Page 159 - 00. Complete Version - Progress Report IPEN 2014-2016

Nuclear Science and Technology | Progress Report 159

Neutron tomography

Fig. 10. Top view of the reactor under operation (left) and of the equipment for neutron tomography of IPEN-CNEN/SP

The neutron tomography (NT) is a non-de- Neutron tomography applications
structive imaging technique to investigate
the internal structure of objects, mainly the ARCHAEOLOGICAL SAMPLE. Figure 11 (left)
hydrogenous ones like oil, water, adhesives, shows a small bone embedded into a pluvial
plastics, etc., even wrapped by thick metal lay- rock basically consisting of quartz and sand.
ers. Thus the information provided by NT are This sample was evaluated by the NT tech-
complementary to those provided by X-rays.
The Brazilian Institute for Nuclear Technolo-
gy IPEN-CNEN/SP has an equipment for NT
showed in Figure 10, which is installed at the
IEA-R1 Nuclear Research Reactor and opera-
tional since 2011. This equipment is able to
provide high quality images, and a tomogra-
phy is obtained as follows: the object to be in-
spected is positioned in a sample holder, to be
irradiated in the neutron beam; the transmit-
ted neutrons impinge a scintillator, forming a
2D (two dimensional) brilliant image of its in-
ternal structure; a plane mirror reflects this im-
age to a high sensitivity video camera which is
positioned at 900 with respect to the neutron
beam and it is captured and stored in a com-
puter; at the end of the capture, the object is
rotated a small fraction of angle and another
image is captured; after a complete rotation
of 3600, 400 images are captured which are
mathematically processed and the tomogra-
phy is obtained; the time to obtain a tomog-
raphy is about 400 sec. and the maximal size
of the object is about 15 cm.
Fig.11. Archaeological sample photo (left) and tomog-
raphy (right) showing the embedded bone.