10th ITPA TG Meeting on Diagnostics April 06, Moscow Radiation Effects WG Eric Hodgson (presented by Benoit Brichard) Input from JA: T.Nishitani, T.Shikama. RF: A. Krasilnikov, K.Vukolov. US: L.Snead Last meeting of Radiation Experts at 15th IEA Workshop held during ICFRM-12 (Dec 05) in Santa Barbara. 18 people attended the 4 1/2 h meeting. Updates on activities from EU, JA, RF, and US. 6-7 April EFDA Ceramics Irradiation meeting Now have ITER, but still waiting new structure for common tasks.

EU update 1 EU laboratories involved in TW4/6-IRRCER programmes AEUL Riga Ferroelectric bolometers CEA Cadarache NBI insulation CIEMAT Madrid H/D/T effects, windows, bolometers, T/RIEMF, RIC/RIED IPP.CR Prague Hall probes FZK Karlsruhe H/D/T effects, ECRH windows MEdC Bucharest Windows, fibres, optoelectronic components ÖAW Vienna Ferroelectric bolometers SCK/CEN Mol Bolometers, fibres, T/RIEMF, RIED

EU update 2 MI cables (CIEMAT, SCK/CEN) RIEMF - serious problem - difficult to separate Rad. and T effects TIEMF (centre conductor) detailed study (CIEMAT, SCK/CEN) EMF (V)  T. No annealing of the effect observed up to 550 C Not due to geometry Combined effect of inhomogenieties, transmutation/dpa and temperature gradient Need more data and experimental test To fully understand further the combined RIEMF/TIEMF effect

Damage to MI cable Cu core Impurity analysis underway “Normal” copper wire copper core in MI cable ! Severe damage in Cu core extracted from MI cable Cause of TIEMF ? No TIEMF effect observed in “normal” copper wire

AISI304L Core to Core induced voltage VaVa 10 kΩ VabVab VbVb Is it radiation damage related (Dpa) ? Cu In-core irradiation in BR2 Transmutation ? Change of seebeeck coefficient

EU update 3 Bolometers (AEUL, CIEMAT, IPP, Ö AW, SCK/CEN) JET resistance type: Pt on Alumina and AlN n irradiated - SCK/CEN ---> 0.01 dpa, 400 C PIE: Pt and substrates OK Problem: electrical contacts Ferroelectric type: PbZrO 3 being prepared

Pt on Al 2 O 3 and AlN Double Pt meanders Absorber, reverse side First check T and ionization effects Move to neutron irradiation (BR2) Good linearity of sensor No change in resistance at 350°C up to dpa Pt/AlN Pt/Al 2 O 3 T°C Problem with electrical contact that not withdstand high temperature

RIED in Al 2 O dpa => small differences (a few pA) are observed. = > start of microstructural analysis Irradiation facility fully operational –Active vaccuum, mbar –Active Heating up to 400°C

Pt on Si 3 N 4 IPP bolometer - “SiN” for mica First check T and ionization effects ---> No adverse effects Also Pt on Si3N4 (IPP)

EU update 4 Hall probes ( IPP.CR, Ukraine ) InSb Hall devices (MSL, Lviv, Ukraine) showed acceptable performance up to dpa (70% of original sensitivity) But upper temperature for operation is low (< 100C) 7 new sensors based on solid solutions of InSb and InAs and similar materials with potential high T survival ( > 200°C ) 1st in-reactor tests completed --> But none survived beyond dpa at C. Problems: electrical connections, solder joints, thin wire insulation....

EU update 5 Optical properties (CIEMAT, MEdC, SCK/CEN) Enhanced surface degradation (optical and electrical) from low energy H and He implantation. General problem ? Mirrors: Coatings for extended UV reflectivity No suitable UV fibres, and UV absorption extends to visible H loading has limitations Windows: High energy proton irradiations => for low dose  ≈ n

Window materials MeV p irradiation of KU1 and KS-4V Produces very similar absorption to gamma irradiation for doses < dpa KU1 Gamma KU1 14 MeV p KS-4V 14 MeV p 14 MeV proton irradiation

Window materials Surface degradation Electrical current (µA) Optical Absorption (cm -1 ) XPS analysis shows extreme O loss Results => Si and SiO rich surface zone General problem for insulator surfaces ? A.U Low energy He ion bombardment of KS-4V Produces enhanced absorption and surface electrical conductivity

Optical Fibre Silica fibre for UV-VIS, hydrogen loading technique IR-fibres for thermography Fiber current sensor (cf next presentation)

Optical fibre - 1 Silica and sapphire fibres Silica fibre, Al jacket Gamma irradiation UV transmission quickly saturates and extends into the blue region (>400 nm)

Optical fibre x10 17 n/cm 2 23 MGY 80°C Wavelength [nm] STU+H2 KS4V+H STU KU1+H2 and STU RIA [dB/m] With these Al-coated H 2 - loaded fibres we can enter the cryostat but probably not into the diagnostic block, unless we could change the fibres. Looking for improvement ? 200 µm AL-coated H2- loaded optical fibre, STU,KU1,KS4V BR2-Irradiation

Coated mirrors Work on mirror coatings for general protection and LOCA SiO 2 (SiO) and alumina MgF (HfO 2 ) for extended UV No change when irradiated in N 2 atmosphere but …

No protection against LOCA Radiation + humidity Degradation attacks the Al coating even when protected Enhanced diffusion and reactions (Al(OH) 3 ) Swelling SiO -> SiO 2 Usually, SiO 2 better resistance against corrosion

EU update 6 T diffusion / effects (CIEMAT, FZK) Windows the primary barrier to confine tritium Modelling on effects of H isotopes (T) in diamond indicates strong trapping. In-situ radiation enhanced diffusion in different materials is now being measured. Work starting on effects of H isotopes on physical properties

Deep traps for H isotopes Modelling shows deep wells for T trapping in diamond (8 eV) Work on ionizing radiation effects underway

Radiation enhanced diffusion Disc samples electron irradiated on vacuum side H/D on other side High sensitivity leak detector for diffusion Pressure sensors for absorption Disc for analysis electrons H/D chamber

EU update 7 EFDA Ceramics Irradiation Meeting 6-7 April 06 2 day meeting with presentations of all on-going EU TW5/6 tasks Information / presentations shortly available New data base task / specifications discussed

JA update JAEA, NIFS, Tohoku IMF (Data from T.Shikama and T Nishitani ) RIC - stable insulators for blanket applications. Data for gamma, and fission and fusion neutrons Fast ion conductor behaviour during reactor irradiation 450 nm radioluminescence in silicas - band suppression with OH content (full agreement with earlier data) Radiation and temperature measurements using luminescence

DT neutron Gamma ray Fission reactor ▲ Y 2 O 3 ◆ CaZrO 3 ● Er 2 O 3 Under irradiation CaZrO 3 (8.8 Gy/s, Bias: +250V) RIC Without irradiation Y 2 O 3 (5.1 Gy/s, Bias: +250V) Under irradiation Without irradiation RIC Teruya Tanaka (NIFS) on RIC of MHD insulators for blanket application

Bun Tsuchiya JMTR irradiation: H-inplanted in ceramic material Conclusion: RIC enhancement in H-inplanted material

Normalized luminescence intensity (arbitrary units) Under successive ion irradiation 2.7 eV: B2αbands in low-OH silica 1.9 eV: NBOHC in high-OH silica At very low fluences 3.1 eV: Intrinsic B2βbands in low-OH silica Shinji Nagata on radioluminescence of silica Luminescence decrease with OH content MeV H + 1 x H/m 2 0 ppm OH 200 ppm OH 800 ppm OH Photon energy (eV)

Aichi Inouye and Shinji Nagata on radioluminescene of ruby

Luminescence – LLPs by Kentaro Toh Two types of long lasting phosphors (LLPs), strontium aluminate doped with europium and dysprosium (SrAl 2 O 4 :Eu 2+,Dy 3+ and Sr 4 Al 14 O 25 :Eu 2+,Dy 3+ ) show intrinsic luminescent peaks. The luminescence of LLPs at 570 nm did not exhibit luminescence immediately after the fast neutron irradiation. Luminescent spectra of SrAl 2 O 4 :Eu 2+,Dy 3+ and Sr 4 Al 14 O 25 :Eu 2+,Dy 3+ Development for radiation monitors ?

Temperature measurement by thermoluminescence from silica by Akihiro Honda

RF update FORC, Kurchatov, TRINITI (Data from Anatoli Krasilnikov) Fibres – RL and RIA Irradiations at IR-8 (Kurchatov) At 3x10 13 n/cm 2 /s, 400 Gy/s to n/cm 2, 16 MGy Fibres from FORC, Heraeus, Mitsubishi, and Fijukura H loaded fibres give best results (lowest RL) RL  reactor power (=> nuclear radiation monitor)

H2 Loaded

Radiation induced luminescence spectra. Figures denote fibre numbers according to Table 1. Fast neutron fluence  n/см 2, gamma-dose –7.2 МGy(Si), fast neutron fluxe -2.8  n/см 2 s, gamma-dose rate –400 Gy/s. Luminescence spectra corrected for re-absorption IR-8 reactor irradiation A.V. Bodarenko & al., instru. and exp. tech., 2006, Vol. 49, No2, pp Time evolution Luminescence spectrum H2-loaded fibres

US update ORNL (Data from L. Snead, D. Swain, D. Rasmussen, K. Leonard) “Long ago” US was active during ITER CDA, on RIC in MI cables, RIED, windows Now beginning activity once again: ICRH insulators, thermal conductivity degradation, multilayer mirrors

Ion Cyclotron Insulators Radiation Effects Five ceramics (alumina in polycrystal and single crystal form) –Al 2 O 3 (Wesgo Al995, Deranox 999*); Al 2 O 3 (Kyocera single crystal), –BeO (Thermalox), –AlN (Tokuyama SH-15), –Si 3 N 4 (Kyocera SN-235P), –single crystal MgAl 2 O 4 (Princeton Scientific Corp.) HFIR fission reactor irradiation at o C: 0.001, 0.01, 0.1 dpa ( n/cm 2, E>0.1 MeV) Pre- and post-irradiation testing of dielectric properties (dielectric constant, loss tangent at ~100 MHz) and thermal conductivity *Only one Deranox 999 specimen irradiated, at 0.1 dpa (material supplied by Eric Hodgson)

Theory is being developed to better understand defects Thermal conductivity in ceramic materials can be described as a summation of various scattering centers for phonons as : The appropriateness of addition of thermal resistances is suggested by the addition of inverse relaxation times to obtain the combined relaxation time. Above 1/3 of the Debye temperature defect scattering is temperature independent. Umklapp (phonon Scattering) boundaries intrinsic defects radiation defects Thermal defect resistance Thermal Conductivity of Ceramics for Diagnostic Application

More complex defects formed during higher dose irradiation are more thermally stable. 60°C Neutron Irradiated Alumina

Defect Resistance in Alumina 1/K rd can be broken into vacancy, loop (and void) terms. Following this analysis, maximum vacancy concentration can be calculated and compared with optical F-center measurements. Large discrepancy indicates that majority of thermal conductivity degradation in alumina (T irr = 60°C) is dominated by loops. This is reinforced by increased difficulty in annealing of defects at higher doses.

Performance of Diaelectric Mirrors Under Irradiation Work just starting. Purpose : Development of multilayer dielectric and performance of these materials under neutron and gamma irradiation. Approach: Fabrication of mirror structures without use of silica containing layers. - substrate materials, sapphire and silicon carbide - layer materials: Alumina Magnesium aluminate spinel Hafnium Oxide Magnesium Oxide Intermediate dose irradiation to be carried out in June 06. (0.01 to ~ 1 dpa)