ecloud simulations update

Ecloud Simulations Update

Humberto Maury Cuna

E-cloud Simulation Meeting

Janaury 11th, 2013

Thanks to L. Taviant, G. Iadarola, D. Sagan. G. Dugan, F. Zimmermann

OutlineHeat load benchmarking at 4 TeV

and 25-ns bunch spacing.Future work: Photon distribution

Heat-load benchmarking at 4 TeV and 25 nsFill number

Bunch intensity

(x1011)

Fill pattern R0 SEY

34253427342834293436

1.1 (84b)1.2 (156b)1.1 (372b)1.06 (804b)0.91 (804b)

25ns_84b_72_0_0_BBMD125ns_156b_72_72_72_BBMD225ns_372_72bpi_6inj_2012_MD25ns_804b_72bpi_12inj_2012_MD25ns_804b_72bpi_12inj_2012_MD

0.3-

0.7

1.3-

1.7

Only dipoles considered.Simulations done with PyECLOUD.

Measured heat load

0 5 10 15 20 25 300.0

0.1

0.2

0.3

0.4

0.5

Qec

ave

rage

(W/m

per

aper

ture

)

Time (h)

Fill 3429Fill 3436

Thanks to Laurent Tavian

1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.700.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

Low

-energ

y e

lectr

on R

eflectivity (R

0)

Secondary emission yield (max

)

0.00300

0.0494

0.0958

0.142

0.187

0.235

0.281

0.328

0.374

Heat load (W/m)

Heat load values at 4 TeV - 25 ns - Fill 3428

δmax = 1.58

1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.700.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

Low

-ener

gy

elec

tron refl

ectivi

ty (R

0)

Secondary emission yield (max

)

0.010

0.11

0.21

0.34

0.41

0.50

0.60

0.70

0.80

Heat load (W/m)

Heat load values at 4 TeV - 25 ns - Fill 3429

δmax = 1.54

1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.700.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

Low

-ener

gy

elec

tron refl

ectivi

ty (R

0)

Secondary emission yield (max

)

0.0040

0.092

0.18

0.27

0.36

0.45

0.53

0.62

0.71

Heat load values at 4 TeV - 25 ns - Fill 3436

Heat load (W/m)

δmax = 1.51

SEY time evolution (1):

0 5 10 15 20 25 30 351.50

1.52

1.54

1.56

1.58

1.60

Sec

ondar

y em

issi

on y

ield

( m

ax)

Time (h)

0.5

R0

SEY time evolution (1):

0 5 10 15 20 25 30 351.50

1.52

1.54

1.56

1.58

1.60

Sec

ondar

y em

issi

on y

ield

( m

ax)

Time (h)

0.5

R0

What about if R0 is higher?

SEY time evolution (II):

0 5 10 15 20 25 30 351.42

1.44

1.46

1.48

1.50

1.52

1.54

1.56

1.58

1.60

Secondary

em

issio

n y

ield

( m

ax)

Time (h)

0.5 0.7

R0

~4-5%

SEY time evolution (III):

0 5 10 15 20 25 30 351.40

1.42

1.44

1.46

1.48

1.50

1.52

1.54

1.56

1.58

1.60

Sec

ondary

em

issi

on y

ield

( m

ax)

Time (h)

0.5 0.7

R0R0

< 3%

< 3%

3x photo emission yield

OutlineHeat load benchmarking at 4 TeV

and 25-ns bunch spacing.Future work: Synrad3d

Synrad3D It simulates the production and scattering of

synchrotron radiation generated by an electron (or proton) beam in a high energy machine.

Developed at Cornell University by David Sagan and Gerry Dugan.

It can handle any planar lattice and a wide variety of vacuum chamber profiles.

• It uses Monte Carlo techniques to generate photons based on the standard synchrotron radiation formulas for dipoles, quadrupoles and wigglers.

• Photons are tracked to the vacuum chamber wall, where the probability of being scattered is determined by the angle of incidence, the energy of the photon, and the properties of the wall’s surface.

Photon emission throughout the ring, averaged over different magnetic environments.

Actual Cesr vacuum chamber, specular reflection only, beam energy 2.1 GeV

SYNRAD3D predictions for photon absorption site distributions

polar angle

chamber wall

Thanks to G. Dugan

MotivationEmploy Synrad3d to simulate the

photon distribution for future machines as LEP III

LHC (coming soon) and LHC-like machines.

ConclusionsFor R0 = 0.5 SEY = 1.51For R0 = 0.7 SEY = 1.45Changing 3x peef only decrease

SEY’s values less than 3%.Synrad3D is a useful tool to find

the photon distribution and then use it as input file to Ecloud or PyEcloud.

Thank you for your attention