Pulsecho systems provides halogen leak detectors. These halogen leak detectors are used to detect gaseous impurities in the ambient atmosphere by drawing the sample through its sensing tip [similar to ionization chamber] using a micro pump. These leak detectors are light, portable and easy to use instruments. The sensing tip is mounted in a flexible probe which can be bent as required. Sensitivity is about 3 to 5 parts of halogen gas per million parts of air [ppm]. The leak detectors gives beeping audio indication through their built-in speaker which increases in speed and frequency as the leak is approached or with increase in concentration of halogen gas in air. An earphone is provided for use in noisy locations. Some of the salient features include small compact, portable with battery operation, high sensitivity [3 to 5 parts per million], long flexible probe for hard to reach areas, sensitivity automatically reset to ambient level of contamination, sensor can stand to large doses of halogen gas, etc. Applications include halide gas leak detection in air-conditioning, refrigeration, hospital sterilizing equipment, high-voltage circuit breakers, leak testing, to detect all halogen gases freon, sf6, etc.