Energetic Heavy Ion Irradiation Research Articles

Heavy ion tracks in polycarbonate. Comparison with a heavy ion irradiated model compound (diphenyl carbonate)

The chemical modifications induced by energetic heavy ion irradiation of polycarbonate (PC) film are determined by GPC, HPLC, ESR, TGA, IR and UV spectrophotometry. The main results of the irradiation are creation of radicals, chain scission, cross-linking and appearance of new chemical groups in the main polymer chain. As far as the creation of new groups is concerned, they are determined by means of a model compound of PC: the diphenyl carbonate (DPC). The following compounds are identified after energetic heavy ion irradiation of DPC: salicylic acid, phenol, 4,4'-biphenol, 2,4'-biphenol, 2,2'-biphenol, 4-phenoxyphenol, 2-phenoxyphenol, phenyl ether, phenyl benzoate, phenyl salicylate, 2-phenylphenol and 2-phenoxyphenyl benzoate. A similarity between the heavy ion irradiation and a heat treatment has also been established with DPC. On the basis of these results, we try to give an explanation of the preferential attack along the tracks of the irradiated film. Also, an explanation of the well-known beneficial effect of an UV exposition of the irradiated film on the selectivity of this preferential chemical attack is suggested.

Energetic Heavy-Ion Irradiation Effects Studied by Mössbauer Spectroscopy

Energetic Heavy-Ion Irradiation Effects Studied by Mössbauer Spectroscopy

Ion beam mixing of [formula omitted] and [formula omitted] multilayers

We have submitted bilayers of La(OH) 3 Cu and multilayers of La(OH) 3 SrOCu to energetic heavy ion irradiation at 300 K and 700 K in order to investigate the possibility of preparing La 2CuO 4 and (La 1 − xSr x) 2 CuO 4 through the ion beam mixing technique. For comparison purposes, similar samples were annealed at 700 K. Results are given concerning the modification of the atomic compositions (La, Sr, Cu, O and H), the atomic depth distributions, the compound formation, induced either by irradiation or by thermal annealing. The specific role of the ion beam mixing process is emphasized.

Radiation-induced disordering and amorphization—An in situ HVEM study of uranium silicide with comparison to natural processes in zirconolite

We present here results of in situ TEM diffraction observations of the response of U3Si and U3Si2 when subjected to 1 MeV electron irradiation or to 1.5 MeV Kr ion irradiation, and observations of damage occuring in natural zirconolite. High energy electron irradiation or energetic heavy ion irradiation were performed in situ at the HVEM-Tandem User Facility at Argonne National Laboratory. In this Facility, a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter have been interfaced to a 1.2 MeV AEI high voltage electron microscope. This allows a wide variety of in situ experiments to be performed with simultaneous ion irradiation and conventional transmission electron microscopy. During the electron irradiation, the electron beam was focused to a diameter of about 2 μ.m at the specimen thin area. The ion beam was approximately 2 mm in diameter and was uniform over the entire specimen. With the specimen mounted in a heating holder, the temperature increase indicated by the furnace thermocouple during the ion irradiation was typically 8 °K.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

Stability of cascade clusters in gold under energetic heavy ion irradiation

Abstract Energetic heavy ion irradiation has been used as a simulation technique for high energy cascade formation in fusion reactor materials irradiated with 14 MeV neutrons. In the present study, the stability of cascade cluster formation in gold under heavy ion irradiation is investigated using an ‘in-situ observation’ facility. Cascade clusters are observed to form instantaneously in gold during elevated temperature irradiation. These clusters are found to be vacancy type and annihilate with short lifetimes. Cascade overlap is believed to cause relatively large loop formation. The number of subclusters in a cascade is decreased at higher temperatures. About 5% of the incident particles produce visible defect clusters (or cluster groups) at 670 K. Defect accumulation processes are also analyzed by simple formulae.

Highly Energetic Heavy Ion Irradiation Effects in Ferrites

Highly Energetic Heavy Ion Irradiation Effects in Ferrites