TUPLE —  Tuesday Poster Session-Lake Erie   (03-Sep-19   16:30—18:00)
Paper Title Page
TUPLE01 Python Scripts for RF Commissioning at FRIB -1
  • 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 [0.512 MB]  
Ultra-Smooth and High QE Cesium Telluride Photocathodes by a Modified Co-Deposition Approach  
  • J. Cen, M. Gaowei, E.M. Muller, J. Sinsheimer, J. Smedley, J. Walsh
    BNL, Upton, New York, USA
  • A.M. Alexander, V.N. Pavlenko
    LANL, Los Alamos, New Mexico, USA
  • D.P. Juarez-Lopez
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J. Xie
    ANL, Lemont, Illinois, USA
  Funding: (1) U.S. Department of Energy: KC0407-ALSJNT-I0013, DE-AC02-98CH1088, SBIR grant DE-SC0009540, DE-AC02-98CH10886, DE-AC02-06CH11357. and DE-AC02-98CH10886. (2) NSF award DMR-0936384 and DMR-1332208.
Cesium telluride (CsTe) photocathodes have been chosen for electron sources by worldwide accelerators, due to their relatively high quantum efficiency and stable performance in complex operation environments. However, common sequential methods struggle to produce high quantum efficiency and high surface smoothness. In our recent study, we were able to achieve low surface roughness, high crystallinity and a quantum efficiency of 19% @ 266 nm by a modified co-deposition method. We further compared the traditional sequential and the newly developed co-evaporation method via in situ X-ray measurements and revealed the chemical and structural evolution of each growth method. In addition, our in situ decomposition experiments have disclosed that the CsTe photocathodes from these the two methods had distinguishable decomposition processes, which could be the essential reasons that our co-deposition method gives much higher quantum efficiency. These findings will be an important guide for future design and development of CsTe photocathodes.
TUPLE04 An Iris Diaphragm Beam Detector for Halo or Profile Measurements -1
  • 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.
TUPLE05 Optical System for Observation of FRIB Target -1
  • 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 [1.867 MB]  
TUPLE06 Skimmer-Nozzle Configuration Measurements for a Gas Sheet Beam Profile Monitor -1
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.
TUPLE07 Overview of FRIB’s Diagnostics Controls System -1
  • 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 [2.223 MB]  
TUPLE08 Commissioning Update on RF Station #5 of AWA -1
  • 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.
Silicon Detector for Heavy Ion Linac Tuning at NSCL/FRIB  
  • Q. Zhao
    FRIB, East Lansing, Michigan, USA
  Funding: 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
Silicon detectors are used to set up the synchronous phase of resonators at ReA3. It also used during the beam commissioning of the first three cryomodules at FRIB. The detector was placed off beam axis and detected particles scattered from a very thin gold foil. The gold foils were made in-house and the foil thickness was measured in two independent methods. Our silicon detector has good timing resolution, so it can measure both beam energy and bunch profile with different preamplifiers. Since the silicon detector installed close to the superconducting resonators, the system was cleaned, assembled and aligned in a cleaning room. We will describe the electronics for signal amplification and data acquisition, present the bench test results with an alpha source together with beam measurement results.
TUPLE11 Proposed Enhanced Imaging Station in the 6-GeV Booster-to-Storage Ring Transport Line for APS Upgrade -1
  • A.H. Lumpkin
    Fermilab, Batavia, Illinois, USA
  • W. Berg, J.C. Doolingpresenter, 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.
TUPLE13 Analytical Thermal Analysis of Thin Diamond in High-Intensity High-Repetition-Rate Application -1
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 [0.912 MB]  
TUPLE15 BPM Processor Upgrades at SPEAR3 -1
  • 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.
TUPLE16 RFA Measurement of E-Cloud Generation Process at Fermilab Main Injector -1
  • 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.  
Beam Loss in the First Segment of the FRIB Linac  
THZBB4   use link to access more material from this paper's primary 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 TUPLE17 [2.473 MB]  
poster icon Poster TUPLE17 [0.643 MB]  
Error Minimization in Transverse Phase-Space Measurements Using Quadrupole and Solenoid Scans  
SUPLO03   use link to access more material from this paper's primary paper code  
THZBB6   use link to access more material from this paper's primary 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 TUPLE18 [2.150 MB]  
Beam Dynamics in a High Gradient RF Streak Camera  
TUYBB6   use link to access more material from this paper's primary 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 TUPLE19 [6.883 MB]