1 / 12

HOM loss calculation of IP chambe r

HOM loss calculation of IP chambe r. Nakano Hiroshi 7-Jul-2009 (presented by Hitoshi Yamamoto) Thanks to Tetsuo Abe and other experts. Beam parameters. Nano beam option s z (mm) = 6(LER)/6(HER) n- = 3.89x10 10 n+ = 6.78x10 10 #bunch = 3425(LER,HER). HOM calculation.

simon-bowman
Download Presentation

HOM loss calculation of IP chambe r

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. HOM loss calculationof IP chamber Nakano Hiroshi 7-Jul-2009 (presented by Hitoshi Yamamoto) Thanks to Tetsuo Abe and other experts

  2. Beam parameters • Nano beam option • sz (mm) = 6(LER)/6(HER) • n- = 3.89x1010 • n+ = 6.78x1010 • #bunch = 3425(LER,HER)

  3. HOM calculation • GdfidL: 3D field calculation tool • Options • Two modes • Grid moves with bunch (window wake = yes) • Grid fixed to lab (window wake = no) • Symmtries • 1/2,1/4 etc. • Mesh sizes

  4. Beam pipe data LER HER 15mm 60mrad(3.438deg) 10mm Bended to use ports (pipes continue infinitely)

  5. Calculation method Window wake=yes Mesh size 0.5 mm 1/1 model 1/2 model Window wake=no Mesh size 0.3mm Mesh size 1mm Compare 6 ways of results ~30mm ~400mm port Is it long enough? *Window wake =Yes: use bunch-fixed grid =No: use pipe-fixed grid Are mesh sizes good? Calculated in various crossing angles

  6. Results of HER Crossing angle big small Loss factor big small 0.0004 V/pC ( ) 5.3 [W] 6 ways agreed with each other within 10~20% 60mrad

  7. Consideration A B If the change from “A” to “B” was slow, the loss factor might be small. EM will not stay A B At small angles, the change is quasi-static; penetration of field to the side chamber is ~zero.

  8. Results with 0.2 mm mesh 0.000551 V/pC (7.3W) HER (r = 15mm) 0.00145 V/pC (58W) LER (r = 10mm) 65W GdfidL seems to work correctly. HOM losses from and beams were calculated with 0.2 mm mesh size to get more ‘accurate’ values.

  9. New geometries IP HER r = 15mm before r = 10mm LER HER Type-1 IP LER HER Type-2 IP LER color: center of pipe All pipes have 10mm radius. dashed: beam trajectory Crossing angle of the beams is 60mrad.

  10. Type-1 HER *mesh size = 0.2mm, 1/2 model b a b c loss factor LER 100 480 7.0 0.68 100 580 7.0 0.66 a 100 680 7.0 0.77 c 150 480 5.5 0.82 150 580 5.5 0.90 150 680 5.5 0.82 36~48W (HER+LER) Check with finer mesh Loss factor -> 1.2 * 10^-3[V/pC] ( in case of mesh size = 0.08mm) 64W

  11. Type-2 c HER *mesh size = 0.13mm, 1/2 model b’ HER / LER LER a’ b’ c loss factor a’ 86 480 7.3 1.9 / 2.3 165 480 5.0 2.4 / 2.1 84 680 7.5 1.8 / 2.4 165 680 5.0 2.1 / 2.2 115~119W (HER+LER) Check with finer mesh Loss factor -> 2.1 / 2.4 * 10^-3[V/pC] ( in case of mesh size = 0.08mm) 124W

  12. Summary • GdfidL gives stable(reliable) results • Within 10~20% • For different calculation modes, use of symmetries, length of wake calculation, mesh size, etc. • Crossing beam pipe designs for nano beam option have been evaluated for HOM • HOM loss is of order 50W~100W • Larger for larger crossing angles

More Related