Evaluation Of Radiation Effects Research Articles

Evaluation of irradiation effects on the microstructure and properties of Ag-sheathed Bi-2212 superconducting round wire for future application in CFETR

The Chinese Fusion Engineering Test Reactor (CFETR) is designed to build a fusion engineering Tokamak reactor generating fusion power of 200–1500 MW, and to test the breeding tritium during fusion reaction. This may require a maximum magnetic field up to 15 T in the central solenoid and toroidal field coils. New superconducting materials should be developed for satisfying the next-generation fusion reactors with critical requirements. Recently, Bi2Sr2CaCu2Ox (denoted as Bi-2212) is considered as one of the most promising potential superconductors to be used as the magnets in CFETR, however, they will be subjected to harsh irradiation under operating conditions. The irradiation effects of the high-energy helium ions on the Ag-sheathed Bi-2212 superconducting round wire have been explored for the first time in this work. The microstructure and the critical current at 4.2 K of the superconducting wire before and after irradiation have been carefully investigated. Room-temperature x-ray diffraction (XRD) profiles showed that all the peaks shifted rightward significantly with a broadened (111)Ag peak, indicating that the high-energy He+ irradiation resulted in appreciable defects and strain in the superconducting wire. Meanwhile, the in-situ high-temperature XRD tests showed that the lattice constant and the thermal expansion coefficient were deduced in the irradiated sample to be due to the presence of the generated defects. After irradiation, the grain size of the Ag sheath was refined, and the lattice of Bi-2212 superconductor was distorted obviously, as confirmed by transmission electronic microscopy. The critical current IC at 4.2 K of the superconducting wires in the field of 0–12T determined by the four-probe technique, decreased substantially after irradiation because of the lattice distortion and the consequently induced strain in the Bi-2212 superconductor. This work provides a solid basis for evaluating and understanding the irradiation effects upon the Ag-sheathed Bi-2212 superconducting wire, more promising for future application in CFETR.

Inside Cover: In situ diode laser fenestration: An ex‐vivo evaluation of irradiation effects on human aortic tissue (J. Biophotonics 9/2019)

The laser technology can be successfully used for the intraoperative modification of an endograft during the endovascular aneurysm repair procedure. This paper presents the first diode laser irradiation study to assess whether the laser operative conditions, which ensure the fabric alteration, are harmless for the biological tissue surrounding the endoprosthesis. The work provides a microscopic and histological evaluation of its effects on ex‐vivo human aortic tissue.Further details can be found in the article by Roberta Piazza, Filippo Micheletti, Sara Condino, et al. (e201900032). image

Structural behavior of β-thorium phosphate diphosphate (β-TPD) irradiated with ion beams

β-thorium phosphate diphosphate ceramic (β-TPD), β-Th 4(PO 4) 4P 2O 7, was proposed as a potential actinide-bearing phase for nuclear waste storage. Self-irradiation by α-decays, due to the actinide loading, could affect the good intrinsic performances of this material. The evaluation of irradiation effects on the chemical durability of the ceramic is a crucial issue. Radiation effects were simulated by external ion beam irradiations. Under high-energy ion irradiation, amorphization was achieved above a critical threshold for electronic energy loss ( S e = 5 MeV μm −1). Thermal annealing enables to fully recover the initial crystalline structure after heating for 15 h above 973 K. Amorphization appears thus completely reversible. The activation energy of annealing is equal to 2.8 eV. Ion beam induced amorphization and recrystallization by thermal annealing were found to be isotropic processes. Irradiations in the nuclear stopping regime lead to a complete amorphization of β-TPD at a critical dose of 0.2 dpa.

Neuroradiology of Brain Stem and Cervicomedullary tumours

Brain stem and cervicomedullary tumours are typical of paediatric age, 80% of them occurring in patients under 18 years of age, and comprising 10–15% of all childhood and adolescent brain tumours, as well as 20–25% of infratentorial locations.They are characteristically pontine tumours (60% of the cases), but they commonly extend to involve the medulla, midbrain and cerebellum. Although most brain stem tumours are low grade gliomas, their prognosis is extremely severe (no more than 20% of patients are alive 3 years after diagnosis and the 5-year survival rate is 5%) because both the typical infiltrating nature and the neuro-anatomical location usually make them surgically unresectable. Surgery is generally limited to biopsy, partial decompression, or excission of the exophytic components, because of the extremely severe functional sequelae of even minor resections. Thus, the mainstay of therapy has been based on irradiation alone or combined with chemotherapy, doses of 5000–5500 cGy being usually adequate...

Biserm, Neutron and Proton Data Library for Evaluation of Irradiation Effects in Structural Materials in the Energy Range Up to 800 Mev

A library of cross-sections BISERM has been developed for the analysis of radiation damage sensitivity of nuclear power plant structural materials irradiated by nucleons of energies up to 800 MeV. ...

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