Positron annihilation lifetime spectroscopy (PALS) is a powerful tool for defect characterisation in a wide range of materials. To investigate inhomogeneous defect distributions, for example, near fatigue cracks or in dispersive alloys, with PALS, a monochromatic pulsed positron beam of variable energy with a diameter in the range of 1 µm and a pulse width of 200 ps FWHM is required. The Scanning Positron Microscope (SPM) has been developed for this purpose and was operated with a radioactive positron source in the laboratories at the University of the Bundeswehr. To overcome the limit of low count rates achievable with radioactive sources, the SPM is transferred to the intense positron source NEPOMUC at the MLZ in Garching within this work.     «

Positron annihilation lifetime spectroscopy (PALS) is a powerful tool for defect characterisation in a wide range of materials. To investigate inhomogeneous defect distributions, for example, near fatigue cracks or in dispersive alloys, with PALS, a monochromatic pulsed positron beam of variable energy with a diameter in the range of 1 µm and a pulse width of 200 ps FWHM is required. The Scanning Positron Microscope (SPM) has been developed for this purpose and was operated with a radioactive po...     »