Profile: Ludlum Measurements, Inc. specializes in designing, manufacturing, and supplying radiation detection & measurement equipment. Our product includes gamma portal monitor, small article monitor, pressure compensated ion chamber, security area monitor, and medical physics products. Our small article monitor model 54 has USB port for printer-free operation and calibration. Our air ionization chamber survey meter model 9-4 features include 5-decade ion chamber, automatic temperature & pressure compensation, high-background zero capability, and low-battery warning.