1. (RADIATION DAMAGE STUDY FOR SPES)
RDS_SPES PROJECT
(RADIATION DAMAGE STUDY FOR SPES)
Aldo Zenoni, Brescia University and INFN, Pavia – CERN, February 4th 2015

2. PRESENT PARTNERS OF THE RDS_SPES PROJECT1
SPES Exotic Beams Production Group, LNL, Legnaro
L.E.N.A. Laboratory, Pavia University
INFN Sezione di Pavia (Department), Pavia University
Applied Physics Group and Laboratory of Materials Science and Technology, Brescia University
SPES TIS
Triga Mark II
1 Project mostly supported by INFN and SPES Project at LNL, Legnaro
Aldo Zenoni, CERN,

3. Partner locations (Northern Italy)
UniBS
LENA UniPV
INFN
INFN LNL
Legnaro
Aldo Zenoni, CERN,

4. SUMMARY Motivations for the RDS_SPES Project
The L.E.N.A. Laboratory at Pavia University (irradiations)
The Laboratory of Materials Science and Technology at Brescia University (analysis of materials/components)
Possible extensions of the project
Conclusions and prospects
Cherenkov light
Material scientists
Aldo Zenoni, CERN,

5. Target & Ion Source complex (TIS) (a technological challenge)
HV 40 kV
Ionizer & transfer tube
Thermomechanical stresses
TIS Heater
2000°C
Complicated multistep-process for ion extraction
1013 fissions/s
15 day irradiation
5 year cooling
Radioactive ion effusion and diffusion
40 MeV protons
200 mA, 8 kW
Highly radioactive environment
200 mm
Only automatic handling possible
7 238UCx
coaxial disks
1.3 mm thickness
3 graphite dump disks
Aldo Zenoni, CERN,

6. Production of neutron rich isotopes by 238U fission (a nuclear reactor environment)
1013 n/(s MeV)
1013 fission/s
neutrons
gammas
15 days
Aldo Zenoni, CERN,

7. Radiation biological hazard TIS bunker at irradiation time (FLUKA)
4 m walls
1 mSv/h
vertical plane
horizontal plane
3 m ceiling
RIB
y (cm)
proton beam
z (cm)
neutron dose
RIB
y (cm)
vertical plane
proton beam
neutron dose
103 Sv/h
Aldo Zenoni, CERN,
x (cm)

8. Material properties modifications by radiation damage
Some critical TIS components
(mainly polymeric materials)
Chamber joints (O-rings)
Viewport glass and joints
Insulators
Proton beam joints
Chamber handling guides
Chamber base insulators
Pneumatic motors
Electrical motors
AC power wire jackets
Optical fiber core/cladding
Electronic components
Safe and stable operation performance must be guaranteed; no manual handling is possible
Aldo Zenoni, CERN,

9. The SPES Radioactive Ion Beam (RIB) front-end line
Steerers and triplet of quadrupoles
Diagnostic box (FC+BP)
Slits and Diagnostic box (BP+FC)
Triplet of quadrupoles
Wien filter
Emittance meter
Target-ion source
Aldo Zenoni, CERN,

10. Material damage by ionizing radiation and neutrons
Polymeric materials
Very sensitive to ionizing radiation > 103 Gy
Covalent bonds broken (chain scission)
New chemical bonds formed (cross linking, reticulation)
Free radical formation
Radiation damage affected by temperature, additives, atmospheric conditions (oxygen)
Gas H, He formation
Irreversible effects – mechanical, chemical, electrical, thermal properties affected
Molecular weight, solubility, Young’s modulus, elongation, hardness, embrittlement, viscosity
Ceramics, glasses
Mechanical properties unaffected when irradiation < 107 Gy and neutron fluences < 1019 n/cm2
Darkening and loss of transparency in glasses
Metals and alloys
Reasonably unaffected by ionizing radiation
Atom displacement by neutron collisions E> 1 keV
High neutron fluence needed > 1016 n/cm2
Creation of lattice vacancies and interstitials
H and He gas formation, decrease in density
Plastic properties markedly affected: yield strength, ultimate tensile strength, elongation, fatigue stress, hardness, impact strength, creep, etc.
Damage may be recovered by annealing
Thermal neutrons may induce transmutation
interstitials
vacancies
Displacement dynamics
Aldo Zenoni, CERN,

11. Material damage by radiation is a long-known technological problem
Space science
Nuclear reactor technology
Accelerator technology
CERN Reports on radiation damage tests; the reference
Cable insulating materials; CERN (1979)
Thermosetting and thermoplastic resins; CERN (1979)
Materials used around high energy accelerators; CERN (1982)
Selected electrical insulating materials for HP and HV applications; CERN (1985)
Halogen free cable-insulating materials; CERN (1989)
Radiation tests at cryogenic temperatures on organic materials for LHC; CERN (1996)
Thermosetting and thermoplastic resins composite materials; CERN (1998)
Adhesives; CERN (2001)
Aldo Zenoni, CERN,

12. Typical report information CERN 82-10 (1982)
(extensive and systematic work)
Dose limits are specific to the item tested and to the end-point criteria applied
General information on materials: thermoplastic resins
Specific information: cable insulation by a supplier
Mainly g dose: 95%
switched-off reactor
Irradiation sources:
7 MW Astra reactor, Austria ( n/(s cm2); 106 Gy/h)
ASTRA fuel elements or 60Co source (to avoid activation) (104 Gy/h)
CERN accelerators ( Gy/h)
TAPIRO fast reactor at ENEA, Italy (1012 n/(s cm2) )
Aldo Zenoni, CERN,

13. Rad-hard study performed on SPES front-end critical components - I
TEFLON and VITON are excluded
15 days operation are foreseen
Front-end MCNPX simulation
Dose rate
Rad dose limit
from CERN reports
Max operating days
before failure
Top view
Side view
Aldo Zenoni, CERN,

14. Rad-hard study performed on SPES front-end critical components - II
PEEK, EPDM, KAPTON, TPE-SBR are used instead of weaker materials
SPES Front-end
Open questions with existing data :
Are irradiation conditions adopted close to reality? (Mainly g dose tested)
Are end-point criteria adapted to the item use?
Are specific material/component included in the available data?
Aldo Zenoni, CERN,

15. Reasons to propose a program for rad-hard tests for SPES front-end
Radiation hardness of materials and components is a critical item for ISOL sources in construction or foreseen (SPES, REX-ISOLDE, ALTO, SPIRAL2, iTHEMBA, EURISOL ….)
Data in the literature are somewhat abundant but often not recent
New materials, products and suppliers are available and should be tested
Specific materials and products utilized in the assembly should be tested in spite of generic materials
Existing data mainly refer to gamma ray damage
Reliable tests should reproduce as close as possible real operating conditions
Specific mechanical, electrical, optical requirements of materials and products should be tested against radiation damage
Complex components ad electrical motors or electronic circuits should be tested.
Interest for a systematic campaign of rad-hard tests for ISOL sources and other applications has been expressed by a number of potential partners
Aldo Zenoni, CERN,

16. The RDS_SPES Project resources
(Radiation Damage Study for SPES)
Supported by INFN, Pavia and SPES Project at LNL, Legnaro
L.E.N.A. Triga Mark II nuclear research reactor for material and component irradiations at Pavia University
Tests of physical and operational properties of materials and components at the Laboratory of Materials Science and Technology at Brescia University
Know-how on simulation and transport programs MCNPX, FLUKA, GEANT4, PHITS, in UniBS, LENA, LNL
Aldo Zenoni, CERN,

17. Draft research program of RDS_SPES Project
Compilation of materials and products to be rad-hard tested with definitions of the actual mechanical, electrical, optical, operational requirements to be guaranteed
Simulation of the radiation fields and cumulated dose expected on the critical SPES Front-end components in the foreseen operational conditions
Irradiation campaigns at L.E.N.A. on sample materials and products. Radiation fields as close as possible to the expected ones (neutrons vs gammas). Systematics on adsorbed dose levels.
Test of physical and operational properties of irradiated materials and components for different levels of irradiated dose
Analysis of the relation between physical properties changes and structural modifications due to radiation damage in materials (mainly polymers)
One or two year research program
Aldo Zenoni, CERN,

18. L.E.N.A. Laboratory at Pavia University (Laboratorio Energia Nucleare Applicata)
Reactor tank:
1.98 m diameter, 6.4 m height with demineralized water
In operation since 1965
Biological shield concrete
1 m thickness
Reactor core:
44.6 cm diameter 64,8 cm height
TRIGA Mark II pool research reactor
light water and HxZr moderated
250 kW steady-state power
90 symmetric holes: fuel elements, control rods, neutron source, irradiation channels
Graphite reflector 30 cm thickness
Aldo Zenoni, CERN,

19. T.R.I.G.A. Mark II pool research reactor
(Training, Research and Isotope production General Atomics)
Vertical cross section
Core and in-core irradiating channels
biological shielding
graphite elements
control rods
neutron source
Central thimble
Rabbit
Thermalizing column
Thermal column
Thimble F
water pool for large samples
fuel elements
20% 235U enriched
92% HxZr
Reactor core
First core configuration (1965)
Aldo Zenoni, CERN,

20. T.R.I.G.A. Mark II pool research reactor
(Irradiation facilities)
Radial graphite reflector 30 cm thickness
neutron fluxes in n/(s cm2)
Rabbit channel
(7.40x1012) pneumatic sample extraction
Central thimble (1.72x1013) aluminum pipe
3.8 cm diameter
Thimble F aluminum pipe 3.8 cm diameter
Lazy Susan
(2.40x1012)
Thermal channel
(2.52x1011)
7.0 cm diameter
Rotating rack for 80 samples at a time
27 polyethylene vials
0.8 cm diameter
3.0 cm height
Aldo Zenoni, CERN,

21. T.R.I.G.A. Mark II pool research reactor
(Irradiation beam ports)
neutron fluxes in n/(s cm2)
Water pool
biological medical applications
Ø 20.3 cm
Ø 15.2 cm
Thermal column
(1.19x1010)
well thermalized isotropic flux
(1.14x1012)
Thermalizing column
Various levels of thermalization
(9,07x109)
(1.12x1011)
Aldo Zenoni, CERN,

22. T.R.I.G.A. Mark II pool research reactor
(Irradiation fluxes)
Irradiation facility
Measured flux
n/(s cm2)
Central thimble
(1.72 ± 0.17) 1013
Rabbit channel
(7.40 ± 0.95) 1012
Lazy Susan
(2.40 ± 0.24) 1012
Thermal channel
(2.52 ± 0.36) 1011
Thermal column
(1.19 ± 0.08) 1010
(1.14x1012)
(9.07x109)
(1.12x1011)
(1.1x109)
Aldo Zenoni, CERN,

23. (Measurement design, irradiations, sample analyses)
The L.E.N.A. Laboratory
(Measurement design, irradiations, sample analyses)
LENA building
LENA staff
Present activities:
Studies of radioisotope production for medical and industrial applications
Trace element search by neutron activation
Radiation damage studies on electronic circuits and materials for space and accelerator physics
Radiocarbon dating of archeological and historical samples and artifacts
Forensic analyses and inquires
Collaboration to research projects in medicine (BNCT ) and nuclear and particle physics.
Spectroscopy and radiochemistry
Aldo Zenoni, CERN,

24. (Mechanical and Industrial Engineering Department)
Laboratory of Materials Science and Technology (LMST) at Brescia University
(Mechanical and Industrial Engineering Department)
Member of:
INSTM (Italian National Consortium of Materials Science and Technology)
ESIS (European Structural Integrity Society),Technical Committee 4 (Polymers, Adhesives and Composites)
sites.google.com/site/materialssciencetechnologylab/
Main research areas:
Development of advanced engineering polymeric materials
Mechanics of polymers, composites and nanocomposites
Rheology of polymers and polymer-based systems
Technology and engineering of plastics products
Aldo Zenoni, CERN,

25. LMST equipment and available facilities
(Mechanical tests)
Mechanical and rheological tests
Universal dynamometer for mechanical testing - Instron
Instrumented pendulum for impact tests - Ceast
Dynamic dynamometer - Instron
Dynamic Mechanical Thermal Analyzer (DMTA) - Polymer Lab
Dynamic Mechanical Thermal Analyzer (DMTA) - TA Instruments
Instrument for creep tests on polymers
Equipment for specimen preparation - Ceast
Twin-bore capillary rheometer - Ceast
Rotational rheometer - TA Instruments
Melt Flow Indexer - Ceast
Elongational rheometer
Capillary rheometer
Dynamic dynamometer
Universal dynamometer
Aldo Zenoni, CERN,

26. LMST equipment and available facilities
(physico-chemical tests and process design)
Physico-chemical and morphologial analyses
Differential Scanning Calorimetry (DSC) - Mettler Toledo
Modulated DSC - TA Instruments
Thermogravimetric Analysis (TGA) - TA Instruments
Infrared Spectrometry (FTIR) - Jasco
UV-vis Spectrophotometry - Perkin-Elmer
Gel Permeation Chromatography (GPC)
Gas Chromatography - Perkin-Elmer
Standard equipment for synthesis and chemical analyses
Travel optical microscope - Leica
Access to Scanning Electron Microscopy (SEM)
Infrared spectrometer (FTIR)
Processing machines
Single-screw extruder - Fuji
Brabender mixer - Brabender
Injection molding machine - Arburg
Compression molding machine -Collin
Access to compounding machine – Coperion
Computer Aided Engineering software analyses
Plastic injection molding design software - Moldflow (Autodesk)
Multiphysics modeling and simulation software - COMSOL Multiphysics
Compression molding machine
Aldo Zenoni, CERN,

27. Tests on mechanical and thermal properties of pre and post-irradiated polymeric samples
Tensile tests (mechanical: elastic modulus, tensile strength and elongation at break)
Impact tests (mechanical: impact strength)
Bending tests (mechanical: flexural strength )
DSC analysis (thermal: glass transition temperature, melting temperature, degree of crystallinity )
Rheological tests (molecular weight, molecular cross-linking, etc.)
Infrared analysis (structural analysis)
SEM microscopy (structural analysis)
Gas chromatography (analysis of evolved gases)
Gel permeation chromatography (molecular weight)
Swelling test (cross link density)
Impact pendulum
Calorimeter DSC
Test will be performed at LMST in Brescia
Polymeric materials should not suffer activation
Aldo Zenoni, CERN,

28. Possible extensions of the RDS_SPES Project (Partners)
ALTO
Possible partners who expressed interest in the project:
Potential partners
first meeting
ESS (European Spallation Source), Lund, Sweden
Lund,
ALTO, IPN Orsay, France (radioactive beam production)
LNL, Legnaro,
CERN, Sources, Targets & Interactions Group, Geneva (Switzerland)
CERN, Geneva,
iTHEMBA Labs, Western Cape, South Africa (radioactive beam production)
To be fixed
iTHEMBA Labs
The effort could be better aimed and qualified if a larger Collaboration among interested partners will be established, sharing experience, know how and resources
Aldo Zenoni, CERN,

29. Three main questions for inorganic materials:
Possible extensions of the RDS_SPES Project (Metals and alloys, Ceramics, electronic circuits)
Three main questions for inorganic materials:
High irradiation neutron fluences needed to test damage in metals and ceramics; are TRIGA fluxes adequate to needs?
A metallurgy test laboratory is needed to perform pre and post irradiation tests on metallic samples
Metals may be activated by neutron irradiation, transmutation effects
Just an observation: a lot of interest, but lack of background and expertise in the present collaboration
Electronic circuits and components:
No particular problems; integrated electronics is very sensitive to radiation damage
Aldo Zenoni, CERN,

30. Possible answers to questions concerning investigation on inorganic materials: 1), 2)
Are TRIGA fluxes adequate to needs?
This has to be verified. Possibly a factor 10 lower than the highest reactor fluxes
Consider also that radiation damage and damage evolution can be predicted by computational models to a certain extent.
Reliable radiation damage correlation requires integration of theoretical, computational end experimental tools.
A metallurgical laboratory is needed to perform the tests
The Group of Metallurgy of the Brescia University is interested in a possible collaboration; pre e post irradiation mechanical test on (non activated) metallic samples may be performed in Brescia
The same interest has been manifested by the Groups of Metallurgy and Machine Design of the Padua University
Aldo Zenoni, CERN,

31. The Laboratory of Metallurgy at the Brescia University
Tests at the Brescia Metallurgy Laboratory
All metal plastic properties can be tested: yield strength, ultimate tensile strength, elongation to fracture, fatigue stress, hardness, impact strength, creep, ductility, brittleness, etc.
Microindentation and nanoindentation testing equipments are available for non destructive tests
Vickers microindenter
diecasting plant
optical microscopy
Aldo Zenoni, CERN,
strain machine

32. The Laboratories of Metallurgy and Machine Design at the Padua University
Metallurgy studies performed
Neutron damage on microstructure:
Tests on mechanical properties: hardness, tensile strength, fatigue, etc
Steels and alloys for nuclear reactor use: valve bodies, cooling systems, canisters
Optical, SEM, TEM microscopy
Hardness measurement instrumentation
X ray diffractrometer
Corrosion laboratory
High temperature fatigue tests
Aldo Zenoni, CERN,

33. Possible answers to questions concerning investigation on inorganic materials: 3)
Metals may be activated by neutron irradiation
If metallic samples are activated by neutron irradiation, some testing equipment may be installed in the mechanical workshop inside the LENA building
If needed and justified, automated “hot cells” may be installed too
Rad-waste creation and disposal must be carefully evaluated
A list of possible “hot” analysis may be considered and studied on a case by case basis
LENA mechanical workshop
LENA mechanical workshop
Aldo Zenoni, CERN,

34. Conclusions and prospects
We are convinced that the RDS_SPES Project on radiation damage may be a timely and useful initiative for many European (and worldwide) facilities presently in construction in the field of nuclear physics and applications
The atouts of the Project are the availability of the LENA Laboratory for irradiations and Materials Science Laboratories to perform pre and post irradiation tests on materials and components
Possible collaborations and sharing of experience, knowhow and resources could be strategic to aim the project effort at best.
ESS Lund and ALTO Orsay have already expressed their interest in joining the collaboration
In next weeks we will start the first campaign of radiation damage study on vacuum O-rings
Aldo Zenoni, CERN,

35. SPARE SLIDES
Aldo Zenoni, CERN,

36. Materials employed for the simulations
name
composition
EPDM
Etylene-Propylene Diene Monomer
rubber
PEEK
Polyether ether ketone
organic thermoplastic polymer
PMMA
polymethilacrilate
Plexiglass, lucite
SBR
Styrene-butadiene
TPE
Thermoplastic elastomer
VITON
Fluoropolymer elastomer
TEFLON
Politetrafluoretene
KAPTON
poly-oxydiphenylene-pyromellitimide
FPE
Fluorinate ethylene propylene
Aldo Zenoni, CERN,

37. Materials employed for the simulations
Aldo Zenoni, CERN,