General Information

The high intensity UV Source UVS 40A2 can be operated with various discharge gases, such as helium, neon, krypton, argon, xenon or hydrogen.

The operation of the lamp is based on the principle of a cold cathode capillary discharge. There is a windowless direct-sight connection between the discharge area and the target.

The discharge current is electronically stabilized. The lamp is water cooled in order to allow for high discharge currents An integral port aligner facilities the positioning of the light spot on the sample.

Selection of the light capillary.

The light capillary can be adapted to the experiment by selecting its length and inner diameter. It is available with ID 1; ID 1,5. Standard is ID 1,5. The outer diameter of the capillary is 8mm. It is inserted into a shielding tube of O.D. 9,5mm. Any length in vacuum between 10 and 350mm is available. The inner diameter and the length affect the performance of the UVS 40A2.

The discharge has a maximum photon intensity at a pressure of several mbar in the lamp (10^-2…10^-1 mbar in the first pumping stage). Be means of the two differential pumping stages between the discharge region and the experimental chamber, the pressure in the chamber can be kept typically in the 10^-8 to 10^-9 mbar range. This depends on the pumping system and the dimension of the light capillary.

Clean Discharge.

The UVS 40A2 is designed to maintain a continuous gas flow through the discharge region. This is of great advantage in maintaining the cleanness of the discharge capillary and results in very long service intervals before the capillary has to be cleaned.

Differential Pumping

For the first differential pumping stage a two-stage rotary pump is well suited. For improving the vacuum in the analysis chamber, the gas load may be reduced be means of a second differential pumping stage. For this purpose a small turbomolecular pump may by used.