Element lampHollow cathode lamp, also known as hollow cathode lamp, is a special light source that can excite a fixed wavelength. It is widely used in analytical instruments such as atomic absorption spectrometer and atomic fluorescence spectrometer to detect the content of specific elements in samples. Element lamps work based on the characteristic spectral lines of elements. When current passes through, the elements inside the lamp are excited, producing light of a specific wavelength. After passing through the spectroscopic system, these rays are detected by the instrument to determine the presence and content of the corresponding elements in the sample. The discharge is concentrated in the cathode cavity, generating a glow discharge through the collision of electrons with carrier gas atoms, which in turn excites characteristic spectral lines of element emission.
Element lampIts performance characteristics are mainly reflected in the following aspects:
1. High spectral purity
High purity cathode material: The cathode of the lamp is made of high-purity (usually ≥ 99.99%) metal or alloy of the element to be tested, ensuring that the emitted spectral lines are almost free of interference from impurity elements.
Sharp line spectrum: It can emit very narrow characteristic spectral lines (sharp lines), effectively avoiding the spectral line overlap of other coexisting elements in the sample, ensuring the selectivity and accuracy of analysis. For example, the 228.8 nm spectral line emitted by cadmium lamps has high purity and can accurately detect trace amounts of cadmium in water samples.
2. High and stable luminous intensity
High intensity output: By optimizing the cathode design (such as a "sealed" cathode) and the gas pressure inside the lamp, high-intensity characteristic spectra can be generated at lower operating currents (typically 5-20 mA).
Excellent stability: The relative standard deviation (RSD) of the luminous intensity of modern elemental lamps can be controlled within 1%. This means that in long-term and large-scale sample analysis, the light source output is stable, significantly reducing detection errors caused by light source fluctuations.
3. Low noise and low background
Low Signal Noise: High quality element lamps have extremely low signal noise (for example, some brands may have less than 0.3%), which can effectively improve the signal-to-noise ratio (S/N), thereby enhancing the sensitivity and accuracy of detection.
Low background radiation: The background radiation intensity on both sides of the characteristic spectral line is very small (usually less than 1% of the analysis line intensity), reducing background interference and making the measurement results more accurate.
4. Long service life
Strong durability: Advanced vacuum treatment and cathode manufacturing processes are adopted, significantly extending the service life of the lamp.
Longevity index: The lifespan of general element lamps can reach over 5000 milliampere hours (mA · h), and even volatile elements such as arsenic and mercury can reach over 3000 mA · h, effectively reducing the frequency of replacement and operating costs for users.
5. Fast preheating and low starting voltage
Short preheating time: Typically, stable light output can be achieved within 5-30 minutes, eliminating the need for long waiting times and improving experimental efficiency.
Low starting voltage: The starting voltage generally does not exceed 360V, which can meet the high-frequency lighting requirements of various brands of atomic absorption spectrometers (such as 200Hz or 400Hz), and has good compatibility.
6. Diversity and compatibility
Complete range: Provides over 70 types of single element lights and over 120 types of multi-element lights (up to 7 elements can be combined), covering the vast majority of analyzable elements.
Diverse interfaces: We offer models with different outer diameters (such as 1.5 inches/38mm, 2 inches/50mm) and pins (2, 4, 9, etc.), which can be matched with mainstream domestic and foreign brands (such as PerkinElmer, Varian, Thermo, Shimadzu, Beijing Puxi, etc.) of instruments.
7. High sensitivity and selectivity
As the "light source core" of atomic absorption spectroscopy analysis, the characteristic spectral lines emitted by the element lamp can be efficiently absorbed by the sample atomic vapor, providing reliable data support for the quantitative detection of trace elements (with detection limits up to μ g/L or even ng/L), and having high chemical sensitivity and selectivity.