Tests at HiRadMat of advanced SiC and Al2O3 as model targets for radioisotope beam production

Experiment proposal

Collaboration:Michal Czapski*, Thierry Stora*, Stefano Sgobba*, Raul Luis***, Stefano Marzari*,

Serena Cimmino*, Daniel Urffer**, Caroline Tardivat**

*CERN: EN-STI-RBS & EN-MME-MM**Saint Gobain CREE (advanced ceramics R&D)***ITN Lisbon

• 2010 - Sandrina Fernandes’ PhD thesis at CERN

dedicated to submicro- and nano-structured porous

ceramics to produce more intense beams of exotic

isotopes (before historical targets had grain size of 5 -30

microns)

• The discovery is further extended for ISOLDE and the

other facilities worlwide are starting to duplicate these

findings

History of the project:

Comparison ageing studies of influence of pulsed beams of 1.4 GeV

(ISOLDE) and 450 GeV (HiRadMat) on new advanced model targets of

tailored-made microstructure (synthesized at Saint Gobain - Centre

Recherche Etudes Europeens – world leader in ice-templating

method) to understand how beam energy impacts ageing (causing

decrease of good release efficiencies of ISOLDE targets)

Goal of the proposal :

Marie Curie Initial Training Network

CATHI(Cryogenics, Accelerators and Targets at HIE ISOLDE)

ESR 8Target Material Studies

Ageing under pulsed beams

Michal Czapski (EN/STI-RBS and EN/MME-MM*)

Diffusion

Effusion

Ionization

Target properties

• high production istope cross-section

• good diffusion and effusion properties

• low adsorbtion enthalpy

• high resistance to radiation damage

• limited sintering and ageing

• high operational temperature

• high thermal conductivity

ISOTOPE PRODUCTION MECHANICAL PROPERTIES

Pulsed Beams

• HIGHER INSTANTANEOUS RIB INTENSITIES• BETTER SELECTIVITY (BEAM GATE OPERATION)• ANNEALING OF INSTANTANEOUS DEFECTS IN THE REMAINING PORTION OF

CYCLE

• CREATION OF THERMAL CYCLING GRADIENTS (THERMAL STRESS, PULSED BEAM INDUCED FATIGUE)

Materials

SiC Al2O3

• radiation resistance• high thermal conductivity• high thermal shock

resistance• high-strength• high-hardness• good chemical properties

• good thermo-chemical stability

• high thermal conductivity• stable in air and oxidation

atmosphere

SiC

Al2O3

Material preparation at Saint Gobain CREE*

ICE-TEMPLATING METHOD(CNRS/SG CREE patent)

Open prosity 30 – 70 %

*European R&D center of the market leader in SiC production

JUNE – JULY 2012

Experiment8 samples: (pellets Ø 2 cm x 2 cm) – 4 SiC & 4 Al2O3

beam: NORMGPS – 1.4 GeV, 3.2x1013/pulse (2.4 µs/1.2s, 3-4 bunches), σ = 2.3RaBIT setup (Rapid p-beam Irradiation Transport – a pneaumatic system; shuttles sent in front of HRS front-end)

beam: SPS – 450 GeV, 4.9x1013/pulse (7.2 µs/18s, 1 – 288 bunches), σ = 2.0Max. cycles = 100 (desirable 10x more)Setup - 8 samples in a row

Previous experience – irradiation of SiC and Al2O3 at PSI

TARPIPE exp. (INJECTOR 2) – good agreement with experimental results

Fernandes, S., Thèse 4813 (2010), CERN

Cooling down period – 1 year

Al2O3

porosity50%

SiC

porosity50%

Post-irradiation studyat EN/MME-MM

EDS

SEM

XRD

Irradiation assisted stress corrosion

cracking

Microstructural changes

Microcompositional effects:

• recrystalisation, • phase

transformation • grain size change• pore shrinkage• grain coarsing

diffusion and segregation of impurities

THANK YOU