![]() The power supply current range is 0 to 25mA and a 600V ignition followed with 300V sustained power. This is often aided by use of a lock-in circuit. By looking for a resonance on a data plot of the voltage signal versus source tuning parameter, the light source can be tuned to the desired frequency. ![]() Whether you require a single dedicated element or a multi-element. To tune the light source to a specific transition frequency, a tuning parameter (often the driving current) of the light source is varied. For maximum flexibility from your Thermo Scientific iCE 3000 Series Atomic Absorption spectrometer, a huge range of pre-coded and un-coded Thermo Scientific Hollow Cathode Lamps are available, to handle your chosen elements for analysis. ![]() The newly created ions cause an increase in the current across the cathode/anode and a resulting change in the voltage, which can then be measured. Indirect photoionization can then occur when electron collisions with the excited atom eject an atomic electron. By shining the light source into the HCL, one can excite or even eject electrons (directly photoionize) from the atoms inside the lamp, so long as the light source includes frequencies corresponding to the right atomic transitions. Īn HCL can also be used to tune light sources to a specific atomic transition by making use of the optogalvanic effect, which is a result of direct or indirect photoionization. These photons will then excite the atoms in the sample, which will release their own photons and be used to generate data. As these excited atoms decay to lower states, they will emit photons. Both the buffer gas and the sputtered cathode atoms will in turn be excited by collisions with other atoms/particles in the plasma. The buffer gas ions will then be accelerated into the cathode, sputtering off atoms from the cathode. For maximum flexibility from your Thermo Scientific iCE 3000 Series Atomic Absorption spectrometer, a huge range of pre-coded and un-coded Thermo Scientific Hollow Cathode Lamps are available, to handle your chosen elements. A large voltage across the anode and cathode will cause the buffer gas to ionize, creating a plasma. : Spectroscopy, Elemental & Isotope Analysis. Īn HCL usually consists of a glass tube containing a cathode, an anode, and a buffer gas (usually a noble gas). An HCL takes advantage of the hollow cathode effect, which causes conduction at a lower voltage and with more current than a cold cathode lamp that does not have a hollow cathode. for atomic absorption spectrometers) and as a frequency tuner for light sources such as lasers.
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