Intra-Beam Scattering modeling for - PowerPoint Presentation

Slide1

Intra-Beam Scattering modeling for SuperB and CLIC

Mauro

Pivi

work performed while at

SLAC

Tau-Charm @ High Luminosity Workshop

27-30 May, 2013

Analytical IBS in SuperB

LER (lattice V12)

Effect is reasonably small. Nonetheless, there are some interesting questions to answer:

What will be the impact of IBS during the damping process?Could IBS affect the beam distribution, perhaps generating tails?



h

=2.412 nm

@N=6.5e10

v=5.812 pm@N=6.5e10

z=4.97 mm@N=6.5e10

Theo

Demma

2012

Intra-Beam Scattering (IBS) Simulation Algorithm: CMAD

CMAD parallel code:

C

ollective effects & MADLattice read from MADX files containing Twiss functions and transport matricesAt each element in the ring, the IBS scattering routine is called. At each element:

Particles

of the beam are grouped in cells.Particles inside a cell are coupled

Momentum of particles is changed

because of scattering.Particles are transported to the next element.Radiation damping and excitation effects are evaluated at each turn. Vertical dispersion is included Code: Electron Cloud + IBS + Radiation Damping & Quantum Excitation

IBS applied at each element of the RingM. Pivi, T. Demma (SLAC, LAL), A. Chao (SLAC)27-30 May, 2013

For two particles colliding with each other, the changes in momentum for particle 1 can be expressed as:

with the equivalent polar angle

eff and the azimuthal angle  distributing uniformly in [0; 2], the invariant changes caused by the equivalent random process are the same as that of the IBS in the time interval ts

IBS -

Zenkevich-

Bolshakov Algorithm

Tau-Charm @ high LSIRE code uses similar implementation (A. Vivoli Fermilab, Y. Papaphilippou CERN)27-30 May, 2013

IBS modeling: animation

http://www-user.slac.stanford.edu/gstewart/movies/particlesimulation_animation/

IBS evaluation in SuperB

Parameter

Unit

ValueEnergy

GeV

4.18

Bunch population

10106.5

 Circumferencem1257 

Emittances (H/V)nm/pm1.8/4.5 Bunch Length

mm

3.99

Momentum spread

%

0.0667

Damping times (H/V/L)

ms

40/40/20

N. of macroparticles

-

10

5

N. of grid cells

-

64x64x64

Bane

Piwinski

IBS-

Track

/CMAD

M.

Pivi

, T.

Demma

27-30 May, 2013

- IBS-

Track

- C-MAD

One turn evolution:

compare codes and theory

One turn evolution:

compare codes

IBS evaluation for CLIC DR

Ideal lattice

CMAD simulations compare with theory

: o

ne turn evolution

of

emittance growth in the CLIC Damping Ring. Energy (GeV)2.86emitx (m)5.554e-11

emity (m) 5.8193 e-13Deltap 1.209209e-3sigmaz (m) 0.001461

IBS Distribution study

Parameter

c

2799

Confidence

Z

1857.56<1e-6X

1455.68<1e-6Y 778.2280.6920

M. Pivi (SLAC), T. Demma (INFN)

Previous

work

at CERN: SIRE IBS Distribution studyParameterValueEq. ex (m rad)2.001e-10Eq. ey (m rad

)2.064e-12

Eq. sd

1.992e-3

Eq. sz (m)1.687e-3Parameterc2999

ConfidenceDp/p3048.7<1e-15X1441.7<1e-15Y1466.9<1e-15

A. Vivoli , Y. Papaphilippou CERN

‘Equivalent’ Long term

Emittance

Evolution in SuperB LER These preliminary simulations are performed using a factor F=10 faster damping time and a factor 10 larger beam intensity

t

x = 10-1

x 40 ms ty = 10-1x 40 ms ts = 10 -1x 20 msFor SuperB V12 LER Nb= 2x10

10 - 12x1010

e

x

(m)

ez (m) Injection1100e-91.5e-4Extraction w/ IBS25e-93.3e-6Extraction w/o IBS23e-9

2.97e-6

IBS in SuperB

Damping Ring

Evolution

of emittance with radiation damping and IBSJust 1 IP per tun is considered hereBeam injection

with IBSwithout IBS

IBS evaluation next steps

Code validation: benchmark recent experiments made at

CesrTA

and SLS with simulations Tau-Charm factory estimate gives larger IBS growth than SuperB because of larger beam intensity and lower energyCode predictions: long term beam evolution in Tau-Charm and CLIC Damping RingsIncluded magnet vertical misalignments and vertical dispersionNext: Include magnet rotation and coupling also to closely benchmark experimental data (CesrTA, SLS)

Summary

Developed multi-particle simulation codes for Intra-beam scattering

Codes in agreement with theoretical models

Estimations for Super-BPlans for methodical evaluation of IBS in Tau-Charm are needed.

Thanks to:M. Boscolo, M. E. Biagini

, A. Chao