Keyword: experiment
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MOYBA1 LHC Status and Plans luminosity, operation, electron, proton 8
 
  • X. Buffat
    CERN, Geneva, Switzerland
  
  Performance and accelerator physics challenges from LHC Run 2 are reviewed, along with the ongoing preparation and plans for LHC Runs 3 and 4.  
slides icon Slides MOYBA1 [13.269 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBA1  
About • paper received ※ 26 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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MOZBA3 Strongly Tapered Helical Undulator System for TESSA-266 undulator, electron, laser, permanent-magnet 63
 
  • T.J. Campese, R.B. Agustsson, I.I. Gadjev, A.Y. Murokh
    RadiaBeam, Santa Monica, California, USA
  • W. Berg, A. Zholents
    ANL, Lemont, Illinois, USA
  • P.E. Denham, P. Musumeci, Y. Park
    UCLA, Los Angeles, USA
  
  Funding: DOE SBIR Award No. DE-SC0017102
RadiaBeam, in collaboration with UCLA and Argonne National Laboratory (ANL), is developing a strongly tapered helical undulator system for the Tapering Enhanced Stimulated Superradiant Amplification experiment at 266 nm (TESSA-266). The experiment will be carried out at the APS LEA facility at ANL and aims at the demonstration of very high energy conversion efficiency in the UV. The undulator system was designed by UCLA, engineered by RadiaBeam, and is presently in fabrication at RadiaBeam. The design is based on a permanent magnet Halbach scheme and includes a short 30 cm long buncher section and four 1 m long undulator sections. The undulator period is fixed at 32 mm and the magnetic field amplitude can be tapered by tuning the gap along the interaction. Each magnet can be individually adjusted by 1.03 mm, offering up to 25% magnetic field tunability with a minimum gap of 5.58 mm. A custom designed 316L stainless steel beampipe runs through the center with a clear aperture of 4.5 mm. This paper discusses the design and engineering of the undulator system, fabrication status, and plans for magnetic measurements, and tuning. 		 
slides icon Slides MOZBA3 [8.942 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOZBA3  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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MOZBB2 Experiments with Metamaterial-Based Metallic Accelerating Structures wakefield, acceleration, radiation, GUI 78
 
  • X. Lu
    SLAC, Menlo Park, California, USA
  • M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • X. Lu, I. Mastovsky, J.F. Picard, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  • M.M. Peng
    AAI/ANL, Lemont, Illinois, USA
  • J. Seok
    UNIST, Ulsan, Republic of Korea
  
  Funding: U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award No. DE-SC0015566 at MIT and No. DE-AC02-06CH11357 at ANL
We present experimental studies of metamaterial (MTM) structures for wakefield acceleration. The MTM structure is an all-metal periodic structure with its period much smaller than the wavelength at X-band. The fundamental TM mode has a negative group velocity, so an electron beam traveling through the structure radiates by reversed Cherenkov radiation. Two experiments have been completed at the Argonne Wakefield Accelerator (AWA), namely the Stage-I and Stage-II experiments. Differences between the two experiments include: (1) Structure length (Stage-I 8 cm, Stage-II 20 cm); (2) Bunch number used to excite the structure (Stage-I up to 2 bunches, Stage-II up to 8 bunches). In the Stage-I experiment, two bunches with a total charge of 85 nC generated 80 MW of RF power in a 2 ns long pulse. In the Stage-II experiment, the highest peak power reached 380 MW in a 10 ns long pulse from a train of 8 bunches with a total charge of 224 nC. Acceleration of a witness bunch has not been demonstrated yet, but the extracted power can be transferred to a separate accelerator for two-beam acceleration or directly applied to a trailing witness bunch in the same structure for collinear acceleration. 		 
slides icon Slides MOZBB2 [8.172 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOZBB2  
About • paper received ※ 27 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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MOZBB6 Measuring the Mean Transverse Energy of Pump-Probe Photoemitted Electrons electron, cathode, photon, vacuum 87
 
  • C.M. Pierce, I.V. Bazarov, L. Cultrera, J.M. Maxson
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This work was supported by the U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams.
Low effective mass semiconductor photocathodes have historically failed to exhibit the sub-thermal mean transverse energies (MTEs) expected of them based on their band structure. However, conservation of transverse momentum across the vacuum interface, and therefore a low MTE in these materials, has been observed in time resolved ARPES*. To help bridge this gap, we measured the MTE of the pump probe photoemitted electrons seen in the ARPES experiment using methods typical of accelerator physics. We compare the results of these measurements with those of both communities and discuss them in the context of photoemission physics.
* Kanasaki, J., Tanimura, H., & Tanimura, K. (2014). Imaging Energy-, Momentum-, and Time-Resolved Distributions of Photoinjected Hot Electrons in GaAs. Physical Review Letters, 113(23), 237401. 		 
slides icon Slides MOZBB6 [7.348 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOZBB6  
About • paper received ※ 28 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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MOPLM04 First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization quadrupole, storage-ring, emittance, operation 98
 
  • S.C. Leemann, Ph. Amstutz, W.E. Byrne, M.P. Ehrlichman, T. Hellert, A. Hexemer, S. Liu, M. Marcus, C.N. Melton, H. Nishimura, G. Penn, F. Sannibale, D.A. Shapiro, C. Sun, D. Ushizima, M. Venturini
    LBNL, Berkeley, USA
  
  Funding: This research is funded by the US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM04  
About • paper received ※ 26 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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MOPLM07 Simulation of Beam Aborts for the Advanced Photon Source to Probe Material-Damage Limits for Future Storage Rings simulation, storage-ring, emittance, photon 106
 
  • M. Borland, J.C. Dooling, R.R. Lindberg, V. Sajaev, Y.P. Sun
    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.
Damage to tungsten beam dumps has been observed in the Advanced Photon Source (APS), a 7-GeV, third-generation storage ring light source. This issue is expected to be much more severe in the APS Upgrade, owing to doubling of the stored charge and much lower emittance. An experiment was conducted in the existing APS ring to test several possible dump materials and also assess the accuracy of predictions of beam-induced damage. Prior to the experiments, extensive beam abort simulations were performed with ELEGANT to predict thresholds for material damage, dependence on vertical beam size, and even the size of the trenches expected to be created by the beam. This paper presents the simulation methods, simple models for estimating damage, and results. A companion paper in this conference presents experimental results. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM07  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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MOPLM14 Studies of Beam Dumps in Candidate Horizontal Collimator Materials for the Advanced Photon Source Upgrade Storage Ring simulation, storage-ring, photon, emittance 128
 
  • J.C. Dooling, W. Berg, M. Borland, G. Decker, L. Emery, K.C. Harkay, R.R. Lindberg, A.H. Lumpkin, G. Navrotski, V. Sajaev, Y.P. Sun, K.P. Wootton, A. Xiao
    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
We present the results of experiments intended to show the effects of beam dumps on candidate collimator materials for the Advanced Photon Source Upgrade (APS-U) storage ring (SR). Due to small transverse electron beam sizes, whole beam loss events are expected to yield dose levels in excess of 10 MGy in beam-facing components, pushing irradiated regions into a hydrodynamic regime. Whole beam aborts have characteristic time scales ranging from 100s of ps to 10s of microseconds which are either much shorter than or roughly equal to thermal diffusion times. Aluminum and titanium alloy test pieces are each exposed to a series of beam aborts of varying fill pattern and charge. Simulations suggest the high energy/power densities are likely to lead to phase transitions and damage in any material initially encountered by the beam. We describe measurements used to characterize the beam aborts and compare the results with those from the static particle-matter interaction code, MARS; we also plan to explore wakefield effects. Beam dynamics modeling, done with elegant is discussed in a companion paper at this conference. The goal of this work is to guide the design of APS-U SR collimators. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM14  
About • paper received ※ 27 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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MOPLS01 Spectroscopic Correlations to Resistive Switching of Ion Beam Irradiated Films radiation, ECR, scattering, 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 icon 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  
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MOPLS09 Engineering Design of Gallium-Nickel Target in Niobium Capsule, with a Major Focus on Determining the Thermal Properties of Gallium-Nickel Through Thermal Testing and FEA, for Irradiation at BLIP target, radiation, proton, niobium 170
 
  • S.K. Nayak, S. Bellavia, H. Chelminski, C.S. Cutler, D. Kim, D. Medvedev
    BNL, Upton, New York, USA
  
  Funding: Funding:This abstract is authored by BSA operated under contract number DE-SC0012704. This research is supported by the U.S. DOE Isotope Program, managed by the Office of Science for Nuclear Physics.
The Brookhaven Linac Isotope Producer (BLIP) produces several radioisotopes using a variable energy and current proton beam. The targets irradiated at BLIP are cooled by water and required to be isolated in a target capsule. During the design stage, thermal analysis of the target and cladding is carried out to determine the maximum beam power a target can handle during irradiation without destruction. In this work we designed a capsule for Gallium-Nickel (Ga 80%, Ni 20%) alloy target material and irradiated the target at the BLIP to produce the radioisotope Ge-68. Since no literature data is available on Ga4Ni’s thermal conductivity (K) and specific heat (C), measurements were carried out using thermal testing in conjunction with Finite Element Analysis (FEA). Steady-state one dimensional heat conduction method was used to determine the thermal conductivity. Transient method was used to calculate the specific heat. The test setup with same methodologies can be used to assess other targets in the future. Here, we will detail these studies and discuss the improved design and fabrication of this target. 		 
poster icon Poster MOPLS09 [0.751 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLS09  
About • paper received ※ 27 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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MOPLH06 Study of the Mean Transverse Energy and the Emission Mechanism of (N)UNCD Photocathodes cathode, electron, photon, emittance 181
 
  • G. Chen
    IIT, Chicago, Illinois, USA
  • G. Adhikari, W.A. Schroeder
    UIC, Chicago, Illinois, USA
  • S.P. Antipov, E. Gomez
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Baryshev, T. Nikhar
    Michigan State University, East Lansing, Michigan, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: This project is supported by NSF grant No. NSF-1739150, NSF-1535676, and NSF grant No. PHYS-1535279.
Nitrogen incorporated ultrananocrystalline diamond ((N)UNCD) is promising for photocathode applications due to its high quantum efficiency (QE). The mean transverse energy (MTE) which, along with QE, defines the brightness of the emitted electron beam must be thoroughly characterized and understood for (N)UNCD. Our previous work* further corroborated the important role of graphitic grain boundaries (GB’s). UNCD consists of diamond (sp3-hybrized) grains and graphitic (sp2-hybrized) GB’s: GB’s are behind the high emissivity of (N)UNCD and therefore play a crucial role in defining and controlling the MTE. In this work, the MTE of two different (N)UNCD samples having different ratios of sp3/sp2 were measured versus the primary photon energies. As a reference, MTE of highly oriented pyrolytic graphite (HOPG, canonical sp2-hybrized graphite) was also measured.
* G. Chen et al., Appl. Phys. Lett. 114, 093103 (2019). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH06  
About • paper received ※ 27 August 2019       paper accepted ※ 12 September 2019       issue date ※ 08 October 2019  
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MOPLH09 Photoluminescence Studies of Alkali-Antimonide Photocathodes electron, cathode, laser, photon 188
 
  • P. Saha, O. Chubenko, S.S. Karkare
    Arizona State University, Tempe, USA
  • H.A. Padmore
    LBNL, Berkeley, California, USA
  
  Alkali-antimonide photocathodes have a very high quantum efficiency and a low intrinsic emittance, making them excellent electron sources for Energy Recovery Linacs, X-ray Free Electron Lasers, Electron Cooling, and Ultrafast Electron Diffraction applications. Despite numerous studies of their photoemission spectra, there has been nearly no conclusive experimental investigation of their basic electronic and optical properties (e.g. band gap, electron affinity, optical constants, etc.), which determine the nature of photoemission. Therefore, the systematic study and deep understanding of fundamental characteristics of alkali-antimonide photocathodes are required in order to develop next-generation electron sources with improved crystal and electronic structures to fit specific application. Here we report on the development of an experimental setup to measure photoluminescence (PL) spectra from alkali-antimonide photocathodes, enabling estimation of a material band gap and defect state energies, and provide preliminary results for Cs3Sb films.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH09  
About • paper received ※ 27 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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MOPLH10 Field-Emission Electron Source Embedded in a Field-Enhanced Conduction-Cooled Superconducting RF Cavity cavity, electron, cathode, niobium 192
 
  • D. Mihalcea, V. Korampally, A. McKeown, O. Mohsen, P. Piot, I. Salehinia
    Northern Illinois University, DeKalb, Illinois, USA
  • R. Dhuley, M.G. Geelhoed, P. Piot, J.C.T. Thangaraj
    Fermilab, Batavia, Illinois, USA
  
  We present simulations and experimental progress toward the development of a high-current electron source with the potential to deliver high charge electron bunches at GHz-level repetition rates. To achieve these goals electrons are generated through field-emission and the cathode is immersed in a conduction-cooled superconducting 650-MHz RF cavity. The field-emitters consist of microscopic silicon pyramids and have a typical enhancement factor of about 500. To trigger field-emission, the peak field inside the RF cavity of about 6 MV/m is further enhanced by placing the field-emitters on the top of a superconducting Nb rod inserted in the RF cavity. So far, we cannot control the duration of the electron bunches which is of the order of RF period. Also, the present cryo-cooler power of about 2 W limits the beam current to microamp level.  
poster icon Poster MOPLH10 [1.063 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH10  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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MOPLH13 STARRE Lab: The Sub-THz Accelerator Research Laboratory laser, electron, GUI, operation 199
 
  • J.F. Picard, S.C. Schaub, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  Funding: Department of Energy, Office of HEP, DE- SC0015566; Office of Fusion Energy Sciences, DE-FC02-93ER54186; National Institutes of Health, NIBIB, EB004866 and EB001965;
This work presents the development of the STARRE Lab, a facility at MIT for testing breakdown in high gradient accelerator structures at 110 GHz. The system utilizes a Laser-Driven Semiconductor Switch (LDSS) to modulate the output of a megawatt gyrotron, which generates 3 μs pulses at up to 6 Hz. The LDSS employs silicon (Si) and gallium arsenide (GaAs) wafers to produce nanosecond-scale pulses at the megawatt level from the gyrotron output. Photoconductivity is induced in the wafers using a 532 nm Nd:YAG laser, which produces 6 ns, 230 mJ pulses. A single Si wafer produces 110 GHz RF pulses with 9 ns width, while under the same conditions, a single GaAs wafer produces 24 ns 110 GHz RF pulses. In dual-wafer operation, which uses two active wafers, pulses of variable length down to 3 ns duration can be created at power levels greater than 300 kW. The switch has been successfully tested at incident 110 GHz RF power levels up to 720 kW.* The facility has been used to successfully test an advanced 110 GHz accelerator structure built by SLAC to gradients in excess of 220 MV/m.
*J.F. Picard et al., Appl. Phys. Lett. 114, 164102 (2019); doi: https://doi.org/10.1063/1.5093639
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH13  
About • paper received ※ 24 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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MOPLH19 Beam Dynamics Simulations for a Conduction-Cooled Superconducting RF Electron Source electron, cathode, simulation, emittance 213
 
  • O. Mohsen, V. Korampally, A. McKeown, D. Mihalcea, P. Piot, I. Salehinia
    Northern Illinois University, DeKalb, Illinois, USA
  • R. Dhuley, M.G. Geelhoed, J.C.T. Thangaraj
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by DOE awards DE-SC0018367 with NIU and DE-AC02-07CH11359
The development of robust and portable high-average power electron sources is key to many societal applications. An approach toward such sources is the use of cryogen-free superconducting radiofrequency cavities. This paper presents beam-dynamics simulations for a proof-of-principle experiment on a cryogen-free SRF electron source being prototyped at Fermilab. The proposed design implement a geometry that enhances the electric field at the cathode surface to simultaneously extract and accelerate electrons. In this paper, we explore the beam dynamics considering both the case of field and photoemission mechanism. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH19  
About • paper received ※ 02 September 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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MOPLH22 Focusing Studies of an Electron Beam in Diamond Field Emitter Array Cathodes cathode, electron, focusing, laser 217
 
  • R.L. Fleming, H.L. Andrews, D. Gorelov, C.-K. Huang, D. Kim, J.W. Lewellen, K.E. Nichols, V.N. Pavlenko, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  
  Funding: Los Alamos National Laboratory LDRD Program
We present the simulations and test results for focusing studies performed on diamond field emitter array cathodes. This design utilized a simple variable-focus solenoidal lens in conjunction with a scanning wire technique in order to measure the beam spot size. The spot size was measured by scanning a thin copper wire across the beam in 1 µm increments, with voltage being measured and averaged at each location in order to map the location and intensity of the beam. Scans were taken at different distances away from the magnetic center of the lens, and show good agreement with our simulations of the beam. Ultimately this has allowed us to focus the beam to a spot size of 5.72 µm with an average current of 15.78 µA. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH22  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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MOPLO14 From Start to Finish: Using 3D Printing Techniques to Build CBETA permanent-magnet, dipole, collider, lattice 263
 
  • G.J. Mahler, S.J. Brooks, S.M. Trabocchi
    BNL, Upton, New York, USA
  
  Funding: NYSERDA contract with BNL
The extensive use of a simple 3D printer allowed for fast prototyping and development of many components used to build CBETA. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO14  
About • paper received ※ 14 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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TUXBA3 Robust Thermoacoustic Range Verification for Pulsed Ion Beam Therapy proton, target, radiation, simulation 294
 
  • S.K. Patch
    UWM, Milwaukee, Wisconsin, USA
  • B.M. Brahim, D. Santiago-Gonzalez
    ANL, Lemont, Illinois, USA
  
  Funding: * Supported by the U.S D.O.E., Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. Measurements were performed at ANL’s ATLAS facility, which is a DOE Office of Science User Facility.
Lack of online range verification generally limits application of proton therapy to cancers in the brain, spine, and to pediatric patients. Previously, thermoacoustic range verification (TARV) has been demonstrated in weakly scattering media with known sound speed [1]. At ATLAS, we demonstrated the accuracy and robustness of TARV relative to ultrasound (US) images despite acoustic heterogeneity and sound speed errors representing in vivo conditions [2]. 250 ns pulses deposited 0.26 Gy of 16 MeV protons and 2.3 Gy of 60 MeV helium ions into liquid targets. TA signals were detected by an US array that also generated US images. An air gap phantom displaced the Bragg peak by 6.5 mm and the scanner’s propagation speed setting was altered by ±5%. Weak and strong scatterers were placed between the Bragg peak and US array. Estimated Bragg peak locations were translated 6.5 mm by the air gap phantom and agreed with TRIM simulations to within 0.3 mm, even when TA emissions traveled through a strong acoustic scatterer. Soundspeed errors dilated, and acoustic heterogeneities deformed both US images and TA range estimates, confirming that TARV is accurate relative to US images.
[1] Hickling, et al, Med Phys, 45(7), 2018. (review article)
[2] S. Patch, D. Santiago, & B. Mustapha, Med Phys, 46(1), 2019.
 		 
slides icon Slides TUXBA3 [4.449 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUXBA3  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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TUYBB4 Online Modelling and Optimization of Nonlinear Integrable Systems lattice, optics, 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 icon 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, optics 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 icon 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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TUYBB6 Beam Dynamics in a High Gradient RF Streak Camera electron, cathode, photon, gun 326
 
  • F. Toufexis, V.A. Dolgashev, A. Landa
    SLAC, Menlo Park, California, USA
  
  Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515.
Traditionally, time-resolved experiments in storage ring synchrotron light sources and free-electron lasers are performed with short x-ray pulses with time duration smaller than the time resolution of the phenomenon under study. Typically, storage-ring synchrotron light sources produce x-ray pulses on the order of tens of picoseconds. Newer diffraction limited storage rings produce even longer pulses. We propose to use a high-gradient RF streak camera for time-resolved experiments in storage-ring synchrotron light sources with potential for sub-100 fs resolution. In this work we present a detailed analysis of the effects of the initial time and energy spread of the photo-emitted electrons on the time resolution, as well as a start-to-end beam dynamics simulation in an S-Band system.
* F. Toufexis, et al, "Sub-Picosecond X-Ray Streak Camera using High-Gradient RF Cavities", in Proceedings of IPAC’19. 		 
slides icon Slides TUYBB6 [5.958 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB6  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUZBA5 Algorithms Used in Action and Phase Jump Analysis to Estimate Corrections to Quadrupole Errors in the Interaction Regions of the LHC lattice, quadrupole, software, interaction-region 349
 
  • J.F. Cardona
    UNAL, Bogota D.C, Colombia
  
  Action and phase jump analysis has been used to estimate corrector strengths in the high luminosity interaction regions of the LHC. It has been proven that these corrections are effective to eliminate the beta-beating that is generated in those important regions and that propagates around the ring. More recently, it was also shown that the beta-beating at the interaction point can also be suppressed by combining k-modulation measurements with action and phase jump analysis. Applying this technique to the re-commissioning of the LHC in 2021 requires a good knowledge of the software developed for action and phase jump analysis over the years. In this paper a detailed description is made of all the modules that are part of this software and the corresponding algorithms.  
slides icon Slides TUZBA5 [0.431 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA5  
About • paper received ※ 22 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUZBB5 Transverse Ion Beam Emittance Growth Due to Low Frequency Instabilities in Microwave Ion Source Plasma plasma, emittance, electron, HOM 363
 
  • C. Mallick, M. Bandyopadhyay, R. Kumar
    Institute for Plasma Research, Bhat, Gandhinagar, India
  
  The ion source is accompanied by the generation of low frequency (LF) plasma instabilities (PI). Its signature is also visible in high current heavy ion beam required for any accelerator. These LFs affect the profile of the ion beam in transverse phase-space. These issues are investigated in detail by measuring the emittance of beam. Beam oscillations are extracted from the transverse emittance data by taking Fast Fourier Transform (FFT) of it. PI frequencies are identified in the measured electromagnetic emission from the plasma, in which these frequencies appeared as sidebands around pump frequency 2.45 GHz. The PI components i.e.,ion acoustic (IA) and ion cyclotron (IC) waves are also visible in the FFT spectra. Low and high frequency oscillations in the beam are 476 kHz and ~1.3 MHz respectively. These two groups of frequencies also exist within the PI induced IA (238 - 873 kHz) and IC (1.29 - 1.3 MHz) frequency ranges. The measured emittance (rms-normalized) in horizontal and vertical phase-space varies from 0.002-0.098 𝜋 mm mrad and 0.004-0.23 𝜋 mm mrad respectively. PI induced beam oscillation is the reason behind such broad transverse emittance growth.
Reference
’S. Kumar et al.,Phys. Rev. Accel. Beams 21, 093402 (2018)’
’R. D’Arcy et al., Nucl. Instrum. Methods Phys. Res. A 815 7(2016)’
’L. Groening et al., Phys. Rev. Lett. 113, 264802 (2014)’ 		 
slides icon Slides TUZBB5 [5.298 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB5  
About • paper received ※ 26 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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TUZBB6 Nonlinear Tune-Shift Measurements in the Integrable Optics Test Accelerator optics, 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 icon 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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TUPLM01 Experimental Studies of Resonance Structure Dynamics With Space Charge resonance, space-charge, simulation, quadrupole 372
 
  • L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, S. Bernal, I. Haber, D.F. Sutter, G.D. Wyche
    UMD, College Park, Maryland, USA
  
  Funding: Funding for this project is provided by DOE-HEP award #DE-SC0010301
Space charge is one of the fundamental limitations for next generation high intensity circular accelerators. It can lead to halo growth as well as beam loss, and affect resonance structure in ways not completely understood. We employ the University of Maryland Electron Ring (UMER), a circular 10 keV storage machine, to experimentally study the structure of betatron resonances for beams of varying degrees of space charge intensity. Experimental techniques such as tune scans and frequency maps are employed. Results are also compared to computer simulations using the WARP code. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM01  
About • paper received ※ 26 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLM07 First Experimental Observations of the Plasma-Cascade Instability in the CeC PoP Accelerator electron, plasma, lattice, solenoid 379
 
  • I. Petrushina
    SUNY SB, Stony Brook, New York, USA
  • Y.C. Jing, V. Litvinenko, J. Ma, I. Pinayev, G. Wang, Y.H. Wu
    BNL, Upton, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
  • K. Shih
    SBU, Stony Brook, New York, USA
  
  Preservation of the beam quality is important for attaining the desirable properties of the beam. Collective effects can produce an instability severely degrading beam emittance, momentum spread and creating filamentation of the beam. Microbunching instability for beams traveling along a curved trajectory, and space charge driven parametric transverse instabilities are well-known and in-depth studied. However, none of the above include a microbunching longitudinal instability driven by modulations of the transverse beam size. This phenomenon was observed for the first time during the commissioning of the CeC PoP experiment. Based on the dynamics of this instability we named it a Plasma-Cascade Instability (PCI). PCI can strongly intensify longitudinal micro-bunching originating from the beam’s shot noise, and even saturate it. Resulting random density and energy microstructures in the beam can become a serious problem for generating high quality electron beams. On the other hand, such instability can drive novel high-power sources of broadband radiation. In this paper we present our experimental observations of the PCI and the supporting results of the numerical simulations.  
poster icon Poster TUPLM07 [17.319 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM07  
About • paper received ※ 27 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, optics, 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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TUPLM20 Generation of High-Charge Magnetized Electron Beams Consistent With JLEIC Electron Cooling Requirements emittance, electron, cathode, simulation 414
 
  • A.T. Fetterman, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • S.V. Benson, F.E. Hannon, S. Wang
    JLab, Newport News, Virginia, USA
  • D.J. Crawford, D.R. Edstrom, 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.
The proposed Jefferson Lab Electron-Ion Collider (JLEIC), currently under design, relies on electron cooling in order to achieve the desired luminosity. This includes an electron beam with >55 Mev, 3.2 nC bunches that cools hadron beams with energies up to 100 GeV. To enhance the cooling, the electron beam must be magnetized with a specific eigen-emittance partition. This paper explores the use of the Fermilab Accelerator Science and Technology (FAST) facility to demonstrate the generation of an electron beam with parameters consistent with those required in the JLEIC high-energy cooler. We demonstrate via simulations the generation of the required electron-beam parameters and perform a preliminary experiment to validate FAST capabilities to produce such beams. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM20  
About • paper received ※ 07 September 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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TUPLM21 Optical Stochastic Cooling Program at Fermilab’s Integrable Optics Test Accelerator radiation, lattice, electron, optics 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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TUPLM22 Off Axis Dependence of Current Dependent Coherent Tune Shifts in the UMER Ring space-charge, electron, dipole, storage-ring 422
 
  • D.F. Sutter, B.L. Beaudoin, L. Dovlatyan
    UMD, College Park, Maryland, USA
  
  Funding: Work supported by U. S. Department of Energy grant number DESC00010301
The University of Maryland Electron Ring (UMER) was built to explore space charge effects in the extreme - beyond the space charge limit of most existing storage rings. At the nominal operating kinetic energy of 10 keV, the beam is also non relativistic. We have experimentally verified that the current dependent coherent tune shift obeys the Laslett formula over a wide current range for a cylindrical geometry and non penetrating magnetic fields when the beam is on axis; i.e. the average closed orbit displacement around the ring is essentially zero.* In the current experiment this measurement is extended to the change in current dependent coherent tune shift as the average closed orbit is moved off axis. It can be displaced over approximately ±10 mm of the vacuum pipe diameter of 50 mm without loss of beam. Because the 36 bending magnets in UMER are very short, we treat each of them as a local kick and then increment each by a calculated small amount to achieve the desired, global closed orbit displacement. Experimental results are compared to predictions by Zotter and others.
* D. für Sutter, M.Cornacchia, et al, "Current dependent tune shifts in the University of Maryland electron ring", NAPAC 2013.
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM22  
About • paper received ※ 29 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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TUPLM25 Connecting Gas-Scattering Lifetime and Ion Instabilities scattering, 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  
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TUPLM26 Progress Toward a Laser Amplifier for Optical Stochastic Cooling laser, radiation, undulator, synchrotron-radiation 434
 
  • A.J. Dick, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • M.B. Andorf
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Optical Stochastic Cooling (OSC) is a method of beam cooling using optical frequencies which compresses the phase space of the beam by correcting the deviation of each particle’s momentum. A particle bunch passing through an undulator produces radiation which is amplified and provides the corrective energy kick. In this project, we are testing a method of amplifying synchrotron radiation (SR) for the eventual use in OSC. The SR is amplified by passing through a highly-doped Chromium:Zinc Selenide (Cr:ZnSe) crystal which is pumped by a Thulium fiber laser. The SR will be produced by one of the bending magnets of the Advanced Photon Source. The first step is to detect and measure the power of SR using a photo-diode. The gain is then determined by measuring the radiation amplified after the single-pass through the crystal. This serves as a preliminary step to investigate the performance of the amplification of beam-induced radiation fields. The planned experiment is an important step towards achieving active OSC in a proof-of-principle demonstration in IOTA.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM26  
About • paper received ※ 02 September 2019       paper accepted ※ 13 September 2019       issue date ※ 08 October 2019  
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TUPLM36 Temperature Measurements of the NSLS-II Vacuum Components impedance, vacuum, cavity, detector 443
 
  • A. Blednykh, G. Bassi, C. Hetzel, B.N. Kosciuk, D. Padrazo Jr, T.V. Shaftan, V.V. Smaluk, G.M. Wang
    BNL, Upton, New York, USA
  
  This paper is dedicated to the analysis of our recent experience from ramp-up of operating current at NSLS-II from 25 mA at the end of commissioning in 2014 to 475 mA achieved in studies today. To approach the design level of the ring intensity we had to solve major problems in overheating of the chamber components. Since the beginning of the NSLS-II commissioning, the temperature of the vacuum components has been monitored by the Resistance Temperature Detectors located predominantly outside of the vacuum chamber and attached to the chamber body. A couple of vacuum components were designed with the possibility for internal temperature measurements under the vacuum as diagnostic assemblies. Temperature map helps us to control overheating of the vacuum components around the ring especially during the current ramp-up. The average current of 475mA has been achieved with two main 500MHz RF cavities and w/o any harmonic cavities. In this paper we discuss the heating results for a 15ps bunch length (at low current) of the following vacuum components: Large Aperture BPM, Small Aperture BPM, Bellows, Flanges, Ceramics Chambers and Stripline Kickers.  
poster icon Poster TUPLM36 [3.696 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM36  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLH07 High-Gradient Short Pulse Accelerating Structures electron, wakefield, impedance, acceleration 500
 
  • S.V. Kuzikov, S.P. Antipov, E. Gomez
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  
  High gradients are necessary for lots of applications of electron accelerators. As the maximum gradient is limited by effects of RF breakdown, we present a development of an electron accelerating structure operating with a short multi-megawatt RF pulse. The structure exploits an idea to decrease the breakdown probability due to RF pulse length reduction. This concept requires to distribute RF power so that all accelerating cells are fed independently each other. This implies waveguide net system which allows to delay and to distribute properly RF radiation along the structure keeping synchronism of particles and waves. We have designed an X-band pi-mode structure including the RF design, optimization, and engineering. The structure will be tested as an RF power extractor at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. In this regime we anticipate to obtain 10 ns, gigawatt power level RF pulses generated by train consisted of eight 25-50 nC relativistic bunches.  
poster icon Poster TUPLH07 [0.999 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH07  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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TUPLH08 X-Ray and Charged Particle Detection by Detuning of a Microwave Resonator laser, electron, resonance, coupling 503
 
  • S.P. Antipov, P.V. Avrakhov, E. Dosov, E. Gomez, S.V. Kuzikov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S. Stoupin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  
  Funding: DOE SBIR
Charged particle detection is important for beam alignment, beam loss and background control. In case of halo detection, traditional wire scanner measurement utilizing carbon or tungsten wires is limited by the damage threshold of these materials. In this paper we present an electrodeless method to measure halo with a diamond scraper. This measurement utilizes a microwave resonator placed around the diamond scraper which is sensitive to charged particle-induced conductivity. Due to this transient induced conductivity in the dielectric, a microwave coupling to the resonator changes. Diamond in this case is chosen as a radiation hard material with excellent thermal properties. The absence of electrodes makes the device robust under the beam. The same measurement can be done for x-ray flux monitoring which is important for measurement feedback and calibration at modern x-ray light sources. In this case x-rays passing through the diamond sensing element enable a photo-induced conductivity and that in turn detunes the cavity placed around the diamond. Diamond being a low-Z material allows for in-line x-ray flux measurement without significant beam attenuation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH08  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLO05 Fixed Target Operation at RHIC in 2019 target, controls, kicker, operation 542
 
  • C. Liu, I. Blacker, M. Blaskiewicz, K.A. Brown, D. Bruno, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, D. Kayran, N.A. Kling, Y. Luo, D. Maffei, G.J. Marr, B. Martin, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, I. Pinayev, S. Polizzo, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, P. Thieberger, A. Zaltsman, K. Zeno, I.Y. Zhang, W. Zhang
    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.
RHIC operated in fixed target mode at beam energies 4.59, 7.3, and 31.2 GeV/nucleon in 2019 as a part of the Beam Energy Scan II program. To scrape beam halo effectively at the fixed target which is 2.05 m away from the center of the STAR detectors, lattice design with relative large beta function at STAR was implemented at the two lower energies. The kickers of the base-band tune (BBQ) measurement system were engaged to dilute the beam transversely to maintain the event rate except for 31.2 GeV/nucleon. In addition, beam orbit control, tune and chromaticity adjustments were used to level the event rate. This paper will review the operational experience of RHIC in fixed target mode at various energies. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO05  
About • paper received ※ 21 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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TUPLO12 Off-Momentum Optics Correction in RHIC optics, lattice, closed-orbit, 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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TUPLE04 An Iris Diaphragm Beam Detector for Halo or Profile Measurements detector, electron, GUI, laser 566
 
  • A. Liu
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  Funding: DOE contract DE-SC0019538
Beam halo includes the part of beam that ends up outside of the phase space of the main beam core. It can arise from field emission in the gun and accelerating structures (dark current) and be emitted independently in time and space from the photoelectric emission at the cathode generated by the drive laser. In order to fully understand and characterize the beam halo, Euclid is developing an iris diaphragm detector that allows the beam core to pass without interception, while the halo is collimated. The detector can also work for beam profile measurements. This paper discusses about the recent studies on the iris detector. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE04  
About • paper received ※ 27 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEXBA2 Recent Results and Opportunities at the IOTA Facility electron, radiation, undulator, proton 599
 
  • A.L. Romanov, D.R. Broemmelsiek, K. Carlson, D.J. Crawford, N. Eddy, D.R. Edstrom, J.D. Jarvis, V.A. Lebedev, S. Nagaitsev, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari, A. Valishev, A. Warner
    Fermilab, Batavia, Illinois, USA
  • S. Chattopadhyay, S. Szustkowski
    Northern Illinois University, DeKalb, Illinois, USA
  • Y.K. Kim, N. Kuklev, I. Lobach
    University of Chicago, Chicago, Illinois, USA
  
  The Integrable Optics Test Accelerator (IOTA) was recently commissioned as part of the Fermilab Accelerator Science and Technology (FAST) facility. The IOTA ring was briefly operated with electrons at 47 MeV followed by a 6-months run with 100 MeV electrons. The main goal of the first run was to study beam dynamics in the integrable lattices with elliptical nonlinear magnets and in the quasi-integrable case with profiled octupole channel. The flexibility of the IOTA ring allowed a wide range of complementary studies, such as experiments with a single electron; studies of fluctuations in undulator radiation and operation with low emittance beams. Over the next year the proton injector will be installed and two runs carried out. One run will be dedicated to the refinement of nonlinear experiments and another will be dedicated to the proof-of-principle demonstration of Optical Stochastic Cooling.  
slides icon Slides WEXBA2 [12.702 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEXBA2  
About • paper received ※ 31 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEYBA5 Diamond Field Emitter Array Cathode Experimental Tests in RF Gun cathode, gun, electron, emittance 618
 
  • K.E. Nichols, H.L. Andrews, D. Kim, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • S.P. Antipov
    Euclid Beamlabs LLC, Bolingbrook, USA
  • G. Chen
    IIT, Chicago, Illinois, USA
  • M.E. Conde, D.S. Doran, G. Ha, W. Liu, J.F. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  
  Funding: LANL/LDRD
Diamond Field Emitter Array (DFEA) cathodes are arbitrarily shaped arrays of sharp (~50 nm tip size) nano-diamond pyramids with bases on the order of 3 to 25 microns and pitches 5 microns and greater. These cathodes have demonstrated very high bunch charge in tests at the L-band RF gun at the Argonne National Laboratory (ANL) Advanced Cathode Test Stand (ACTS). Intrinsically shaped electron beams have a variety of applications, but primarily to achieve high transformer ratios for Dielectric Wakefield Accelerators (DWA) when used in conjunction with Emittance Exchange (EEX) systems. Here we will present results from a number of recent cathode tests including bunch charge and YAG images. We have demonstrated shaped beam transport down the 2.54-meter beamline. In addition we will present emission simulations that demonstrate shielding effects for this geometry. 		 
slides icon Slides WEYBA5 [13.017 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBA5  
About • paper received ※ 01 September 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEYBB1 ELENA Commissioning electron, proton, MMI, antiproton 626
 
  • D. Gamba, M.E. Angoletta, P. Belochitskii, L. Bojtár, F. Butin, C. Carli, B. Dupuy, Y. Dutheil, T. Eriksson, P. Freyermuth, C. Grech, M. Hori, J.R. Hunt, M. Jaussi, L.V. Jørgensen, B. Lefort, S. Pasinelli, L. Ponce, G. Tranquille
    CERN, Meyrin, Switzerland
  • R. Gebel
    FZJ, Jülich, Germany
  • C. Grech
    University of Malta, Information and Communication Technology, Msida, Malta
  • M. Hori
    MPQ, Garching, Munich, Germany
  
  The Extra Low ENergy Antiproton storage ring (ELENA) is an upgrade project at the CERN AD (Antiproton Decelerator). ELENA will further decelerate the 5.3 MeV antiprotons coming from the AD down to 100 keV. ELENA features electron cooling for emittance control during deceleration thus preserving the beam intensity and allowing to extract bright bunches towards the experiments. The lower energy will allow for increasing the antiproton trapping efficiency up to two orders of magnitude, which is typically less than 1% with the present beam from AD. The ring was completed with the installation of the electron cooler at the beginning of 2018. Decelerated beams with characteristics close to the design values were obtained before the start of CERN Long Shutdown 2 (LS2). During LS2 electrostatic transfer lines from the ELENA ring to the experimental zones will be installed, replacing the magnetic transfer lines from the AD ring. The latest results of commissioning with H− and antiprotons and the first observation of electron cooling in ELENA will be presented, together with an overview of the project and status and plans for LS2 and beyond.  
slides icon Slides WEYBB1 [20.792 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB1  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEYBB5 A Crab-Crossing Scheme for Laser-Ion Beam Applications laser, linac, cavity, injection 639
 
  • A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, Y. Liu, A. Rakhman, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
  
  Lasers have recently been used in many applications to H− beams, including laser charge exchange, laser wire scanners, and laser temporal pulse patterning. The H− beam in these applications has wide variation ofμpulse length width dependence on focusing of the RF cavities, energy spread of the beam, and space charge forces. Achieving the required laser pulse length for complete overlap with the H− can be challenging in some scenarios when available laser power constrained. The scheme proposed here utilizes a crab-crossing concept between the laser and the ion beam to achieve overlap of a short laser pulse with an arbitrarily long H− beam pulse. An experiment to test the hypothesis in the context of H− charge exchange is described.  
slides icon Slides WEYBB5 [5.201 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB5  
About • paper received ※ 30 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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WEZBA6 A 100 kW 1.3 GHz Magnetron System with Amplitude and Phase Control controls, cavity, klystron, power-supply 656
 
  • M.E. Read, T. Bui, G. Collins, R.L. Ives
    CCR, San Mateo, California, USA
  • B.E. Chase, J. Reid
    Fermilab, Batavia, Illinois, USA
  • J.R. Conant, C.M. Walker
    CPI, Beverley, Massachusetts, USA
  
  Funding: United States Department of Energy Grant No. DE-SC0011229.
Calabazas Creek Research, Inc., Fermilab, and Communications & Power Industries, LLC, developed a 100 kW peak, 10 kW average, 1.3 GHz, magnetron-based, RF system for driving accelerators. Efficiency varied between 81% and 87%. Phase locking uses a novel approach that provides fast amplitude and phase control when coupled into a superconducting accelerator cavity [1]. The system was successfully tested at Fermilab and produced 100 kW in 1.5 ms pulses at a repetition rate of 2 pps. A locking bandwidth of 0.9 MHz was achieved with a drive signal of 269 W injected through a 4 port circulator. The phase locking signal was 25 dB below the magnetron output power. The spectrum of the phase locked magnetron was suitable for driving accelerator cavities. Phase modulation was demonstrated to 50 kHz (the limit of the available driver source). The average power was limited by available conditioning time. Scaling indicates 42 kW of average power should be achievable. Estimated cost is less than $1/Watt of delivered RF power, exclusive of power supplies or modulators. System design and performance measurements will be presented.
[1] B. Chase, R. Pasquinelli, E. Cullerton, P. Varghese, "Precision Vector Control of a Superconducting RF Cavity driven by an Injection Locked Magnetron," Jou. of Instrumentation, Vol. 10 March 2015. 		 
slides icon Slides WEZBA6 [2.515 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA6  
About • paper received ※ 27 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEPLM06 NuMI Beam Muon Monitor Data Analysis and Simulation for Improved Beam Monitoring target, simulation, proton, diagnostics 677
 
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illinois, USA
  • A. Bashyal
    Oregon State University, Corvallis, USA
  • T.J. Rehak
    Drexel University, Philadelphia, Pennsylvania, USA
  • D.A. Wickremasinghe, K. Yonehara
    Fermilab, Batavia, Illinois, USA
  • Y. Yu
    IIT, Chicago, Illinois, USA
  
  Funding: Work supported by US DOE grants DE-SC0019264 and DE-SC0017815 and Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359.
The NuMI muon monitors (MMs) are a very important diagnostic tool for monitoring the stability of the neutrino beam used by the NOvA experiment at Fermilab. The goal of our study is to maintain the quality of the MM signal and to establish the correlations between the neutrino and muon beam profile. This study could also inform the LBNF decision on the beam diagnostic tools. We report on the progress of beam scan data analysis (beam position, spot size, and magnetic horn current scan) and comparison with the simulation outcomes. 		 
poster icon Poster WEPLM06 [6.150 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM06  
About • paper received ※ 30 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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WEPLM13 Multipactor Electron Cloud Analysis in a 17 GHz Standing Wave Accelerator Cavity electron, multipactoring, cavity, simulation 687
 
  • H. Xu, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  Funding: US Department of Energy High Energy Physics
Theoretical predictions of single-surface one-point multipactor modes have been confirmed in experiments with a 17 GHz standing wave single cell disk-loaded waveguide accelerator structure operated in gradient range of 45-90 MV/m. A dc-biased probe placed outside of a slit in the side wall of the structure was used to measure the internal dark current electron energy distribution. The results indicated that the electrons had kinetic energy up to about 50 eV, in agreement with our CST particle-in-cell (PIC) simulations. Further theoretical calculations were performed to calculate the frequency detuning introduced by the multipactor electron cloud on the cell side wall for different electron cloud thicknesses and densities. We found that the detuning (Δf/f) due to the electron cloud was small, about two orders of magnitude smaller than the reciprocal of the cavity loaded quality factor. This detuning is sufficiently small that it does not cause significant power reflection. Similar calculations were carried out for high gradient operation of accelerator structures at frequencies of 2.856 GHz and 110.0 GHz, showing similar small detuning by multipactor discharges. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM13  
About • paper received ※ 19 August 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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WEPLM47 Analysis of High Field Q-Slope (HFQS) Causes and Development of New Chemical Polishing Acid cavity, SRF, superconductivity, niobium 699
 
  • D. Luo, E.S. Metzgar, L. Popielarski, K. Saito, S.M. Shanab, G.V. Simpson
    FRIB, East Lansing, Michigan, USA
  • T. Nakajima, I. Nasu, J. Taguchi
    Nomura Plating Co, Ltd., Osaka, Japan
  
  Funding: U.S. National Science Foundation under Grant PHY-1565546.
In our previous studies of High Field Q-slope (HFQS) we have concluded that nitrogen contamination from the nitric acid is the main cause of the degradation of the Q in buffered chemical polished cavities. Our conclusion is made based on previously unresolved phenomena which are found from huge amount of published cavity test data, include fine grain, large grain and single crystal cavities treated with EP and BCP. According to this analysis, we have started developing new nitrogen-free chemical polishing acid. Hydrogen peroxide with HF mixture was reported able to react with Nb, and there’s no extra element contamination in it, so we replace the conventional BCP with this mixture to start our study. In this paper, some Nb coupon sample results with new acid will be reported. We complete the first step of developing the new acid and we got the Nb finish roughness no worse than conventional BCP. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM47  
About • paper received ※ 13 September 2019       paper accepted ※ 04 December 2019       issue date ※ 08 October 2019  
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WEPLM56 Development of Helium Gas Charge Stripper with Plasma Window plasma, vacuum, cathode, heavy-ion 720
 
  • J. Gao, F. Marti
    FRIB, East Lansing, Michigan, USA
  • A. Lajoie
    NSCL, East Lansing, Michigan, USA
  
  Funding: This work is supported by NSF Award PHY-1565546.
The cascade arc discharge, also called "plasma window", was suggested to be used as an interface to provide an effective separation between atmosphere and vacuum [1]. As suggested by Thieberger and Hershcovitch at Facility for Rare Isotope Beams (FRIB) workshop in 2009, helium plasma window offers an alternative to a large pumping system used in helium gas charge stripper for high intensity heavy ion beam accelerator facilities [2]. In this report, we present the recent progress on the development of helium plasma window with both 6mm and 10 mm diameter apparatus [3]. The size dependent sealing performance of helium plasma window has been investigated. Various diagnostics tools have been developed to improve our understanding of underlying physics. Over 140 hours continuous unattended operation of helium plasma window in recirculating gas system has been achieved, which suggests our system to be a feasible charge stripper solution for heavy ion beam accelerators. We also discuss anticipated future developments of plasma window.
[1] A. Hershcovitch, Phys. Plasma 5, 2130 (1998).
[2] H. Imao, et al., Phys. Rev. ST Accel. Beams 15, 123501 (2012).
[3] A. LaJoie, J. Gao and F. Marti, IEEE Transactions on Plasma Science (2019)
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM56  
About • paper received ※ 27 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEPLM67 Optimization of a Single-Cell Accelerating Structure for Rf Breakdown Test With Short Rf Pulses accelerating-gradient, acceleration, collider, linear-collider 747
 
  • M.M. Peng, J. Shi
    TUB, Beijing, People’s Republic of China
  • M.E. Conde, G. Ha, C.-J. Jing, W. Liu, J.G. Power, J. Seok, J.H. Shao, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  RF breakdown is one of the major limitations to achieve high gradient acceleration for future structure-based normal conducting linear colliders. Previous statistic research shows that the breakdown rate is proportional to Ea30 * tp5, which indicates that the accelerating gradient Ea could be improved by using shorter RF pulses (tp). An X-band 11.7~GHz metallic single-cell structure has been designed for RF breakdown study up to 273~MV/m using short pulses (~3ns) generated by a 400~MW power extractor at Argonne Wakefield Accelerator (AWA) facility. The structure has also been scaled to 11.424~GHz for the long pulse (100-1500~ns) breakdown study driven by a klystron and a pulse compressor at Tsinghua X-band High Power Test-stand (TPoT-X), with the gradient up to 246~MV/m with 200~MW input power.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM67  
About • paper received ※ 05 September 2019       paper accepted ※ 26 November 2019       issue date ※ 08 October 2019  
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WEPLM68 Design of a Dielectric-Loaded Accelerator for Short Pulse High Gradient Research acceleration, wakefield, simulation, accelerating-gradient 751
 
  • M.M. Peng, J. Shi
    TUB, Beijing, People’s Republic of China
  • M.E. Conde, G. Ha, C.-J. Jing, W. Liu, J.G. Power, J. Seok, J.H. Shao, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  The short-pulse two-beam acceleration approach is a promising candidate to meet the cost and luminosity requirements for future linear colliders. Dielectric-loaded structure has been intensely investigated for this approach because of its low fabrication cost, low RF loss, and potential to withstand GV/m gradient. An X-band 11.7~GHz dielectric-loaded accelerator (DLA) has been designed for high power test with short RF pulses (3~ns) generated from a power extractor driven by high charge bunches at Argonne Wakefield Accelerator (AWA) facility. The gradient is expected to be over 100~MV/m with the maximum input power of 400~MW.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM68  
About • paper received ※ 05 September 2019       paper accepted ※ 27 November 2019       issue date ※ 08 October 2019  
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WEPLS02 Simulation of a Klystron Input Cavity using a Steady-State Full-Wave Solver simulation, klystron, cavity, electron 768
 
  • A.R. Gold, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  The simulation of vacuum electronic radio-frequency (RF) power sources is generally done through semi-analytical modeling approaches. These techniques are computationally efficient as they make assumptions on the source topology, such as the requirement that the electron beam travel longitudinally and interact with cylindrical modes. To simulate more general interactions, transient particle-in-cell (PIC) codes are currently required. We present here simulation results of a 5045 klystron using a newly developed steady state code which does not make assumptions on the beam configuration or geometry of the structure and resonant modes. As we solve directly for the steady-state system dynamics, this approach is computationally efficient yet, as demonstrated through comparison with experimental results, provides similar accuracy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS02  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLS03 Analytical Expression for a N-Turn Trajectory in the Presence of Quadrupole Magnetic Errors quadrupole, betatron, simulation, lattice 772
 
  • Y. Rodriguez Garcia, J.F. Cardona
    UNAL, Bogota D.C, Colombia
  • Y. Rodriguez Garcia
    UAN, Bogotá D.C., Colombia
  
  The action and phase jump method is a technique, based on the use of turn-by-turn experimental data in a circular accelerator, to find and measure local sources of magnetic errors through abrupt changes in the values of action and phase. At this moment, this method uses at least one pair of adjacent BPMs (Beam Position Monitors) to estimate the action and phase at one particular position in the accelerator. In this work, we propose a theoretical expression to describe the trajectory of a charged particle for an arbitrary number of turns when a magnetic error is present in the accelerator. This expression might help to estimate action and phase at one particular position of the accelerator using only one BPM in contrast to the current method that needs at least two BPMs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS03  
About • paper received ※ 26 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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WEPLS11 Simulation of Transparent Spin Experiment in RHIC polarization, closed-orbit, resonance, lattice 789
 
  • H. Huang, Y.S. Derbenev, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virgina, USA
  • P. Adams, H. Huang, F. Méot, V. Ptitsyn, W.B. Schmidke
    BNL, Upton, New York, USA
  • Y. Filatov
    MIPT, Dolgoprudniy, Moscow Region, Russia
  • A.M. Kondratenko, M.A. Kondratenko
    Science and Technique Laboratory Zaryad, Novosibirsk, Russia
  
  Funding: Work supported by the U.S. DOE under Contracts No. DE-AC05-06OR23177 and DE-AC02-98CH10886.
The transparent spin mode has been proposed as a new technique for preservation and control of the spin polari-zation of ion beams in a synchrotron. The ion rings of the proposed Jefferson Lab Electron-Ion Collider (JLEIC) adopted this technique in their figure-8 design. The transparent spin mode can also be setup in a racetrack with two identical Siberian snakes. There is a proposal to test the predicted features of the spin transparent mode in Relativistic Heavy Ion Collider (RHIC), which already has all of the necessary hardware capabilities. We have earlier analytically estimated the setup parameters and developed a preliminary experimental plan. In this paper we describe simulation setup and benchmarking for the proposed experiment using a Zgoubi model of RHIC. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS11  
About • paper received ※ 03 September 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLH08 Use of the Base-Band Tune Meter Kickers During the FY18 STAR Fixed Target Run at 3.85 GeV/u kicker, target, detector, controls 820
 
  • P. Adams, N.A. Kling, C. Liu, G.J. Marr
    BNL, Upton, New York, USA
  
  The base-band tune meter (BBQ) kickers proved to be a useful tool in managing STAR trigger rates during the RHIC FY18 3.85GeV/u Fixed Target Run. The STAR collected over 3 times their original event goal, since it was possible to optimize the STAR trigger rates throughout the length of the physics store.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH08  
About • paper received ※ 16 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEPLH10 Efficiency Estimation for Sequential Excitation Laser Stripping of H− Beam laser, electron, cavity, proton 827
 
  • T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A. Rakhman
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: ORNL is managed by UTBattelle, LLC, under contract DEAC0500OR22725 for the U.S. Department of Energy.
A new laser stripping scheme for charge exchange injection of H− beam is considered. The sequential scheme for the planned demonstration experiment includes two step excitation that requires much smaller laser power compared to the traditional 1-step excitation. The new scheme can be applied to a wider range of H− beam energies and provides more flexibility on the choice of laser frequency. In this paper we discuss the two-step excitation method and estimate laser stripping parameters and stripping efficiency for the SNS accelerator and its future H− energy upgrade to 1.3 GeV. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH10  
About • paper received ※ 22 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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WEPLH11 RHIC Quench Protection Diode Radiation Damage radiation, kicker, detector, laser 831
 
  • K.A. Drees, O. Biletskyi, D. Bruno, A. Di Lieto, J. Escallier, G. Heppner, C. Mi, T. Samms, J. Sandberg
    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.
Each of RHIC’s superconducting magnets is protected by a silicon quench protection diode (QPD). In total, RHIC has over 800 diodes installed inside the cryostat close to the vacuum pipe~[RHICconfig]. After years of operation with high energy heavy ion beams we experienced a first permanently damaged QPD in the middle of our FY2016 Au Au run and a second damaged diode in the following year. In 2016 the run had to be interrupted by 19 days to replace the diode, in 2017 RHIC could still operate with a reduced ramping speed of the superconducting magnets. Both diodes were replaced and examined "cold" as well as "warm". This paper reports on what we have learned so far about the conditions leading up to the damage as well as the damage itself. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH11  
About • paper received ※ 23 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLH20 Modeling of H− Ion Source at LANSCE ion-source, plasma, operation, electron 848
 
  • N.A. Yampolsky, I. Draganić, L. Rybarcyk
    LANL, Los Alamos, New Mexico, USA
  
  Funding: Work supported by the US Department of Energy under Contract Number DE-AC52-06NA25396
We report on the progress in modeling performance of the H− ion source at LANSCE. The key aspect we address is the lifetime of the tungsten filament. The lifetime depends on multiple parameters of the ion source and can dramatically vary in different regimes of operation. We use the multiphysics approach to model the performance of the ion source. The detailed analysis has been made to recognize key physical processes, which affect the degradation of the filament. The analysis resulted in the analytical model, which includes relevant processes from the first principles. The numerical code based on this model has been developed and benchmarked. The results of the modeling show good agreement with experimental data. As a result, the developed model allows predicting the performance of the ion source in various regimes of operation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH20  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLO02 Progress on Muon Ionization Cooling Demonstration with MICE simulation, emittance, detector, instrumentation 852
 
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: STFC, NSF, DOE, INFN, CHIPP andd more
The Muon Ionization Cooling Experiment (MICE) at the Rutherford Appleton Laboratory has collected extensive data to study the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. Further studies are providing more and deeper insight. 		 
poster icon Poster WEPLO02 [0.477 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO02  
About • paper received ※ 30 August 2019       paper accepted ※ 17 November 2020       issue date ※ 08 October 2019  
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WEPLO12 Design of a PIP-II Era Mu2e Experiment proton, target, solenoid, collider 865
 
  • M.A. Cummings, R.J. Abrams, T.J. Roberts
    Muons, Inc, Illinois, USA
  • D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  
  We present an alternative Mu2e-II production scheme for the Fermilab PIP-II era based on production schemes we devised for muon-collider and neutrino-factory front ends. Bright muon beams generated from sources designed for muon collider and neutrino factory facilities have been shown to generate two orders of magnitude more muons per proton than the current Mu2e production target and solenoid. In contrast to the current Mu2e, the muon collider design has forward-production of muons from the target. Forward production from 8 GeV protons would include high energy antiprotons, pions and muons, which would provide too much background for the Mu2e system. In contrast, the 800 MeV PIP-II beam does not have sufficient energy to produce antiprotons, and other secondaries will be at a low enough energy that they can be ranged out with an affordable shield of ~ 2 meters of concrete.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO12  
About • paper received ※ 01 September 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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WEPLO16 Energy Spread Measurements for 400 MeV LINAC Beam at Fermilab Booster using a LASER Notcher System booster, linac, injection, laser 868
 
  • C.M. Bhat, D.E. Johnson
    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.
To mitigate 8 GeV beam losses at extraction in the Fermilab Booster synchrotron, a LASER notcher system for multi-turn injection that produces notches at 720 keV is used. These notches synchronize with the revolution period of the beam [ref. HB2018, page 416] at injection in the Booster. Recently, a dedicated notching pattern that keeps a single 201 MHz LINAC bunch untouched in the middle of a notch is developed to measure the beam energy spread by studying the time evolution of this bunch in the Booster. A complementary to this method, recently, it has been realized that one can also measure energy spread of the LINAC beam by injecting <2 Booster turn beam and studying the time evolution of the multiple 201 MHz LINAC bunches. In this paper we present the general principle of the method and results from our measurements. 		 
poster icon Poster WEPLO16 [0.193 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO16  
About • paper received ※ 28 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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WEPLO20 High Gradient High Efficiency C-Band Accelerator Structure Research at LANL simulation, operation, cavity, electron 882
 
  • E.I. Simakov, A.W. Garmon, T.C. Germann, M.F. Kirshner, F.L. Krawczyk, J.W. Lewellen, D. Perez, G. Wang
    LANL, Los Alamos, New Mexico, USA
  • A. Fukasawa, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  
  Funding: Los Alamos National Laboratory LDRD Program
This poster will report on the status of the new high gradient C-band accelerator project at LANL. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. Our goal is to use a multi-disciplinary approach that includes accelerator design, molecular dynamics simulations, and advanced manufacturing to develop high gradient, high efficiency RF structures for both compact and facility-size accelerator systems. We considered common operation frequencies for accelerators and identified C-band as the optimal frequency band for high gradient operations based on achievable gradients and means to control wakefields. We are putting together a high gradient C-band test facility that includes a 50 MW Toshiba klystron and cryo-coolers for operating copper NCRF accelerator cavities at long pulse duration. We plan to conduct high gradient testing of the optimized RF structures made of copper and novel copper alloys. LANL modeling capabilities will be used to systematically study the formation of breakdown precursors at high fields to develop basic theoretical understanding of the breakdown. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO20  
About • paper received ※ 27 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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THYBA5 Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab radiation, electron, undulator, wiggler 934
 
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • A. Halavanau, Z. Huang, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • K. Kim
    ANL, Lemont, Illinois, USA
  • V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari
    Fermilab, Batavia, Illinois, USA
  • A.Y. Murokh
    RadiaBeam, Marina del Rey, California, USA
  • T.V. Shaftan
    BNL, Upton, New York, USA
  
  We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab, with an InGaAs PIN photodiode and an integrating circuit. In this paper, we present a theoretical model for the experimental data from previous similar experiments and in our present experiment, we attempt to verify the model in an independent and a more systematic way. Moreover, in our experiment we consider the regime of very small fluctuation when the contribution from the photon shot noise is significant, whereas we believe it was negligible in the previous experiments. Accordingly, we present certain critical improvements in the experimental setup that let us measure such a small fluctuation.  
slides icon Slides THYBA5 [8.048 MB]  
poster icon Poster THYBA5 [3.079 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THYBA5  
About • paper received ※ 24 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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THZBB3 Novel Emittance Measurement Combining Foil Focusing and Pepper-Pot Techniques focusing, emittance, electron, space-charge 961
 
  • K.A. Schultz, G.T. Ortiz, M.E. Schulze
    LANL, Los Alamos, New Mexico, USA
  • C. Carlson, D. Guerrero
    NSTec, Los Alamos, New Mexico, USA
  
  Funding: Work supported by the US National Nuclear Security Agency and the US Department of Energy under contract DE-AC52-06NA25396.
In this paper, we describe a direct measurement of foil focusing of an intense, relativistic electron beam com-bined with the pepper-pot technique to perform emit-tance measurements. Foil focusing occurs when a thin, grounded, conducting foil shorts out the radial electric field of a transiting electron beam, causing its self-magnetic field to focus the beam. A 40-ns pulse was extracted from the main pulse of the 16-MeV, 1.65 kA beam from Axis-II of the Dual Axis Radiographic Hy-drodynamic Test Facility to perform the measurements. We show that not accounting for foil focusing signifi-cantly reduces the measured emittance. 		 
slides icon Slides THZBB3 [5.382 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB3  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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FRXBA5 The Role of Laser Shaping in Microbunching Instability Suppression and Seeded X-Ray Free Electron Emission laser, bunching, FEL, electron 990
 
  • J. Tang, S. Carbajo, F.-J. Decker, Z. Huang, J. Krzywiński, R.A. Lemons, W. Liu, A.A. Lutman, G. Marcus, T.J. Maxwell, S.P. Moeller, D.F. Ratner, S. Vetter
    SLAC, Menlo Park, California, USA
  
  Microbunching instability (MBI) driven by collective effects in an accelerator is known to be detrimental for the performance of X-ray free electron lasers. At the Linac Coherent Light Source (LCLS), laser heater (LH) system was installed to suppress the microbunching instability by inducing a small amount of slice energy spread to the electron beam. The distribution of the induced energy spread greatly effects MBI suppression and can be controlled by shaping the transverse profile of the heater laser. In this paper, we present theoretical and experimental results on utilizing a Laguerre-Gaussian 01 Mode (LG01) laser at LCLS to obtain better suppression of the instability. We demonstrate experimentally that Gaussian-shaped energy distribution is induced by LG01 mode LH and final microbunching gain is better suppressed. We finally discuss the role of LH spatial shaping in soft X-ray self-seeded (SXRSS) FEL emission and demonstrate that this LH configuration is capable of generating high spectral brightness FEL pulses.  
slides icon Slides FRXBA5 [3.162 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA5  
About • paper received ※ 28 August 2019       paper accepted ※ 12 September 2019       issue date ※ 08 October 2019  
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