1 / 19

The prototype of single-shot bunch profile monitor

This paper discusses the development and design of a non-destructive single-shot bunch profile monitor based on coherent Smith-Purcell radiation. The monitor allows for accurate bunch length measurement and reconstruction of the longitudinal profile. The history and challenges of the project are also explored, along with future steps and considerations for implementation.

warren-wilder
Download Presentation

The prototype of single-shot bunch profile monitor

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. The prototype of single-shot bunch profile monitor I. V. Konoplev, H. Harrison, A. J. Lancaster, G. Doucas JAI, Department of Physics, University of Oxford The prototype of single-shot bunch profile monitor

  2. Overview Background and motivations Single-shot monitor: the development of the concept Conceptual design Adapting to an accelerator and parameters essential for users Conclusion The prototype of single-shot bunch profile monitor

  3. Motivations • Design of a non-destructive single-shot longitudinal bunch profile monitor based on spectrum analysis of coherent Smith-Purcell radiation for a wide variety of accelerator facilities. • Study of properties of cSPr • cSPr has very specific and well understood properties – possibility to separate it from background radiation in a single shot manner • Different spectral components of the signal are displaced spatially – a frequency spectrum can be measured without the use of an external spectrometer • Profile reconstruction via spectrum analysis of cSPr: • Non-invasive diagnostic • Accurate bunch length measurement and if required reconstruction of the detailed longitudinal profile

  4. Coherent radiation spectroscopy for beam profile measurements • Coherent Synchrotron radiation • Free Electron Lasers • Coherent Diffraction and Transition radiation

  5. Basic about Smith-Purcell radiation • Coherent (intensity is proportional to (Ne)2), polarised, directional radiation emitted from a periodic structure • Induced by a charged bunch travelling above the structure • Radiation has angular dispersion – frequency spectrum can be measured • Longitudinal bunch profile is encoded within the frequency spectrum

  6. History of the project • Proposed as longitudinal beam diagnostic in the 90’s • Group at Oxford developed a beam profile monitor • Installed at SLAC in 2007. • The monitor was intrinsically multi-shot – many bunches were measured and averaged to give a single profile measurement • Demonstrated the feasibility of the technique for longitudinal bunch diagnostics (FACET, E203 Collaboration) • Since 2015 the group has been working towards a single-shot design Single-Shot monitor for CLARA

  7. The multi-shot monitor

  8. Single-shot monitor: Challenges • Background Radiation Use the polarisation of Smith-Purcell to separate the signal from the background • Signal cross-talk – Previously three gratings were on a carousel Have separate inclined gratings with separate arrays of detectors located at different azimuthal angles • Broad-band of signal: calibration and finding appropriate detectors and optics very big challenge Each detector channel is tuned for a specific frequency

  9. Operation of single shot monitor

  10. Single-shot monitor: Remove Background

  11. 0.07mm - periodicity 1mm - periodicity Directionality of cSPr

  12. How many channels ? No noise measured/design

  13. The impact of noise 33 Detectors 11 Detectors

  14. Multi-grating layout • Background radiation is subtracted via polarisation measurements and analysis • Gratings will be longitudinally spaced avoiding geometry problems • Rotated around azimuthal angle to reduce length of the apparatus and avoid the cross-talk • Number of gratings / detectors required has being investigated

  15. Adapting to an accelerator • The set of gratings needed to detect in the appropriate frequency range (typically 0.1-15THz) depends on the length of the bunch • The energy and number of electrons (charge) will determine the cSPr energy emitted and therefore the type of the detectors used • Pyroelectrics (£75) • Schottky Barrier Diodes (£1k) • The specific diagnostics needs (e.g. bunch length, resolution of profile) and the expected bunch shape will be important when determining how many detectors and their positions. • Expected noise level

  16. Single-shot design

  17. Cost of the monitor with 33 channels

  18. Next steps: considering a specific accelerator for tests • Number of channels – 5 at start (11 – final) • Cost vs performance • SBD detectors operating in 0.1THz to 1THz • Single grating operation at start (use 4 grating carrousel to study cSPr properties and monitor performance) • Vacuum chamber (tested), remote control electronics (tested) and most of the components are tested and monitor is partially assembled. • Plan to install the monitor in 2019 if beam time and space is granted.

  19. Thank you

More Related