Optical masks

A similar process uses a 30 cm. hollow cathode ion source with its optics masked to 10 cm. Argon is introduced to establish the discharge followed by methane in a 28/100 ratio of methane molecules to argon atoms. The energy level is 100 eV, the acceleration voltage 600 V, and the resulting deposition rate 0.5 to 0.6 im/ hour.t" ]... 

An alternative and general mode of determining the molecular weight of one constituent is to optically mask the other152,153. Thus, if i>B = 0, then any observed... 

Table 16. Molecular weights (MA) by LS of polymer A alone and in the presence of polymer B when the latter is optically masked by conditions wherein r>B = 0 or = 0...

Fused silica, Si02 9.0 Stepper optics, mask blanks... 

Photodiode arrays (PDAs) A spectrally segmented PDA spectrophotometer has also been developed. Radiation from the plasma is predispersed and transmitted through an optical mask prior to dispersion by an echelle grating onto a PDA. Limits of detection are similar to those obtained by conventional detection systems, except at low wavelengths where degradation has been observed. 

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