Modification of the vacuum chamber in atlas effect on impedance and related quantities
Download
1 / 5

Modification of the vacuum chamber in ATLAS Effect on impedance and related quantities - PowerPoint PPT Presentation


  • 115 Views
  • Uploaded on

Modification of the vacuum chamber in ATLAS Effect on impedance and related quantities. E. M étral, N. Mounet and B. Salvant with the help of R. Veness and M. A. Gallilee. Impedance contributions. Two different contributions are to be distinguished:

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Modification of the vacuum chamber in ATLAS Effect on impedance and related quantities' - mare


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Modification of the vacuum chamber in atlas effect on impedance and related quantities

Modification of the vacuum chamber in ATLASEffect on impedance and related quantities

E. Métral, N. Mounet and B. Salvant

with the help ofR. Veness and M. A. Gallilee


Impedance contributions
Impedance contributions

  • Two different contributions are to be distinguished:

    • Resistive wall impedance, due to the resistivity of the beam pipe. This will be increased when the radius is reduced (29 mm → 22.5 mm).

    • Geometrical impedance, due to the new conical transitions (tapering, angle 3.7 deg) in the modified situation.

      Note: this contribution is much smaller than the one coming from the unshielded bellows (in the same area).


Power loss due to the impedance
Power loss due to the impedance

  • Resistive wall part, in the most critical case (up to now), i.e. short bunches, and two beams of 2808 bunches each:

  • Geometrical part: negligible (≈10-7 W/m)

→ about 30% increase in the power loss (obtained with two different approaches). Becomes ~1.9 W/m.


Impact on beam stability transverse effective impedance
Impact on beam stability: Transverse effective impedance

  • Sacherer transverse effective impedance:

→ Transverse effective impedances for both current and future situations are estimated to be negligible with respect to the rest of the ring.


Conclusion
Conclusion

  • Power loss (from resistive-wall): at most 1.9 W/m (with bunches of 0.8 ns at 3.5 TeV), increased by 30% with respect to the previous configuration.

  • With our current understanding, there is very little effect of the vacuum pipe modification on the beam stability (longitudinal and transverse).


ad