Transition to Operations (TTO) Project Synopsis

Title (Symbol):Radiabeam/SLAC Dechiper(DECHIRPER)(Keep it crisp and be consistent)

Project Type:ASP(Could be more than one type e.g. TTO/AIP or TTO/ASP)

Date/Revision:February 8, 2016(Change date whenever this document is changed)

Project Lead:R. Iverson(A single person should be designated)

Team members:Maxwell, Tim; Krejcik, Patrick; Lutman, Alberto; Guetg, Marc; Zemella, Johann; Zhang, Zhen; Bane, Karl; Stupakov, Gennady; Novokhatski, Alexander; Marinelli, Agostino; Gassner, Georg; Reese, Edward; Babbitt, Alisha; Oven, Ziga; Cedillos, Antonio; Carrasco, Manny A.; Stanek, Michael W.; Huang, Zhirong; (If appropriate, note key personnel needed to make this project work.)

Scope(The Scope statement should set the TTO project work boundaries. State it carefully.)

The scope of the work includes:

  1. Machine Protection System –The physics team in conjunction with the controls and engineering groups will verify that sufficient engineering safeguards are in place to prevent the following:
  2. The Dechirper being hit by sustained, direct beam
  3. Collision of opposing Dechirper rails
  4. Irradiation of the downstream LCLS undulators
  5. This is generally covered generally by the existing LCLS MPS
  6. Dechirper control software can and should provide additional precautions to protect the undulator hall (TDUND) during potentially invasive procedures
  7. Develop a new slow feedback to control the beam position and pointing both entering and exiting the Dechirper (R. Iverson, L. Piccoli).
  8. Procedure documentation – The team will review and enhance written procedures for all of the following and maintain such documentation in the MCC Wiki:
  9. Introductory explanation of the Dechirper and its use in chirp control
  10. Dechirper operation procedures and documentation for each of the following:
  11. EPICS motion control panels (T. Maxwell, Z. Oven, A. Babbitt)
  12. Feedback system control (R. Iverson, L. Piccoli, A. Lutman, P. Krejcik)
  13. Alignment (M. Guetg, T. Maxwell)
  14. Chirp and bandwidth control (T. Maxwell, M. Guetg)
  15. FAQ & any Known Issues that arise (All)
  16. The physics team and/or controls group will maintain documentation on Machine Protection System control and status when the Dechirper is in use.
  17. GUI development for Dechirper setup
  18. Enhance TREX GUI to provide quantitative electron chirp and bandwidth analysis.
  19. Develop a global GUI that scripts the setup procedure and combines the views from other GUIs such as the TREX, feedbacks etc. (M. Guetg, T. Maxwell)
  20. Work with ACR Operations to tailor the Dechirper GUI to streamline operation (physics team).
  21. Training
  22. The physics team will train LCLS operators by referring to the above documentation and GUIs.
  23. Throughout the training phase, the physics team will revise the written procedures based on operator feedback.
  24. The physics team will take into consideration potential future applications of the Dechirper (passive streaker, slice orbit spoiler) and ensure future documentation links to the setup and troubleshooting documentation created by this TTO.

New capabilities using the Dechirper to measure the electron bunch length with attosecond resolution and to deliver 2-pulse-2-color beams are under development but are not part of this TTO project.

Goals(Note specific goals that indicate the TTO project is complete)

The goal is to streamline and automate the method for aligning the Dechirper and controlling FEL bandwidth such that any accelerator operator can independently follow the procedure and set the Dechirper in a few minutes.

Duration(Give a rough estimate of the time requirements)

  1. The estimated remaining MD time required is 12 hours.
  2. The total estimated duration of this activity is 2 months.

Description

The Dechirper consists of two modules containing opposing rails that are two meters in length. The rails are flat plates with small corrugations. Both modules are installed just after dogleg-2 on the linac to undulator beam line. The jaws of the upstream module move in the vertical plane and the jaws of the downstream module move in the horizontal plane. The gap of the Dechirper rails can be controlled by both the DechirperMatlab GUI or directly by EPICs control panels. The XTCAV screen is used to assess and tune the energy spread of the electron bunches. The SXR spectrometer or the FEE spectrometer can be used to assess and tune the FEL bandwidth for soft or hard x-rays, respectively.

The Radiabeam/SLAC Dechirper can be used to either increase or decrease the energy chirp along the electron bunch to provide flexible control of the time-correlated LCLS FEL bandwidth. It can be used for all electron energies and bunch lengths.