Backscattering of MeV Electrons. An Analysis of Tabata’s Experiment with Geant4.

A series of simulations were conducted with Geant4 in order to verify the electron backscattering experiments performed by Tabata in the low Z elements of Be, C, and Al. In general, quite good agreement was obtained by carefully choosing the physics lists employed. These results invalidate the claim made before about the presence of experimental errors in the above work.

New measurement of the β-spectrum of 210Bi with a silicon 4πβ-spectrometer

The shape of 210Bi β-spectrum was measured using a spectrometer based on Si(Li) detectors with a 4π geometry. Full absorption spectrometer allows for a direct measurement of the β-spectra without using the electron backscattering corrections for the response function. The measured value of nuclear shape factor C(W)=1+(-0.4378±0.0072)W+ (0.0526±0.0021) W2 is in agreement with the results of previous studies.

Alkali-silica reaction (ASR) - Investigation of crystallographic parameters of natural sands by backscattered electron diffraction

abstract: This study involved analyzing several natural sands to ascertain the possible causes for distress due to ASR. The analyses were performed using the following techniques: X-ray diffractometry, accelerated mortar bar tests (AMBT), electron backscattering diffraction and elementary chemistry analyses, by FEG-SEM/EBSD/EDS. These experiments allowed identifying the presence of several mineral composites (such as microcline, anorthite, among others), as well as the microstructural-crystallographic planes of quartz (such as the Dauphiné type). From the results it could be inferred that the multiple techniques used, especially the FEG-SEM / EBSD, proved to be promising in the analysis of the ASR potential of sands for use in Portland cement mortars and concretes.