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History and background
Published in Andrea Chen, Randy Hsiao-Yu Lo, Semiconductor Packaging, 2016
Andrea Chen, Randy Hsiao-Yu Lo
Simply put, a semiconductor package is a semiconductor chip enclosed or encapsulated to assure environmental protection, and it provides for a reliable means of interconnection to the next level of integration. The package is dubbed the first level of packaging, with the circuit board being the second level and the final enclosure the third level.
Radiation protection evaluation and spontaneous discharge performance of betavoltaic tritium batteries using well-aligned titanium dioxide nanotube arrays
Published in Radiation Effects and Defects in Solids, 2023
Yi-Sin Chou, Yu-Chang Liu, Yu-Zhen Zeng, Shi-Chern Yen
Control rods are used in nuclear reactors to control the fission rate of nuclear fuel (uranium or plutonium) that can absorb many neutrons without decaying on their own. Selected elements have different neutron capture cross sections for neutrons of different energies (14). The Chernobyl nuclear power plant is a graphite water-cooled reactor. The fuel rods are placed in a graphite buffer to slow down the neutrons and maintain the chain reaction, and the control rods control the power produced by the reactor. Using graphite as a neutron absorber is inefficient compared to chemical elements such as boron, cadmium, silver, hafnium or indium (15). C-14 comes from an abandoned nuclear reactor with activated graphite moderator around the fuel rods. It was originally used as a neutron retarder (16). Moreover, C-14 can also be produced by using other materials through electron beam irradiation (17). C-14 has become a common main radiation source used in nuclear batteries. Prototype cells for Nanodiamond Batteries (NDBs) were first presented at the University of Bristol’s annual lecture (18). The battery is equipped with a semiconductor package C-14, using waste graphite containing C-14, combined with general carbon materials (19). The beta particles of C-14 contain very low radiation intensity, and the periphery is covered with non-radioactive synthetic diamond material. Therefore, there is no risk of radiation leakage, and the radiation dose is even lower than that of a banana (20). Common nuclear power plants, such as boiling water reactor (BWR), pressurized water reactor (PWR), and heavy water reactor (HWR), operate using thermal neutrons. Graphite is less used as a control rod materials for nuclear reactors, so not much C-14 radioactive waste is produced (21).