Author: Smedley, J.
Paper Title Page
WEPA42 A Modular X-Ray Detector for Beamline Diagnostics at LANL 725
  • P.M. Freeman, B. Odegard, R. Schmitz, D. Stuart, J. Yang
    UCSB, Santa Barbara, California, USA
  • J. Bohon, M.S. Gulley, E.-C. Huang, J. Smedley
    LANL, Los Alamos, New Mexico, USA
  • L. Malavasi
    WPI, Worcester, MA, USA
  An X-ray detector is being developed for diagnostic measurement and monitoring of the Drift Tube LINAC (DTL) at the Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Lab. The detector will consist of a row of x-ray spectrometers adjacent to the DTL that will measure the spectrum of X-rays resulting from bremsstrahlung of electrons created in vacuum by the RF. Each spectrometer will monitor a specific gap between drift tubes, and will consist of an array of scintillating crystals coupled to SiPMs read out with custom-built electronics. The spectrometer is designed with one LYSO and three NaI crystals. The LYSO provides a tagged gamma source with three peaks that are used for calibration of the NaI. A prototype of the spectrometer was tested at the LANSCE DTL to validate the feasibility of measuring gamma spectra and performing self-calibration in situ. A summary of test results with the LANSCE prototype will be presented, along with a detector system design that aims to be modular and inexpensive across all modules in the DTL. Plans for future development will be presented as well.  
poster icon Poster WEPA42 [1.308 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA42  
About • Received ※ 04 August 2022 — Revised ※ 06 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 11 August 2022
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A Time-Resolved Beam Halo Monitor for Accelerator Beam Diagnostics Using Diamond Detectors and High Speed Digitizers  
  • I.S. Mostafanezhad, K.T. Flood, L.M. Macchiarulo, B. Rotter
    Nalu Scientific, LLC, Honolulu, USA
  • J. Bohon
    LBNL, Berkeley, California, USA
  • E.M. Muller
    BNL, Upton, New York, USA
  • J. Smedley
    LANL, Los Alamos, New Mexico, USA
  • J. Smedley
    SLAC, Menlo Park, California, USA
  We will describe the development and prospects for the Time-Resolved Beam Halo Monitor (TR-BHM) along with results from initial beam tests. The TR-BHM is a detector system for measuring and characterizing the spatial and temporal structure of particle halos accompanying accelerated particle bunches utilizing diamond strip detectors read out by system-on-chip (SoC) high-speed waveform digitizers developed by Nalu Scientific LLC (NSL). It will provide a powerful non-destructive in-situ beam diagnostic detector for real-time measurements and control of beam parameters for the next generation of light sources. The theory, detection methodology, and instrumentation will be discussed, as well as measurement results from full-system x-ray beam calibration tests and preparations for an upcoming prototype installation at FACET.  
slides icon Slides THZE6 [9.370 MB]  
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TUYD3 The Quest for the Perfect Cathode 281
  • J.W. Lewellen, J. Smedley, T. Vecchione
    SLAC, Menlo Park, California, USA
  • D. Filippetto
    LBNL, Berkeley, California, USA
  • S.S. Karkare
    Arizona State University, Tempe, USA
  • J.M. Maxson
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • P. Musumeci
    UCLA, Los Angeles, California, USA
  Funding: U.S. Department of Energy.
The next generation of free electron lasers will be the first to see the performance of the laser strongly dependent on the materials properties of the photocathode. A new injector proposed for the LCLS-II HE is an example of this revolution, with the goal of increasing the photon energy achievable by LCLS-II to over 20 keV. We must now ask, what is the optimal cathode, temperature, and laser combination to enable this injector? There are many competing requirements. The cathode must be robust enough to operate in a superconducting injector, and must not cause contamination of the injector. It must achieve sufficient charge at high repetition rate, while minimizing the emittance. The wavelength chosen must minimize mean transverse energy while maintaining tolerable levels of multi-photon emission. The cathode must be capable of operating at high (~30 MV/m) gradient, which puts limits on both surface roughness and field emission. This presentation will discuss the trade space for such a cathode/laser combination, and detail a new collaborative program among a variety of institutions to investigate it.
slides icon Slides TUYD3 [1.632 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUYD3  
About • Received ※ 02 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 14 August 2022 — Issue date ※ 26 September 2022
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