1 / 11

LHC Beam screen: impact of the weld on the wakes

LHC Beam screen: impact of the weld on the wakes. Preliminary analysis E. Metral, G. Rumolo, B. Salvant, C. Zannini. Overview. Model studied Comparing structure within and without weld Numerical noise. Model studied. LHC design as it is built and installed.

topper
Download Presentation

LHC Beam screen: impact of the weld on the wakes

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. LHC Beam screen: impact of the weld on the wakes Preliminary analysis E. Metral, G. Rumolo, B. Salvant, C. Zannini

  2. Overview • Model studied • Comparing structure within and without weld • Numerical noise

  3. Model studied LHC design as it is built and installed In this step we are only interested to understand the effect of the weld . weld

  4. Model studied a=46.4 mm b=36.8 mm w=2 mm L=1m w b a L

  5. Overview • Model studied • Comparing structure within and without weld • Numerical noise

  6. Comparing within and without weld For a displacement in x of 5 mm the horizontal dipolar wake with weld seems to be five time larger than the wake without weld

  7. Horizontal dipolar wake with weld versus displacement The displacement is considered negative if it is in the direction opposite the weld The horizontal dipolar wake with weld for a displacement in x of -5 mm seems to be twenty-five time larger than the wake with weld for a displacement in x of 5 mm

  8. For a displacement in x of -5 mm the horizontal dipolar wake with weld seems to be five time smaller than the wake without weld

  9. Changing the transverse dimension of the weld w Ssteel corresponds to w/2 Increasing the transverse dimension of the weld the horizontal dipolar wake increase almost linearly.

  10. Overview • Model studied • Comparing structure within and without weld • Numerical noise

  11. Numerical noise • The high value of conductivity that we need to simulate determines a very small signal and then the simulation results (longitudinal wake) are very noisy. The transverse wakes are obtained integrating this wake using the Panofsky-Wenzel theorem. In the frame of these issues can we consider reliable the results shown previously? • To verify the correctness of the results we can simulate the worst case for the noise: the structure without weld. We can simulate the structure with two different conductivity high and low conductivity and then rescaling the results at the same conductivity and compare them. The results obtained with low conductivity are more reliable because the numerical noise is insignificant. To obtain a good comparison it means that even though the signal is very noisy the code is able to make a good integration and we can be more confident of the results obtained. Sigmacopper is the conductivity of the cold Copper σ=1.82e9 S/m Decreasing the conductivity the results increase as the square root of the conductivity

More Related