Positron annihilation diagram

I peak-effects, physical and magnetic phase diagrams) -Raman, IR spectra -neutron diffraction -specific heat -thermal conductivity -positron annihilation (fundamental superconducting parameters, BCS theory)... 

In particular, the most powerful method for studing lattice defects, due to the high sensitivity of positrons to open volume defects such as vacancies, vacancy clusters, voids, dislocations, grain boundaries, etc., is positron annihilation spectroscopy (PAS). A diagram illustrating the applicability of PAS and other techniques as a function of defect size and density versus depth in material is shown in Figure 4.25. Thus, PAS represents a non-local experimental technique that is sensitive to microstructural defects at the atomic scale. A well-established theory of positron annihilation phenomena is currently available. Especially for metallic materials, it is possible to perform ab initio calculations of positron parameters for various defects and atomic arrangements [72,73]. 

Figure 13-8 Schematic diagram of a PET imaging system with multiple scintillation detectors that localize the positron decay along a tine. By using multiple position-sensitive detectors around the patient, the annihilation photons are acquired along many parallel lines and many angles simultaneously with four rings of deteaors (only one ring shown). After use of reconstruction algorithms, the internal distribution of the radioactivity can be determined and displayed on a cathode ray tube.

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