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summary=Optical Spectrometer| | summary=Optical Spectrometer| | ||
image=Tek7J20.jpg| | image=Tek7J20.jpg| | ||
caption=Tektronix 7J20 in 7633 mainframe| | caption=Tektronix 7J20 in [[7633]] mainframe| | ||
introduced=1975 | | introduced=1975 | | ||
discontinued=1976 | | discontinued=1976 | | ||
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}} | }} | ||
The '''Tektronix 7J20''' is | The '''Tektronix 7J20''', which only appears in the 1975 catalog, is a "rapid scan" optical spectrometer for the 250 nm to 1100 nm region. | ||
Rapid scan means that it can capture the spectrum quickly enough to show spectral changes at temporal resolution of a few milliseconds. | |||
The instrument is based on a [https://en.wikipedia.org/wiki/Monochromato Czerny-Turner Monochromator], | |||
in essence a narrow slit followed by a [https://en.wikipedia.org/wiki/Diffraction_grating diffraction grating]. | |||
A [https://en.wikipedia.org/wiki/Vidicon vidicon tube] scans the optical spectrum and produces a periodic electric signal which is then displayed by the scope mainframe. | |||
[[File:7J20-principle.jpg | thumb | 400px | center | Operating principle (click to enlarge) ]] | |||
The 7J20 is very rare. According to Dennis Tillman, ''Best estimate is ~40 were actually built.'' | |||
{{BeginSpecs}} | |||
{{Spec | Spectral range | 250 nm to 1100 nm }} | |||
{{Spec | Resolution (Grating A) | ≤4 nm in a 400 nm span (selectable 300-700, 400-800, 500-900, 600-1000, or 700-1100 nm }} | |||
{{Spec | Resolution (Grating B) | ≤0.4 nm in a 40 nm span continuously variable through the spectral range }} | |||
{{Spec | Slit | 10 to 5000 μm wide (1-2-5 sequence), 10 mm high }} | |||
{{Spec | Filters | ND1, ND 2, 500 nm monopass, 800 nm monopass, UV block (≤400 nm), UV pass (250-330 nm), open (no filter) }} | |||
{{Spec | Scan | 10 or 20 ms base sweep, 50 to 1000 ms (1-2-5) settings run successive 20 ms sweeps up to the selected integration time }} | |||
{{Spec | Display span | Grating A, 40, 20, 10 or 4 nm/Div ; Grating B, 4, 2, 1 or 0.4 nm/Div }} | |||
{{EndSpecs}} | |||
== | ==Price== | ||
$12,000 in 1975 ($55,000 equivalent in 2017) | |||
==Pictures== | ==Pictures== | ||
<gallery> | <gallery> | ||
Tek7J20.jpg | Tek7J20.jpg | 7J20 in [[7633]] mainframe | ||
</gallery> | </gallery> | ||