Development and implementation of an automatic counting system for CR-39 solid state nuclear track detectors.

1. Development and implementation of an automatic counting system for CR-39
solid state nuclear track detectors.
Alssabbagh M, Tan LK, Ng KH, Vincent P
Department of Biomedical Imaging and University of Malaya Research Imaging
Centre, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur
ABSTRACT
Purpose of Study: The CR-39 solid state passive nuclear track detector is a popular
method to measure charged particle and neutron radiation. Heavy charged particles
passing through these passive detectors leave a narrow trail of damages; these damage
trails are easily visible at modest optical magnification levels. Traditional manual method
for counting the tracks on CR-39 detectors using an optical microscope is labor intensive
and highly operator dependent. In this research an affordable and fast automatic CR-39
track counting system is performed.
Materials and Method: A set of CR-39 detectors with dimensions of 1.5x1.3 cm was
exposed to Ra-226 with activity of 122KBq for different periods of time. NaOH solution
was used for etching process. A digital light microscope was used to take images of the
tracks with minimum resolution of 0.3 Megapixels.
Results: The preliminary results showed that the system is successful at recognizing
and counting the tracks using their intensity, shape, and size properties. The tracks were
also classified after separating the tracks from the background and removing those
smaller than the threshold value. The automatic system was also compared to manual
counting methods for verification.
Conclusion: This system was shown to be an effective of analyzing the tracks in
time less than one minute which can be used to estimate the radiation concentration
in particular area depending on the track concentration.