06: Beam Instrumentation, Controls, Feedback and Operational Aspects
Paper Title Page
TUXBB1
Beam Instrumentation and Measurement Challenges  
 
  • M.G. Minty
    BNL, Upton, New York, USA
 
  Since the inception of particle accelerators about 100 years ago, nearly every field of modern society has benefited from their continued development. Applications include discovery science (identification of basic matter constituents and their interactions), nuclear weapon and energy development, material and biological sciences as well as medical sciences including cancer therapies. Common to all accelerators is the need for accurate and precise measurements of the beam’s properties to optimize accelerator performance. This tutorial will cover select beam instrumentation basics, applications of these for characterizing accelerator performance, then present instrumentation challenges for future particle accelerators.  
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TUYBB1
Vacuum System Solutions for Small Vacuum Chamber Next Generation Storage Rings  
 
  • O. Omolayo
    LBNL, Berkeley, California, USA
 
  Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
The extremely low emittance promised by multi-bend achromat (MBA) based lattices can be achieved only by strong focusing and combined functions magnets that are challenging the present technology for those magnets. Such a level of focusing can be achievable only if significantly small gap magnets are used. Such a requirement imposes extremely small vacuum chamber cross-section with very small vacuum conductance. A new vacuum strategy using distributed pumping and other challenging solutions are adopted to achieve the goals. This talk describes these challenges and presents a review of the technological solutions presently pursued.
 
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TUYBB2 Manipulating H Beams with Lasers 309
 
  • A. Rakhman, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, Y. Liu, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
In recent years lasers have been playing a vital role in many H− beam measurements and experiments. This talk will review current state of development of various applications using lasers for manipulating H− ion beams in accelerators. A wide range of applications will be reviewed such as beam diagnostics, laser-assisted charge-exchange injection, generation of arbitrary H0 pulse patterns and others. An overview of ongoing developments and prospects for other laser H− beam interactions will also be given.
 
slides icon Slides TUYBB2 [16.483 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB2  
About • paper received ※ 28 August 2019       paper accepted ※ 12 September 2019       issue date ※ 08 October 2019  
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TUYBB3 Final Design of the APS-Upgrade Storage Ring Vacuum System 315
WEPLM10   use link to see paper's listing under its alternate paper code  
 
  • J.A. Carter, B. Billett, B. Brajuskovic, M.A. Lale, A. McElderry, O.K. Mulvany, J.R. Noonan, M.M. O’Neill, R.R. Swanson, K.J. Wakefield, D.R. Walters, G.E. Wiemerslage, J. Zientek
    ANL, Lemont, Illinois, USA
 
  Funding: Argonne National Laboratory’s work was supported by the U.S. Department of Energy, Office of Science under contract DE-AC02-06CH11357.
The Advanced Photon Source Upgrade project is progressing from its final design phase into production for the future 6 GeV, 200 mA upgrade of the existing APS. The storage ring arc vacuum system will include over 2500 custom vacuum chambers ranging from 70 mm to 2.5 meters in length and typically feature a narrow 22 mm inner diameter aperture. The scope of NEG coatings was increased to 40% of the length along the e-beam path to ensure efficient conditioning and low pressure requirements can be met. The final design phase required advancing previous work to a procurement-ready level and to address local and system level challenges. Local challenges include designing thin-walled vacuum chambers with carefully controlled lengths and outer profiles and also mitigating significant radiation heat loads absorbed along vacuum chamber walls. System level challenges include planning for the complex machine assembly, networking components to utilities, managing the quality of upcoming procurements. This presentation will highlight the major design challenges and solutions for the storage ring vacuum system and also plans for production and installation.
 
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poster icon Poster TUYBB3 [5.028 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB3  
About • paper received ※ 27 August 2019       paper accepted ※ 30 August 2019       issue date ※ 08 October 2019  
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TUYBB4 Online Modelling and Optimization of Nonlinear Integrable Systems 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 322
SUPLS10   use link to see paper's listing under its alternate paper code  
TUPLS15   use link to see paper's listing under its alternate paper code  
 
  • 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 326
TUPLE19   use link to see paper's listing under its alternate paper code  
 
  • 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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TUPLM29 Current Status and Prospects of FRIB Machine Protection System 437
TUPLM28   use link to see paper's listing under its alternate paper code  
 
  • Z. Li, D. Chabot, S. Cogan, S.M. Lidia
    FRIB, East Lansing, Michigan, USA
 
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) is designed to accelerate beam up to 400 kW power with kinetic energy ≥ 200 MeV/u. Fast response of the machine protection system is critical for FRIB beam commissioning and operation to prevent damage to equipment. The beam commissioning of the first linac segment, including fifteen cryomodules, has been completed. Four ion species were accelerated to a beam energy of 20.3 MeV/u with duty factors from 0.05 percent to continuous wave. The peak beam current exceeded 10 percent of the final requirements. This paper summarizes the status of the machine protection system deployed in the production, Machine interlock response time of ~8 μs was achieved. Incentives for future development include being able to achieve smooth and reliable beam operation, faster machine protection response time and real time data analysis of failure mode.
 
poster icon Poster TUPLM29 [2.067 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM29  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLS02 APS Upgrade Insertion Device Vacuum Chamber Design 450
 
  • J.E. Lerch, T.J. Bender, O.K. Mulvany, M.E. Szubert
    ANL, Lemont, Illinois, USA
 
  A straight section vacuum system (nominally 5.363 meters long) has been designed for the APS upgrade project. This vacuum system will be used in straight sections equipped with hybrid permanent magnet undulators (HPMU). The vacuum system assembly consists of the insertion device vacuum chamber (IDVC), the vacuum chamber distributed support, and the photon absorber. Numerous functional requirements constrained the IDVC design. These constraints included incorporation of the beam aperture transition into the end of the aluminium vacuum chamber extrusion (storage ring aperture to IDVC aperture), thin walls (~600 microns) surrounding the beam aperture to allow for as small a magnetic gap as possible, and complicated weld paths to ensure a continuous beam surface to minimize impedance. Additionally, extensive FEA and raytrace analysis were performed to ensure that the chamber would not fail due to structural or thermal perturbations.  
poster icon Poster TUPLS02 [3.816 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS02  
About • paper received ※ 26 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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TUPLS03 Advanced Photon Source Upgrade 453
 
  • M.E. Szubert, E.R. Anliker, T.J. Bender, J.E. Lerch
    ANL, Lemont, Illinois, USA
 
  The Advanced Photon Source Upgrade (APS-U) in-cludes four straight sections equipped with full length Superconducting Undulators (SCUs). These sections require vacuum systems that must span 5.383 meters at nominal length, accommodate the SCU device, and ac-commodate additional magnets for the canted configura-tions. In the direction of the beam, the upstream portion of the vacuum system is a copper chamber doubling as a photon absorber with a design that is manufactured to allow a 13.5 mm canting magnet gap. This portion of the vacuum system operates at room temperature and shad-ows the length of the vacuum chamber that operates within the cryostat at 20K. The vacuum chamber inside the cryostat is a weldment including a machined alumi-num extrusion allowing for an 8mm magnetic gap, stain-less steel thermal insulators, copper shields, and bel-lows/flange assembly. The vacuum system includes an-other room temperature copper chamber and absorber on the downstream end of the straight section. The vacuum system provides Ultra-high Vacuum (UHV) continuity through the straight section, connecting the storage ring vacuum systems.  
poster icon Poster TUPLS03 [0.974 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS03  
About • paper received ※ 26 August 2019       paper accepted ※ 13 September 2019       issue date ※ 08 October 2019  
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TUPLS04 Re-Evaluation of the NSLS-II Active Interlock Window 456
 
  • R.P. Fliller, III, C. Hetzel, Y. Hidaka, T. Tanabe
    BNL, Upton, New York, USA
 
  Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The NSLS-II Active Interlock is the system which protects the NSLS-II Storage Ring vacuum chamber from damage due to synchrotron radiation. The Active Interlock measures the beam position and angle at all insertion devices and issues a beam dump if the beam is outside of the pre-defined window. The window is determined by thermal analysis of vacuum apertures and considers the effects of local magnets such as canting magnets, etc. Recently, it was realized that the insertion device correction coils where not considered in the initial evaluation of the envelope. The purpose of these coils is to correct for the orbit deviations caused by imperfections in the insertion devices that steer the beam. The usual effect is to negate any angle induced by the device, however, if the coil is not set properly the beam may have a larger angle than permitted by the Active Interlock even though the angle calculation does not show it. In this paper we discuss the effect of the insertion device coils on the electron beam and the steps taken to account for this effect in the Active Interlock.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS04  
About • paper received ※ 27 August 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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TUPLS05 High-Level Physics Application for the Emittance Measurement by Allison Scanner 459
 
  • T. Zhang, S.M. Lund, T. Maruta
    FRIB, East Lansing, Michigan, USA
  • C.Y. Wong
    NSCL, East Lansing, Michigan, USA
 
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DESC0000661
On the ion accelerator, transverse emittance diagnostics usually happens at the low-energy transportation region, one device named "Allison Scanner" is commonly used to achieve this goal. In this contribution, we present the software development for both the high-level GUI application and the online data analysis, to help the users to get the beam transverse emittance information as precise and efficient as possible, meanwhile, the entire workflow including the UI interaction would be smooth and friendly enough. One soft-IOC application has been created for the device simulation and application development. A dedicated 2D image data visualization widget is also introduced for general-purposed PyQt GUI development.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS05  
About • paper received ※ 26 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLS07 Helical Transmission Line Test Stand for Non-Relativistic BPM Calibration 463
SUPLO05   use link to see paper's listing under its alternate paper code  
 
  • C.J. Richard
    NSCL, East Lansing, Michigan, USA
  • S.M. Lidia
    FRIB, East Lansing, Michigan, USA
 
  Measurements of non-relativistic beams by coupling to the fields are affected by the properties of the non-relativistic fields. The authors propose calibrating for these effects with a test stand using a helical line which can propagate pulses at low velocities. Presented are simulations of a helical transmission line for such a test stand which propagates pulses at 0.033c. A description of the helix geometry used to reduce dispersion is given as well as the geometry of the input network.  
poster icon Poster TUPLS07 [3.469 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS07  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLS08 Analysis of Allison Scanner Phase Portraits Using Action-Phase Coordinates 467
SUPLO06   use link to see paper's listing under its alternate paper code  
 
  • C.J. Richard
    NSCL, East Lansing, Michigan, USA
  • J.-P. Carneiro, L.R. Prost, A.V. Shemyakin
    Fermilab, Batavia, Illinois, USA
 
  Allison scanners provide detailed information on the beam transverse phase space. An effective way for analyzing the beam distribution from these measurements is to use action-phase coordinates, where beam propagation in a linear lattice is reduced to advancing the phase. This report presents such analysis for measurements performed with a 2.1 MeV, 5 mA H beam in the MEBT of the PIP2IT test accelerator at Fermilab. In part, with the choice of calculating the Twiss parameters over the high intensity portion of the beam, the beam core is found to be phase-independent with intensity decreasing exponentially with action, while the beam tails exhibit a clear phase dependence that is stable over the beam line.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS08  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLS09 Precision Insertion Device Control and Simultaneous Monochromator Fly Scanning for NSLS-II 471
 
  • D.A. Hidas, P.L. Cappadoro, T.M. Corwin, J. Escallier, A. Hunt, M. Musardo, J. Rank, C. Rhein, J. Sinsheimer, T. Tanabe, I. Waluyo
    BNL, Upton, New York, USA
 
  Funding: Department of Energy Office of Science DE-SC0012704
Beginning in January of 2019, 8 of the 10 In-Vacuum Undulators installed in the NSLS-II storage ring underwent in-house in-situ control system upgrades allowing for control of the magnetic gap during motion down to the 50 nanometer level with an in-position accuracy of nearly 5 nanometers. Direct linking of Insertion Devices and beamline monochromators is achieved via a fiber interface allowing precise, simultaneous, nonlinear motion of both devices and providing a fast hardware trigger for real-time accurate insertion device and monochromator fly scanning. This presentation will detail the accuracy of motion and its effect on the produced spectra as well as the variation of flux when both insertion device and monochromator are in simultaneous motion.
 
poster icon Poster TUPLS09 [0.668 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS09  
About • paper received ※ 28 August 2019       paper accepted ※ 01 September 2019       issue date ※ 08 October 2019  
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TUPLS10 Troubleshooting and Characterization of Gridded Thermionic Electron Gun 474
 
  • M.S. Stefani
    ODU, Norfolk, Virginia, USA
  • F.E. Hannon
    JLab, Newport News, Virginia, USA
 
  Jefferson National Laboratory has, in collaboration with Xelera research group, designed and built a gridded thermionic election gun with the potential for magnetization; in an effort to support research towards electron sources that may be utilized for the electron cooling process in the Jefferson Laboratories Electron Ion collider design. Presented here is the process and result of troubleshooting the electron gun components and operation to ensure functionality of the design.  
poster icon Poster TUPLS10 [10.691 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS10  
About • paper received ※ 27 August 2019       paper accepted ※ 13 September 2019       issue date ※ 08 October 2019  
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TUPLS11 NEG-Coated Copper Vacuum Chambers for the APS-Upgrade Storage Ring Vacuum System 477
 
  • O.K. Mulvany, B. Billett, B. Brajuskovic, J.A. Carter, A. McElderry, K.J. Wakefield
    ANL, Lemont, Illinois, USA
 
  Funding: Argonne National Laboratory’s work was supported by the U.S. Department of Energy, Office of Science under contract DE-AC02-06CH11357.
The APS-Upgrade (APS-U) storage ring features a diverse group of vacuum chambers including seven distinctive, non-evaporable getter (NEG)-coated copper vacuum chambers per each of the 40 sectors. These chambers feature a 22-millimeter diameter aperture along the electron-beam path, with two vacuum chambers permitting photon extraction through a keyhole-shaped extension to this aperture. The chambers range from 0.3-meters to 1.7-meters in length and fit within the narrow envelope of quadrupole and sextupole magnets. Six of the seven copper vacuum chambers intercept significant heat loads from synchrotron radiation; five of these designs are fabricated entirely from OFS copper extrusions and are equipped with a compact Glidcop® photon absorber. A hybrid vacuum chamber, fabricated from OFS copper extrusion and a copper chromium zirconium (CuCrZr) keyhole transition, also intercepts synchrotron radiation. The seventh vacuum chamber design features a keyhole aperture across its length and is entirely fabricated from CuCrZr. This paper details the careful balance of vacuum chamber functionality, manufacturability, and the overall design process followed to achieve the final designs.
 
poster icon Poster TUPLS11 [4.941 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS11  
About • paper received ※ 27 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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TUPLS12 Final Design of NEG-Coated Aluminum Vacuum Chambers & Stainless Steel Keyhole Vacuum Chambers for the APS-U Storage Ring 480
 
  • A. McElderry, B. Billett, J.A. Carter, K.J. Wakefield
    ANL, Lemont, Illinois, USA
 
  Funding: Argonne National Laboratory’s work was supported by the U.S. Department of Energy, Office of Science under contract DE-AC02-06CH11357.
The APS-Upgrade storage ring features a diverse group of vacuum chambers which includes eight NEG (non-evaporable getter) coated aluminum chambers and two copper coated stainless steel keyhole-shaped chambers per sector (40 total). Each chamber contains a 22 mm diameter electron beam aperture; the keyhole chambers also include a photon extraction antechamber. The chambers vary in length of approximately 289 ’ 792 mm and fit within the narrow envelope of quadrupole and sextupole magnets. Each design is a balance of functionality, manufacturability, and installation space. An innovative CAD skeleton model system and ray tracing layout accurately determined synchrotron radiation heat loads on built-in photon absorbers and the internal envelope of the keyhole antechamber. Chamber designs were optimized using thermal-structural FEA for operating and bakeout conditions. The group of chambers require complex manufacturing processes including EDM, explosion-bonded metals, furnace brazing, and welding with minimal space. This paper describes the design process and manufacturing plan for these vacuum chambers including details about FEA, fabrication plans, and cooling/bakeout strategies.
 
poster icon Poster TUPLS12 [2.581 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS12  
About • paper received ※ 27 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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TUPLS13 Evaluation of the Xilinx RFSoC for Accelerator Applications 483
 
  • J.E. Dusatko
    SLAC, Menlo Park, California, USA
 
  As electronic technology has evolved, accelerator system functions (e.g. beam instrumentation, RF cavity field control, etc.) are increasingly performed in the digital domain by sampling, digitizing, processing digitally, and converting back to the analog domain as needed. A typical system utilizes analog to digital (ADC) and digital to analog (DAC) converters with intervening digital logic in a field programmable gate array (FPGA) for digital processing. For applications (BPMs, LLRF, etc.) requiring very high bandwidths and sampling rates, the design of the electronics is challenging. Silicon technology has advanced to the state where the ADC and DAC can be implemented into the same device as the FPGA. Xilinx, Inc. has released a muti-GHz sample rate RF System on Chip (RFSoC) device. It presents many advantages for implementing accelerator and particle detector systems. Because direct conversion is possible, RF analog front/back end and overall system design is simplified. This paper presents the results of an evaluation study of the RFSoC device for accelerator and detector work, including test results. It then discusses possible applications and work done at SLAC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS13  
About • paper received ※ 30 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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TUPLS14 Analyzing Accelerator Operation Data with Neural Networks 487
 
  • F.Y. Wang, X. Huang, Z. Zhang
    SLAC, Menlo Park, California, USA
 
  Funding: Work is supported by DOE contract DE-AC02-76SF00515 (SLAC) and DOE contracts 2018-SLAC-100469 and 2018-SLAC-100469ASCR.
Accelerator operation history data are used to train neural networks in an attempt to understand the underly-ing causes of performance drifts. In the study, injection efficiency of SPEAR3 [1] over two runs is modelled with a neural network (NN) to map the relationship of the injection efficiency with the injected beam trajectory and environment variables. The NN model can accurately predict the injection performance for the test data. With the model, we discovered that an environment parameter, the ground temperature, has a big impact to the injection performance. The ideal trajectory as a function of the ground temperature can be extracted from the model. The method has the potential for even larger scale application for the discovery of deep connections between machine performance and environment parameters.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS14  
About • paper received ※ 29 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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TUPLE01 Python Scripts for RF Commissioning at FRIB 563
 
  • H. Maniar, E. Daykin, D.G. Morris, A.S. Plastun, H.T. Ren, S. Zhao
    FRIB, East Lansing, Michigan, USA
 
  Abstract RF commissioning at FRIB involves QWR cavities (β=0.085 and β=0.041), HWR cavities (β=0.29 and β=0.53) and few room temperature devices. Each RF system has many process variables for LLRF and amplifier control located on different pages of CS-Studio. Efficient handling of all these PVs can be challenging for RF experts. Several scripts using Python have been developed to facilitate this process. User interface application has been developed using Qt Designer and PyQt package of Python, for ease of access of all scripts. These scripts are useful for mass ac-tions (for multiple systems) including turning on/ off LLRF controllers and amplifiers, resetting interlocks/ errors, chang-ing a PV value, etc. Python scripts are also used to quickly prototype the auto-start procedure for QWR cavities, which eventually is implemented on IOC driver. The application sends commands to IOC driver with device name, PV name and value to be changed. Future developments can be con-verting to state-notation language on IOC to add channel access security. This application intends to reduce time and efforts for RF commissioning at FRIB.  
poster icon Poster TUPLE01 [0.429 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE01  
About • paper received ※ 27 August 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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TUPLE04 An Iris Diaphragm Beam Detector for Halo or Profile Measurements 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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TUPLE05 Optical System for Observation of FRIB Target 570
 
  • I.N. Nesterenko, G. Bollen, M. Hausmann, A. Hussain, S.M. Lidia, S. Rodriguez Esparza
    FRIB, East Lansing, Michigan, USA
  • G. Bollen
    NSCL, East Lansing, Michigan, USA
  • G. Bollen
    MSU, East Lansing, Michigan, USA
  • I.N. Nesterenko
    BINP SB RAS, Novosibirsk, Russia
 
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Facility for Rare Isotope Beams (FRIB) is a next-generation rare-isotope research facility under construction at Michigan State University (MSU). FRIB will produce rare-isotope beams of unprecedented intensities by impinging a 400 kW heavy-ion beam on a production target and by collecting and purifying the rare isotopes of interest with a fragment separator. A thermal imaging system (TIS) has been developed to monitor the beam spot on the production target. The main features and characteristics of optical system is presented. The prototype of optical system has been tested.
 
poster icon Poster TUPLE05 [1.840 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE05  
About • paper received ※ 27 August 2019       paper accepted ※ 06 November 2020       issue date ※ 08 October 2019  
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TUPLE06 Skimmer-Nozzle Configuration Measurements for a Gas Sheet Beam Profile Monitor 573
SUPLO07   use link to see paper's listing under its alternate paper code  
 
  • S. Szustkowski, S. Chattopadhyay, B.T. Freemire
    Northern Illinois University, DeKalb, Illinois, USA
  • S. Chattopadhyay, D.J. Crawford, B.T. Freemire
    Fermilab, Batavia, Illinois, USA
 
  Funding: US Department of Energy, Office of High Energy Physics, General Accelerator Research and Development (GARD) Program
Understanding the characteristics of the gas sheet being produced and optimal configuration of the gas injection system is essential to the the performance of a gas sheet beam profile monitor. A gas injection system test stand has been built at Fermilab to test various nozzle and slit configurations. The distance between the nozzle and slit can be changed to find an optimal configuration. Using a moveable cold cathode gauge the gas profile is measured.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE06  
About • paper received ※ 28 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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TUPLE07 Overview of FRIB’s Diagnostics Controls System 576
 
  • B.S. Martins, S. Cogan, M.G. Konrad, S.M. Lidia, D.O. Omitto, P.J. Rodriguez
    FRIB, East Lansing, Michigan, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
In this work we will present an overview of the diagnostics systems put in place by FRIB’s Beam Instrumentation and Measurements department. We will focus on the controls and integration aspects for different kinds of equipment, such as pico ammeters and motor controllers, used to drive and readback the devices deployed on the beamline, such as profile monitors, Faraday cups, etc. In particular, we will discuss the controls software used in our deployment and how we make use of continuous integration and deployment systems to automate certain tasks and make the controls system in production more robust.
 
poster icon Poster TUPLE07 [2.302 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE07  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLE08 Commissioning Update on RF Station #5 of AWA 580
 
  • W. Liu, M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • C. Jing
    Euclid Beamlabs LLC, Bolingbrook, USA
 
  Funding: The US Department of Energy, Office of Science
The RF system of Argonne Wakefield Accelerator (AWA) facility has grown over the years from one RF power station into 4 RF power stations. The demand for RF power keeps growing as the capability of AWA continues to grow. Now the 5th RF station is needed to fulfill the RF power needs of AWA facility. Some details regarding the construction and commissioning of the 5th RF station of AWA facility are documented in this paper.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE08  
About • paper received ※ 29 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLE11 Proposed Enhanced Imaging Station in the 6-GeV Booster-to-Storage Ring Transport Line for APS Upgrade 583
 
  • A.H. Lumpkin
    Fermilab, Batavia, Illinois, USA
  • W. Berg, J.C. Dooling, K.P. Wootton, C. Yao
    ANL, Lemont, Illinois, USA
 
  Funding: This manuscript has been authored by FRA, LLC under Contract No.DE-AC02-07CH11359 with the U.S.DoE, Office of HEP. Work supported by U.S.DoE, Office of Science, under Contract No.DE-AC02-06CH11357.
One of the challenges of the injector for the Advanced Photon Source Upgrade (APS-U) is the measurement and monitoring of the required high charge electron beam at 6 GeV between the Booster synchrotron and the storage ring in the transport line (BTS. In APS-U charges of up to 17 nC per micropulse are specified with a beam geometrical horizontal emittance of 60 nm rad. Vertical beam sizes at the imaging station of ~80 µm (σ) are expected so system resolutions of <30 µm are warranted. A phased approach to enhance the imaging station performance has been initiated. Recently, the 20-year-old Chromox screen oriented at 45 degrees to the beam was replaced by a 100-micron thick YAG:Ce screen which gave an improved screen resolution of <10 micron(σ. However, the optical magnification of the system still needs to be increased. In addition, the high areal charge densities are expected to exceed the scintillator mechanism’s saturation threshold so an optical transition radiation (OTR) screen will be added to the station for high-charge studies. A final phase would be the use of optical diffraction radiation (ODR) as a non-intercepting, beam-size monitor during top-up injections.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE11  
About • paper received ※ 22 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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TUPLE13 Analytical Thermal Analysis of Thin Diamond in High-Intensity High-Repetition-Rate Application 587
SUPLO09   use link to see paper's listing under its alternate paper code  
 
  • Y. Hong, B. Yang
    University of Texas at Arlington, Arlington, USA
  • J. Wu, G. Zhou
    SLAC, Menlo Park, California, USA
 
  Thin diamond plates are used in monochromator for X-ray Free-Electron Laser self-seeding scheme. To function properly, they must endure high-intensity and high-repetition-rate laser pulses without crossing thresholds set by various adverse effects, such as thermal strain-induced diffraction distortion and graphitization. In this work, a theoretical model is developed, and an analytical solution is derived to elucidate potential thermal runaway under edge cooling condition. It is shown that the crystal edge cooling can effectively mitigate the issue to a certain extent. The analytical solution can be used as an efficient tool for XFEL operation parameter setup.  
poster icon Poster TUPLE13 [0.939 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE13  
About • paper received ※ 27 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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TUPLE15 BPM Processor Upgrades at SPEAR3 591
 
  • F. Toufexis, S. Condamoor, W.J. Corbett
    SLAC, Menlo Park, California, USA
  • L.W. Lai
    SINAP, Shanghai, People’s Republic of China
  • P. Leban
    I-Tech, Solkan, Slovenia
 
  Funding: Work sponsored by US Department of Energy Contract DE-AC02-76SF00515.
We are upgrading the BPM processors in the SPEAR3 accelerator complex as several of the existing systems have reached end of life. To reduce the resources required for maintenance we have evaluated and installed several commercial BPM processors from the SPARK series of Libera/Instrumentation Technologies. In SPEAR3 we evaluated the SPARK-ERXR turn-by-turn BPM processor as a replacement to the in-house developed/commercially built Echotek processors that are used for a range of accelerator physics studies. We show measurements of the orbit dynamics with another SPARK-ERXR in the booster synchrotron from beam injection up to ejection. We have further evaluated a Spark-EL in the transport lines to replace the in-house built uTCA-based single-pass BPM processors. In this paper we show measurements and discuss our experience with the Libera SPARK series of BPM processors and comment on the software integration.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE15  
About • paper received ※ 28 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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TUPLE16 RFA Measurement of E-Cloud Generation Process at Fermilab Main Injector 595
 
  • Y. Ji
    IIT, Chicago, Illinois, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
  • R.M. Zwaska
    Fermilab, Batavia, Illinois, USA
 
  Fermilab aims to provide greater beam power for the neutrino physics program. As the beam power increases, the unwanted production of secondary electrons in the beam pipe, known as ‘electron cloud’ or ‘E-cloud’ may become disruptive to high intensity operation. Instrumentation has been deployed in the Fermilab Main Injector (MI) to study E-cloud. One of these is a Retard Field Analyzer (RFA) that can be used to directly measure E-cloud generation at the location of the instrument. Studies of the dependence of E-cloud on beam intensity and bunch length have been carried out. The experimental results are compared to POSINST simulations. These simulations are guided by measurements from a Secondary Electron Yield (SEY) test stand installed in the MI to measure the SEY of materials such as the beam pipe stainless steel. The SEY has a strong influence on the E-cloud density. Results of these comprehensive studies comparing the RFA data with realistic MI simulations will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE16  
About • paper received ※ 28 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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WEPLM01 Studies in Applying Machine Learning to Resonance Control in Superconducting RF Cavities 659
SUPLO01   use link to see paper's listing under its alternate paper code  
 
  • J.A. Diaz Cruz, S. Biedron, M. Martinez-Ramon, R. Pirayesh, S.I. Sosa Guitron
    University of New Mexico, Albuquerque, USA
  • J.A. Diaz Cruz
    SLAC, Menlo Park, California, USA
 
  Traditional PID, active resonance and feed-forward controllers are dominant strategies for cavity resonance control, but performance may be limited for systems with tight detuning requirements, as low as 10 Hz peak detuning (few nanometers change in cavity length), that are affected by microphonics and Lorentz Force Detuning. Microphonic sources depend on cavity and cryomodule mechanical couplings with their environment and come from several systems: cryoplant, RF sources, tuners, etc. A promising avenue to overcome the limitations of traditional resonance control techniques is machine learning due to recent theoretical and practical advances in these fields, and in particular Neural Networks (NN), which are known for their high performance in complex and nonlinear systems with large number of parameters and have been applied successfully in other areas of science and technology. In this paper we introduce NN to resonance control and compare initial performance results with traditional control techniques. An LCLS-II superconducting cavity type system is simulated in an FPGA, using the Cryomodule-on-Chip model developed by LBNL, and is used to evaluate machine learning algorithms.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM01  
About • paper received ※ 05 September 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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WEPLM02 Finding Beam Loss Locations in a Linac with Oscillating Dipole Correctors 663
 
  • A.V. Shemyakin, K. Seiya
    Fermilab, Batavia, Illinois, USA
  • R. Prakash
    RRCAT, Indore, India
 
  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
The paper proposes a method of finding the beam loss locations in a linac. If the beam is scraped at an aperture limitation, moving its centroid with two dipole correctors located upstream and oscillating in sync produces a line at the corresponding frequency in spectra of current-sensitive devices downstream of the loss point. The phase of this signal contains information about the location of the beam loss. Similar lines appear also in the position signals of Beam Position Monitors (BPMs). The phases of the BPM position lines change monotonically (within each 2π) along the linac and can be used a reference system. The phase of the loss signal compared with this reference system pinpoints the beam loss location, assuming that longitudinal coordinates of the BPMs are known. If the correctors deflection amplitudes and the phase offset between their waveforms are chosen optimally and well calibrated, the same measurement provides values of the β-function and the betatron phase advance at the BPM locations. Optics measurements of this type can be made parasitically, with negligible effect on the emittance, if a long measurement time is acceptable.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM02  
About • paper received ※ 27 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEPLM03 The LLRF Control Design and Validation at FRIB 667
 
  • S. Zhao, W. Chang, S.H. Kim, H. Maniar, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, H.T. Ren, N.R. Usher
    FRIB, East Lansing, Michigan, USA
  • N.R. Usher
    Ionetix, Lansing, Michigan, USA
 
  Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
One of the challenges in designing the low level radio frequency (LLRF) controllers for the Facility for Rare Isotope Beams (FRIB) is the various types of cavities, which include 5 different frequencies ranging from 40.25 MHz up to 322 MHz, and 4 different types of tuners. In this paper, the design strategy taken to achieve flexibility and low cost and the choices made to accommodate the varieties will be discussed. The approach also allowed easy adaptation to major design changes such as replac-ing two cryo-modules with two newly designed room temperature bunchers and the addition of high-voltage bias to suppress multi-pacting in half wave resonators (HWRs). With the successful completion of the third accelerator readiness review (ARR03) commissioning in early 2019, most of the design has been validated in the real accelerator system, leaving only HWRs which are constantly undergoing tests in cryo-module bunker. The integrated spark detector design for HWRs will also be tested in the near future.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM03  
About • paper received ※ 31 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLM04 Precision Cavity Higher-Order Mode Tuning Scheme for Stabilizing the Stored Beam in the Advanced Photon Source Upgrade 670
 
  • L. Emery, P.S. Kallakuri, U. Wienands
    ANL, Lemont, Illinois, USA
  • D. Teytelman
    Dimtel, Redwood City, California, 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
The Advanced Photon Source Upgrade will suffer longitudinal multi-bunch instability because of the presence of several monopole higher-order mode (HOMs) of the 12 352-MHz rf cavities. Even with a feedback system, it would be good to mitigate any driving terms with conventional means such as tuning HOM frequencies with temperature. However the latter is problematic because there will be 90 or so HOMs that are potentially harmful. A scheme is developed, utilizing the measured spectrum of HOMs, to find the best temperature setting for each cavity. We present measurements of 30 or so HOMs, and a thermal model of HOM frequencies using cavity wall power and cooling water temperature as inputs to maintain the optimum tuning condition with sufficient accuracy. The newly acquired Dimtel iGp12 processor box is central to the HOM frequency measurements.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM04  
About • paper received ※ 29 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLM05 Continuous Monitoring of Spectral Features of Electron Beam Orbit Motion at NSLS-II 673
 
  • B. Podobedov, A.A. Derbenev, K. Ha, T.V. Shaftan
    BNL, Upton, New York, USA
 
  NSLS-II ring is equipped with state-of-the art beam position monitors (BPMs) which are indispensable in all aspects of machine studies and operations. Among other data, they can provide, on demand, up to 10 seconds of fast-acquisition (FA) data, sampled at ~10 kHz. Analysis of these data in time, frequency and spatial domains provides valuable insights into orbit stability, locations of residual noise sources, performance of feedback systems, etc. In addition, changes in FA signal spectral features are often the earliest indicators of potential equipment problems. This is why we recently implemented an Input / Output Controller (IOC) software that runs during regular user operation, and, once a minute, acquires 10 second buffers of FA data from 180 BPMs around the ring. These buffers are processed to determine the amplitudes and frequencies of the strongest spectral peaks as well as some other measures of fast beam orbit noise. Processed results can be monitored in real time and are also archived for offline analysis and troubleshooting. In this paper we discuss the implementation of this system and the insights we gained from it over about two years of operations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM05  
About • paper received ※ 31 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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WEPLM06 NuMI Beam Muon Monitor Data Analysis and Simulation for Improved Beam Monitoring 677
SUPLO04   use link to see paper's listing under its alternate paper code  
 
  • 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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WEPLM07 Low Level RF Test System for the Compact X-Ray Light Source at Arizona State University 680
 
  • H.S. Marks, W.S. Graves, M.R. Holl, L.E. Malin
    Arizona State University, Tempe, USA
 
  A compact femtosecond X-Ray Light Source (CXLS) for time-resolved scientific and medical studies is being constructed at Arizona State University. The CXLS X-rays will be generated by the inverse Compton scattering (ICS) collision of 200 mJ, 1 ps, IR laser pulses with 300 fs electron bunches with energy up to 35 MeV. The electron beam is accelerated via a photoinjector and three standing-wave 20-cell linac sections driven by two klystrons delivering up to 6 MW 1 µs pulses at 9.3 GHz with a pulse repetition rate of 1 kHz. For initial testing of the CXLS klystrons a hybrid digital-analog low-level RF (LLRF) driver has been developed which allows for inter-pulse phase and amplitude corrections based on feedback from waveguide-couplers. The micro-controller based system can also be programmed to adjust continuously in advance of predictable drifts.  
poster icon Poster WEPLM07 [2.226 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM07  
About • paper received ※ 27 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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WEPLM11 Closed Loop Modeling of the APS-U Orbit Feedback System 683
 
  • P.S. Kallakuri, A.R. Brill, J. Carwardine, N. Sereno
    ANL, Lemont, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357.
Orbit stabilization to 10% of the expected small beam sizes for Advanced Photon Source Upgrade (APS-U) requires pushing the state of the art in fast orbit feedback (FOFB) control, both in the spatial domain and in dynamical performance. We are building a Matlab/Simulink fast orbit feedback system model to guide decisions about APS-U fast orbit feedback system implementation and to provide a test bench for optimal-control methodologies and orbit correction algorithms applicable to the APS-U. A transfer function model was built from open-loop frequency-response and step-response measurements of the present APS and subsequently validated against closed-loop measurements. A corresponding model for APS-U fast orbit feedback was generated by substituting measured responses of APS-U prototype corrector magnets and power supplies into this same model. Stabilizing PID gains are designed using model, and simulated dynamic performance of the new controller is validated through experiments.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM11  
About • paper received ※ 27 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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THXBA1
Machine Learning Demonstrations on Accelerators  
 
  • A.L. Edelen
    SLAC, Menlo Park, California, USA
 
  Machine learning has been used in various ways to improve acclerator operation including the development of surrogate models to improve real-time modeling, advanced optimization of accelerator operating configurations such as quadrupole or undulator strengths, development of virtual diagnostics to ’measure’ accelerator and beam parameters, and prognostics to improve operating time.  
slides icon Slides THXBA1 [31.075 MB]  
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THXBA2 Analysis of Beam Position Monitor Requirements with Bayesian Gaussian Regression 912
WEPLM09   use link to see paper's listing under its alternate paper code  
 
  • Y. Li, R.S. Rainer
    BNL, Upton, New York, USA
  • W.X. Cheng
    ANL, Lemont, Illinois, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
 
  Funding: This research is supported by U.S. Department of Energy under Contract No. DE-SC0012704, and the NSF under Cooperative Agreement PHY-1102511.
With a Bayesian Gaussian regression approach, a systematic method for analyzing a storage ring’s beam position monitor (BPM) system requirements has been developed. The ultimate performance of a ring-based accelerator, based on brightness or luminosity, is determined not only by global parameters, but also by local beam properties at some particular points of interest (POI). BPMs used for monitoring the beam properties, however, can not be located at these points. Therefore, the underlying and fundamental purpose of a BPM system is to predict whether the beam properties at POIs reach their desired values. The prediction process is a regression problem with BPM readings as the training data, but containing random noise. A Bayesian Gaussian regression approach can determine the probability distribution of the predictive errors, which can be used to conversely analyze the BPM system requirements. This approach is demonstrated by using turn-by-turn data to reconstruct a linear optics model, and predict the brightness degradation for a ring-based light source. The quality of BPMs was found to be more important than their quantity in mitigating predictive errors.
 
slides icon Slides THXBA2 [3.205 MB]  
poster icon Poster THXBA2 [7.083 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THXBA2  
About • paper received ※ 16 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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THXBA3 Adaptive Machine Learning and Feedback Control for Automatic Particle Accelerator Tuning 916
 
  • A. Scheinker
    LANL, Los Alamos, New Mexico, USA
 
  Free electron lasers (FEL) and plasma wakefield accelerators (PWA) are creating more and more complicated electron bunch configurations, including multi-color modes for FELs such as LCLS and LCLS-II and custom tailored bunch current profiles for PWAs such as FACET-II. These accelerators are also producing shorter and higher intensity bunches than before and require an ability to quickly switch between many different users with various specific phase space requirements. For some very exotic setups it can take hours of tuning to provide the beams that users require. In this work, we present results adaptive machine learning and model independent feedback techniques and their application in both the LCLS and European XFEL to 1) control electron bunch phase space to create desired current profiles and energy spreads by tuning FEL components automatically, 2) maximize the average pulse output energy of FELs by automatically tuning over 100 components simultaneously, 3) preliminary results on utilizing these techniques for non-invasive electron bunch longitudinal phase space diagnostics at PWAs.  
slides icon Slides THXBA3 [8.110 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THXBA3  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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THXBA4 Update on BPM Signal Processing Circuitry Development at AWA 919
 
  • W. Liu, M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • C. Jing
    Euclid Beamlabs LLC, Bolingbrook, USA
 
  Funding: The US Department of Energy, Office of Science
Beam position monitor (BPM) is widely used in accelerator facilities worldwide. It is a device which is capable of providing, non-destructively, accurate beam centroid and charge information of a passing charged beam. A typical BPM system contains customized hardware and specialized processing electronics. The cost is often too high for small facilities to afford them. As a small facility, Argonne Wakefield Accelerator (AWA) decided to develop a solution with high cost-efficiency to fit in its budget. Some details about the development are presented in this paper.
 
slides icon Slides THXBA4 [8.544 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THXBA4  
About • paper received ※ 29 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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THXBA5
Electro-Optic Sampling Beam Position Monitor  
 
  • K.D. Hunt-Stone, R.A. Ariniello, J.R. Cary, C.E. Doss
    CIPS, Boulder, Colorado, USA
  • J.R. Cary
    Tech-X, Boulder, Colorado, USA
  • M.D. Litos
    Colorado University at Boulder, Boulder, Colorado, USA
 
  Funding: This work was supported in part by the U.S. D.O.E. grant number DE-SC0017906.
Electron beam-driven plasma wakefield accelerator (PWFA) experiments at SLAC’s FACET-II research facility will require diagnostics that can measure the transverse position of both the drive beam and the witness beam in a single shot. This is a challenge for ordinary beam position monitors due to the close temporal spacing between the two bunches, usually on the order of 300 fs. Here we will discuss the concept for an electro-optic sampling beam position monitor (EOS-BPM) that can measure the transverse position of the individual bunches with roughly 10 µm spatial resolution, and 50 fs temporal resolution. The EOS-BPM has the advantage of being a non-destructive, single shot measurement. It uses two EO crystals on either side of the beamline. The half-cycle THz fields of the electron beams induce a birefringence in the crystals which are probed by a chirped laser pulse. The longitudinal current profile is spectrally encoded into the probe laser, while the transverse position for each bunch is encoded in the relative strength of the signal in either crystal. We present simulations demonstrating the effectiveness of an EOS-BPM in the context of PWFA experiments planned for FACET-II.
 
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THZBB1
Commissioning of the FRIB Beam Instrumentation  
 
  • S.M. Lidia
    FRIB, East Lansing, Michigan, USA
 
  A large variety of beam instrumentation have been developed, installed and commissioned. This talk will present various aspects of physics and engineering of beam instrumentation devices and their performance during the beam commissioning.  
slides icon Slides THZBB1 [20.535 MB]  
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THZBB2
Single-Shot Wakefield Measurement System  
 
  • Q. Gao
    TUB, Beijing, People’s Republic of China
 
  A new experimental technique for the accurate measurements of wakefields is presented. Knowledge of wakefields is required for many applications ranging from the suppression of wakefields that arise from geometrical discontinuities to the enhancement of wakefields in structure and plasma based wakefield accelerators. In the past, direct measurements of wakefields were done with the drive-witness technique wherein the delay of a short witness beam trailing collinearly behind a high-charge drive beam is scanned over multiple shots and the wakefield is inferred from the energy spectrum of the witness beam. That technique is limited by shot-to-shot jitter, overlap of the drive and witness energy spectrum and the loss of all time-domain information. In this paper, we describe a new technique that overcomes these limitations by measuring the longitudinal phase space of a long witness beam and the drive beam in a single shot. We conclude by presenting experimental results to demonstrate its feasibility using a dielectric structure wakefield accelerator.  
slides icon Slides THZBB2 [4.073 MB]  
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THZBB3 Novel Emittance Measurement Combining Foil Focusing and Pepper-Pot Techniques 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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THZBB4 Beam Loss in the First Segment of the FRIB Linac 965
TUPLE17   use link to see paper's listing under its alternate paper code  
 
  • R. Shane, S. Cogan, S.M. Lidia, T. Maruta
    FRIB, East Lansing, Michigan, USA
 
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Beam loss in accelerators is an unavoidable and often unwanted reality, but it is not without its use. Information from beam loss can be leveraged to optimize the tune and improve beam quality, in addition to monitoring for machine fault and failure conditions. The folded geometry at the Facility for Rare Isotope Beams (FRIB) presents a unique challenge in the detection of radiative losses, resulting in the introduction of non-traditional measurement schemes. In addition to neutron detectors and pressurized ionization chambers, FRIB will utilize halo ring monitors, fast thermometry within the cryomodules, and differential beam-current measurements. This paper will present an analysis of beam-loss measurements from commissioning the first segment of the FRIB accelerator, and a discussion of ways to evaluate and monitor the health of the beam loss monitoring system.
 
slides icon Slides THZBB4 [2.477 MB]  
poster icon Poster THZBB4 [0.584 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB4  
About • paper received ※ 04 September 2019       paper accepted ※ 17 November 2020       issue date ※ 08 October 2019  
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THZBB5 Present Status and Upgrades of the SNS Ion Beam Bunch Shape Monitors 968
 
  • V. Tzoganis, A.V. Aleksandrov, R.W. Dickson
    ORNL, Oak Ridge, Tennessee, USA
 
  Six interceptive Feschenko-style longitudinal bunch profile monitors have been deployed in the normal conducting part of the SNS linac and HEBT. They have been operational for more than 10 years and although their performance has been satisfactory, reliability and parts obsolescence must be addressed. The upgrade plan focuses in mainly two areas, electronics architecture modernization and improvement of measurement resolution. In the first phase that is presented here the objective is to improve the control and readout electronics taking advantage of more recent technology. This will primarily address the obsolescence issues with older components, the frequent RF power failures, the non-trivial maintenance and troubleshooting and will lead to a simpler and more reliable system. This contribution describes in detail the implemented upgrades and presents the first experimental data.  
slides icon Slides THZBB5 [4.926 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB5  
About • paper received ※ 29 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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THZBB6 Error Minimization in Transverse Phase-Space Measurements Using Quadrupole and Solenoid Scans 971
SUPLO03   use link to see paper's listing under its alternate paper code  
TUPLE18   use link to see paper's listing under its alternate paper code  
 
  • C.Y. Wong
    NSCL, East Lansing, Michigan, USA
  • S.M. Lund
    FRIB, East Lansing, Michigan, USA
 
  Quadrupole and solenoid scans are common techniques where a series of beam profile measurements are taken under varying excitation of the linear focusing elements to unfold second-order phase-space moments of the beam at an upstream location. Accurate knowledge of the moments is crucial to machine tuning and understanding the underlying beam dynamics. The scans have many sources of errors including measurement errors, field errors and misalignments. The impact of these uncertainties on the moment measurement is often not analyzed. This study proposes a scheme motivated by linear algebra error bounds that can efficiently select a set of scan parameters to minimize the errors in measured initial moments. The results are verified via a statistical error analysis. These techniques are being applied at the Facility for Rare Isotope Beams (FRIB). We find that errors in initial moments can be large under conventional scans but are greatly reduced using the procedures described.  
slides icon Slides THZBB6 [2.153 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB6  
About • paper received ※ 04 September 2019       paper accepted ※ 04 December 2019       issue date ※ 08 October 2019  
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