Neutron imaging

There are two principal neutron imaging techniques in NR - direct and transfer (indirect). In the former the neutron converter and the detector are simultaneously exposed in the neutron beam while in the transfer technique only the converter screen is exposed and activated by the neutrons, and transfered out of the neutron beam to subsequently expose the detector. Various types of IP can be used in both of neutron imaging techniques. 

For direct neutron imaging both IP-ND with inherently present neutron converter material (Gd oxide) or common IP in combination with Gd metal or vapour deposited... 

Gd converter can be used. Both techniques were studied and compared with the common direct neutron imaging with Gd metal converter (0.1mm thick) and single coated fine grained radiographic film, exposed in a vacuum cassette. The unprotected IP ( TR type ) in combination with the Gd metal converter were also exposed in a vacuum cassette. Our experience can summarized as follows ... 

The use of IP can enable the NR and neutron imaging in general with rather low intensity neutron beams which is Of importance both for neutron beam research as well as for extending NR for the in-the field use in the industry. With the existing reactor based neutron facilities the use of IP can drastically reduce the inspection time ... 

Concerning the spatial resolution of NR images the present IP are not adequate to the best film based direct neutron imaging techniques. However, with time-and the development of new IP technology there are good possibilities to improve the inherent unsharpness of the IP systems to the level even better than with Gd/film combination ... 

D. Kramer, J. Zhang, R. Shimoi, et al. In situ diagnostic of two-phase flow phenomena in polymer electrolyte fuel cells by neutron imaging. Part A. Experiment, data treatment, and quantification. Electrochimica Acta 50 (2005) 2603-2614. 

Ress, D. et al. Neutron Imaging of Laser Fusion Targets." St ienee. 956 (August... 

Bellows et al.28 first used the neutron imaging technique to measure water gradient profiles within the Nation membrane of... 

Figure 1. Typical experimental setup for neutron imaging of a fuel cell (reprinted from30 Copyright (2004), with permission from Elsevier).

Neutron imaging Two-dimensional H20 (liquid) Relatively high resolution technique, real-time data, applicable to typical fuel cell designs Need a powerful neutron source, very difficult to separate anode/cathode effects... 

Figure 1. Schematic layout of the NIST BT-2 neutron imaging facility, including the main neutron optic components as well as the location of the fuel cell test and control infrastructure.

Figure 2. The neutron spectrum at die NIST BT2 neutron imaging facility. The spectrum is not corrected for die neutron detection efficiency, which increases as die square root of die energy.

The Fluence Rate and Approximate LID for the Five Apertures Available at the NIST Neutron Imaging Facility. The Slits in Positions 1 and 2 Reduce the Geometric Blur Along One Direction by About a Factor of 5 over the Previous Configuration for Use in High-Resolution Imaging of the Through-Plane Water Content. 

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