12345367839 393 342 1 731567 !"# 7$7%&$'(()$*+

CERN AB-ATB-IF 26 October 2005

Overview on Task #3 • Beam sharing from the “Target Station” point of view • Program on target materials – New SiC microstructures – Preparation for irradiation at PSI – Specific surface by BET isotherms

CERN AB-ATB-IF 26 October 2005

Beam sharing – Etam Noah Talk about EURISOL proton beam from a target perspective

• For operation of 4 targets in parallel at EURISOL: – Targets share primary proton beam in time. – Targets inevitably ‘see’ a pulsed beam structure.

• ISOLDE as an example: – ISOLDE proton beam is pulsed. – Experience of damaging effect of pulsed beams on targets.

• ‘Ideal’ EURISOL beam: – Define pulse width.

• Example of a feasible proton beam for EURISOL

ISOLDE beam • Isolde proton beam: – Pulse power = 4.5kW – Bunch power = 5.9GW – Variables: • Pulse selection: 0 to 12 • Beam intensity: 1012 ppp to 3.4 × 1013 ppp

1.2 s pulse

230 ns

120 ns

• Beam variables defined by: – – – –

Target type Target characterisation User requirements Target ageing

1.2s pulse 14.4s supercycle

~ 1.2 s

EURISOL Beam sharing (inspired from ISOLDE) Beam sharing Beam for 100 kW target station

#1: 100kW: 1 ms #2: 100kW: 1 ms #3: 100kW: 1 ms #4: 5MW: 47ms to 50 ms

1 ms 49 ms a)

b) 50 ms 1s c)

d)

ISOLDE targets • Damaging impact of pulsed beam: – Shock waves – High thermal gradients and instabilities

*Photos from R. Catherall

A working scheme inspired by CERN developments Switch between high power and low power targets within one pulse × 125000 bunches

× 71875 holes

0.36 ms high power target

0.2 ms switching

× 3125 bunches

• Primary proton beam: – – – –

5 MW average power 0.57 ms pulse length 50 Hz repetition rate 200000 bunches per pulse

0.57 ms pulse

20 ms

0.009 ms low power target

Beam sharing summary • Parallel operation of up to 4 targets: – Targets inevitably ‘see’ a pulsed beam – Targets and proton beam must be engineered to limit damaging effects of pulsed beams

• Make use of experience acquired running targets under pulsed beam conditions • Achievable working schemes exist: – Switching between targets within a proton beam pulse – Smoother sharing of beam energy

Diffusion studies for different Silicon Carbide microstructures Sandrina Fernandes Fractional activity (%)

120 100 80 7Be 24Na

60

28M g

40 20 0 1200

1400

1600

1800

2000

2200

Tem perature (degree C) Release of Be, Na and Mg species from SiC Graphite Conversion as a function of temperature for an heating time of 15 minutes

Diffusion studies for different Silicon Carbide microstructures T=1300ºC

T=1300ºC

D24Na~ 1 e-5 m2/s

D24Na~ 1 e-6 m2/s

D28Mg ~ 1 e-5 m2/s

D28Mg~ 1 e-5 m2/s

T=1740ºC

T=1740ºC

D24Na ~ 1 e-5 m2/s

D24Na ~ 1 e-4 m2/s

D28Mg ~ 1 e-5 m2/s SiC (4µ µm) + Graphite (density = 1.6 g/cm3)

SiC foam (density = 1.1

g/cm3)

D28Mg=~ 1 e-5 m2/s T=1740ºC

T=1840ºC D24Na~ 1 e-5

m2/s

D28Mg~ 1 e-5 m2/s

D24Na~ 1 e-6 m2/s D28Mg ~ 1 e-7 m2/s T=1980ºC D24Na~ 1 e-4 m2/s

SiC (4µ µm) + 3% polysilazane (density = 1.9 g/cm3)

D28Mg~ 1 e-5 m2/s SiC Graphite conversion (density = 2.6 g/cm3)

D. Roux, Corporate R&D D. Urrfer, Ceramics R&D European R&D center for ceramics

Specific surface by BET isotherms III

nad

nad

II

Calcinated SiC + Starfire Binder (1350ºC)

B p/p0

p/p0

Gas adsorption isotherms (IUPAC)

BET plot SiC Xe T=77K 8E-20

CERN AT-VAC V. Baglin

p/Nads(psat-p)

7E-20 6E-20 5E-20 4E-20 3E-20 y = 5.86E-19x + 1.06E-20

2E-20

2

R = 9.99E-01

1E-20 0E+00 0.00

0.03

0.06

0.09

0.12

p/p0

S=0.36 m2/g

(σXe = 25 Å2)

Irradiation of target materials at PSI Elian Bouquerel 3 weeks of 100kW, 1 GeV proton beam, of operation on the Eurisol targets will be demanding with respect to heat dissipation and ageing.

Irradiation of target materials at PSI

Energy Deposition simulated along the beam dump (in GeV/cm3/pr), by Fluka.

Heat Dissipation

Heat transfer in the sample holder

Heat transfer in the sample container

• Radioactive decay of the beam dump is investigated –

Copper as beam dump is the best option at the moment

Next steps (2006) • After Swiss authorities approval, perform irradiation at PSI: production of materials, test jig, themperature readout, remote control. • Systematic study and analysis on innovative materials (Diffusion coef, specific surface). • Design on paper of the 4 target+ion source. • Start testing specific parts (inflatable metallic sealings, 2 connected containers at ISOLDE).