Hydrogen detection near surfaces and shallow interfaces with resonant nuclear reaction analysis

Nuclear resonant reaction analysis techniques for hydrogen depth profiling in solid materials typically have used15N ion beams at 6.40 MeV and19F ion beams at 6.42 MeV, which require a tandem accelerator. We report a new technique using an18O ion beam at a resonance energy of 2.70 MeV, which requires only a single stage accelerator. Improved values of the nuclear parameters for the 2.70 MeV (18O) and 6.40 MeV (15N) resonances are reported. The beam energy spread was investigated for different ions and ion charge states and found to scale with the charge state. Data obtained using atomic and molecular gas targets reveal the research potential of Doppler spectroscopy. Examples of hydrogen depth profiling in solid materials using15N and18O ion beams are presented.

Hydrogen depth profiling using 18 O ions

Nanoparticles, which range in size from 1 to 100 nm in at least one dimension, exhibit unique physicochemical properties that are dependent upon their size, shape, dispersion, surface functionalization or de-functionalization, and binding with biomembranes and proteins. Because the size effects are exponential, a minor change in a nanoparticle's structure may cause major alterations in their properties. Bulk materials (>500 nm), on the other hand, have constant physical properties regardless of their size or shape. It is well established that the biological activity of nanoparticles depends upon their physicochemical properties and size. Therefore, an accurate determination of a nanoparticle's size and properties is a prerequisite for controlling its biological properties and/or stability. This chapter elucidates some of the methods commonly used for nanoparticle characterization.

Chapter 4 – Experimental Methodologies for the Characterization of Nanoparticles

The manuscript reviews several selected applications of Activation Analysis that differ from classical laboratory measurements by the fact that they do not require sampling of the analysed object and/or measurements under analytical laboratory conditions. One of great advantages of the Activation Analysis lies in its versatility that allows it to be applied under conditions not available for other analytical techniques.

Non-classical applications of chemical analysis based on nuclear activation

A γ-ray detection system with nearly 4π geometry for applications in materials science is described. The energy resolution of the NaI(Tl)-bore hole detector was found to be about 2% for 10 MeV γ-rays. The total detection efficiency has been determined to be above 80% for γ-energies between 0.5 and 20 MeV. A precision of the efficiency calibration of about 2% has been obtained for a wide range of γ-energies. The experimental results were found to be in excellent agreement with computer simulations using the GEANT computer code. The high efficiency of the system combined with its relatively high energy resolution opened a wide range of applications. Examples are the simultaneous detection of light isotopes in thin films by (d,pγ) nuclear reactions, high depth resolution profiling of isotopes by narrow, low-energy resonances in (p,γ) reactions, and hydrogen profiling using the 6.4 MeV resonance in the 1H(15N,αγ)12C reaction.

Gamma-ray detection with a 4π NaI spectrometer for material analysis

High resolution depth profiling in near-surface regions of solids by narrow nuclear reaction resonances below 0.5 MeV with low energy spread proton beams

C Angulo

Papers

High resolution depth profiling in near-surface regions of solids by narrow nuclear reaction resonances below 0.5 MeV with low energy spread proton beams