14
VSC
®
80: Light sources (Vapour discharge tubes)
Mercury (Hg)
Wavelength (nm)
Vapour discharge tubes
Illumination modes: Reflected light sources (Spot lighting)
High intensity spot lighting sources are intended for the fluorescence examination of documents.
Differently coloured sources are available to suit the type of trace deposit sought. The sources may be
activated in any combination. An appropriate longpass filter must be used to view the fluorescence.
VSC
®
80: Reflected light sources: Spot lighting
Colour
Nominal wavelength (nm)
Bandwidth (10%)
Peak
Software control
Violet
395
– 440
410
Blue
420
– 485
445
Blue-Green
450
– 520
475
Cyan
475
– 535
500
Green
490
– 535
525
Orange
540
– 615
590
Red
600
– 655
640
Deep red
625
– 680
660
Far red
680
– 750
740
White
420
– 670
Vapour discharge tubes
Mercury vapour lamps
Vapour discharge lamps emit light with a narrow line spectrum that is characteristic of the vapour used.
Mercury vapour is suitable for producing emission at the wavelengths that are commonly used to excite
UV fluorescence: 313 nm (UV-B); 254 nm (UV-C). UV-B and UV-C sources are mounted behind
shortpass optical filters.
254
313
VSC
®
80: M ercury vapour lamps
▼
▼
UV
Visible
IR
UV-C
UV-B
UV-A
▲
▲
▲
▲
▲
▲
100
180
280
315
400
7 00
Wavelength (nm)
313 nm
x2
254 nm
x2
Shortpass filter (λ < 400 nm)
Wavelength (nm)