Concentrating particles in a turbulent gas flow may include receiving, in a receptacle, a turbulent gas flow that includes particles. The concentration of particles in a gas flow exiting the receptacle at a first port is increased as compared with a concentration of the particles in the gas flow received by the receptacle. The increased concentration of particles is accomplished by removing a portion of the gas flow by using a second port, and fluidly communicating the gas flow through a tube in the receptacle. The tube has a smaller diameter at the end of the tube at which the gas flow exits the tube than diameter at the end of the tube at which the gas flow is received.