NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 1

The EURISOL Beta-beam Acceleration Scenario:

Ion Losses

A. Fabich, CERN

NuFact’06, UCIrvine

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 2

Outline

EURISOLDS Beta-beam layout Accumulation & accelerator cycle Ion intensities

Accelerator chain Decay distribution Dynamic vacuum

Decay ring Stored energy Particle turnover

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 3

Beta-beam EURISOL design

Neutrino

Source

Decay Ring

Ion production

ISOL target & Ion source

Proton Driver

SPS

Acceleration to medium

energy RCS

PS

Acceleration to final energy

PS & SPS

Beam to experiment

Ion acceleration

Linac

Beam preparation ECR

pulsed

Ion production Acceleration Neutrino source

Low-energy part

High-energy part

Decay ringBmax = 1000 TmB = ~6 TC = ~7000 m Lss= ~2500 m 6He: = 100 18Ne: = 100

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 4

mag

net

cyc

le (

abs

tra

ct)

cycle of 6He

Machine cycle

Baseline version:

Production 6He, 18Ne

ECR, Linac and RCS Cycling at 10 Hertz

Accumulation in the PS Accumulation of 20 RCS bunches (~2 seconds)

Acceleration through PS and SPS as fast as possible top = 100 for both isotopes

Injection into decay ring Merging with circulating bunches Every 6 s for 6He and every 3.6 s for 18Ne

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 5

For the design goal of2.9*1018 antineutrinos/year1.1*1018 neutrinos/year

Required isotope intensities: For cycling of version EURISOL DS

Typical intensities of 108-109 ions for LHC injector operation (PS and SPS)

Ion intensities (1)

6He 18Ne

Decay ring [ions stored] 9.7*1013 7.5*1013

SPS ej [ions/cycle] 9. 0*1012 4.3*1012

PS ej [ions/cycle] 9.5*1012 4.3*1012

Source rate to ECR [ions/s] 2*1013 2*1013

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 6

Ion intensities (2)

Cycle optimized for neutrino rate.

30% of first 6He bunch injected are reaching decay ring Overall only 50% (6He) and 80% (18Ne) reach decay ring

Normalization Single bunch intensity to maximum/bunch Total intensity to total number accumulated in RCS

Bunch20th

15th

10th

5th1st

total

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 7

Decay losses

Relative decay distribution similar for both isotopes

~90% of all decays before entering decay ring occur in the PS

Can be translated into power losses and compared with “existing” high intensity

operation …

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 8

pressure evolution in the PS V7

1E-10

1E-09

1E-08

1E-07

0 0.5 1 1.5 2 2.5 3 3.5

t / s

av

era

ge

pre

ss

ure

/ P

a

He

Ne

1E-9

Loss distribution and dyn. vacuumloss distribution in the PS

1E+03

1E+04

1E+05

0 5 10 15 20 25 30

S / m

be

am

lo

ss

es

/ a

.u.

HeNe

loss distribution in the SPS (1 normal cell)

1E+02

1E+03

1E+04

1E+05

1E+06

0 10 20 30 40 50 60

S / m

Lo

ss

es

/ a

.u.

He2+

Ne10+

loss distribution in the PS V7

1E+02

1E+03

1E+04

1E+05

0 10 20 30 40 50

S / m

be

am

lo

ss

es

/ a

.u.

He

Ne

pressure evolution in the SPS

1E-07

1E-06

0.0 1.0 2.0 3.0 4.0 5.0

t / sav

erag

e p

ress

ure

/ P

a

HeNeHe G7Ne G7

PS

SPS

New“PS”

Pressure evolution due to desorption

P. Spiller et al., GSI

Ave

rage

pre

ssur

e [m

bar]

1E-10

1E-11

1E-12

1E-8

Ave

rage

pre

ssur

e [m

bar]

1E-9

PS

SPS

New“PS”

NuFact'06 WG3, Aug. 2006

A. Fabich, CERN Beta-beam Ion Losses, 9

Beam intensities in the decay ring

Stored energy LHC refers to proton operation.

Transverse density: =Estored/(2*Pi*x*y)

Beta-beam operates at reasonable stored energy and energy density. “Stored energy” is most relevant for irregular operation.

LHC project report 773

bb

bb

NuFact'06 WG3, Aug. 2006

A. Fabich, CERNBeta-beam Ion Losses,

10

Particle turnover 810 kJ respect. 1150 kJ beam energy/cycle injected ejected

All ions have to be removed again Either as parent or daughter ion

1) Decay deposition in arcs: protect SC dipoles from quench caused by deposition accumulated after drift (quench limit 10W/m)

2) Decays accumulated along straight section: 300 or 400 kJ dumped per cycle (50 or 120 kW average) via extraction system at end of straight section

3) Momentum collimation at/after merging process: Cycle average: 62 or 230 kW (6 resp 3.6 s)

LHC: 10 kW average, peak 100 kW over seconds or 500 kW peak Process average: 1.2 or 2.8 MW (0.3 s, continuous collimation during bunch compression)

p-collimation

me

rgin

g

decay losses

inje

ctio

n1)+2)

3)