In situ irradiation testing of nuclear ceramics and oxides with - - PowerPoint PPT Presentation

In situ irradiation testing of nuclear ceramics and oxides with heavy ions of fission fragments energy

V.A.Skuratov1, G.Bujnarowski1,2, Yu.S.Kovalev1, K.Havancsak3, J.Stano4

1 Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research,

Dubna, Russia

2Institute of Physics, Opole University, 45-052 Opole, Poland 3Eötvös University, H-1117 Budapest, Hungary 4BIONT, a.s., 842 29, Bratislava, Slovakia

Outline Outline

• Introduction
• High energy heavy ion irradiation facility in FLNR JINR
• Study of structural effects of dense ionization in nuclear ceramics and oxides

with heavy ions of fission fragment energy

• Real time examination of mechanical stress in Al2O3 under swift heavy ion

irradiation

• Residual stress depth profiles in oxide materials irradiated with high energy

heavy ions

• Outlook

Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

The overall intention of this work is to yield sufficient basic data to determine and compare the radiation tolerance of several ceramics and single crystals (MgAl2O4, MgO, Al2O3, ZrO2, SiC, ZrC, AlN, Si3N4) considered as candidates for inert matrix fuel hosts Our central objectives are:

• to study the temperature dependence of swift heavy ion-induced phase

transformations and dense ionization effect on pre-existing defect structure in irradiating materials

• to elucidate the correlation between surface and material bulk radiation damage

induced by heavy ions with energies above 1 MeV/amu

• real time examination of stress accumulation in ceramic materials under swift heavy

ion bombardment

Ion tracks in spinel irradiated with 430 MeV Kr ions to a fluence of 1.1×1012 cm-2 at room temperature. The average TEM track diameter is ~2 nm.

S.J. Zinkle, V.A. Skuratov. Nucl. Instr. Meth. B 141 (1998), 737-746.

Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

High-resolution lattice image of Si3N4 irradiated with 710 MeV Bi ions (plan- view specimen)

AlN > 34 SiC > 34 Al2O3 > 41 Si3N4 15 MgAl2O4 8 Material Se, keV/nm

Threshold ionizing radiation levels for track formation in ceramics

Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

S.J. Zinkle, V.A. Skuratov and D.T. Hoelzer. Nucl. Instr. Meth. 2002, B 191,1-4, pp. 758-766.

High-resolution lattice image of α-Al2O3 irradiated with 710 MeV Bi ions a fluence of 7×1012 cm-2 The average TEM track diameter is ~3 to 4 nm.

V.A. Skuratov, S.J. Zinkle, A.E. Efimov, K. Havancsák. Nucl. Instr. Meth. B203(2003), 136-140.

Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

TEM micrograph of α-A2O3 target irradiated at S at Se

e=41 keV/nm

=41 keV/nm to a fluence

• f 7×1012 cm-2 (S.J.Zinkle, ORNL)

The presence of numerous subgrains suggests that considerable internal stresses were induced by the Bi ion irradiation Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

1E9 1E10 1E11 1E12 1E13 1E14 150 160 170 180 190 200 210 220 230 240

Sapphire Kr 250 MeV

substrate τmean (ps)

Fluence (ions cm

• 2)

The mean positron lifetime as a function of dose. The figure shows different stages of point defect accumulation

Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

3D AFM image of of MgAl2O4 surface irradiated with 710 MeV Bi ions. Ion fluence 5x1010 cm-2.

Mean hillock height versus incident electronic energy deposition

Threshold electronic stopping power value needed for the hillocks production: MgO, Se ≈ 15. 8 keV/nm; MgAl2O4, Se ≈ 15. 5 keV/nm; Al2O3, Se ≈ 25 keV/nm SiC, Se > 34 keV/nm

15 20 25 30 35 40 45 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 MgO MgAl2O4 Al2O3 YSZ

h, nm Se, keV/nm

Bi Xe Kr

Main questions addressed to real time measurements: Radiation damage and stress accumulation processes before and after ion track region overlapping Variation in the stress state under ion irradiation characterized by specific ionizing energy losses higher and lower than the threshold

• f radiation damage formation via electronic excitations.

Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy Examination of the dense ionization effect in ceramics and oxides with heavy ions of fission fragments energy

U400M E = 6 ÷ 100 MeV/n U400 - E = 0.5 ÷ 20 MeV/n IC-100 - E ≈ 1.2 MeV/n FLNR cyclotron complex U200 U200 -

• E = 3

E = 3 ÷ ÷ 15 MeV/n 15 MeV/n

This heavy ion irradiation facility is suitable

for irradiating large area (10x60 cm) polymer films just as small metal, semiconductor and ceramic samples in well controlled circumstances.

A homogeneous ion beam distribution has been achieved using horizontal and vertical

high-frequency electrostatic or low-frequency electromagnetic scanning systems. Ion beam homogeneity is better than 5%.

Ion beam transport line for applied research at U-400 FLNR cyclotron

B+2, Ne+4, Ar+7, Fe+8, Kr+15, I23, Xe+23, W+32 ions with energy ≈ 1.2 MeV/n

SEM data: d=0.2 um

Experimental set-up for ion-beam-induced luminescence measurements on IC-100 FLNR JINR cyclotron

R1 AND R2 FREQUENCY SHIFT UNDER COMPRESSIVE STRESSES

10000 7500 5000 2500 14380 14400 14420 14440 FREQUENCY (cm-1) INTENSITY (COUNTS) NEON R2 R1 STRESS FREE 3.2 GPa COMPRESSION

FREQUENCY SHIFT AS A FUNCTION OF STRESS

COMPRESSIVE STRESS - σ (GPa) R2 R1 2

• 2
• 4
• 6
• 8
• 10
• 12
• 14

1 2 3 4 5 6 SHIFT ²v (cm -1) ²v = 1.50 σ − 0.073 σ2 ²v = 2.16 σ − 0.052 σ2 R2 R1

Basis of the piezospectroscopic effect – the applied stress strains the lattice and alters the energy of transitions between electronic states ∆ν = Πij×σij

Πij – piezospectroscopic coefficients

Typical piezospectroscopic probes: Cr3+ in Al2O3 Eu3+, Nd3+ in silica glasses Sm3+ in borosilicate glasses

STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION

0.015 0.025 0.013 P, W cm-

2

1.3×108 80 300 Bi+51, 710 6.3×108 80 300(I) 300 (II) Kr+26, 245 3×108 300 Ar+16, 280 Φ, cm-2s-1 Т, К Ion type and energy, MeV

Ion irradiation parameters

∆ν = ∆ν(σ) + ∆ν(T) + ∆ν(nCr) the hydrostatic stress component σh = (σ11+ σ22 + σ33)/3 ≈ ∆ν2/7.61 σh (GPa), ∆ν(cm-1)

3x10

11

6x10

11

9x10

11

6x10

12

0.2 0.0

• 0.2
• 0.4
• 0.6
• 0.8

1.5 0.0

• 1.5
• 3.0
• 4.5
• 6.0

Bi,80K Bi,300K Kr,80K Kr,300K (II) Kr,300K (I) Ar,300K

∆σh, GPa ion fluence, cm

• 2

CL

∆ν, cm

• 1

STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION

The magnitude of integrated stress in Al2O3 induced by hundred keV- some MeV ion irradiation depends

• n the ratio of electronic to nuclear stopping power

G.W. Arnold, G.B. Kreft, and C.B. Norris, Appl. Phys. Lett., 25(1974) 540.

The knowledge about of high energy heavy ion-induced stress is of considerable practical value in view of simulation of fission product impact in radiation resistant oxides and ceramics, considered as candidate materials for nuclear waste management STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION

Dose dependence of the R-lines spectra under 167 MeV Xe ion irradiation. Ion beam incidence angle is 60o. T=80 K. STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION

The R-lines spectra measured during Kr, Xe and Bi tilted ion bombardment as a function of ion fluence. Spectra are normalized on maximum of the R1-line intensity The threshold of damage formation through dense ionization is about 20 keV/nm. B. Canut et al. Phys. Rev.

B 51 (1995) 12194. 670 MeV Bi Se=41 keV/nm 167 MeV Xe Se=24.7 keV/nm 107 MeV Kr Se=16.4 keV/nm

! No stress relaxation occurs if Se less than threshold value of damage formation via electronic excitation

Dose dependence of the difference between current and first registered R1-line spectrum during 167 MeV Xe ion irradiation STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION STRESS IN Al2O3:Cr UNDER SWIFT HEAVY ION IRRADIATION

Dose variation of the R-lines spectra under 167 MeV Xe and 107 MeV Kr ion irradiation at normal ion beam incidence

each Cr3+ ion acts as an independent strain sensor The splitting of the R-lines directly indicates on the presence of differently stressed regions in the irradiating ruby specimen

The stresses are compressive in basal plane of the sample and tensile in perpendicular direction

Confocal microscope LASER CONFOCAL SCANNING MICRISCOPY (LCSM) STUDY OF RESIDUAL STRESS PROFILES IN Al2O3:Cr AFTER SWIFT HEAVY ION IRRADIATION LASER CONFOCAL SCANNING MICRISCOPY (LCSM) STUDY OF RESIDUAL STRESS PROFILES IN Al2O3:Cr AFTER SWIFT HEAVY ION IRRADIATION Conventional

• ptical microscope

LCSM Solar TII

Photoluminescence R-lines spectra registered in virgin and 710 MeV Bi ion irradiated ruby specimens

Stress tensor components and ionizing energy loss profiles in ruby

The signs of the stress tensor components indicate that stresses are compressive in basal plane of the sample and tensile in perpendicular direction

Depth-resolved R-lines photoluminescence spectra measured using LCSM technique (postradiation examination)

240 MeV Kr, 300 K, ion fluence -1014 cm-2 virgin