Sensidyne, LP FirstCheck 4000 853-0201-01

The PhoCheck Plus is the first and only humidity resistant Photoionization Detector (PID) on the market. The PhoCheck Plus incorporates a patented Fence Electrode Technology with a dynamic detection range capable of 1 ppb - 10,000 ppm. PhoCheck Plus is the only instrument of its kind able to detect VOCs, including some TICs TIMs and WMDs, at very low ppb toxic thresholds. Typically contamination occurs in a PID due to build-up of ionic material on the cell wall. The lamp produces charged ions and, while most recombine, some condense on the cell walls. The presence of humidity in ionic contamination results in a path for current to leak from cathode to anode along the cell wall — this is known as “Wall Effect.” However through the patented Fence Electrode Technology this leak is “mopped up” and background current that causes drift is eliminated.