K. J. Long

Bio: K. J. Long is an academic researcher. The author has contributed to research in topics: Crystallographic defect & Electron paramagnetic resonance. The author has an hindex of 2, co-authored 2 publications receiving 319 citations.

Fundamental defect centers in glass: Electron spin resonance and optical absorption studies of irradiated phosphorus‐doped silica glass and optical fibers

Abstract: Defect centers induced by ionizing radiation (50–100‐keV x rays, 60Co γ rays) in high purity P‐doped silica glass have been observed and elucidated by ESR spectroscopy. Four generic species are well characterized on the basis of the observed 31P hyperfine splittings and g values as defects analogous to PO2−3 (phosphoryl), PO4−4 (phosphoranyl), PO2−2 (phosphinyl), and PO2−4 radicals. The latter species, also termed the phosphorus‐oxygen‐hole center (POHC), is shown to occur in two variants comprising holes trapped on one or two nonbridging oxygens. Radiation‐induced Si E′ centers with and without P next‐nearest‐neighbors were also identified, and a singlet resonance S due to E′ type defects such as (OSi2)Si⋅ and/or (O2Si)Si⋅ was observed to grow in with annealing above ∼800 K, regardless of whether or not the sample was irradiated. The structures, formation mechanisms, and precursors of these defects have been determined or inferred for all centers. Radiation‐induced optical absorption spectra over the ran...

A review of electron spin spectroscopy and its application to the study of paramagnetic defects in crystalline quartz

Abstract: A comprehensive review (ca. 230 references) is presented of the present (1983) state of knowledge of paramagnetic defects in crystalline quartz, as derived from electron paramagnetic resonance spectroscopy and related techniques. An auxiliary description of relevant concepts in solid state electron paramagnetic resonance (EPR), suitable for the non-specialist, is included. The centres described include those arising from impurity ions (Al, H, Cu, Ag, Ge, P, Ti, Fe) as well as those (E′) associated with oxygen ions missing in the quartz structure. Emphasis is placed on the structural information derivable from EPR. A brief survey of the present state of understanding of the optical bands caused by the defects is also given.

Radiation effects in glasses used for immobilization of high-level waste and plutonium disposition

Abstract: This paper is a comprehensive review of the state-of-knowledge in the field of radiation effects in glasses that are to be used for the immobilization of high-level nuclear waste and plutonium disposition. The current status and issues in the area of radiation damage processes, defect generation, microstructure development, theoretical methods and experimental methods are reviewed. Questions of fundamental and technological interest that offer opportunities for research are identified.

Radiation Effects on Silica-Based Optical Fibers: Recent Advances and Future Challenges

Abstract: In this review paper, we present radiation effects on silica-based optical fibers. We first describe the mechanisms inducing microscopic and macroscopic changes under irradiation: radiation-induced attenuation, radiation-induced emission and compaction. We then discuss the influence of various parameters related to the optical fiber, to the harsh environments and to the fiber-based applications on the amplitudes and kinetics of these changes. Then, we focus on advances obtained over the last years. We summarize the main results regarding the fiber vulnerability and hardening to radiative constraints associated with several facilities such as Megajoule class lasers, ITER, LHC, nuclear power plants or with space applications. Based on the experience gained during these projects, we suggest some of the challenges that will have to be overcome in the near future to allow a deeper integration of fibers and fiber-based sensors in radiative environments.

Method for Manufacturing Semiconductor Device

Abstract: An object is to provide a method for manufacturing a semiconductor device, in which the number of photolithography steps can be reduced, the manufacturing process can be simplified, and manufacturing can be performed with high yield at low cost A method for manufacturing a semiconductor device includes the following steps: forming a semiconductor film; irradiating a laser beam by passing the laser beam through a photomask including a shield for shielding the laser beam; subliming a region which has been irradiated with the laser beam through a region in which the shield is not formed in the photomask in the semiconductor film; forming an island-shaped semiconductor film in such a way that a region which is not irradiated with the laser beam is not sublimed because it is a region in which the shield is formed in the photomask; forming a first electrode which is one of a source electrode and a drain electrode and a second electrode which is the other one of the source electrode and the drain electrode; forming a gate insulating film; and forming a gate electrode over the gate insulating film