NAPAC2019 - List of Keywords (scattering)

Paper	Title	Other Keywords	Page
MOPLS01	Spectroscopic Correlations to Resistive Switching of Ion Beam Irradiated Films	radiation, ECR, experiment, laser	160
	K.N. Rathod, N.A. Shah, P.S. Solanki Saurashtra University, Rajkot, Gujarat, India K. Asokan IUAC, New Delhi, India K.H. Chae, J.P. Singh Korea Institute of Science and Technology, Advanced Analysis Center, Seoul, Republic of Korea
	Researchers concentrated on resistive random access memories (RRAMs) due to excellent scalability, high integration density, quick switching, etc,. Intrinsic physical phenomenon of RRAMs is resistive switching. In this work, ion beam irradiation was used as a tool to modify resistive switching of pulsed laser deposited (PLD) Y0.95Ca0.05MnO3/Si films. Ion irradiation induced optimal resistive switching with spectroscopic correlations has been attributed to oxygen vacancy gradient. Resistive switching ratio is estimated to be increased for the film irradiated with fluence 1×10¹¹ ions/cm² due to irradiation induced strain and oxygen vacancies verified by X’ray diffraction (XRD), Raman, atomic force microscopy (AFM), Rutherford backscattering spectrometry (RBS) and near-edge X-ray absorption fine structure (NEXAFS) measurements. Strain relaxation and oxygen vacancy annihilation have been realized for higher fluence (1×1012 and 1×1013 ions/cm²) owing to local annealing effect. Present study suggests that the films understudy can be considered as emerging candidates for RRAMs. X.J. Zhu et al., Front. Mater. Sci. 6 (2012) 183, 206. ** D.S. Jeong et al., Rep. Prog. Phys. 75 (2012) 076502:1,31.
	Poster MOPLS01 [0.745 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLS01
About •	paper received ※ 26 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPLH11	Nanostructured Photocathodes for Spin-Polarized Electron Beams	cathode, polarization, lattice, electron	196
	E.J. Montgomery, C. Jing, S. Poddar Euclid Beamlabs LLC, Bolingbrook, USA A. Afanasev GWU, Washington, USA R. Kumar, G.J. Salamo University of Arkansas, Fayetteville, Arkansas, USA S. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by US DOE Office of Science, Office of Nuclear Physics, SBIR grant DESC0019559. CNM work supported by US DOE Office of Science, Basic Energy Sciences, contract DE-AC02-06CH11357. We present progress on incorporation of nanopillar arrays into spin-polarized gallium arsenide photocathodes in pursuit of record high tolerance to ion back-bombardment. Our goal is to exceed the 400 Coulomb record for a high polarization milliampere-class electron source set at Jefferson Laboratory in 2017, while maintaining high quantum efficiency (QE) and spin polarization with a superlattice. Because the Mie effect is resonant, uniformity and careful control over nanostructure geometry is key. We report excellent uniformity and straight sidewall geometry with improved optical absorption using a painstakingly optimized inductively coupled plasma reactive ion etch. We also report the application of Kerker theory to spin-polarized photocathode nanopillar arrays, setting new requirements on nanostructure dimensions to avoid spoiling spin polarization. Finally, we also report initial steps toward re-establishing U.S. production of strained superlattice photocathodes towards integration with nanopillar arrays.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH11
About •	paper received ※ 03 September 2019 paper accepted ※ 12 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPLO06	Black Gun Technologies for DC Photoinjectors	gun, vacuum, electron, laser	247
	E.J. Montgomery, C. Jing, S. Poddar Euclid Beamlabs LLC, Bolingbrook, USA J.E. Butler Euclid TechLabs, LLC, Solon, Ohio, USA S. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by the US DOE Office of Science, Office of Nuclear Physics, grant number DESC0019688. Work at Argonne CNM under Contract No. DE-AC02-06CH11357. Euclid Beamlabs is developing a new "Black Gun" concept in direct current (DC) photoinjectors. To reduce electron-stimulated desorption indirectly influenced by stray photoemission, we are testing advanced optical coatings and low-scattering optics compatible with the extreme high vacuum (XHV) environment of modern DC photoinjectors. Stray light in DC photoinjectors (in proportion to the photoemitted charge) causes off-nominal photoemission, initiating electron trajectories which intercept downstream surfaces. This causes electron-stimulated desorption of atoms, which ionize and may back-bombard the cathode, reducing its charge lifetime. Back-bombardment is key for high average current or high repetition rate. First, we report on progress developing optical skimmers based on Butler baffles to collimate both incoming and outgoing laser beams. Second, we describe candidate coatings for reduction of scattered light. Requirements for these coatings are that they be conducting, optically black at the drive laser wavelength, conformally applied to complex geometry, and XHV-compatible with negligible outgassing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO06
About •	paper received ※ 04 September 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM24	Electron Heating by Ions in Cooling Rings	electron, radiation, proton, damping	426
	H. Zhao, M. Blaskiewicz BNL, Upton, New York, USA
	Hadron beam cooling at high energy is a critical technique for Electron-Ion Colliders (EIC). We consider using an electron storage ring for the EIC at BNL. For such a cooler, the electron beam quality plays an important role since it directly determines the cooling rate. Besides the effects of IBS, space charge and synchrotron damping, which are calculable with well known methods, the heating effect by ions also needs to be carefully considered in electron beam dynamics. In this paper, we present an analytical model to calculate the heating rate by ions and give some example calculations. In addition, this model was benchmarked by applying it on the IBS calculation. * Work supported by States Department of Energy
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM24
About •	paper received ※ 26 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM25	Connecting Gas-Scattering Lifetime and Ion Instabilities	experiment, electron, storage-ring, vacuum	430
	B. Podobedov, M. Blaskiewicz BNL, Upton, New York, USA
	Recently there is a renewed interest in fast ion instability (FII) which is of concern for future low-emittance electron storage rings, such as MBA light sources and colliders, i.e. eRHIC. While analytical theories and numerical codes exist to model the effect, due to various assumptions and limitations, accurate experimental verification is often desirable. Unfortunately, one of the most critical parameters for FII (as well as the classical "trapped-ion" instability), the residual ion concentration, is usually the most uncertain. Vacuum gauges and residual gas analyzers (RGAs) provide some useful data, but they are often not accurate enough, and, more importantly, they cannot directly probe the ion concentration along the beam orbit. In this paper we show how one could use gas-scattering lifetime measurements to infer the residual gas concentration suitable for ion instability experiment modelling.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM25
About •	paper received ※ 21 September 2019 paper accepted ※ 19 November 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEYBB3	Foil Scattering Model for Fermilab Booster	injection, booster, proton, operation	632
	C.M. Bhat, S. Chaurize, J.S. Eldred, V.A. Lebedev, S. Nagaitsev, K. Seiya, C.-Y. Tan, R. Tesarek Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. At the Fermilab Booster, and many other proton facilities, an intense proton beam is accumulated by injection an H⁻ beam through a stripping foil. The circulating beam scatters off the injection beam and large-angle Coulomb scattering leads to uncontrolled losses concentrated in the first betatron period. We measure the foil scattering rate in the Booster as a function of linac current, number of injection-turns, and time on injection foil. We find that current Booster operations has a 1% foil scattering loss rate and we make projections for the Proton Improvement Plan II (PIP-II) injector upgrade. We find that accurate modeling of the foil scattering loss must account for beam emittance in conjunction with the scattering rate and ring acceptance. Estimate of beam emittance at injection are discussed.
	Slides WEYBB3 [5.690 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB3
About •	paper received ※ 28 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLE08	Parallel Tracking-Based Modeling of Gas Scattering and Loss Distributions in Electron Storage Rings	lattice, simulation, storage-ring, electron	901
	M. Borland ANL, Lemont, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Estimation of gas scattering lifetimes in storage rings is typically done using a simple approach that can readily be performed by hand. A more sophisticated approach uses linear mapping of the angular dynamic acceptance around the ring and allows including variation of gas pressure and composition. However, neither approach is appropriate for highly nonlinear lattices, in which the angular acceptance does not map according to the linear optics. Further, these approaches provide no detailed information about the location of losses. To address these limitations, a tracking-based approach was implemented in the program Pelegant. We describe the implementation and performance of this method, as well as several applications to the Advanced Photon Source Upgrade. M. Borland, J. Carter, H. Cease, and B. Stillwell, Proc. IPAC 2015, 546. ** Y. Wang and M. Borland, AIP Conf. Proc. 877, 241 (2006).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE08
About •	paper received ※ 27 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPLS01

Spectroscopic Correlations to Resistive Switching of Ion Beam Irradiated Films

radiation, ECR, experiment, laser

160

K.N. Rathod, N.A. Shah, P.S. Solanki
Saurashtra University, Rajkot, Gujarat, India
K. Asokan
IUAC, New Delhi, India
K.H. Chae, J.P. Singh
Korea Institute of Science and Technology, Advanced Analysis Center, Seoul, Republic of Korea

Researchers concentrated on resistive random access memories (RRAMs) due to excellent scalability, high integration density, quick switching, etc*,**. Intrinsic physical phenomenon of RRAMs is resistive switching. In this work, ion beam irradiation was used as a tool to modify resistive switching of pulsed laser deposited (PLD) Y0.95Ca0.05MnO3/Si films. Ion irradiation induced optimal resistive switching with spectroscopic correlations has been attributed to oxygen vacancy gradient. Resistive switching ratio is estimated to be increased for the film irradiated with fluence 1×10¹¹ ions/cm² due to irradiation induced strain and oxygen vacancies verified by X’ray diffraction (XRD), Raman, atomic force microscopy (AFM), Rutherford backscattering spectrometry (RBS) and near-edge X-ray absorption fine structure (NEXAFS) measurements. Strain relaxation and oxygen vacancy annihilation have been realized for higher fluence (1×1012 and 1×1013 ions/cm²) owing to local annealing effect. Present study suggests that the films understudy can be considered as emerging candidates for RRAMs.
* X.J. Zhu et al., Front. Mater. Sci. 6 (2012) 183, 206.
** D.S. Jeong et al., Rep. Prog. Phys. 75 (2012) 076502:1,31.

Poster MOPLS01 [0.745 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLS01

About •

paper received ※ 26 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019

Export •

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

MOPLH11

Nanostructured Photocathodes for Spin-Polarized Electron Beams

cathode, polarization, lattice, electron

196

E.J. Montgomery, C. Jing, S. Poddar
Euclid Beamlabs LLC, Bolingbrook, USA
A. Afanasev
GWU, Washington, USA
R. Kumar, G.J. Salamo
University of Arkansas, Fayetteville, Arkansas, USA
S. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by US DOE Office of Science, Office of Nuclear Physics, SBIR grant DESC0019559. CNM work supported by US DOE Office of Science, Basic Energy Sciences, contract DE-AC02-06CH11357.
We present progress on incorporation of nanopillar arrays into spin-polarized gallium arsenide photocathodes in pursuit of record high tolerance to ion back-bombardment. Our goal is to exceed the 400 Coulomb record for a high polarization milliampere-class electron source set at Jefferson Laboratory in 2017, while maintaining high quantum efficiency (QE) and spin polarization with a superlattice. Because the Mie effect is resonant, uniformity and careful control over nanostructure geometry is key. We report excellent uniformity and straight sidewall geometry with improved optical absorption using a painstakingly optimized inductively coupled plasma reactive ion etch. We also report the application of Kerker theory to spin-polarized photocathode nanopillar arrays, setting new requirements on nanostructure dimensions to avoid spoiling spin polarization. Finally, we also report initial steps toward re-establishing U.S. production of strained superlattice photocathodes towards integration with nanopillar arrays.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH11

About •

paper received ※ 03 September 2019 paper accepted ※ 12 September 2019 issue date ※ 08 October 2019

Export •

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

MOPLO06

Black Gun Technologies for DC Photoinjectors

gun, vacuum, electron, laser

247

E.J. Montgomery, C. Jing, S. Poddar
Euclid Beamlabs LLC, Bolingbrook, USA
J.E. Butler
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by the US DOE Office of Science, Office of Nuclear Physics, grant number DESC0019688. Work at Argonne CNM under Contract No. DE-AC02-06CH11357.
Euclid Beamlabs is developing a new "Black Gun" concept in direct current (DC) photoinjectors. To reduce electron-stimulated desorption indirectly influenced by stray photoemission, we are testing advanced optical coatings and low-scattering optics compatible with the extreme high vacuum (XHV) environment of modern DC photoinjectors. Stray light in DC photoinjectors (in proportion to the photoemitted charge) causes off-nominal photoemission, initiating electron trajectories which intercept downstream surfaces. This causes electron-stimulated desorption of atoms, which ionize and may back-bombard the cathode, reducing its charge lifetime. Back-bombardment is key for high average current or high repetition rate. First, we report on progress developing optical skimmers based on Butler baffles to collimate both incoming and outgoing laser beams. Second, we describe candidate coatings for reduction of scattered light. Requirements for these coatings are that they be conducting, optically black at the drive laser wavelength, conformally applied to complex geometry, and XHV-compatible with negligible outgassing.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO06

About •

paper received ※ 04 September 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLM24

Electron Heating by Ions in Cooling Rings

electron, radiation, proton, damping

426

H. Zhao, M. Blaskiewicz
BNL, Upton, New York, USA

Hadron beam cooling at high energy is a critical technique for Electron-Ion Colliders (EIC). We consider using an electron storage ring for the EIC at BNL. For such a cooler, the electron beam quality plays an important role since it directly determines the cooling rate. Besides the effects of IBS, space charge and synchrotron damping, which are calculable with well known methods, the heating effect by ions also needs to be carefully considered in electron beam dynamics. In this paper, we present an analytical model to calculate the heating rate by ions and give some example calculations. In addition, this model was benchmarked by applying it on the IBS calculation.
* Work supported by States Department of Energy

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM24

About •

paper received ※ 26 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLM25

Connecting Gas-Scattering Lifetime and Ion Instabilities

experiment, electron, storage-ring, vacuum

430

B. Podobedov, M. Blaskiewicz
BNL, Upton, New York, USA

Recently there is a renewed interest in fast ion instability (FII) which is of concern for future low-emittance electron storage rings, such as MBA light sources and colliders, i.e. eRHIC. While analytical theories and numerical codes exist to model the effect, due to various assumptions and limitations, accurate experimental verification is often desirable. Unfortunately, one of the most critical parameters for FII (as well as the classical "trapped-ion" instability), the residual ion concentration, is usually the most uncertain. Vacuum gauges and residual gas analyzers (RGAs) provide some useful data, but they are often not accurate enough, and, more importantly, they cannot directly probe the ion concentration along the beam orbit. In this paper we show how one could use gas-scattering lifetime measurements to infer the residual gas concentration suitable for ion instability experiment modelling.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM25

About •

paper received ※ 21 September 2019 paper accepted ※ 19 November 2019 issue date ※ 08 October 2019

Export •

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

WEYBB3

Foil Scattering Model for Fermilab Booster

injection, booster, proton, operation

632

C.M. Bhat, S. Chaurize, J.S. Eldred, V.A. Lebedev, S. Nagaitsev, K. Seiya, C.-Y. Tan, R. Tesarek
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
At the Fermilab Booster, and many other proton facilities, an intense proton beam is accumulated by injection an H⁻ beam through a stripping foil. The circulating beam scatters off the injection beam and large-angle Coulomb scattering leads to uncontrolled losses concentrated in the first betatron period. We measure the foil scattering rate in the Booster as a function of linac current, number of injection-turns, and time on injection foil. We find that current Booster operations has a 1% foil scattering loss rate and we make projections for the Proton Improvement Plan II (PIP-II) injector upgrade. We find that accurate modeling of the foil scattering loss must account for beam emittance in conjunction with the scattering rate and ring acceptance. Estimate of beam emittance at injection are discussed.

Slides WEYBB3 [5.690 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB3

About •

paper received ※ 28 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLE08

Parallel Tracking-Based Modeling of Gas Scattering and Loss Distributions in Electron Storage Rings

lattice, simulation, storage-ring, electron

901

M. Borland
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Estimation of gas scattering lifetimes in storage rings is typically done using a simple approach that can readily be performed by hand. A more sophisticated approach uses linear mapping of the angular dynamic acceptance around the ring and allows including variation of gas pressure and composition*. However, neither approach is appropriate for highly nonlinear lattices, in which the angular acceptance does not map according to the linear optics. Further, these approaches provide no detailed information about the location of losses. To address these limitations, a tracking-based approach was implemented in the program Pelegant**. We describe the implementation and performance of this method, as well as several applications to the Advanced Photon Source Upgrade.
* M. Borland, J. Carter, H. Cease, and B. Stillwell, Proc. IPAC 2015, 546.
** Y. Wang and M. Borland, AIP Conf. Proc. 877, 241 (2006).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE08

About •

paper received ※ 27 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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