Correction for dynamic bias error in transmission measurements of void fraction
2012 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 83, no 12, 125110- p.Article in journal (Refereed) Published
Dynamic bias errors occur in transmission measurements, such as X-ray, gamma, or neutron radiography or tomography. This is observed when the properties of the object are not stationary in time and its average properties are assessed. The nonlinear measurement response to changes in transmission within the time scale of the measurement implies a bias, which can be difficult to correct for. A typical example is the tomographic or radiographic mapping of void content in dynamic two-phase flow systems. In this work, the dynamic bias error is described and a method to make a first-order correction is derived. A prerequisite for this method is variance estimates of the system dynamics, which can be obtained using high-speed, time-resolved data acquisition. However, in the absence of such acquisition, a priori knowledge might be used to substitute the time resolved data. Using synthetic data, a void fraction measurement case study has been simulated to demonstrate the performance of the suggested method. The transmission length of the radiation in the object under study and the type of fluctuation of the void fraction have been varied. Significant decreases in the dynamic bias error were achieved to the expense of marginal decreases in precision.
Place, publisher, year, edition, pages
2012. Vol. 83, no 12, 125110- p.
error correction; fission reactor cooling; flow measurement; light water reactors; measurement errors; two-phase flow
Other Physics Topics
IdentifiersURN: urn:nbn:se:uu:diva-189683DOI: 10.1063/1.4772704ISI: 000312834300066OAI: oai:DiVA.org:uu-189683DiVA: diva2:582058