HNU PID Lamp Sensitivity
PHOTOIONIZATION DETECTOR LAMP TECHNOLOGY The Photoionization Detector (PID) is very sensitive and provides a response to a wide range of organic and some inorganic compounds at part per billion (ppb) levels. The HNU PID consists of an ultraviolet lamp and an ion chamber. The detector measures the concentration of gases present in a sample using the method of pbotoionization. Photoionization occurs when a molecule absorbs a photon (light energy) of sufficient energy, creating a positive ion and an electron as shown below: R + h n = R + + e - The sample drawn into the ion chamber is exposed to photons generated by the ultraviolet lamp. Molecules in the sample with ionization potentials less than or equal to the energy level of the lamp are ionized. The ionization potential is that energy in electron volts (eV) needed to free an electron from a molecule. A positively biased accelerator electrode repels these ions, causing them to travel to the collecting electrode, where an analo
