New design of the CDB-spectrometer at NEPOMUC for T-dependent defect spectroscopy in Mg

Surface and bulk investigations at the high intensity positron beam facility NEPOMUC

“…In particular for CDB-measurements on Mg-based alloys and ion irradiated Mg-samples we refer to Ref. [9]. Recently performed DB-studies on layered samples are presented in Ref.…”

Interrelation between mechanical response, strain field, and local free volume evolution in glassy polymers: Seeking the atomistic origin of post-yield softening

“…NEPOMUC holds a universal record in providing one of the highest intensity, slow positron beams of around 10 9 moderated positrons per second with a primary beam energy of 1 keV [28,31,32]. The positron beam is guided into the Doppler-broadening spectrometer and focused onto the sample with a beam diameter of around 250 μm [33,34]. In order to image the lateral distribution of the (nano-)voids in the sample, a region of typically 50-100 mm 2 was scanned with 30 keV beam energy.…”

Characterization of ion-irradiated ODS Fe–Cr alloys by doppler broadening spectroscopy using a positron beam

“…diffusion effects occurring at 600°C may significantly broaden the implantation widths. The Doppler spectrometer allows us to record the annihilation photo-peak at different positron implantation energies up to 30 keV [33]. The positron beam diameter and the beam intensity at the sample were fixed using a 2 mm aperture.…”