Tests at HiRadMat of advanced SiC and Al 2 O 3 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
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 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 8 Target 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 SiCAl 2 O 3 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
Al 2 O 3
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
Experiment 8 samples: (pellets Ø 2 cm x 2 cm) – 4 SiC & 4 Al 2 O 3 beam: NORMGPS – 1.4 GeV, 3.2x10 13 /pulse (2.4 µs/1.2s, 3-4 bunches), σ = 2.3 RaBIT setup (Rapid p-beam Irradiation Transport – a pneaumatic system; shuttles sent in front of HRS front-end) beam: SPS – 450 GeV, 4.9x10 13 /pulse (7.2 µs/18s, 1 – 288 bunches), σ = 2.0 Max. cycles = 100 (desirable 10x more) Setup - 8 samples in a row Previous experience – irradiation of SiC and Al 2 O 3 at PSI TARPIPE exp. (INJECTOR 2) – good agreement with experimental results Fernandes, S., Thèse 4813 (2010), CERN Previous experience – irradiation of SiC and Al 2 O 3 at PSI TARPIPE exp. (INJECTOR 2) – good agreement with experimental results Fernandes, S., Thèse 4813 (2010), CERN Cooling down period – 1 year
Al 2 O 3 porosity 50%
SiC porosity 50%
Post-irradiation study at 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