21 research outputs found
Recommended from our members
The Development of a Hibachi Window for Electron Beam Transmission in a KrF Laser
In support of Inertial Fusion Energy (IFE), a 150 {micro}m thick silicon (Si) wafer coated on one side with a 1.2 {micro}m nanocrystalline diamond foil is being fabricated as an electron beam transmission (hibachi) window for use in KrF lasers. The hibachi window separates the lasing medium from the electron beam source while allowing the electron beam to pass through. The hibachi window must be capable of withstanding the challenging environment presented in the lasing chamber, which include: fluorine gas, delta pressure >2 atm at 5 Hz, and a high heat flux due to the transmission of electrons passing through the foil. Tests at NRL/Electra and at PPPL have shown that a device employing these novel components in the stated configuration provide for a robust hibachi window with structural integrity
Thermal annealing recovery of intersubband transitions in proton-irradiated GaAs/AlGaAs multiple quantum wells
Intersubband transitions in 1 MeV proton-irradiated GaAs/AlGaAs multiple quantum wells were studied using an optical absorption technique and isochronal thermal annealing. The intersubband transitions were completely depleted in samples irradiated with doses as low as 4 × 1014 cm-2. More than 80% recovery of these depleted transitions was achieved after the samples were thermally annealed at temperatures less than 650°C. The total integrated areas and peak position energies of the intersubband transitions in irradiated and unirradiated samples were monitored as a function of annealing temperature. It was noted that the recovery of the depleted intersubband transitions in irradiated samples depend on the irradiation dose and thermal annealing temperature
Recommended from our members
Development of a Silicon Based Electron Beam Transmission Window for Use in a KrF Excimer Laser System
The Princeton Plasma Physics Laboratory (PPPL), in collaboration with the Naval Research Laboratory (NRL), is currently investigating various novel materials (single crystal silicon, , and ) for use as electron-beam transmission windows in a KrF excimer laser system. The primary function of the window is to isolate the active medium (excimer gas) from the excitation mechanism (field-emission diodes). Chosen window geometry must accommodate electron energy transfer greater than 80% (750 keV), while maintaining structural integrity during mechanical load (1.3 to 2.0 atm base pressure differential, approximate 0.5 atm cyclic pressure amplitude, 5 Hz repetition rate) and thermal load across the entire hibachi area (approximate 0.9 W centre dot cm superscript ''-2''). In addition, the window must be chemically resistant to attack by fluorine free-radicals (hydrofluoric acid, secondary). In accordance with these structural, functional, and operational parameters, a 22.4 mm square silicon prototype window, coated with 500 nm thin-film silicon nitride (Si sub 3 N sub 4), has been fabricated. The window consists of 81 square panes with a thickness of 0.019 mm +- 0.001 mm. Stiffened (orthogonal) sections are 0.065 mm in width and 0.500 mm thick (approximate). Appended drawing (Figure 1) depicts the window configuration. Assessment of silicon (and silicon nitride) material properties and CAD modeling and analysis of the window design suggest that silicon may be a viable solution to inherent parameters and constraints