Secondary tungsten sources

Sensitivity is specified by baseline noise. For years, noise specification has been benchmarked at 1.0 x 10 absorbance unit (AU) (Figure 4.9b). A wavelength range of 190-600 nm is typical, though sensitivity is substantially lower >400 nm due to a lack of energy of the deuterium source in the visible region. Many detectors allow a secondary tungsten source to increase sensitivity in... 

I. Raw Materials [5.1,5.2,5.6]. There exist three different types of tungstenbearing materials which are currently in use as raw materials for APT production scheelite ore concentrates and wolframite ore concentrates are the primary sources, and various tungsten-containing scrap materials act as secondary sources. 

Sodium and lithium Both sodium [15] and lithium [16] electrodeposition was successful in neutral chloroaluminate ionic liquids that contained protons. These elements are interesting for Na- or Li-based secondary batteries, where the metals would serve directly as the anode material. The electrodeposition is not possible in basic or acidic chloroaluminates, only proton-rich NaQ or LiQ buffered neutral chloroaluminate liquids were feasible. The protons enlarged the electrochemical window towards the cathodic regime so that the alkali metal electrodeposition became possible. For Na the proton source was dissolved HQ that was introduced via the gas phase or via 1-ethyl-3-methylimidazolium hydrogen dichloride. Triethanolamine hydrogen dichloride was employed as the proton source for Li electrodeposition. For both alkali metals, reversible deposition and stripping were reported on tungsten and stainless steel substrates, respectively. 

Other sources are incandescent electric lamps (tungsten), the Welsbach mantle, hot glass, and the quartz-jacketed high-pressure mercury arc. The tungsten ribbon filament lamp makes a good secondary standard (compared to a primary blackbody) in the near... 

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