Dynamic characterization of a high speed gamma-ray tomograph *

R. Maad1,2, B. T. Hjertaker1,2, G. A. Johansen1,2 and Ø. Olsen1,2

1 Department of Physics and Technology, University of Bergen, Allégaten 55, N-5007 Bergen, Norway.

2 The Michelsen Centre for Industrial Measurement Science and Technology,

P.O. Box 6031, N-5892 Bergen, Norway

E-mail: rachid.maad@ift.uib.no

ABSTRACT

A HSGT (High Speed Gamma-ray Tomograph) has been designed and built at the University of Bergen with the objective to monitor rapid changes in multiphase hydrocarbon flow regimes. Dynamic characterization of the HSGT for rotational and translational movements is presented in this paper, which is based on calculation of the RMSE (Root Mean Square Error) of the acquired tomogram compared to that of the test phantom. The test phantom consists of two spherical holes with different radius in a polypropylene sample. The ILST (Iterative Least Square) reconstruction algorithm is used to reconstruct the HSGT sensor data. The results of the dynamic characterization show that the HSGT can sustain imaging of a rotational object with angular velocities ~30 rad/s. For translational movement (free fall) the HSGT is able to detect internal cross sectional structures with velocities up to ~ 4 ms-1.

Keywords High speed gamma-ray tomography, multiphase hydrocarbon flow, flow dynamics characterization, data acquisition and control, CompactRIO, FPGA.