Keyword: controls
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MOPLH16 Femtosecond Laser Microfabrication for Advanced Accelerator Applications laser, FEM, polarization, cathode 207
 
  • S.P. Antipov, E. Dosov, E. Gomez, S.V. Kuzikov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  
  Funding: DOE SBIR
Femtosecond laser microfabrication allows for precise dimension control and reduced thermal stress of the machined materials. It can be applied to a wide range of materials from copper to diamond. Combined with secondary operations like polishing laser microfabrication can be utilized in various state of the art components required for AAC community. In this paper we will review several applications of laser microfabrication for Advanced Accelerator research and development. These will include wakefield structures (corrugated metal and dielectric loaded), plasma capillaries, x-ray refractive optics, high power laser optical components: mirrors, phase plates. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH16  
About • paper received ※ 28 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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MOPLO09 A Pulsed, Current Regulated Magnet Power Supply for Small Magnets quadrupole, injection, operation, timing 252
 
  • G.D. Wyche, B.L. Beaudoin, L. Dovlatyan, D.F. Sutter
    UMD, College Park, Maryland, USA
  
  Funding: Work supported by U. S. Department of Energy grant number DESC00010301
The University of Maryland Electron Ring (UMER) has two pulsed quadrupoles in the injection section that must be current regulated to the same precision as the other DC quadrupoles in the ring, as well as accurately synchro-nized to the ring operating cycle. To meet this need, a practical pulsed current, regulated power supply has been designed and built using a commercial power operational amplifier for output, standard operational amplifiers for feedback control and monitoring, and matched resistor pairs to produce the desired transfer function of 10 Volts to 6 Amperes. For other applications the circuit can be modified to produce a range of transfer functions by varying the appropriate resistor pair ratios. Output pulse width and timing are generated by a standardized TTL pulse from the control system that gates the output of the amplifier. Installed safety circuitry detects the absence of a proper control pulse, an open circuit or shorted output, and measures and returns to the control system the actual operating amplitude of the current pulse. In this paper we present the design, implementation, and operational results of the prototyped pulsed current source. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO09  
About • paper received ※ 28 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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MOPLO24 A Novel Technique for Pulsed Operation of Magnetrons without Modulation of Cathode Voltage cathode, operation, cavity, injection 290
 
  • G.M. Kazakevich, R.P. Johnson
    Muons, Inc, Illinois, USA
  • T.N. Khabiboulline, V.A. Lebedev, G.V. Romanov, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Modern pulsed superconducting accelerators of megawatt beams require efficient RF sources controllable in phase and power. For each Superconducting RF (SRF) cavity is desirable a separate RF source with power up to hundreds of kW with pulse duration in the millisecond range. The efficiency of the traditional RF sources (klystrons, IOTs, solid-state amplifiers) is lower than that of the magnetrons, while the cost of a unit of RF power is much higher. Therefore the magnetron-based RF sources would significantly reduce the capital and operation costs in comparison with the traditional RF sources. A recently developed an innovative technique makes possible the pulsed generation of magnetrons powered below the self-excitation threshold voltage. This technique does not require pulse modulators to form RF pulses. The magnetron operation in this regime is stable, low noise, controllable in phase and power, and provides higher efficiency than other types of RF power sources. It allows operation in pulsed modes with large duty factor. The developed technique and its experimental verification are considered and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO24  
About • paper received ※ 29 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLM15 Arbitrary Transverse Profile Shaping using Transverse Wigglers wiggler, emittance, focusing, electron 403
 
  • G. Ha, M.E. Conde, J.G. Power
    ANL, Lemont, Illinois, USA
  
  Funding: This work is supported by the U.S. Department of Energy, Offices of HEP and BES, under Contract No. DE-AC02-06CH11357.
Argonne Wakefield Accelerator (AWA) group demonstrated arbitrary longitudinal shaping capability of thee emittance exchange (EEX) beamline in 2016. Several different transverse masks were used to shape the beam transversely, and the transmission through the mask was around 40%. The masking is one of the easiest ways to control the profile, but this low transmission would make significant drop of the beam quality due to a higher charge requirement in the gun, and it can make thermal issues for high repetition rate or high intensity beams. At the same time, it only controls the profile not a 2D phase space. We recently proposed a scheme to generate a tunable bunch train using a EEX beamline with a transverse wiggler. This wiggler provides a sinusoidal magnetic field which makes a sinusoidal modulation on the transverse phase space. If the beam passes series of transverse wigglers with different period and strength, one can make arbitrary correlation on the horizontal position and momentum. It opens up totally new way to control all longitudinal properties including arbitrary current profile shaping without charge loss. In this poster, we present the concept of the work and plan. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM15  
About • paper received ※ 02 September 2019       paper accepted ※ 13 September 2019       issue date ※ 08 October 2019  
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TUPLM16 Double-Horn Suppression in EEX Based Bunch Compression octupole, simulation, emittance, quadrupole 407
 
  • J. Seok, M. Chung
    UNIST, Ulsan, Republic of Korea
  • M.E. Conde, G. Ha, J.G. Power
    ANL, Lemont, Illinois, USA
  
  Nonlinearities on the longitudinal phase space in-duce a double-horn current profile when the bunch is compressed strongly. Since this double-horn can de-grade the performance of FELs due to the CSR it makes, the suppression of the double-horn is one of important beam dynamics issues. Emittance exchange (EEX) can be interesting option for this issue due to its longitudinal controllability. Since EEX exchanges the longitudinal phase space and transverse phase space, higher order magnets such as octupole can control the nonlinearity. In this paper, we present simulation re-sults on the suppression of the double-horn current profile using EEX based bunch compression. We use a double EEX beamline installed at the Argonne Wake-field Accelerator facility for the simulation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM16  
About • paper received ※ 03 September 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 LLRF, operation, machine-protect, FPGA 437
 
  • 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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TUPLS05 High-Level Physics Application for the Emittance Measurement by Allison Scanner EPICS, emittance, software, GUI 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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TUPLS09 Precision Insertion Device Control and Simultaneous Monochromator Fly Scanning for NSLS-II insertion-device, insertion, photon, feedback 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 cathode, electron, gun, operation 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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TUPLS13 Evaluation of the Xilinx RFSoC for Accelerator Applications detector, electron, interface, instrumentation 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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TUPLH17 Design Study of Low-Level RF Control System for CW Superconducting Electron Linear Accelerator in KAERI SRF, LLRF, linac, cavity 512
 
  • S.H. Lee, J.Y. Lee
    Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
  • P. Buaphad, I.G. Jeong, Y.J. Joo, H.R. Lee
    University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
  • M.-H. Chun, I.H. Yu
    PAL, Pohang, Republic of Korea
  • Y. Kim
    KAERI, Jeongeup-si, Republic of Korea
  
  Korea Atomic Energy Research Institute (KAERI) has been operating a 20 MeV superconducting RF linear accelerator (SRF LINAC) to conduct research on atom/nuclear reaction using neutron Time-Of-Flight (nTOF). It can accelerate electron beams up to 20 MeV with 1 kW continuous wave (CW) operation mode. Unfortunately, this machine has been aged over 15 years that brings about considerably difficulty in normal operation due to the performance degradation of sub-systems. To improve the operation condition of 20 MeV SRF LINAC, we has been carrying out an upgrade project with replacement and repair of old sub-systems from 2018. This paper describes a design study of Low-Level RF (LLRF) feedback system to raise the stability and acceleration efficiency of the electric field generated in the superconducting RF cavity structure in 20 MeV SRF LINAC.  
poster icon Poster TUPLH17 [0.644 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH17  
About • paper received ※ 30 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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TUPLH18 NSLS-II Inject Linac RF Control Electronics Upgrade linac, klystron, network, operation 516
 
  • H. Ma
    BNL, Upton, New York, USA
  
  Funding: US DOE
The electron LINAC injector of NSLS-II synchrotron light-source runs both Single-Bunch beam and long Multi-Bunch beam of up to 150 bunches. The key component for achieving this dual injector beam mode support capability is a high-speed rf modulator (or RFM) in the LINAC RF electronics front-end, which performs the necessary rf control and the beam loading compensation of different injection beams. The original LINAC rf electronics front-end successfully supported the machine commissioning and meets the basic needs of the machine operation. The upgrade being pursued is focused on improving the RFM control performance through replacing the current analog implementation in the RFM with a much more capable digital implementation, while still maintaining the necessary control bandwidth that is required for long and short Multi-Bunch beams. A variety of modern COTS rf transmission/reception DSP technology will be incorporated in the new design. The improvement in the reliability of network connection between the RFM’s and their host server is another focus in the upgrade, and the solution includes the adoption of the COTS TCP/IP and other communication protocol offload engines. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH18  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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TUPLO05 Fixed Target Operation at RHIC in 2019 target, experiment, 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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TUPLE01 Python Scripts for RF Commissioning at FRIB cavity, EPICS, LLRF, linac 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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TUPLE07 Overview of FRIB’s Diagnostics Controls System EPICS, diagnostics, software, operation 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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TUPLE15 BPM Processor Upgrades at SPEAR3 booster, EPICS, synchrotron, software 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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WEXBB1 Adaptive Machine Learning and Automatic Tuning of Intense Electron Bunches in Particle Accelerators FEL, electron, feedback, target 609
 
  • A. Scheinker
    LANL, Los Alamos, New Mexico, USA
  
  Machine learning and in particular neural networks, have been around for a very long time. In recent years, thanks to growth in computing power, neural networks have reshaped many fields of research, including self driving cars, computers playing complex video games, image identification, and even particle accelerators. In this tutorial, I will first present an introduction to machine learning for beginners and will also touch on a few aspects of adaptive control theory. I will then introduce some problems in particle accelerators and present how they have been approached utilizing machine learning techniques as well as adaptive machine learning approaches, for automatically tuning extremely short and high intensity electron bunches in free electron lasers.  
slides icon Slides WEXBB1 [58.913 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEXBB1  
About • paper received ※ 28 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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WEYBB6 Design Considerations and Operational Features of the Collimators for the Fermilab Main Injector and Recycler collimation, proton, radiation, operation 642
 
  • B.C. Brown, P. Adamson, R. Ainsworth, D. Capista, K.J. Hazelwood, I. Kourbanis, N.V. Mokhov, D.K. Morris, V.S. Pronskikh, I.L. Rakhno, I.S. Tropin, M. Xiao, M.-J. Yang
    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.
The Fermilab Main Injector system delivers 700 kW of 120 GeV Proton beam for neutrino experiments. Since 2013 this has been achieved using slip stacking accumulation in the Recycler with up to 12 batches from the Fermilab Booster per Main Injector Ramp Cycle. To control activation from beam loss, collimation systems in the Booster to Recycler transfer line, in the Recycler and in the Main Injector are employed. Residual radiation measurements around the ring with detailed studies at the collimators are required to maintain adequate loss control. We will review design considerations, operational parameters and activation results for more than ten years of operation. Simulations with MARS15 are used to explore the activation rates and the isotopic composition of the resulting activation. 		 
slides icon Slides WEYBB6 [12.713 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB6  
About • paper received ※ 30 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEZBA2 Experience and Lessons in FRIB Superconducting Quarter-Wave Resonator Commissioning cavity, cryomodule, MMI, linac 646
 
  • S.H. Kim, H. Ao, F. Casagrande, W. Chang, C. Compton, A. Facco, V. Ganni, E. Gutierrez, W. Hartung, N. Hasan, P. Knudsen, T.L. Larter, H. Maniar, S.J. Miller, D.G. Morris, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, L. Popielarski, H.T. Ren, K. Saito, M. Thrush, D.R. Victory, J. Wei, M. Xu, T. Xu, Y. Yamazaki, C. Zhang, S. Zhao
    FRIB, East Lansing, Michigan, USA
  
  The superconducting (SC) linear accelerator (linac) for the Facility for Rare Isotope Beams (FRIB) has one quarter-wave resonator (QWR) segment and two half-wave resonator (HWR) segments. The first linac segment (LS1) contains twelve β = 0.041 and ninety-two β = 0.085 QWRs operating at 80.5 MHz, and thirty-nine SC solenoids. Superconducting radiofrequency (SRF) commissioning and beam commissioning of LS1 was completed in April 2019. The design accelerating gradients (5.1 MV/m for β = 0.041 and 5.6 MV/m for β = 0.085) were achieved in all cavities with no multipacting or field emission issues. The cavity field met the design goals: peak-to-peak stability of ±1% in amplitude and ±1° in phase. We achieved 20.3 MeV/u ion beams of Ar, Kr, Ne, and Xe with LS1. In this paper, we will discuss lessons learned from the SRF commissioning of the cryomodules and methods developed for efficient testing, conditioning, and commissioning of more than 100 SC cavities, each with its own independent RF system.  
slides icon Slides WEZBA2 [2.841 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA2  
About • paper received ※ 03 September 2019       paper accepted ※ 05 December 2019       issue date ※ 08 October 2019  
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WEZBA5 Development of a Marx Modulator for FNAL Linac operation, flattop, power-supply, high-voltage 653
 
  • T.A. Butler, F.G. Garcia, M.R. Kufer, K.S. Martin, H. Pfeffer
    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.
A Marx-topology modulator has been designed and developed at the Fermi National Accelerator Laboratory under the Proton Improvement Plan (PIP). This modulator replaces the previous triode hard-tube design, increasing reliability, lowering operational costs, and maintaining waveform accuracy. The Marx modulator supplies the anode of the 7835 VHF power triode tube with a 35 kV, 375 Amp, 460 µs pulse at 15 Hz. It consists of 54 individual Marx cells, each containing a 639 µF capacitor charged to 900 Volts, combined in series with IGBT switches to create the desired output waveform. This requires variable rise and fall times, flattening of capacitive droop, and feedforward beam loading compensation. All five 201.25 MHz RF systems have been upgraded to Marx modulators to ensure continued operation of the linear accelerator. 		 
slides icon Slides WEZBA5 [15.252 MB]  
poster icon Poster WEZBA5 [3.029 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA5  
About • paper received ※ 28 August 2019       paper accepted ※ 05 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 cavity, klystron, power-supply, experiment 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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WEPLM01 Studies in Applying Machine Learning to Resonance Control in Superconducting RF Cavities cavity, LLRF, simulation, resonance 659
 
  • 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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WEPLM03 The LLRF Control Design and Validation at FRIB LLRF, cavity, MMI, cryomodule 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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WEPLM05 Continuous Monitoring of Spectral Features of Electron Beam Orbit Motion at NSLS-II operation, undulator, feedback, cavity 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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WEPLM07 Low Level RF Test System for the Compact X-Ray Light Source at Arizona State University klystron, electron, cavity, LLRF 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 feedback, power-supply, vacuum, simulation 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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WEPLM21 High-Quality Resonators for Quantum Information Systems SRF, cavity, cryogenics, photon 690
 
  • S.V. Kuzikov
    IAP/RAS, Nizhny Novgorod, Russia
  • S.P. Antipov, P.V. Avrakhov, E. Gomez
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  We analyze ultra-high-quality factor resonators for quantum computer architectures. As qubit operation requires external DC fields, we started our study with a conventional closed copper cavity which naturally allows external magnetic field. In order to increase quality factor and to keep DC magnetic field control at a level less than critical field, an open SRF resonator promises much higher quality. The next step resonator is a photonic band gap (PBG) resonator. This resonator allows easy external either magnetic or electric field control. It consists of a periodic 3D set of sapphire rods assembled between two superconducting plates. The PBG resonator exploits unique properties of the crystalline sapphire. Tangent delta for sapphire in X-band is reported at 10-9 ’ 10-10 at 4 K. That is why, the Q-factor of the sapphire PBG resonator can be expected as high as 10 billions at mK temperatures which provides long relaxation times (dephasing etc.). The established PBG design implies obtaining a large Purcell factor, i.e. large ratio of quality to mode volume which is important parameter to establish strong interaction of a qubit with the cavity mode rather than RF noise.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM21  
About • paper received ※ 27 August 2019       paper accepted ※ 01 September 2019       issue date ※ 08 October 2019  
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WEPLM49 New RF System for First Drift Tube Linac Cavity at LANSCE DTL, cavity, power-supply, LLRF 703
 
  • J.T.M. Lyles, R.E. Bratton, G. Roybal, M. Sanchez Barrueta, G.M. Sandoval, Jr., D.J. Vigil, J.E. Zane
    LANL, Los Alamos, New Mexico, USA
  
  Funding: Work supported by the United States Department of Energy, NNSA, under contract 89233218CNA000001
From 2014-2016, the three highest power 201 MHz power amplifier (PA) systems were replaced at the Los Alamos Neutron Science Center 100 MeV DTL. The initial DTL cavity provides 4.25 MeV of energy gain and has been powered by a Photonis (RCA) 4616 tetrode driving a 7835 triode PA for over 30 years. It consumes 110 kW of electrical power for tube filaments, power supplies and anode modulator. The modulator is not required with modern tetrode amplifiers. In 2020 we plan to replace this obsolete 6 tube transmitter with a design using a single tetrode PA stage without anode modulator, and a 20 kW solid-state driver stage. This transmitter needs to produce no more than 400 kW, and will use a coaxial circulator. Cooling water demand will reduce from 260 to 70 gal/min of pure water. High voltage DC power comes from the same power supply/capacitor bank that supplied the old system. The old low-level RF controls will be replaced with digital LLRF with learning capability for feedforward control, I/Q signal processing, and PI feedback. All high power components have been assembled in a complete mockup system for extended testing. Installation of the new RF system begins in January of 2020. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM49  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLM66 Microphonics Studies at STC in Fermilab cavity, resonance, ion-source, cryomodule 743
 
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  • Y.M. Pischalnikov, W. Schappert, A.I. Sukhanov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  
  The spoke test cryostat is used to qualify the 325 MHz single spoke resonators at Fermilab (FNAL). During these tests a large detuning on the cavity was observed. The data acquisition for continuous captures were based on measurements from the piezoelectric actuators. A com-parison of the cavity vibrations measured with RF signal from the cavity and piezoelectric actuator signals are shown. The effects of microphonics on the cavity are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM66  
About • paper received ※ 28 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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WEPLM70 FRIB Tuner Performance and Improvement cavity, linac, cryomodule, MMI 755
 
  • J.T. Popielarski, W. Chang, C. Compton, W. Hartung, S.H. Kim, E.S. Metzgar, S.J. Miller, K. Saito, J.F. Schwartz, T. Xu
    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 under construction at Michigan State University (MSU). The FRIB superconducting driver linac will accelerate ion beams to 200 MeV per nucleon. The driver linac requires 104 quarter-wave resonators (QWRs, β = 0.041 and 0.085) and 220 half-wave resonators (HWRs, β = 0.29 and 0.54). The cryomodules for β = 0.041, 0.085, and 0.29 have been completed and certified; 32 out of 49 cryomodules are certified via bunker test (as of March 2019). FRIB QWR cavities have a demountable niobium tuning plate which uses a warm external stepper motor and the FRIB HWR cavities use pneumatic actuated bellows. Progress on the preparation and performance of the tuners is presented in this paper along with improvements made to ensure meeting frequency specification. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM70  
About • paper received ※ 26 September 2019       paper accepted ※ 19 November 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, experiment 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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WEPLO17 Ultrashort Laser Pulse Shaping and Characterization for Tailored Electron Bunch Generation laser, electron, FEM, diagnostics 871
 
  • T. Xu, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • M.E. Conde, G. Ha, J.G. Power
    ANL, Lemont, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  
  Temporally shaped laser pulses are desirable in various applications including emittance reduction and beam-driven acceleration. Pulse shaping techniques enable flexible controls over the longitudinal distribution of electron bunches emitted from the photocathode. While direct manipulation and measurement of an ultrashort pulse can be challenging in the time domain, both actions can be performed in the frequency domain. In this paper, we report the study and development of laser shaper and diagnostics at Argonne Wakefield Accelerator (AWA). Simulations of the shaping process for several sought-after shapes are presented along with the temporal diagnosis. Status of the experiment at the AWA facility is also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO17  
About • paper received ※ 05 September 2019       paper accepted ※ 04 December 2019       issue date ※ 08 October 2019  
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THXBA3 Adaptive Machine Learning and Feedback Control for Automatic Particle Accelerator Tuning FEL, electron, target, laser 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 detector, electron, pick-up, electronics 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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THYBA6 Active Pointing Stabilization Techniques Applied to the Low Energy RHIC Electron Cooling Laser Transport at BNL laser, electron, operation, cathode 938
 
  • L.K. Nguyen, A.J. Curcio, W.J. Eisele, A.V. Fedotov, A. Fernando, W. Fischer, P. Inacker, J.P. Jamilkowski, D. Kayran, K. Kulmatycski, D. Lehn, T.A. Miller, M.G. Minty, A. Sukhanov
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The electron beam for the Low Energy RHIC electron Cooler (LEReC) at Brookhaven National Laboratory (BNL) is generated by a high-power fiber laser illuminating a photocathode. The pointing stability of the electron beam, which is crucial given its long transport, is highly dependent on the center-of-mass (CoM) stability of the laser spot on the photocathode. For reasons of accessibility during operations, the laser is located outside the accelerator tunnel, and the laser beam is propagated over a total distance of 34 m via three laser tables to the photocathode. The challenges to achieving the required CoM stability of 10 microns RMS on the photocathode include mitigation of the effects of vibrations along the transport and of weather- and season-related environmental effects, while preserving accessibility and diagnostic capabilities. Due to the insufficiency of infrastructure alone in overcoming these challenges, two active laser transport stabilization systems aimed at addressing specific types of position instability were installed during the 2018 Shutdown. After successful commissioning of the full transport in 2018/19, we report on our solutions to these design challenges. 		 
slides icon Slides THYBA6 [3.426 MB]  
poster icon Poster THYBA6 [1.299 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THYBA6  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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THZBA4 Characterization and Modeling of High-Intensity Evolution in the SNS Beam Test Facility emittance, simulation, diagnostics, lattice 954
 
  • K.J. Ruisard, A.V. Aleksandrov, S.M. Cousineau
    ORNL, Oak Ridge, Tennessee, USA
  • Z.L. Zhang
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. Partial support by NSF Accelerator Science grant 1535312
Modern high-power accelerators are charged with delivering reliable beam with low losses. Resolving the complex dynamics arising from space charge and nonlinear forces requires detailed models of the accelerator and particle-in-cell simulation. There has historically been discrepancy between simulated and measured beam distributions, particularly at the low-density halo level. The Beam Test Facility (BTF) at the Spallation Neutron Source is outfitted to study beam evolution in a high-power linear accelerator MEBT. This includes capability for high-dimensional measurements of the post-RFQ beam distribution, including interplane correlations that may be the key to accurate simulation. Beam is transported through a 4.6 m FODO channel (9.5 cells) to a second distribution measurement stage. Plans for validating simulations against BTF measurements of beam evolution in the FODO channel are discussed. 		 
slides icon Slides THZBA4 [8.316 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA4  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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THZBB5 Present Status and Upgrades of the SNS Ion Beam Bunch Shape Monitors electron, power-supply, high-voltage, operation 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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FRXBA3 Applications and Opportunities for the Emittance Exchange Beamline emittance, electron, wiggler, wakefield 981
 
  • G. Ha, M.E. Conde, J.G. Power
    ANL, Lemont, Illinois, USA
  • M. Chung, J. Seok
    UNIST, Ulsan, Republic of Korea
  
  Funding: This work is supported by the U.S. Department of Energy, Offices of HEP and BES, under Contract No. DE-AC02-06CH11357.
Emittance exchange (EEX) provides a powerful method of controlling the longitudinal phase space using the relatively simpler methods of transverse control. An EEX beamline was installed at the Argonne Wakefield Accelerator (AWA) facility in 2015. Several experiments important to the wakefield acceleration, such as a high transformer ratio from shaped bunches, have already been demonstrated. We are currently developing several applications of the EEX beamline including temporal profile shaping, THz radiation generation, time-energy correlation control, diagnostic uses of EEX etc. We will present the on-going EEX program for longitudinal phase space control taking place at the AWA facility, and discuss recently discovered new opportunities. 		 
slides icon Slides FRXBA3 [6.814 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA3  
About • paper received ※ 02 September 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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