A device is proposed for contactless measurement of density profile in oil refining, chemical, and mining industries. The device consists of a gamma-radiation source, a shield, and a proportional counter with xenon accumulation and counting with charge separation. The device is capable of measuring distribution of density of a substance behind a steel wall with a thickness up to 50 mm in the 1-1.5 m height range depending on the specific goal. The operation principle and the results of modeling using GEANT simulation software toolkits are described.