Chinese Cold Neutron Radiography System
RadSci in conjunction with Scitek Consultants Ltd, a Derby engineering R & D company, have designed and manufactured a complete neutron radiography facility for installation on one of the beamlines of a nuclear reactor at a Chinese research centre.
The equipment includes:- the main neutron shutter, an automated neutron aperture selector, an 11m long vacuum flight tube, neutron beam profiler, 3-axis object handling system (up to 300 kg objects), turntable for neutron tomography (up to 25kg objects) and a neutron imaging system based on an Andor iKon-L 4 Mpixel cooled CCD camera and neutron-sensitive scintillation screen.
Stereo Steady-State or Pulsed X-ray Imaging
Short pulses of X-rays can be used to freeze the motion of particulates in multiphase mixtures moving in pipes. Pulsed X-ray sources (like the Golden Engineering 300kV XRS-3 that gives 50 nanosec pulses) can be used with a transportable a-Silicon imaging panel (e.g. Vidisco Blaze X) to provide X-ray imaging capability in the field . If a second system is included with its operation synched to the first system, a stereo X-ray imaging geometry can be selected that will allow the volume around the test object position to be fully calibrated for x,y,z spatial position.
Optimum positioning of the two X-ray sets plus imaging systems is important to enable correspondence of the same point to be easily and accurately made in both images of the stereo pair.
Neutron radiography source at Birmingham University
The Dynamitron accelerator in the Physics Department, University of Birmingham has been optimised for use in BNCT studies. Proton currents in excess of 1 mA have been achieved on a natural lithium target at a proton energy of 2.8 MeV giving 1.37x10exp12 neutrons/sec.
For the BNCT work at Birmingham University, a compact moderator/collimator was modelled using MCNP and manufactured using FluentalTM (Al, AlF, LiF and Li-polythene). Graphite was included as a reflector and heavy water used to cool the lithium target. The neutron beam port was delimited with a thick plate of Li-polyethylene. This provides an intense flux of predominantly epi-thermal neutrons.
Reference: Cuthbertson et al, "In-phantom characterisation studies at the Birmingham Accelerator-Generated epIthermal Neutron Source (BAGINS) BNCT facility", Applied Radiation and Isotopes 61 (2004) 733–738
X-ray and neutron radiography
X-ray and neutron radiography provide different information about any test object. X-rays interact predominantly with the atomic electrons so that a material of higher density attenuates the X-rays more strongly. Neutrons interact with atomic nuclei and the interaction behaviour is not related to material density but to the properties of the nucleus. Some very light elements e.g. hydrogen and boron have a relatively high interaction probability, greater than for aluminium and lead. This makes it possible to see the flow of oil through a metal pipe.
Combining X-ray and neutron radiographs of a test object can provide better interpretation of the image results.
Neutron imaging of operating machinery
An experimental rig for testing bearings with different types of oil jet supplies has been used in neutron radiography and in positron emission tomography imaging. This rig is manufactured from aluminium and steel - see full neutron radiography image.
A recent test was carried out of this rig on a thermal neutron beam to demonstrate the sensitivity obtainable by neutron radiography to visualising thin films of water.