[en] Nuclear Reaction Analysis (NRA) using the ¹⁹F(p,αγ)¹⁶O resonance reaction is a powerful method of fluorine depth profiling. We have used this method to study the fluorine uptake phenomenon in mineral flint, which could potentially develop into a method of dating archeological flint artifacts. Flint samples cut with a rock saw were immersed in aqueous fluoride solutions for different times for the uptake study. The results suggest that fluorine uptake is not a simple phenomenon, but rather a combination of several simultaneous processes. Fluorine surface adsorption appears to play an important role in developing the fluorine profiles. The surface adsorption was affected by several parameters such as pH value and fluorine concentration in the solution, among others. The problem of surface charging for the insulator materials during ion bombardment is also reported

[en] The M-shell x-ray production cross sections for thorium and uranium have been measured for carbon ions with energies from 4.5 to 11.3 MeV with the charge state q increasing from 2 to 4, and oxygen ions with energies from 4.5 to 13.5 MeV with the charge state q increasing from 2 to 5. These cross sections are compared to the predictions of the first Born (PWBA+OBKN) and ECUSAR ionization theories, which were evaluated in a novel manner for the C^+q and O^+q energies and charge states of the data and converted to x-ray production cross sections with atomic parameters for a singly ionized M-shell and multiple ionization in the outer shells. Individual groups of M-shell transitions are also compared to the two ionization theories. The ECUSAR theory is shown to describe the measurements better than the first Born approximation. It is found to be in generally good agreement for all the total M-shell x-ray production and M-shell lines except for the Mγ cross sections. Reasons for the overestimation of the Mγ data are discussed. (paper)

[en] M-shell x-ray production cross sections for thorium and uranium have been determined for protons of energies 0.4-4.0 MeV and helium ions of energies 0.4-6.0 MeV. The M-shell line and total M-shell x-ray production cross sections are compared to the predictions of the first Born approximation and ECUSAR ionization theory using recently recommended atomic parameters. Both theories are in good agreement with the data for protons and He ions above 1 MeV. The data of others for energies above 1 MeV protons on uranium, however, fall significantly under the present measurements. Below 1 MeV, with decreasing energy of these projectiles, the first Born approximation increasingly overestimates our measurements while the ECUSAR theory underestimates them to a similar degree. The same trends are seen versus the data of others.

[en] In this work we demonstrate that the defects that are created by 2-MeV Si ions can interact with dopant atoms both during implantation and during post-implant annealing. We show that the interstitials and vacancies created during MeV Si implantation result in a radiation enhanced diffusion of B and Sb markers, respectively, when the temperature of implantation is above the threshold temperature for formation of mobile dopant complexes. With the use of these dopant markers we also demonstrate that a vacancy-rich near surface region results during post-implant annealing of MeV implanted silicon. The depth distribution and the thermal evolution of clustered vacancies was measured by a Au labeling technique

[en] As feature sizes of Integrated Circuits (ICs) continue to shrink, the sensitivity of these devices, particularly SRAMs and DRAMs, to natural radiation is increasing. In this paper, the Ion Beam Induced Charge Collection (IBICC) technique is utilized to simulate neutron-induced Si recoil effects in ICs. The IBICC measurements, conducted at the Sandia National Laboratories, employed a 10 MeV carbon microbeam with 1μm diameter spot to scan test structures on specifically designed ICs. With the aid of IC layout information, an analysis of the charge collection efficiency from different test areas is presented