Forrest Frank Hopkins

Towards brilliant, compact x-ray sources: a new x-ray photonic device

General Electric has designed an innovative x-ray photonic device that concentrates a polychromatic beam of diverging x-rays into a less divergent, parallel, or focused x-ray beam. The device consists of multiple, thin film multilayer stacks. X-rays incident on a given multilayer stack propagate within a high refractive index transmission layer while undergoing multiple total internal reflections from a novel, engineered multilayer containing materials of lower refractive index. Development of this device could lead to order-of-magnitude flux density increases, over a large broadband energy range from below 20 keV to above 300 keV. In this paper, we give an overview of the device and present GE’s progress towards fabricating prototype devices.

Simulation of Electron Beam Heating of a Cu Thin Film on a Si Substrate

Electron beam interaction with thin films is a critical phenomenon in applications such as nanostructure fabrication, surface treatment and curing, surface sterilization, scanning electron microscopy, and electron beam lithography. Unlike bulk solids, thin films whose thickness is on the same order of magnitude as the penetration depth require consideration of interface effects: namely resistance to heat transfer and more electron scattering. In such cases, the energy deposition profile, the location of interfaces and the associated change in material properties must be accounted for. In this paper we describe the thermal simulation of a thin copper film (0.5 μm, 1 μm, 2μm) on a Si substrate irradiated by an electron beam (10 keV, 20 keV, 40 keV). We explore the effect of the interface position relative to the electron range and the local heating effects associated with continuous or long pulse beams.Copyright