Mercury Vapour Discharge Tubes
Mercury vaapour tubes generally also contain Argon, this being necessary to get the tube to strike and warm-up. In that case, the spectrum seen will exhibit peaks due to both elements.
Generally, the peaks of wavelength <600nm are due to Hg, and the peaks of >600nm are due to Ar. The principal spectral lines for Hg and Ar are listed in the Ocean Optics
calibration source documentation (see links below) and are as follows:
Hg (UV <390nm):
253.65, 296.73, 302.15, 313.16, 334.15, 365.01.
404.66, 407.78, 435.84, 546.08
, 576.96, 579.07.
Ar (IR > 600nm):
696.54, 706.72, 710.75, 727.29 738.40, 750.39, 763.51,
772.40, 794.82, 800.62, 811.53, 826.45, 842.46, 852.14, 866.79, 912.30 922.45.
The Hg lines at 436 and 546nm are used for calibration of the Theremino spectrometer.
The UV lines will be weak or absent in the presence of a glass outer envelope or an acrylic shield. The operation of unshielded silica-glass tubes requires protective clothing and eyewear.
>> Hg Spectrum Tube
>> Hg:Ar Sign tube
>> PJ Hg tube. Fill gas is 75% Ar 25% Ne.
>> Ar spectrum for comparison.
>> Ne spectrum for comparison.
Spectrum of Siemens Sieray
high-pressure Hg lamp operated from a 30mA high-frequency signage ("neon tube") inverter-type power supply. The Sieray was used for street lighting, and has an outer glass envelope to capture UV.
Hanovia HomeSun "Sun Ray" lamp of late 1930s vintage.
This has a fused silica-glass envelope, and was used without filtration
on the basis that it could produce a sun tan. Users had to wear green
goggles in order to avoid developing cataracts. Here the tube is
operated from a 30mA high-frequency signage inverter and placed inside a borosilicate
tube to prevent the strong UV emission at 254nm from causing harm.
>> white fluorescent tube (CFL)
>> insect attractor tube
>> blacklight tube
Ocean Optics HG-1 Hg:Ar calibration source documentation:
Ocean Optics HG-1 Hg:Ar Calibration Source.
HG-1 Hg:Ar Calibration Source Instructions.