1 / 11

EPAC 2006　 MOPLS084

Experimental Comparison at KEK of High Gradient Performance of Different Single Cell Superconducting Cavity Designs. F. Furuta , K. Saito, T. Saeki, H. Inoue, Y. Morozumi, T. Higo, Y. Higashi, H. Matsumoto, S. Kazakov, H. Yamaoka, K. Ueno, Y. Kobayashi, a R. S. Orr and b J. Sekutowicz,

cairo-schultz
Download Presentation

EPAC 2006　 MOPLS084

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. Experimental Comparison at KEK of High Gradient Performance of Different Single Cell Superconducting Cavity Designs. F. Furuta, K. Saito, T. Saeki, H. Inoue, Y. Morozumi, T. Higo, Y. Higashi, H. Matsumoto, S. Kazakov, H. Yamaoka, K. Ueno, Y. Kobayashi, aR. S. Orr and bJ. Sekutowicz, KEK, aUniv. of Toronto/JSPS, bDESY EPAC 2006　MOPLS084 1

  2. Abstract We have performed a series of vertical tests of three different designs of single cell Niobium superconducting cavities at 2 degrees Kelvin. These tests aimed at establishing that an accelerating gradient of 45 MV/m could be reached in any of the designs, while using the standard KEK surface preparation. The designs tested were the Cornel re-entrant shape (RE), the DESY/KEK Low Loss shape (LL), and the KEK ICHIRO series. The cavities underwent surface preparation consisting of centrifugal barrel polishing, light chemical polishing,electropolishing, and final a high-pressure water rinse. All three kinds cavities were used in a series of vertical tests to investigate details of the surface treatment. When using ultra-pure water for the high pressure rinse, the LL cavity reproducibly exceeded a gradient of 45 MV/m, the RE design reproducibly reached a gradient of between 50 MV/m and 52 MV/m, and three of the six ICHIRO cavities reached a gradient of between 45 MV/m and 51 MV/m.

  3. High gradient limitation of Type-2 SRF cavity 2

  4. Principle of 50MV/m Cavity shape designs with low Hp/Eacc from J.Sekutowicz lecture Note TTF: TESLA shape Reentrant (RE): Cornell Univ. Low Loss(LL): JLAB/DESY IchiroｰSingle(IS): KEK 3

  5. Done the Principle proof of the 50MV/m 4 Reentrant Low Loss Ichiro Single

  6. Eacc vs. Year 2nd Breakthrough! 1st Breakthrough! 5

  7. Reproducibility 6 HPR and evacuation were repeated. Low Loss @ 2K Treatment Eacc,max Qo @ Eacc,max EP(30um)+HPR(UPR) 46.5 1.20E10 Re-evacuation 47.3 1.13E10 Re-HPR(UPR) 46.6 1.50E10 Warm-up only 45.0 1.03E10 Re-evacuation44.0 1.20E10 Eacc max Ave. 45.9MV/m, Std. 1.3MV/m , Qo Ave. 1.21e10, Std. 0.18 e10 Reentrant@ 2k Treatment Eacc,max Qo @ Eacc,max Re-evacuation 51.2 0.59E10 Re-HPR(UPW) 52.3 0.97E10 Re-evacuation 51.9 1.11E10 Warm-up only 52.4 1.21E10 Re-HPR(UPW)50.0 0.98E10 Eacc max Ave. 51.6MV/m, Std. 1.0 MV/m Q0 = Ave. 0.97e10, Std. 0.24e10

  8. Temperature dependence of Eacc max 7

  9. Field Emission Analysis b:field enhancement factor Field enhancement factor of IS shape is very small. 8

  10. RF critical field analysis New shapes 9

  11. Summary New cavity shapes with low Hp/Eacc made a breakthrough in high gradient of 50MV/m. Proof of reproducibility was done. From the analysis of field enhancement factor b, it was also shown that the high gradient performance of IS shape is superior to other shapes. Establishment of recipe is ongoing See poster MOPLS087 Cavities prepared by KEK recipe Mean=44.3MV/m, Sigma=6.9 by R.S.Orr 10

More Related