Ecloud simulations for the LHC arcs

Humberto Maury Cuna

E-cloud Simulation Meeting

October 28th, 2011

OutlineA bug in ECLOUD code – XY

distribution for:◦Field-free section◦Quadrupole◦Dipole

Oscillations in quadrupole heat load simulations.

Field-free region – 7 TeV – 1.2x1011 – 25 ns

Quadrupole – 7 TeV – 1.2x1011 – 25 ns

Dipole – 7 TeV – 1.2x1011 – 25 ns

Dipole – Gas ionization

B = 0.01 T 0.54 T

Oscillations in quadrupole Heat load simulationsSimulations parameters:

◦Macroparticles: 2500◦Time steps inter bunch gap: 3000◦Energy: 7 TeV◦Bunch spacing: 25 ns◦Reflectivity: 0.5◦Ibend=2

0.00E+00 5.00E+10 1.00E+11 1.50E+11 2.00E+11 2.50E+110.00E+00

2.00E+00

4.00E+00

6.00E+00

8.00E+00

1.00E+01

1.20E+01

1.40E+01Quadrupole - 7 TeV - 25 ns

y1p1y1p2y1p3y1p4y1p5y1p6y1p7

Nb

Heat

load (

W/m

)

0.00E+00 5.00E+10 1.00E+11 1.50E+11 2.00E+11 2.50E+11 3.00E+110.00E+00

2.00E+00

4.00E+00

6.00E+00

8.00E+00

1.00E+01

1.20E+01

1.40E+01

Quadrupole heat load - SEY = 1.7 - 7 TeV

nistep=3000

nistep=1500

Nb

Heat

load (

W/m

)

ResultsThe “bug” seems to affect only dipoles and just the photoemission case.

The quadrupoles heat load oscillations depends on the SEY and also the number of time steps.

Thank you for your attention

Quadrupole – ibend = 6