1 / 18

Advanced Particle Beam Diagnostics at APS: Overview and Technologies

Explore innovative beam diagnostics techniques including Beam Position Monitoring, Wire Scanners, and Cherenkov Detectors at APS Undulator Section. Learn about Optical Transition Radiation Imaging and innovative BPM technologies.

johnwhittle
Download Presentation

Advanced Particle Beam Diagnostics at APS: Overview and Technologies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Undulator Section e- DiagnosticsGlenn Decker, ANL / APSApril 24, 2002 • Overview • Beam Position Monitoring • Wire Scanners / Cherenkov Detectors • Optical Transition Radiation Imaging Glenn Decker, ANL / APS

  2. Undulator Section Particle Beam Diagnostics Glenn Decker, ANL / APS

  3. Conceptual Design for Combined Button / Cavity BPM Glenn Decker, ANL / APS

  4. Principle of operation of BPM waveguide-cavity coupling Port to coax • Dipole frequency: 11.424 GHz • Dipole mode: TM11 • Coupling to waveguide: magnetic • Beam x-offset couples to “y” position • Sensitivity: 1.6mV/nC/m (1.6109V/C/mm) Magnetic Field Lines Beam Direction Zenghai Li, S. Smith, R. Johnson, SLAC Glenn Decker, ANL / APS

  5. Waveguide-Coupled Cavity-Based BPM Model • Dipole frequency: 11.424 GHz • Dipole mode: TM11 • Coupling to waveguide: radial magnetic • Beam x-offset couples to “y” port • Sensitivity: 1.6mV/nC/m • Explicitly does not couple to TM01 6 mm Zenghai Li, S. Smith, R. Johnson, SLAC Glenn Decker, ANL / APS

  6. Coupling scheme eliminates TM01 from output waveguide Dipole Frequency 11.4 GHz (Arb. Units) Fundamental Frequency 8.8 GHz Glenn Decker, ANL / APS

  7. Longitudinal Cavity Impedance 5e3 WL(V/pC) Dipole Mode 0 0 3 6 9 12 15 18 21 24 Frequency (GHz) Glenn Decker, ANL / APS

  8. LEUTL Capacitive Button Pickup Electrodes Electrical Specifications: Frequency: DC to 20 GHz Impedance: 50 ohm nominal, terminated by a capacitive button Capacitance: 4.8 pF nominal VSWR: 1.03:1 max. to 3 GHz, 1.15:1 to 20 GHz Insertion loss: 0.1 db max. to 3 GHz, 0.5 db max. to 20 GHz Matching: +/- 0.5 ohm in impedance, and +/- 0.1 pF in capacitance. Connector: SMA female ,hermetically sealed with glass insulator. Dielectric Strength: >1500 V at 50/60 Hz Leakage Resistance: > 1013 ohm, from center conductor to outer housing Mechanical Specifications: Diameter: 4 mm Materials: As per Kaman P/N 853881-001 Hermeticity: <10-11 cc He/sec Radiation: >200 megarads gamma 4 mm Dia. Drawing courtesy J. Hinkson ALS Glenn Decker, ANL / APS

  9. Button Pickup Electrode Mechanical Drawing Glenn Decker, ANL / APS

  10. Inexpensive Logarithmic Amplifiers for Button BPM Single Channel Four-Channel Unit with Test Ports Courtesy R. Lill, R. Keane, APS Glenn Decker, ANL / APS

  11. BPM Summary • Cavity BPM’s capable of sub-micron-scale resolution, reproducibility • Prototype unit undergoing characterization at SLAC/NLC • Capacitive button pickup electrodes are a mature technology, capable of providing 1 micron resolution / stability for hours / days • “Belt and suspenders” approach assures highest quality beam alignment capability Glenn Decker, ANL / APS

  12. Cherenkov Detector (Upgrade from PEP-II Design) Courtesy W. Berg, APS Glenn Decker, ANL / APS

  13. Cherenkov Detector Electronics (APS Design) Courtesy A. Pietryla, APS Glenn Decker, ANL / APS

  14. Optical Transition Radiation A. Lumpkin, APS Glenn Decker, ANL / APS

  15. OTR Radiation Pattern Glenn Decker, ANL / APS

  16. Glenn Decker, ANL / APS

  17. Optical Transition Radiation (cont’d) • 11 Intra-undulator OTR Electron-Beam Profile Diagnostics are proposed • Thin foils (1-5 microns thick) can be used to minimize e-beam scattering and bremsstrahlung radiation • Conversion efficiency reasonable for ~ 1 nC of charge and CCD cameras • OTR Techniques have been validated in a number of recent experiments: • Beam sizes of 30 um (sigma) for a 600-MeV beam measured at APS with an Al mirror. (Lumpkin et al.,FEL’98) • Beam sizes of 50 microns sigma for a 4-GeV beam at TJNAF with 0.8-micron thin foil (Denard etal, BIW ’94) • Beam size measurements performed at 30 GeV at SLAC (Catravas etal, PAC ’99) • Beam size of 15 microns rms measured at 30 GeV on a single shot at SLAC (Hogan, E-162) Glenn Decker, ANL / APS

  18. Conclusions • Undulator particle beam diagnostics will build upon knowledge base at APS, SLAC and elsewhere. • Majority of diagnostics require minimal development • Important items are • BPM fabrication / fiducialization and mechanical support. Beam-based alignment relaxes requirements considerably • OTR foil survivability (rep rate limitation?) • Decision on bpm electronics topologies – • downconversion / phase detection with cavities vs dumb power monitor • Log-amp, delta/sum, AM/PM etc. for button pickups Glenn Decker, ANL / APS

More Related