Collimation and background in the pulsed neutron activation method for determination of water flow in pipes
Artikel i vetenskaplig tidskrift, 2007

In a Pulsed Neutron Activation (PNA) flowmeter, the water in a pipe is bombarded with neutron pulses, which introduce activity into the pipe. The activity is mixed with the flow, and gamma radiation emitted from the activity is measured with a detector downstream. The average velocity of the water is then calculated using the time-resolved detector signal. In this paper, the effect of collimation of the neutron radiation has been investigated. Such a collimation would increase the accuracy of the measurement, but the use of a collimator requires the distance between the pipe and the neutron source to be increased, with a corresponding loss in count rate. The results show that this loss makes neutron collimators in PNA of little use. In addition, a method to identify and subtract the background originating from stationary sources in a PNA measurement was developed.


pipe flow

Pulsed neutron activation


Håkan Mattsson

Chalmers, Teknisk fysik, Nukleär teknik

Anders Nordlund

Chalmers, Teknisk fysik, Nukleär teknik

Berit Dahl

Chalmers, Teknisk fysik, Nukleär teknik

International Journal of Nuclear Energy Science and Technology

1741-6361 (ISSN) 1741-637X (eISSN)

Vol. 3 1 12-



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