NA2: Thin actinide targets optimized for high intensity beamsPurpose:Optimize the high power capability and durability of thin actinide targets

(“thin” means 0.1 to few mg/cm2, i.e. not ISOL targets) for neutron and charged-particle induced reactions.

Benefits:Extended target lifetimes and increased primary/secondary beam

intensities at existing European user facilities (LOHENGRIN@ILL, SHIP@GSI, TASCA@GSI, LISE@GANIL,...).

Organisation:Coordinated production and test of fissile and non-fissile actinide targets

under reproducible conditions. Comparison of different target preparation techniques, backings and covers.

Training activities:• Workshop on thin actinide targets.• Permanent link between target producers and target users.• Hands-on experience for students and postdocs.

NA2 Participant Institutions

1. Institut Laue Langevin & LPSC Grenoble, Ftarget production by electrolysis, electrodeposition and painting

on-line target tests under intense neutron flux to measure temperature, fission product intensity and energy distribution

2. IRMM Geel, Btarget production by spray-painting, electrodeposition (and evaporation)

3. LMU Munich, Dtarget production by evaporation (and sputtering)

4. IPN Orsay, Ftarget production by electrodeposition, spray paintingtarget characterization by RBS, alpha, gamma spectroscopyfuture: CACAO project: joint CNRS-IN2P3/CEA hot lab

5. GANIL Caen, Fheavy ion irradiation for validation of dpa-lifetime-relation

Target production in collaboration with Nuclear Chemistry Institute Mainz, LBL Berkeley and Radium Institute St. Peterburg.

Open to other collaborators.

RBS cartography (1.5 mm step)

235U target

NA2: Actinide target production and characterization

LMU LMU

IPNO

IRMM

IRMM

• target thickness monitored on-line via width of fission product energy distribution

• target temperature distribution monitored by pyrometer and IR camera• longterm studies (several weeks) possible

NA2: On-line test of high power actinide targets

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Irradiation time (days)

Fis

sio

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Nuclear burnupObserved burnup

Additional losses due to:• sputtering by fission products• evaporation (e.g. for UF4)• diffusion into backing or cover• loss of adhesion to backing

Burnup of 235U target in 5.5E14 n/cm2/s neutron flux

5.5.1014 n/cm2/s ≈ 88 pA/cm2

comparison to accelerator beams:

simulate at LOHENGRIN long exposition to intense HI beams

NA2: Synergies with other NA or JRA“survival training” for actinide targets at ILL:• very high neutron flux: 5.5E14 n/cm2/s• nuclear heating up to ca. 1000 °C • extremely high radiation damage:

ca. 50 dpa/day, equivalent to damage by 3 A/cm2 340MeV 48Ca beam on 238U target,

i.e. 100 times more intense than present accelerator beams

We identified overlap/possible synergies with the following other LoIs:• ShERN (NA12)• ECOS (NA4 or JRA11)• ISOL-AT (JRA1)

We are ready to merge our LoI and contribute with our capabilities to any of these. We leave the decision to the EURONS2-proposal management team to select the best option for fitting it into the overall EURONS2 proposal.

mass-separated fission fragments,

up to 105 per second, T1/2 ≥ microsec.

The LOHENGRIN fission fragment separator

flux 5.5·1014 n./cm2/s

few mg fission target (0.1-1 mg/cm2, few cm2)

several 1012 fissions/s