Apparatus for in-situ defect analysis (AIDA)
Aim of the project
The aim of the project is is the development and research using an Apparatus for in-situ defect analysis (AIDA). The purpose of the system is the experimental simulation of defect development in novel energy-related materials. The AIDA system allows the invesrtigation of defects near the surface of a material, i.e. in an early stage of defect development, as well as in-situ "live" measurements. Currently, the interaction of such defective materials with hydrogen is investigated. Moreover, oxides and metals for novel data processing concepts are analysed.
Dr. M. Oskar Liedke at the positron injection of the AIDA-I module (right). |
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Schematic representation of the positron implantation into a crystal: After reaching the penetration depth defined by the acceleration energy, positrons start to diffuse within the crystal. Deviations from the unperturbed crystal lattice such as surfaces, interfaces or vacancies often lead to a negative electric potential well trapping the positron. Annihilation with an electron from the nearest neighborhood of the defect allows conclusions about sizes, abundance and chemical surrounding of the defect. For that purpose, either the energy of the annihilation line or the life-time of the positron is measured. |
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Schematic represaentation of the AIDA setup functions. |
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Methods
- Ion irradiation
- Corrosion simulations
- Gas loading
- X-ray photoelectron spectroscopy (XPS)
- Positron-annihilation spectroscopy (PAS) at ELBE
- Nuclear reaction Analysis at IBC
- Resistometry
- Raman spectroscopy
- SQUID-Magnetometry
AIDA set-up
AIDA combines ion implantation, thin film deposition, heating/cooling, positron annihilation spectroscopy as well as resistometry in one vacuum chamber. XPS and gas loading take place without breaking the vacuum. Moreover, ex-situ characterisation methods are available. AIDA consists of two different setups:
AIDA-I (system working):
- Doppler broadening spectroscopy at the monoenergetic positron beam SPONSOR.
- Standard sample size: 10 x 10 x 0.5 mm
- Base pressure: 10-8 mbar
- Temperature range at sample holder: 50...1200 K
- Ions: Prevac Ion source, noble gases, N, O, H, with ion current densities up to 200 μAcm-2 and energies from 1 eV to 5 keV
- Deposition: Prevac rod-evaporator for metals Fe, Co, Ni, Au, Ag, Cr, Pt, Mo, rate: 0.1-0.5 Å/s, controlled by quartz microbalance
- Positron beam: Radioisotope source 22Na, energy: 30 eV – 36 keV, beam diameter: d ~ 4 mm, energy resolution: (1.09 + 0.01) keV at 511 keV
- Detectors: 2 Germanium detectors for coincidence Doppler-broadening spectroskopy
- Resistometer: 4-point probe
AIDA-II (in the commissioning phase):
- Nuclear reaction Analysis at IBC or
- Positron life-time spectroscopy at the monoenergetc positron beam MePS.
- Standard sample size: 10 x 10 x 0.5 mm
- Base pressure implantation chamber: 10-8 mbar
- Base pressure implantation chamber: 10-8 mbar
- Temperature range at sample holder: 50...1200 K
- Ions: Drebit ion source, noble gases, N, O, H, with ion currents up to 20 mA and energies from 2 keV to 30 keV
- Deposition: Prevac rod-evaporator for metals Fe, Co, Ni, Au, Ag, Cr, Pt, Mo, rate: 0.1-0.5 Å/s, controlled by quartz microbalance
- High pressure: Prevac Flow Through High Pressure Reactor, e.g. for H2, temperature range from 77K to 923 K, maximum pressure (static mode): 20 bar
- Positron beam: On-line lifetime spectroscopy, unique time structure: bunch length ~200ps, repetition rate up to 13 MHz, energy: 2...10 keV
- Detectors: CeBr3 scintillation detectors for lifetime spectroscopy
- Resistometer: 4-point probe
Funding
The research infra-structure for AIDA was funded by the german Helmholtz-Association within the Helmholtz Energy Materials Characterization Platform. Gefördert durch: Bundesministerium für Wirtschaft und Energie aufgrund eines Beschlusses des Deutschen Bundestages. Förderkennzeichen 03ET7015. Hinweis: Die Verantwortung für den Inhalt dieser Veröffentlichung liegt beim Autor.
The pre-stage system of AIDA was funded by the Impulse- und Networking fund of the Helmholtz-Association. (FKZ VH-VI-442 Memriox).