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A moveable multi-use neutron imaging facility was constructed based on a compact accelerator D-T neutron source, for use in thermal and fast neutron radiography and tomography. Experiments were carried out to investigate the imaging quality for different standard samples. The smallest width of a slit that can be tested by digitized thermal neutron radiography was found to be 0.06 mm, while the smallest diameter of holes tested by digitized fast neutron radiography was 0.5 mm. A gadolinium wire of 0.2 mm in diameter within a multi-material structure was reconstructed clearly with thermal neutron tomography, and holes in a light material were reconstructed with fast neutron tomography.

Based the China Mianyang Research Reactor (CMRR) and D-T accelerator neutron source, thermal neutron, cold neutron and fast neutron imaging facilities are all installed at China Academy of Engineering Physics (CAEP). Various samples have been imaged by different energy neutrons and shown the neutron imaging application in industry, aerospace and so on. The facilities parameters and recent neutron imaging development will be shown in this paper.

Coded source imaging (CSI) technique could increase the utilization rate of neutron when high L/D required in neutron imaging. The images need to be reconstructed from the raw projections. The reconstruction would amplify the noise of the raw projection, which will affect the quality of reconstructed images. Study of Signal to Noise Ratio (SNR) in CSI shows image quality depends on geometry structure and neutron beam parameters. With analysis method based on correlation reconstruction arithmetic, SNR was detailed to assess the effects from different geometry factors. Numerical simulation as a further supplement proves the rationality of analysis method. The comparison of SNR between CSI and traditional neutron radiography (NR) shows that the SNR of CSI could be better than NR in some conditions.

It is hopeful that fusion-fission hybrid energy system will become an effective approach to achieve long-term sustainable development of fission energy. U-10Zr alloy (which means the mass ratio of Zr is 10%) fuel is the key material of subcritical blanket for fusion-fission hybrid energy system which the irradiation performance need to be considered. Indirect neutron radiography is used to detect the irradiated U-10Zr alloy because of the high residual dose in this paper. Different burnup samples (0.1%, 0.3%, 0.5% and 0.7%) have been tested with a special indirect neutron radiography device at CMRR (China Mianyang Research Reactor). The resolution of the device is better than 50 µm and the quantitative analysis of swelling behaviors was carried out. The results show that the swelling behaviors relate well to burnup character which can be detected accurately by indirect neutron radiography.

Polarimetric neutron tomography provides a powerful tool for direct visualization of magnetic fields in the bulk of matter. However, the measurable field strength has been severely restricted because neutron spin precession angles have to be limited below π due to the phase wrapping problem. In this article we show that in most cases the spin precession limit can be extended by identifying and correcting discontinuities in the sinograms. We present an improved method so that Algebraic reconstruction technique can be applied in the precession interval [ π , 2 π ] to improve the reconstruction quality. Robustness of this method against device parameters and statistical noise has been studied through numerical simulation, some unexpected influence have been found and discussed.

To carry on neutron imaging researches (radiography/tomography), we built a Cold Neutron Radiography Facility (CNRF), based on the China Mianyang Research Reactor (CMRR) at Institute of Nuclear and Chemistry (INPC). This CNRF system utilizes cold neutrons from the C1 neutron guide. The facility consists of beam shutter, flight tubes, beam limiter, object handling system, imaging system, beam stop and data acquisition system. The maximum neutron flux at the sample position is 6 × 106 n/cm2/s, approximately. There are seven pinholes in the collimator system, to offer a possible L/D from 200 to 1300. With different imaging lenses, the imaging system could provide four different FOVs. The performance parameters are tested by Siemens Star and ASTM standard devices-beam purity indicator (BPI) and image sensitivity indicator (SI). Our results show the resolution of CNRF is better than 20 μ m (i.e. 25lp/mm), and its typical radiography image is of Category-I, as defined in ASTM E545.