Method for detecting whether AA-1800 atomic absorption element lamp is stable - Database & Sql Blog Articles

Method for Detecting the Stability of AA-1800 Atomic Absorption Element Lamp

Keywords: atomic absorption element lamp; US instrumentation; AA-1800. One way to assess the stability of an AA-1800 atomic absorption element lamp is by measuring its emission intensity. However, this process typically requires complex testing equipment. Currently, most elemental lamps produced domestically and internationally do not provide absolute values of emission intensity. Moreover, relative indicators vary depending on the power supply mode of different instrument lamps—such as pulse frequency, duty cycle, sensitivity, and optical path loss rate. As a result, manufacturers rarely provide fixed reference values. To determine the relative emission intensity of the lamp, you can use an instrument with a negative high voltage and slit to achieve full lamp brightness (i.e., T=100%). By comparing the intensity levels or adjusting the negative high voltage at the same lamp current, you can evaluate the lamp’s performance. Another important factor is the preheating time before the lamp reaches a stable state. A well-matured lamp should stabilize within no more than 30 minutes. Preheating helps ensure uniform temperature across the cathode, stabilizes the density of the atomic vapor cloud, and ensures consistent excitation. At this point, the internal resistance of the lamp becomes stable, and the emission intensity reaches equilibrium. For example, a copper lamp should show less than 1% drift over 30 minutes, while other elemental lamps should have less than 1% drift over 10 minutes. Additionally, background noise is another key indicator. It refers to the luminous intensity measured at the resonance line during two separate readings. The main sources of background noise are impurities in the carrier gas and the cathode material itself. Cathode lamps generally produce very low self-generated background, typically less than 1%. When conducting a noise test, if no spray is used, the result reflects the combined noise from the lamp. By extending the instrument range by 10 times and observing the peak fluctuations on the recording line, it is required that the upper and lower peaks do not exceed 5 grids, meaning the fluctuation should be less than 0.5% within 3 minutes.