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Tritium depth profile measurements in inner wall tiles from ASDEX-upgrade, JET and TFTR. Madis Kiisk Institute of Physics, University of Tartu Riia 142, 51014 Tartu. Project was carried out at the Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf (FZR), Dresden
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Tritium depth profile measurements in inner wall tiles from ASDEX-upgrade, JET and TFTR Madis Kiisk Institute of Physics, University of Tartu Riia 142, 51014 Tartu • Project was carried out at the Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf (FZR), Dresden • Project was coordinated by the Forschungszentrum Karlsruhe, Tritium Laboratory • Project was suspended in 2003 • Good contacts established with personnel at FZR
Method used for tritium depth profile analysis: • Accelerator Mass Spectrometry (AMS) In connection with the DTE1 campaign at JET, other methods used for tritium analysis: • Full combustion/Liquid scintillation • Autoradiography • Beta Induced X-ray Spectroscopy • Nuclear Reaction Analysis • Thermal desorption • Calorimetry • Pin diode • Ne:YAG Laser
Sampling points and analytical methods used for theplasma exposed and the shadowed edge of the JETInner Divertor tile 1IN3s1 and 1BN7
AMS method • Extremely high sensitivity (detection limit of the small compact tritium-AMS facility is about 5x1010 atoms/cm3) • Good spacial resolution (sample surface sputtering velocity 2-8 nm/s) • No disturbing atomic isobars (3He) • Destruction of molecular isobars (HD, H3) • Realtively fast (60-90 min per sample) • Simultaneus measurements of T and D ions, as well as other ions in interest (Be, Li, B)
Spherical ionizer sputter ion source Two off-axis disks for sample wobbling Gate 100 kV Tandem accelerator PC ADC Einzel lens Energy / current signals Double focusing injection magnet Stopping foil Preamplifier Slits Surface barrier detector Amplifier 2 mg/cm2 foil stripper Slits Faraday cup Einzel lens Current to frequency convertor Double focusing analysing magnet The SF6 insulated 100 kV Tandem Accelerator
Results • Drawbacks: • Calibration lack of standard samples TiH2 (T/H= 9.4x10-12) – LLNL, graphite (T/C= 3.5x10-9) – tritium lab. IFIN-Horia Bucharest) • Results with full combustion method differ by a factor of two for high concentrations and up to one order of magnitude for lower T concentration samples possible explanations: 1) Outgassing from AMS samples in storage 2) Sample preparation 3) During sampling 4) Calibration Does not affect the shape of the depth profile
References: 1) M. Friedrich, W. Pilz, N. Bekris, M. Glugla, M. Kiisk and V. LiechtensteinNucl. Instr. and Meth, B Vol. 223-224 (2004) 21-25. 2) M. Friedrich, W. Pilz, N. Bekris, M. Glugla, M. Kiisk and V. Liechtenstein,Pramana – journal of physics, Vol. 59, No 6, Dec 2002 pp. 1053-1059. 3) M. Friedrich, W. Pilz, G. Sun, R. Behrisch, C. Garcıa-Rosales, N. Bekris, R.-D. Penzhorn, Nucl. Instr. and Meth. B 172 (2000) 655. 4) M. Friedrich, W. Pilz, G. Sun, R.-D. Penzhorn, N. Bekris, R. Behrisch, C. Garcıa-Rosales, Phys. Scr. T 94 (2001) 98. 5) M. Friedrich, W. Pilz, G. Sun, R. Behrisch, C. Garcıa-Rosales, N. Bekris, R.-D. Penzhorn, Nucl. Instr. and Meth. B 161–163 (2000) 216.