Harold G. KirkBrookhaven National Laboratory

Target Considerations for Nufact and Superbeams

ISS Meeting

RAL April 26, 2006

Harold G. Kirk

Main Study Parameter

Design for:

4 MW

Harold G. Kirk

Driving Target Issues

Meson Production Proton Beam Pulse Length Proton Beam Structure

Harold G. Kirk

Stephen Brook’s Analysis

Pions counted at rod surface

B-field ignored within rod (negligible effect)

Proton beam assumed parallel Circular parabolic distribution, rod radius

20cm

1cmSolid Tantalum

Protons

Pions

Harold G. Kirk

Yield of ± and K± in MARS

2.2

Ge

V

3G

eV

4G

eV

20

Ge

V

30

Ge

V

40

Ge

V5

0G

eV

75

Ge

V

10

0G

eV

12

0G

eV

15

Ge

V

10

Ge

V

8G

eV

6G

eV

5G

eV

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

1 10 100 1000

Proton Energy (GeV)

Pio

ns

or

Ka

on

s p

er

Pro

ton

.Ge

V (

tota

l e

mit

ted

)

pi+/(p.GeV)

pi-/(p.GeV)

pi+/(p.GeV)pi-/(p.GeV)

K+/(p.GeV)

K-/(p.GeV)

•No surprises in SPL region•Statistical errors small•1 kaon 1.06 muons

Finer sampling

Harold G. Kirk

The Study 2 Capture Concept

Maximize Pion/Muon Production Soft-pion Production High Z materials High Magnetic Field Solenoid

Harold G. Kirk

The Study2 Target System

Consider Liquid Hg

Count all the pions and muons that cross the transverse plane at z=50m.

For this analysis we select all pions and muons with KE< 0.35 GeV.

Harold G. Kirk

Optimize Soft-pion Production using Hg

Harold G. Kirk

Meson KE < 350 MeV at 50m

Mesons/Proton Mesons/Proton normalized to beam power

Harold G. Kirk

Process mesons through Cooling

Consider mesons within acceptance ofε┴ = 30π mm and εL = 150π mmafter cooling

350 MeV

Use meson count with KE < 350 MeVas a figure of merit.

Harold G. Kirk

Post-cooling 30π Acceptance

Harold G. Kirk

Carbon Target Parameters Search

Harold G. Kirk

Carbon Target Optimization

Set R=1.25cm; tilt angle = 50 mrad; Length=60cm; Z=-40cm

Harold G. Kirk

Proton KE Scan with Carbon

Count mesons within acceptance of

ε┴ = 30π mm and

εL = 150π mm

after cooling

Harold G. Kirk

Summary of Results

Compare Meson production for Hg at 24 GeV and 10 GeV

Compare Meson production for C at 24 GeV and 5 GeV

Compare Meson production for Hg at 10 GeV and C at 5 GeV

GeV

GeV

N

N

24

10

GeV

GeV

N

N

24

101.07 1.10

GeV

GeV

N

N

24

5

GeV

GeV

N

N

24

51.90 1.77

GeVC

GeVHg

N

N

5

10

GeVC

GeVHg

N

N

5

101.18 1.22

Harold G. Kirk

Conclusion

Optimum Input Proton Beam Energy for Study2a configuration with Hg: 8 to 20 GeVSuperbeam proton beams energies:Mini-boone 8GeVBNL AGS 28 GeVJpark 30 to 50 GeVNumi 60 to 120 GeVCNGS 400 GeV

Harold G. Kirk

Driving Target Issues

Meson Production Proton Beam Pulse Length Proton Beam Structure

Harold G. Kirk

Proton Beam Pulse Length

Study 2a J. Gallardo, H. Kirk

Harold G. Kirk

Conclusion

Optimum Proton Beam Pulse Length for Study2a configuration: 1nsSuperbeam proton beams energies:BNL AGS 28 GeV 10nsNumi 4 μsCNGS 2 x 5 μs

Harold G. Kirk

Driving Target Issues

Meson Production Proton Beam Pulse Length Proton Beam Structure

Harold G. Kirk

Protons per pulse required for 4 MW

10 Hz 25 Hz 50 Hz

10 GeV 250 × 1012 100 × 1012 50 × 1012

20 GeV 125 × 1012 50 × 1012 25 × 1012

]Hz[feN]eV[E)w(Prep

arc

Proton Beam Intensity

Harold G. Kirk

Shock Stress Analysis N. Simos

Harold G. Kirk

SUMMARY of Performance

1 MW/50 Hz

12.0 e+12 ppp

YES

4 MW/50 Hz

48.0 e+12 ppp

NO

1 MW/200 Hz

3.0 e+12 ppp

YES

4 MW/200 Hz

12.0 e+12 ppp

MAYBE

Solid Targets

Harold G. Kirk

5 X 50 Proton Beam Structure

Johnstone, Meot, Rees 10 GeV Proton Beam 50 Hz n = 5 sub-structure => 10 x 1012 protons (10TP) per micro-bunch Accelerate 3 to 10 GeV with harmonic 36 structure and frequency of 13.079-13.417 MHz Adiabatically compress to 2ns Further compress to 1ns with f=80.5 MHz and f=201.25MHz

Harold G. Kirk

Pulse Delivery to Target

ΔT = 13 μs => 52 μs bunch structure

Liquid Target

ΔT = 65 μs => 260 μs bunch structure

Solid Target

Harold G. Kirk

Muon Bunch Pattern in Decay Rings

.

148(133)

solid/liquid

80 μ+

80 μ+

80 μ+

80 μ+

80 μ+

127(!30)

127(130)

127(130)

127(130)

2 of 5 interleaved 80 μˉ

bunch trains of 2nd ring

80 full and 127 (or 130) empty RF buckets

> 100ns intervals