Radiography, neutron

New Possibilities in Neutron Radiography with Imaging Plates. 

Stade, T, Rant, J., Kaling, M., Neutron Radiography(5), Proc. 5 World Conf, Berlin, June 1996, German Society for NDT, (1997) 298... 

Rant, J. et al., Proc. 5 Ann. Mtg of European Neutron Radiography Working Group, Bologna (June 1997), ENRWG, to be published elsewhere... 

It is supposed to apply this neutron source to nondestmctive evaluation of products using neutron radiography and elemental analysis of materials by detection of capture gamma rays. 

New process technologies (Ref 53) such as jet mills (Fig 2) and co-precipitation (Ref 97) may allow safe compounding of sensitive or toxic formulations. New analytical tools such as neutron radiography (Ref 92) afford improved non-destructive testing of devices. X-ray fluorescence (Ref 93) and neutron activation (Ref 94) provide quantitative analysis of pyrotechnic compns and their trace contaminants... 

Neutron production, plutonium, 77 585 Neutron radiation, high pressure, 13 431 Neutron-radiography (N-radiography), 77 418... 

One drawback of using the MPL is that the water saturation in the CL increases and causes more flooding [108]. Through neutron radiography imaging, Owejan et al. [147] were able to observe that MEAs that had cathode DLs with MPLs had better distribution of water over the active area at high current densities. DLs without MPLs tended to have more water accumulated in one location of the active area (closer to the outlet). One issue with this work was that the water accumulation observed was for the whole MEA and the water quantities were not separated between the anode and cathode sides. 

J. P. Owejan, T. A. Trabold, D. L. Jacobson, et al. In situ investigation of water transport in an operating PEM fuel cell using neutron radiography. Part 2. Transient water accumulation in an interdigitated cathode flow field. International Journal of Heat Mass Transfer 49 (2006) 4721-4731. 

K. Yoshizawa, K. Ikezoe, Y. Tasaki, et al. Analysis of gas diffusion layer and flow-field design in a PEMFC using neutron radiography. Journal of the Electrochemical Society 155 (2008) B223-B227. 

By contrast, the metals have so far found only limited application save for one important use in the field of nondestructive testing. With the proliferation of research reactors over the past decade, neutron radiography has become a practical tool in the aerospace, nuclear and engineering industries, yet without the availability of gadolinium and dysprosium in the form of thin foils, the technique would be severely restricted. 

Califomium-252 is an intense neutron source. One gram emits 2.4 x 1012 neutrons per second. This isotope shows promise for applications in neutron activation analysis, neutron radiography, and as a portable source for field use in mineral prospecting and oil well logging. 

Another approach to differentiating between the anode and cathode water contents is to perform through-plane visualization. Until recently, neutron radiography was not able to achieve the resolutions necessary to sufficiently resolve a membrane thickness of 25 pm and GDL thicknesses of 200 pm. However, Hussey et al.38 developed a new detector technology based on micro-channel plates that allowed in-plane visualization with a resolution of 30 pm (10 pm is feasible with further detector development). An exposure time of 20 min was used and the possibility of increasing temporal... 

High-Resolution Neutron Radiography Analysis of Proton Exchange Membrane Fuel Cells... 

Figure 3. Schematic drawing of a microchannel plate detector for neutron radiography. Channel diameters range from 6 to 12 p.m, and typical wall thickness are about 2 p.m. The high voltage depends on the particular MCP used and can range from 2 to 6 kV.

Neutron radiography measures the spatially resolved neutron transmission through a sample. The neutron transmission is derived from the Lambert-Beer Law of attenuation, which in differential form is... 

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