Model 629 Hollow Cathode Source Vacuum Ultraviolet Windowless operation Spectral emission lines of gases from 20 to 200 nanometers Rich source of VUV spectral lines Stainless steel cathode, Aluminum anode Stable operation, electrically quiet Available with various apertures allowing simulation of a slit or pin hole Available complete with Model 730 power supply

McPherson, Inc. The Model 629 Hollow Cathode Light Source is a continuous gas discharge source that can be used with molecular or rare gases. It is electrically quiet and is a rich source of vacuum ultraviolet (VUV) spectral lines (to at least 20-nm (62-eV.) The source is a Schueler-type lamp which produces strong ion lines. It differs principally from a capillary discharge source in that the negative glow of the discharge is viewed directly, rather than through the positive column of neutral gas.

The source features a water cooled anode and cathode. The cathode is stainless steel and the anode is aluminum. A Kel-F flange electrically isolates the cathode from the anode. A differential pumping accessory is available to limit the gas load into the spectrometer. For routine operation commercial grade gases are generally used. A 1/8 NPT tapped hole is located in the top of the anode for installation of a thermocouple gauge to monitor pressure. This source requires water cooling via tap or recirculator.

The Model 629 offers the user a flexible source system suitable for wavelength calibration, ultraviolet photoemission spectroscopy (UPS) and other vacuum ultraviolet spectroscopy applications. A paper describing the typical discharge parameters of the Model 629 lamp is available for a fee from the Optical Society of America web site Applied Optics. "Continuous discharge line source for the extreme ultraviolet, F. Paresce, S. Kumar, C. S. Bowyer: Applied Optics, Volume 10, (1971) Issue 8, August 1971, pp. 1904-1908"

A 2000-volt supply producing 250 to 500-mA should be used to operate the source. Refer to the McPherson Model 730 current regulated supply for more information.

PDF format Data Sheet for the Model 629 windowless hollow cathode available here

Sample Spectra

Helium II series lines produced with Model 629 Hollow Cathode windowless source. Spectrum was collected with Model 251 SPRED flat field grazing incidence monochromator (210-mm focal length) fitted with a microchannel plate intensifier and photodiode array.

Spectrum of Model 629 Hollow Cathode windowless source operating with Hydrogen gas discharge. Spectrum was collected with 200-mm focal length Model 234/302 Monochromator and scintillated photomultiplier.

Spectrum of Model 629 Hollow Cathode windowless source operating with Neon and Helium gas. Spectrum was collected with 200-mm focal length Model 234/302 Monochromator and scintillated photomultiplier.