Positron annihilation Doppler broadening measurement for bulk amorphous alloy by using high energy positron generated from LCS gamma-ray at NEW SUBARU

Gamma-induced positron spectroscopy for bulk materials using a MeV energy LCS gamma-ray beam

“…6, the Doppler spectrum of the amorphous sample is more sharply peaked than that of crystal one. This result also agrees well with the result using the fast positron beam [4]. Also, this result corresponds to the result of density measurement [21].…”

“…6 shows the normalized Doppler profiles of the amorphous and crystallized alloys. In this measurement, more than 2.3 × 10 5 counts in the annihilation gamma-ray photon peak were collected for each sample with an accumulation time of 9000 s. This measurement time is about half the time required for our previous fast positron beam experiment on the same samples [4]. This increase in count rate is because there is no loss of generated positrons and almost of them are annihilated in the sample.…”

“…One of these samples is crystallized by annealing at 500 • C for one hour. The structure of these samples was analyzed by X-ray diffraction measurement with Cu-Kα [4]. The density of the samples was measured to be 6.83 g/cm 3 for the amorphous sample and 6.88 g/cm 3 for the crystal sample by the Archimedes method.…”

“…Another method is positron and electron generation via pair creation from a highly energetic photon. In our previous study, we developed a high-energy (∼MeV) or fast positron beam apparatus for bulk materials by positron generation from highly energetic photons at the NewSUBARU synchrotron radiation facility LASTI, University of Hyogo, Japan [3,4]. The use of a fast positron beam has some advantages in PAS.…”

Measurements of Neutrons from Photonuclear Reactions Using Laser Compton Scattering Gamma Rays

“…For example, when we use a collimator with a diameter of 3 mm at a distance of 17 m from the scattering point, the energy spread of the gamma ray beam is approximately 3% for an electron energy of 1-GeV. Over the past few years, this gamma ray beam source has been used for research in various fields such as nuclear transmutation for nuclear waste disposal [7][8][9], useful radio-isotope generation [10,11], nuclear physics studies [12][13][14][15][16], nuclear astrophysics studies [17], positron generation and application to non-destructive inspections of materials [18,19], and detector tests via a high-energy polarized photon beam [20].…”