provide the single bunch and multiple bunch wakefield excitation mechanism for the power build up when using a symmetric Gaussian bunch distribution in our traveling wave (TW) X-band power extraction cavity (PEC). Finally, we determine the achievable X-band power at the end of the PEC structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB57

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TUPOA51

First Steps Toward Incorporating Image Based Diagnostics into Particle Accelerator Control Systems Using Convolutional Neural Networks

390

SUPO10

use link to see paper's listing under its alternate paper code

A.L. Edelen, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
J.P. Edelen
Fermilab, Batavia, Illinois, USA

At present, a variety of image-based diagnostics are used in particle accelerator systems. Often times, these are viewed by a human operator who then makes appropriate adjustments to the machine. Given recent advances in using convolutional neural networks (CNNs) for image processing, it should be possible to use image diagnostics directly in control routines (NN-based or otherwise). This is especially appealing for non-intercepting diagnostics that could run continuously during beam operation. Here, we show results of a first step toward implementing such a controller: our trained CNN can predict multiple simulated downstream beam parameters at the Fermilab Accelerator Science and Technology (FAST) facility's low energy beamline using simulated virtual cathode laser images, gun phases, and solenoid strengths.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA51

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TUPOA52

Updates to the Low-Level RF Architecture for Fermilab

394

J. Einstein, B.E. Chase, E. Cullerton, P. Varghese
Fermilab, Batavia, Illinois, USA
S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
D. Sharma
RRCAT, Indore (M.P.), India

Fermilab has teamed with Colorado State University on several projects in LLRF controls and architecture. These projects include new LLRF hardware, updated controls techniques, and new system architectures. Here we present a summary of our work to date.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA52

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WEPOA42

RF Design of a 1.3-GHz High Average Beam Power SRF Electron Source

789

SUPO42

use link to see paper's listing under its alternate paper code

N. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
I.V. Gonin, R.D. Kephart, T.N. Khabiboulline, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

There is a significant interest in developing high-average power electron sources, particularly those integrated with Superconducting Radio Frequency (SRF) accelerator systems. Even though there are examples of high-average-power electron sources, they are not compact, highly efficient, or available at a reasonable cost. Adapting the recent advances in SRF cavities, RF power sources, and innovative solutions for an SRF gun and cathode system, we have developed a design concept for a compact SRF high-average power electron linac. This design will produce electron beams with energies up to 10 MeV. In this paper, we present the design results of our cathode structure integrated with modified 9-cell accelerating structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA42

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WEPOA43

Simulations of High Current Magnetic Horn Striplines at Fermilab

792

T. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
J. Hylen, R.M. Zwaska
Fermilab, Batavia, Illinois, USA

Both the NuMI (Neutrinos and the Main Injector) beam line, that has been providing intense neutrino beams for several Fermilab experiments (MINOS, MINERVA, NOVA), and the newly proposed LBNF (Long Baseline Neutrino Facility) beam line, which plans to produce the highest power neutrino beam in the world for DUNE (the Deep Underground Neutrino Experiment), need pulsed magnetic horns to focus the mesons that decay to produce the neutrinos. The high-current horn and stripline design has been evolving as NuMI reconfigures for higher beam power and to meet the needs of the future LBNF program. We evaluated the two existing high-current striplines for NuMI and NOvA at Fermilab by producing Electromagnetic simulations of the magnetic horns and the required high-current striplines. In this paper, we present the comparison of these two designs using the ANSYS Electric and ANSYS Maxwell 3D codes with special attention on the critical stress points. These results are being used to support the development of evolving horn stripline designs to handle increased electrical current and higher beam power for NuMI upgrades and for the LBNF experiment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA43

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THPOA37

Study of 2D CSR Effects in a Compression Chicane

1181

C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA
S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

The study of coherent synchrotron radiation (CSR) has been an area of great interest because of its negative impact on FEL performance. The modeling of CSR is frequently performed using a 1D approximation*, as 2D and 3D models can become extremely computational intensive. While experimental evidence is lacking in this area most studies show reasonable agreement between 1D and 2D CSR models for beam parameters in existing accelerators. In this work we focus on 2D modeling of CSR in a four-dipole chicane lattice based on the Jefferson Lab FEL. Comparison is shown between several models and measurement for energy loss due to CSR in the chicane. While good agreement is generally observed we also present investigation of several key differences observed in simulation. In particular, showing how the 1D and 2D CSR models deviate in regards to CSR and beam interaction within the drift spaces of the chicane and the downstream drift at the chicane end.
*E. Saldin, E. Schneidmiller, and M. Yurkov, Nucl. Instr. Meth. A398, 373 (1997).

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA37

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FRA1CO03

An Ultra-High Resolution Pulsed-Wire Magnet Measurement System

1268

A. D'Audney, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

The performance of a Free-Electron Laser (FEL) depends in part on the quality of the magnetic field in the undulator. Imperfections in the magnetic field of an undulator lead to an imperfect electron trajectory, both offset and angle, as well as a relative phase error between the oscillation phase of the electrons and the generated electromagnetic field. The result of such errors is a reduction of laser gain impacting overall FEL performance. A pulsed-wire method can be used to determine the profile of the magnetic field. This is achieved by sending a square-current pulse through a wire placed along the length of the axis that will induce a Lorentz-force interaction with the magnetic field. Measurement of the resulting displacement in the wire over time using a motion detector yields the first or second integrals of the magnetic field and so provides a measure of the local magnetic field strength. Dispersion in the wire can be corrected using algorithms, with a resulting increase in overall accuracy of the measurement. We have designed, constructed and tested a pulsed-wire magnetic measurement system and used this system to characterize the CSU FEL undulator.

Slides FRA1CO03 [4.318 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-FRA1CO03

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