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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
0%
20%
40%
60%
80%
100%
0 2 4 6 8 10 12 14
Irradiation time (days)
Fis
sio
n f
rag
men
t ra
te
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
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