1 / 23

Compton Experiment at the ATF Update since TILC09

Compton Experiment at the ATF Update since TILC09. Junji Urakawa instead of T.Takahashi KEK for collaborators. Positron Workshop Durham 28-October-2009. Optical Cavity for Laser-Compton. 325 MHz. Lcav. Higher laser power L cav = n /2, D L<sub-nm, position for pulse stacking

sohalia-bijoy
Download Presentation

Compton Experiment at the ATF Update since TILC09

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. Compton Experimentat the ATF Update since TILC09 Junji Urakawa instead of T.Takahashi KEK for collaborators Positron Workshop Durham 28-October-2009

  2. Optical Cavity for Laser-Compton 325 MHz Lcav Higher laser power Lcav = n /2, DL<sub-nm, position for pulse stacking ->more enhancement, then more precision Laser should be focused for high power density Efficient laser-Compton scattering DT < sub-ps Accommodate laser cavity in the accelerator

  3. Two Prototype Cavities 2-mirror cavity 4-mirror cavities w/LAL (Hiroshima / Weseda / Kyoto / IHEP / KEK) moderate enhancement moderate spot size simple control high enhancement small spot size complicated control demonstration of g ray gen. accum. exp. w/ cavity and acc. intense g ray generation

  4. 2 MIRROR CAVITY STATUS

  5. Experimental R/D in ATF Hiroshima-Waseda-Kyoto-IHEP-KEK Make a fist prototype 2-mirror cavity Lcav = 420 mm . Put it in ATF ring

  6. Laser Power enhancement 250

  7. AFTER TILC09 • One of the Mirror was replaced with the higher reflectivity one • 99.6% -> 99.9% • power enhancement • 250 -> ~750 • more precise controll required (~0.1nm) • Status of the cavity w/ new mirror • Finess ~2000 with feedback on before vacuum on • now in preparation for beam • hope to get 3 times more photons by the end of the year 99.9% 99.6%

  8. March 2009 August 2009 4 MIRROR CAVITY STATUS

  9. 2D configuration to2D 4mirror cavity has astigmatism. tospot size α 3D configuration toposition in the cavity go to 3D config. to avoid astgmatism tospot size toposition in the cavity

  10. R&D of 4 mirrors cavity startedat KEK(Reported TILC09) (n+1)  Lring = n  Honda

  11. prototype 4 mirror cavity Constructed

  12. tuning mechanizm HV Power spring Piezo Objective: to establish method of: mirror alignment, control cavity length  feed back to the beam compatible cavity

  13. Prototype cavity on the optical table

  14. status of initial tests fundamental resonant mode intensity of transmitted light circumference of the cavity resonance of the cavity with injecting laser observed

  15. two peaks • two separated resonant • peaks each corresponds to left or right handed polarization • 3D cavity only resonates with • circular polarization due to • geometric phase • Useful to: • generate circularly pol. gs • fast switching

  16. Staus of the LAL cavity Spherical mirror interaction point e - beam 8° Spherical mirror R. Cizeron LAL 30/01/2008 Laser injection Flat mirror French colleagues visited KEK in July. discussed detail of the installation procedure setting up at the ATF beam line Central support Flat mirror working to install the cavity in summer 2010

  17. Summary • 2 mirror cavity to demonstrate photon generation and to accumulate experience w/ beams • At the TILC09 • enhancement of 250, 27 gammas / crossing • high reflection mirror (99.6% -> 99.9%) • beam with enhancement ~750 to 1000 this year • 4 mirror ring cavity for higher enhancement and small spot size • at the TILC09 • basic test on optical table • first prototype at KEK and being tested • installation of LALcavity being ready

  18. Urakawa

  19. 4-mirror ring cavity Very Large Focal Point Equivalent Optics of the 4-mirror Cavity tolerance : 4-mirror = 100 x 2-mirror

  20. 2D configuration α 3D configuration

  21. Tolerance of 2-mirror cavity Concentric Configuration and Confocal Configuration concentric confocal

  22. 2-mirror cavity 4-mirror cavity R1=R2=L R1=R2=L/2 L L confocal concentric

  23. data summary Normalized g yield seems to decrease as # bunches/train goes up Bunch (size, timing) fluctuation in the ATF suspected

More Related