Photo Gallery

Mid-1960s Philips Spectraal RbII

The lamp featured here differs markedly from other models in Philips's LL spectral source family in the fact that its rubidium vapor discharge radiates mostly ionic lines rather than the usual atomic ones. This ionic emission is obtained by particular plasma regime which is optimized to enhance the ionization of the metal vapor, a situation which is normally avoided in normal discharge lamps. The argon fill pressure is higher than in standard rubidium spectral lamps, which results in a higher dissipated power and an increased operating temperature. Both factors increase the metal vapor density and its ionization, which result in much higher excitation rates of rubidium ions. Incidentally, the higher argon pressure presents the benefit of lengthening the electrode lifetime because of the reduced sputtering and evaporation rates. However, the diffusion of rubidium atoms inside the burner is more difficult and can lead to heterogeneities in the alkali vapor density.

Like all spectral lamps made by Philips, this special model features several standard components which were used in the manufacture of mass-produced general lighting lamps. For instance, the triple-coiled triple-oxide electrodes and the alkali-resistant two-ply glass discharge tube came from SO-I 140W low-pressure sodium lamps. While the discharge tubes of mass-produced lamps were fabricated using mechanized methods, the burner inside this Spectraal RbII was entirely worked by hands due to the very small production volume of this model. The burner construction is of the first-generation type implemented by Philips in these alkali vapor lamps. The sealing technique consisted first in collapsing the burner's end onto a glass-sheathed fernico seal wire, which was then pushed inward so as to give the seal a flat end-profile. These feedthrough wires were welded to a transversal piece of molybdenum wire which holds the triple-coiled electrodes. The vessel is provided with a dimple the middle, which acts as a cold spot where the metal vapor condenses. This prevents the formation of a light-blocking rubidium mirror, and regulates the vapor pressure of this element. There are two exhaust tubes at each end of the discharge vessel, which enabled a continuous argon flush before seal off in order to remove impurities out of the burner.

This lamp, like all others from the Philips LL spectral family, is designed to operate on commercial 0.9 A auto-leak transformers used for SO-I 140W lamps. The 470 V open voltage of the ballast is high enough to ensure a reliable discharge ignition without the need for electrode pre-heating. The spectral emission from the ionized rubidium vapor features more lines than standard atomic line sources, which makes the Spetraal RbII more useful for applications such as spectroscopy and refractometry. Interestingly, the characteristics of this lamp were never published in the Philips literature and a quick reference to the emitted lines is given in the form of a photographic recording of the spectrum taped directly onto the lamp, near its base.


Keywords: Lamps

Mid-1960s Philips Spectraal RbII


The lamp featured here differs markedly from other models in Philips's LL spectral source family in the fact that its rubidium vapor discharge radiates mostly ionic lines rather than the usual atomic ones. This ionic emission is obtained by particular plasma regime which is optimized to enhance the ionization of the metal vapor, a situation which is normally avoided in normal discharge lamps. The argon fill pressure is higher than in standard rubidium spectral lamps, which results in a higher dissipated power and an increased operating temperature. Both factors increase the metal vapor density and its ionization, which result in much higher excitation rates of rubidium ions. Incidentally, the higher argon pressure presents the benefit of lengthening the electrode lifetime because of the reduced sputtering and evaporation rates. However, the diffusion of rubidium atoms inside the burner is more difficult and can lead to heterogeneities in the alkali vapor density.

Like all spectral lamps made by Philips, this special model features several standard components which were used in the manufacture of mass-produced general lighting lamps. For instance, the triple-coiled triple-oxide electrodes and the alkali-resistant two-ply glass discharge tube came from SO-I 140W low-pressure sodium lamps. While the discharge tubes of mass-produced lamps were fabricated using mechanized methods, the burner inside this Spectraal RbII was entirely worked by hands due to the very small production volume of this model. The burner construction is of the first-generation type implemented by Philips in these alkali vapor lamps. The sealing technique consisted first in collapsing the burner's end onto a glass-sheathed fernico seal wire, which was then pushed inward so as to give the seal a flat end-profile. These feedthrough wires were welded to a transversal piece of molybdenum wire which holds the triple-coiled electrodes. The vessel is provided with a dimple the middle, which acts as a cold spot where the metal vapor condenses. This prevents the formation of a light-blocking rubidium mirror, and regulates the vapor pressure of this element. There are two exhaust tubes at each end of the discharge vessel, which enabled a continuous argon flush before seal off in order to remove impurities out of the burner.

This lamp, like all others from the Philips LL spectral family, is designed to operate on commercial 0.9 A auto-leak transformers used for SO-I 140W lamps. The 470 V open voltage of the ballast is high enough to ensure a reliable discharge ignition without the need for electrode pre-heating. The spectral emission from the ionized rubidium vapor features more lines than standard atomic line sources, which makes the Spetraal RbII more useful for applications such as spectroscopy and refractometry. Interestingly, the characteristics of this lamp were never published in the Philips literature and a quick reference to the emitted lines is given in the form of a photographic recording of the spectrum taped directly onto the lamp, near its base.

IMG_1032m.jpg IMG_9973.JPG Philips_Spectraal_RbII_-_NL_m1960s_a.jpg Elektropodnik_SKTB_9W_-_CSK_l1940s.jpg Tesla_RVIM400_-_CZK_1977.jpg
Lamp/Fixture Information
Manufacturer:Philips
Model Reference:Spectraal RbII
Lamp
Lamp Type:Low-pressure discharge
Filament/Radiator Type:Nonthermal discharge in argon and rubidum vapor
Base:E27
Shape/Finish:Tubular clear
Burning Position:Vertical base up
Electrical
Wattage:12 W
Voltage:13 V
Current:0.9 A
Physical/Production
Factory Location:Eindhoven, the Netherlands
Fabrication Date:Mind 1960s
Application/Use:Spectroscopy
File information
Filename:Philips_Spectraal_RbII_-_NL_m1960s_a.jpg
Album name:Max / Nonthermal discharge lamps
Keywords:Lamps
Filesize:286 KiB
Date added:Aug 10, 2024
Dimensions:1200 x 440 pixels
Displayed:12 times
DateTime Original:2009:07:11 00:02:40
Exposure Time:1/100 sec
FNumber:f/5
Flash:No Flash
Focal length:35 mm
ISO:800
Model:Canon EOS 450D
Software:Adobe Photoshop CS2 Windows
White Balance:1
URL:https://trad-lighting.net/gallery/displayimage.php?pid=187
Favorites:Add to Favorites

Comment 1 to 3 of 3
Page: 1

Ria   [Aug 10, 2024 at 05:57 PM]
You've just reminded me Max, we need to re-upload our Philips spectral lamps Bulb Man
Max   [Aug 10, 2024 at 06:09 PM]
You should indeed Wink
Ria   [Aug 10, 2024 at 06:45 PM]
They're now up Very Happy

Comment 1 to 3 of 3
Page: 1