NAPAC2019 - List of Keywords (optics)

Paper	Title	Other Keywords	Page
MOYBA2	Commissioning of the Phase 2 and Phase 3 SuperKEKB / B-Factory	detector, MMI, luminosity, injection	14
	S. Nakamura KEK, Ibaraki, Japan
	The next generation of B-Factory, the SuperKEKB electron-positron collider at KEK (Japan) has started after two years shutdown from the Phase 1 commissioning in 2016. The first phase for the vacuum scrubbing in 2016 and the second phase focused on the verification of the novel "nano-beam" collision scheme were successfully completed in 2018. The modifications between Phase 1 and Phase 2 follows Phase 3 are installations of the final focus system and the Belle II detector. In order to accomplish the higher luminosity more than the predecessor KEKB , the nano-beam scheme is studied with higher bunch currents to reduce the beam-beam blowup which degrade the luminosity. The new collision scheme is reviewed and the luminosity performance and overall status in the Phase 2 and Phase 3 commissioning are presented.
	Slides MOYBA2 [13.453 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBA2
About •	paper received ※ 30 August 2019 paper accepted ※ 01 September 2019 issue date ※ 08 October 2019
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TUYBB4	Online Modelling and Optimization of Nonlinear Integrable Systems	lattice, experiment, octupole, network	318
	N. Kuklev, Y.K. Kim University of Chicago, Chicago, Illinois, USA A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy. Nonlinear integrable optics was recently proposed as a design approach to increase the limits on beam brightness and intensity imposed by fast collective instabilities. To study these systems experimentally, a new research electron and proton storage ring, the Integrable Optics Test Accelerator, was constructed and recently commissioned at Fermilab. Beam-based diagnostics and online modelling of nonlinear systems presents unique challenges - in this paper, we report on our efforts to develop optimization methods suited for such lattices. We explore the effectiveness of neural networks as fast online surrogate estimators, and integrate them into a beam-based tuning algorithm. We also develop a method of knob dimensionality reduction and subsequent robust multivariate optimization for maximizing key performance metrics under complicated lattice optics constraints.
	Slides TUYBB4 [5.771 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB4
About •	paper received ※ 03 September 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019
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TUYBB5	Design and Analysis of a Halo-Measurement Diagnostics	electron, diagnostics, radiation, experiment	322
	C.J. Marshall, P. Piot Northern Illinois University, DeKalb, Illinois, USA S.V. Benson, J. Gubeli JLab, Newport News, Virginia, USA P. Piot, J. Ruan Fermilab, Batavia, Illinois, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear physics under contract DE-AC05-06OR23177 and DE-AC02-07CH11359. A large dynamical-range diagnostics (LDRD) design at Jefferson Lab will be used at the FAST-IOTA injector to measure the transverse distribution of halo associated with a high-charge electron beam. One important aspect of this work is to explore the halo distribution when the beam has significant angular momentum (i.e. is magnetized). The beam distribution is measured by recording radiation produced as the beam impinges a YAG:Ce screen. The optical radiation is split with a fraction directed to a charged-couple device (CCD) camera. The other part of the radiation is reflected by a digital micromirror device (DMD) that masks the core of the beam distribution. Combining the images recorded by the two cameras provides a measurement of the transverse distribution with over a large dynamical range. The design and analysis of the optical system will be discussed including optical simulation using SRW and the result of a mockup experiment to test the performances of the system will be presented.
	Slides TUYBB5 [3.013 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB5
About •	paper received ※ 02 September 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019
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TUZBB6	Nonlinear Tune-Shift Measurements in the Integrable Optics Test Accelerator	experiment, lattice, electron, betatron	368
	S. Szustkowski, S. Chattopadhyay Northern Illinois University, DeKalb, Illinois, USA S. Chattopadhyay, A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, USA N. Kuklev University of Chicago, Chicago, Illinois, USA
	Funding: US Department of Energy, Office of High Energy Physics, General Accelerator Research and Development (GARD) Program The first experimental run of Fermilab’s Integrable Optics Test Accelerator (IOTA) ring aimed at testing the concept of nonlinear integrable beam optics. In this report we present the preliminary results of the studies of a nonlinear focusing system with two invariants of motion realized with the special elliptic-potential magnet. The key measurement of this experiment was the horizontal and vertical betatron tune shift as a function of transverse amplitude. A vertical kicker strength was varied to change the betatron amplitude for several values of the nonlinear magnet strength. The turn-by-turn positions of the 100 MeV electron beam at twenty-one beam position monitors around the ring were captured and used for the analysis of phase-space trajectories.
	Slides TUZBB6 [12.888 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB6
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
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TUPLM08	Experimental Studies of Single Invariant Quasi-Integrable Nonlinear Optics at IOTA	octupole, experiment, lattice, alignment	383
	N. Kuklev, Y.K. Kim University of Chicago, Chicago, Illinois, USA S. Nagaitsev, A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy. The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report on run 1 results of experimental studies of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread, dynamic aperture, and invariant conservation. We also outline current simulation and hardware improvement efforts for run 2, planned for fall of 2019.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM08
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
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TUPLM21	Optical Stochastic Cooling Program at Fermilab’s Integrable Optics Test Accelerator	experiment, radiation, lattice, electron	418
	J.D. Jarvis, S. Chattopadhyay, V.A. Lebedev, H. Piekarz, P. Piot, A.L. Romanov, J. Ruan Fermilab, Batavia, Illinois, USA S. Chattopadhyay, P. Piot Northern Illinois University, DeKalb, Illinois, USA
	Funding: Fermi National Accelerator Laboratory is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Beam cooling enables an increase of peak and average luminosities and significantly expands the discovery potential of colliders. Optical Stochastic Cooling (OSC) is a high-bandwidth cooling technique that will advance the present state-of-the-art, stochastic-cooling rate by more than three orders of magnitude. A proof-of-principle demonstration with protons or heavy ions involves prohibitive costs, risks and technological challenges; however, exploration of OSC with electrons is a cost-effective alternative for studying the beam-cooling physics, optical systems and diagnostics. The ability to demonstrate OSC was a key requirement in the design of Fermilab’s Integrable Optics Test Accelerator (IOTA) ring. The IOTA program will explore the physics and technology of OSC in amplified and non-amplified configurations. We also plan to investigate the cooling and manipulation of a single electron stored in the ring. The OSC apparatus is currently being fabricated, and installation will begin in the fall of 2019. In this contribution, we will describe the IOTA OSC program, the upcoming passive-OSC experimental runs and ongoing preparations for an amplified-OSC experiment
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM21
About •	paper received ※ 27 August 2019 paper accepted ※ 06 September 2019 issue date ※ 08 October 2019
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TUPLS08	Analysis of Allison Scanner Phase Portraits Using Action-Phase Coordinates	MEBT, quadrupole, ECR, focusing	467
	C.J. Richard NSCL, East Lansing, Michigan, USA J.-P. Carneiro, L.R. Prost, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	Allison scanners provide detailed information on the beam transverse phase space. An effective way for analyzing the beam distribution from these measurements is to use action-phase coordinates, where beam propagation in a linear lattice is reduced to advancing the phase. This report presents such analysis for measurements performed with a 2.1 MeV, 5 mA H⁻ beam in the MEBT of the PIP2IT test accelerator at Fermilab. In part, with the choice of calculating the Twiss parameters over the high intensity portion of the beam, the beam core is found to be phase-independent with intensity decreasing exponentially with action, while the beam tails exhibit a clear phase dependence that is stable over the beam line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS08
About •	paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
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TUPLH09	Thermal Effects on Bragg Diffraction of XFEL Optics	FEL, photon, simulation, synchrotron	506
	Z. Qu, J. Wu, G. Zhou SLAC, Menlo Park, California, USA Y. Ma, Z. Qu UC Merced, Merced, California, USA B. Yang Western Digital, Milpitas, California, USA
	Funding: The US Department of Energy (DOE) (DE-AC02-76SF00515); The US DOE Office of Science Early Career Research Program grant (FWP-2013-SLAC-100164). Crystal optical devices are widely used in X-ray free electron laser (XFEL) systems, monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, and spectrometers. The absorption of X-ray in these optical devices can cause increase of temperature and consequent thermal deformation, which can dynamic change in optic output. In self-seeding XFEL, the thermal deformation and strain in monochromator could cause significant seed quality degradation: central energy shift, band broadening and reduction in seed power. To quantitatively estimate the impact of thermomechanical effects on seed quality, we conduct thermomechanical simulations combined with diffraction to evaluate the seed quality with residual temperature field in a pump-probe manner. With our results, we show that a critical repetition rate could be determined, once the criteria for deviation of the seed quality are selected. This tool shows great potential for the design of XFEL optics for stable operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH09
About •	paper received ※ 28 August 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019
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TUPLO12	Off-Momentum Optics Correction in RHIC	lattice, closed-orbit, experiment, injection	556
	G. Robert-Demolaize, A. Marusic, V. Ptitsyn BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Future operations of the electron-ion collider eRHIC call for beams circulating off of the magnetic center of all arc elements. In order to ensure that both stable beam conditions and the desired circumference change can be achieved, dedicated experiments were conducted during RHIC Run18, which included the first off-momentum linear optics correction. This article reviews the experimental setup as well as the dedicated algorithm for optics correction, and presents the measured radial excursion and residual off-momentum beta-beat.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO12
About •	paper received ※ 27 August 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019
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WEPLS04	Simulations of Low Energy Au⁷⁸⁺ Losses in RHIC	electron, lattice, MMI, closed-orbit	775
	G. Robert-Demolaize, K.A. Drees, Y. Luo BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The RHIC Run19 BES-II program features the commissioning of the Low Energy RHIC electron Cooling (LEReC) Project, which uses electron cooling techniques to compensate for intra-beam scattering and thus to improve the luminosity lifetime. During RHIC operations at 3.85 GeV (beam energy) with LEReC, one needs to ensure that the electron beam energy is properly matched for cooling purposes: if so, some of the circulating Au-79 ions can recombine with an electron, turning into Au-78 and circulating with a large momentum offset. Part of the LEReC commissioning steps is therefore to drive a maximized number of Au-78 ions towards a chosen location of the RHIC mechanical aperture to generate particle showers that can be detected by a Recombination Monitor outside the cryostat. This article introduces the baseline lattice design, then discusses the few scenarios considered for optimizing Au-78 losses at a given location. Each scenario is then simulated using new tracking tools for generating beam loss maps.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS04
About •	paper received ※ 27 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019
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WEPLS10	Modeling of Space-Charge Effects in the ORISS MRTOF Device for Applications to FRIB	focusing, space-charge, operation, linac	786
	R. Hipple MSU, East Lansing, Michigan, USA S.M. Lund FRIB, East Lansing, Michigan, USA
	The Oak Ridge Isotope/Isomer Spectrometer and Separator (ORISS) is an electrostatic multiply reflecting time-of-flight (MRTOF) mass separator constructed by the University Radioactive Ion Beam Consortium (UNIRIB) and Louisiana State University. The device was never fully commissioned, and was eventually shipped to Michigan State University for use at the Facility for Rare Isotopes and Beams (FRIB). The separation process is sensitive to space-charge effects due to the reflection of ions at both ends of the trap, as well as nonlinearities in the optics. In this study we apply the time-based particle-in-cell code Warp to model the effects of intense space-charge during the separation process. We find that the optics can be tuned for isochronous operation and focusing in the presence of intense space-charge to enable separation of bunches with high particle counts. This suggests the device may be effectively utilized at FRIB as a separator, spectrograph and spectrometer.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS10
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
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THXBA2	Analysis of Beam Position Monitor Requirements with Bayesian Gaussian Regression	undulator, brightness, quadrupole, emittance	912
	Y. Li, R.S. Rainer BNL, Upton, New York, USA W.X. Cheng ANL, Lemont, Illinois, USA Y. Hao FRIB, East Lansing, Michigan, USA
	Funding: This research is supported by U.S. Department of Energy under Contract No. DE-SC0012704, and the NSF under Cooperative Agreement PHY-1102511. With a Bayesian Gaussian regression approach, a systematic method for analyzing a storage ring’s beam position monitor (BPM) system requirements has been developed. The ultimate performance of a ring-based accelerator, based on brightness or luminosity, is determined not only by global parameters, but also by local beam properties at some particular points of interest (POI). BPMs used for monitoring the beam properties, however, can not be located at these points. Therefore, the underlying and fundamental purpose of a BPM system is to predict whether the beam properties at POIs reach their desired values. The prediction process is a regression problem with BPM readings as the training data, but containing random noise. A Bayesian Gaussian regression approach can determine the probability distribution of the predictive errors, which can be used to conversely analyze the BPM system requirements. This approach is demonstrated by using turn-by-turn data to reconstruct a linear optics model, and predict the brightness degradation for a ring-based light source. The quality of BPMs was found to be more important than their quantity in mitigating predictive errors.
	Slides THXBA2 [3.205 MB]
	Poster THXBA2 [7.083 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THXBA2
About •	paper received ※ 16 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
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Paper

Title

Other Keywords

Page

MOYBA2

Commissioning of the Phase 2 and Phase 3 SuperKEKB / B-Factory

detector, MMI, luminosity, injection

14

S. Nakamura
KEK, Ibaraki, Japan

The next generation of B-Factory, the SuperKEKB electron-positron collider at KEK (Japan) has started after two years shutdown from the Phase 1 commissioning in 2016. The first phase for the vacuum scrubbing in 2016 and the second phase focused on the verification of the novel "nano-beam" collision scheme were successfully completed in 2018. The modifications between Phase 1 and Phase 2 follows Phase 3 are installations of the final focus system and the Belle II detector. In order to accomplish the higher luminosity more than the predecessor KEKB , the nano-beam scheme is studied with higher bunch currents to reduce the beam-beam blowup which degrade the luminosity. The new collision scheme is reviewed and the luminosity performance and overall status in the Phase 2 and Phase 3 commissioning are presented.

Slides MOYBA2 [13.453 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBA2

About •

paper received ※ 30 August 2019 paper accepted ※ 01 September 2019 issue date ※ 08 October 2019

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TUYBB4

Online Modelling and Optimization of Nonlinear Integrable Systems

lattice, experiment, octupole, network

318

N. Kuklev, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy.
Nonlinear integrable optics was recently proposed as a design approach to increase the limits on beam brightness and intensity imposed by fast collective instabilities. To study these systems experimentally, a new research electron and proton storage ring, the Integrable Optics Test Accelerator, was constructed and recently commissioned at Fermilab. Beam-based diagnostics and online modelling of nonlinear systems presents unique challenges - in this paper, we report on our efforts to develop optimization methods suited for such lattices. We explore the effectiveness of neural networks as fast online surrogate estimators, and integrate them into a beam-based tuning algorithm. We also develop a method of knob dimensionality reduction and subsequent robust multivariate optimization for maximizing key performance metrics under complicated lattice optics constraints.

Slides TUYBB4 [5.771 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB4

About •

paper received ※ 03 September 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019

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TUYBB5

Design and Analysis of a Halo-Measurement Diagnostics

electron, diagnostics, radiation, experiment

322

C.J. Marshall, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
S.V. Benson, J. Gubeli
JLab, Newport News, Virginia, USA
P. Piot, J. Ruan
Fermilab, Batavia, Illinois, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear physics under contract DE-AC05-06OR23177 and DE-AC02-07CH11359.
A large dynamical-range diagnostics (LDRD) design at Jefferson Lab will be used at the FAST-IOTA injector to measure the transverse distribution of halo associated with a high-charge electron beam. One important aspect of this work is to explore the halo distribution when the beam has significant angular momentum (i.e. is magnetized). The beam distribution is measured by recording radiation produced as the beam impinges a YAG:Ce screen. The optical radiation is split with a fraction directed to a charged-couple device (CCD) camera. The other part of the radiation is reflected by a digital micromirror device (DMD) that masks the core of the beam distribution. Combining the images recorded by the two cameras provides a measurement of the transverse distribution with over a large dynamical range. The design and analysis of the optical system will be discussed including optical simulation using SRW and the result of a mockup experiment to test the performances of the system will be presented.

Slides TUYBB5 [3.013 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB5

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paper received ※ 02 September 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019

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TUZBB6

Nonlinear Tune-Shift Measurements in the Integrable Optics Test Accelerator

experiment, lattice, electron, betatron

368

S. Szustkowski, S. Chattopadhyay
Northern Illinois University, DeKalb, Illinois, USA
S. Chattopadhyay, A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA
N. Kuklev
University of Chicago, Chicago, Illinois, USA

Funding: US Department of Energy, Office of High Energy Physics, General Accelerator Research and Development (GARD) Program
The first experimental run of Fermilab’s Integrable Optics Test Accelerator (IOTA) ring aimed at testing the concept of nonlinear integrable beam optics. In this report we present the preliminary results of the studies of a nonlinear focusing system with two invariants of motion realized with the special elliptic-potential magnet. The key measurement of this experiment was the horizontal and vertical betatron tune shift as a function of transverse amplitude. A vertical kicker strength was varied to change the betatron amplitude for several values of the nonlinear magnet strength. The turn-by-turn positions of the 100 MeV electron beam at twenty-one beam position monitors around the ring were captured and used for the analysis of phase-space trajectories.

Slides TUZBB6 [12.888 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB6

About •

paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

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TUPLM08

Experimental Studies of Single Invariant Quasi-Integrable Nonlinear Optics at IOTA

octupole, experiment, lattice, alignment

383

N. Kuklev, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
S. Nagaitsev, A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy.
The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report on run 1 results of experimental studies of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread, dynamic aperture, and invariant conservation. We also outline current simulation and hardware improvement efforts for run 2, planned for fall of 2019.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM08

About •

paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

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TUPLM21

Optical Stochastic Cooling Program at Fermilab’s Integrable Optics Test Accelerator

experiment, radiation, lattice, electron

418

J.D. Jarvis, S. Chattopadhyay, V.A. Lebedev, H. Piekarz, P. Piot, A.L. Romanov, J. Ruan
Fermilab, Batavia, Illinois, USA
S. Chattopadhyay, P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Funding: Fermi National Accelerator Laboratory is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Beam cooling enables an increase of peak and average luminosities and significantly expands the discovery potential of colliders. Optical Stochastic Cooling (OSC) is a high-bandwidth cooling technique that will advance the present state-of-the-art, stochastic-cooling rate by more than three orders of magnitude. A proof-of-principle demonstration with protons or heavy ions involves prohibitive costs, risks and technological challenges; however, exploration of OSC with electrons is a cost-effective alternative for studying the beam-cooling physics, optical systems and diagnostics. The ability to demonstrate OSC was a key requirement in the design of Fermilab’s Integrable Optics Test Accelerator (IOTA) ring. The IOTA program will explore the physics and technology of OSC in amplified and non-amplified configurations. We also plan to investigate the cooling and manipulation of a single electron stored in the ring. The OSC apparatus is currently being fabricated, and installation will begin in the fall of 2019. In this contribution, we will describe the IOTA OSC program, the upcoming passive-OSC experimental runs and ongoing preparations for an amplified-OSC experiment

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM21

About •

paper received ※ 27 August 2019 paper accepted ※ 06 September 2019 issue date ※ 08 October 2019

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TUPLS08

Analysis of Allison Scanner Phase Portraits Using Action-Phase Coordinates

MEBT, quadrupole, ECR, focusing

467

C.J. Richard
NSCL, East Lansing, Michigan, USA
J.-P. Carneiro, L.R. Prost, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Allison scanners provide detailed information on the beam transverse phase space. An effective way for analyzing the beam distribution from these measurements is to use action-phase coordinates, where beam propagation in a linear lattice is reduced to advancing the phase. This report presents such analysis for measurements performed with a 2.1 MeV, 5 mA H⁻ beam in the MEBT of the PIP2IT test accelerator at Fermilab. In part, with the choice of calculating the Twiss parameters over the high intensity portion of the beam, the beam core is found to be phase-independent with intensity decreasing exponentially with action, while the beam tails exhibit a clear phase dependence that is stable over the beam line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS08

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paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

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TUPLH09

Thermal Effects on Bragg Diffraction of XFEL Optics

FEL, photon, simulation, synchrotron

506

Z. Qu, J. Wu, G. Zhou
SLAC, Menlo Park, California, USA
Y. Ma, Z. Qu
UC Merced, Merced, California, USA
B. Yang
Western Digital, Milpitas, California, USA

Funding: The US Department of Energy (DOE) (DE-AC02-76SF00515); The US DOE Office of Science Early Career Research Program grant (FWP-2013-SLAC-100164).
Crystal optical devices are widely used in X-ray free electron laser (XFEL) systems, monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, and spectrometers. The absorption of X-ray in these optical devices can cause increase of temperature and consequent thermal deformation, which can dynamic change in optic output. In self-seeding XFEL, the thermal deformation and strain in monochromator could cause significant seed quality degradation: central energy shift, band broadening and reduction in seed power. To quantitatively estimate the impact of thermomechanical effects on seed quality, we conduct thermomechanical simulations combined with diffraction to evaluate the seed quality with residual temperature field in a pump-probe manner. With our results, we show that a critical repetition rate could be determined, once the criteria for deviation of the seed quality are selected. This tool shows great potential for the design of XFEL optics for stable operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH09

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paper received ※ 28 August 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019

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TUPLO12

Off-Momentum Optics Correction in RHIC

lattice, closed-orbit, experiment, injection

556

G. Robert-Demolaize, A. Marusic, V. Ptitsyn
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Future operations of the electron-ion collider eRHIC call for beams circulating off of the magnetic center of all arc elements. In order to ensure that both stable beam conditions and the desired circumference change can be achieved, dedicated experiments were conducted during RHIC Run18, which included the first off-momentum linear optics correction. This article reviews the experimental setup as well as the dedicated algorithm for optics correction, and presents the measured radial excursion and residual off-momentum beta-beat.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO12

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paper received ※ 27 August 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019

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WEPLS04

Simulations of Low Energy Au⁷⁸⁺ Losses in RHIC

electron, lattice, MMI, closed-orbit

775

G. Robert-Demolaize, K.A. Drees, Y. Luo
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The RHIC Run19 BES-II program features the commissioning of the Low Energy RHIC electron Cooling (LEReC) Project, which uses electron cooling techniques to compensate for intra-beam scattering and thus to improve the luminosity lifetime. During RHIC operations at 3.85 GeV (beam energy) with LEReC, one needs to ensure that the electron beam energy is properly matched for cooling purposes: if so, some of the circulating Au-79 ions can recombine with an electron, turning into Au-78 and circulating with a large momentum offset. Part of the LEReC commissioning steps is therefore to drive a maximized number of Au-78 ions towards a chosen location of the RHIC mechanical aperture to generate particle showers that can be detected by a Recombination Monitor outside the cryostat. This article introduces the baseline lattice design, then discusses the few scenarios considered for optimizing Au-78 losses at a given location. Each scenario is then simulated using new tracking tools for generating beam loss maps.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS04

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paper received ※ 27 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019

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WEPLS10

Modeling of Space-Charge Effects in the ORISS MRTOF Device for Applications to FRIB

focusing, space-charge, operation, linac

786

R. Hipple
MSU, East Lansing, Michigan, USA
S.M. Lund
FRIB, East Lansing, Michigan, USA

The Oak Ridge Isotope/Isomer Spectrometer and Separator (ORISS) is an electrostatic multiply reflecting time-of-flight (MRTOF) mass separator constructed by the University Radioactive Ion Beam Consortium (UNIRIB) and Louisiana State University. The device was never fully commissioned, and was eventually shipped to Michigan State University for use at the Facility for Rare Isotopes and Beams (FRIB). The separation process is sensitive to space-charge effects due to the reflection of ions at both ends of the trap, as well as nonlinearities in the optics. In this study we apply the time-based particle-in-cell code Warp to model the effects of intense space-charge during the separation process. We find that the optics can be tuned for isochronous operation and focusing in the presence of intense space-charge to enable separation of bunches with high particle counts. This suggests the device may be effectively utilized at FRIB as a separator, spectrograph and spectrometer.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS10

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paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

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THXBA2

Analysis of Beam Position Monitor Requirements with Bayesian Gaussian Regression

undulator, brightness, quadrupole, emittance

912

Y. Li, R.S. Rainer
BNL, Upton, New York, USA
W.X. Cheng
ANL, Lemont, Illinois, USA
Y. Hao
FRIB, East Lansing, Michigan, USA

Funding: This research is supported by U.S. Department of Energy under Contract No. DE-SC0012704, and the NSF under Cooperative Agreement PHY-1102511.
With a Bayesian Gaussian regression approach, a systematic method for analyzing a storage ring’s beam position monitor (BPM) system requirements has been developed. The ultimate performance of a ring-based accelerator, based on brightness or luminosity, is determined not only by global parameters, but also by local beam properties at some particular points of interest (POI). BPMs used for monitoring the beam properties, however, can not be located at these points. Therefore, the underlying and fundamental purpose of a BPM system is to predict whether the beam properties at POIs reach their desired values. The prediction process is a regression problem with BPM readings as the training data, but containing random noise. A Bayesian Gaussian regression approach can determine the probability distribution of the predictive errors, which can be used to conversely analyze the BPM system requirements. This approach is demonstrated by using turn-by-turn data to reconstruct a linear optics model, and predict the brightness degradation for a ring-based light source. The quality of BPMs was found to be more important than their quantity in mitigating predictive errors.

Slides THXBA2 [3.205 MB]

Poster THXBA2 [7.083 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THXBA2

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paper received ※ 16 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

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