KY-2 hollow cathode lamp

KY-2 hollow cathode lampStructure and material editing cathode

Most of them are pure metals or alloys, while for some precious metals, they are made into thin sheets and lined on supporting electrodes. The cathode is in the shape of an empty barrel in the middle, hence the name hollow cathode lamp.

anode

A tungsten rod welded with tantalum sheet or titanium wire, because tantalum sheet or titanium wire has a suction effect, can absorb a small amount of harmful gases (such as H2) at high temperatures.

shielded layer

To prevent breakdown of the anode and cathode, a shielding layer is installed between them.

KY-2 hollow cathode lampHCL Structure Diagram [2] 3 Luminescence Principle Editing Hollow cathode lamp (HCL) is a special form of low-pressure gas discharge light source, where the discharge is concentrated in the cathode cavity. When a voltage of 200V-500V is applied between the two poles [3], glow discharge occurs. Under the action of an electric field, electrons collide with carrier gas atoms on their way to the anode and ionize them, releasing secondary electrons and increasing the number of electrons and positive ions to maintain discharge. Positive ions obtain kinetic energy from an electric field. If the kinetic energy of positive ions is sufficient to overcome the lattice energy of the metal cathode surface, atoms can be sputtered out of the lattice when they collide with the cathode surface. In addition to sputtering, heating the cathode also causes thermal evaporation of surface elements. The atoms sputtered and evaporated enter the cavity, and then collide with electrons, atoms, ions, etc. to be excited, emitting resonance radiation characteristic of the corresponding elements. At the same time, the spectral lines emitted by HCL also include internal gas filling, cathode materials, and impurity elements.

Luminescence schematic (using copper as an example) [3] Due to the low pressure of the gas filling inside the lamp, the pressure widening is very small; The cathode temperature is low and the thermal broadening is also very small; Meanwhile, due to the low gas density, self-priming widening does not exist. [3] HCL basically meets the basic requirements of sharp line light sources, such as narrow half width of emission spectral lines, high and stable spectral line intensity, small spectral line background, easy operation, and durability. Moreover, when a larger lamp current is used, the half width of the spectral lines emitted by HCL widens and the spectral line intensity increases. At this time, the negative high voltage of the detector decreases and the absorbance reading stabilizes.

Precautions for use:

① Be careful not to reverse the polarity.

② To stabilize the luminous intensity of the lamp, preheat it for 10-30 minutes at the operating current.

③ If the lamp is not used for a long time, it should be ignited regularly and preheated for 1 hour under working current.

④ If the lamp is left unused for a long time and there are impurities inside, the reverse connection method can be used to remove the gas. Invert the electrode and light it with high current for 30 minutes.