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Abstract
The characteristics of Solid State Nuclear Track Detectors (SSNTDs) and their detection mechanism of
heavy nuclear charge particles, such as alpha particles and fission fragments, were studied. The strips of
CR-39 (Columbia Resin-39), irradiated by Am-241 (alpha source) and Cf-252 (spontaneous fission
source) and after being etched in NaOH 6M solution, were analyzed under optical microscope and
diameters of the spots (tracks) left by alpha particles and fission fragments were measured. The
relationship between track diameter and etching time was studied and critical angle of incidence of the
particle on the strip required for the track formation was also determined.
Introduction
A solid-state nuclear track detector or SSNTD (also known as an etched track detector or a dielectric track
detector, DTD) is a section of a solid material (photographic emulsion, crystal, glass or plastic) exposed
to nuclear radiation (neutrons or charged particles, intermittently as well gamma rays), etched, and
inspected microscopically. The pathway of nuclear particles are imprinted quicker than the body
substance, in addition to the range and form of these trails acquiesce knowledge regarding the charge,
mass, direction of motion of the particles as well as the energy. The benefits over other radiation detectors
include the thorough knowledge accessible on distinctive particles, the perseverance of the passageways
permitting measurements to be made over extended periods of time, and the easy, inexpensive and hearty
construction of the detector.
The foundation of SSNTDs is that charged particles break the detector within nanometers down the path
in such a way that the path can be imprinted persistently more rapidly than the unspoiled substance.
Engraving, characteristically for some hours, extends the dent to tapering depths of micrometer
dimensions, which can be seen with a microscope. For a known particle, the span of the pathway shows
the energy of the particle. The charge can be acquired from the carve rate of the pathway in contrast to
that of the main part. If the particles go through the exterior at normal incidence, the depths are circular;
or else the ellipticity and direction of the elliptical pit mouth suggests the direction of incidence.
SSNTDs are frequently used to learn more about cosmic rays, long-standing radioactive elements, radon
concentration in houses, and the age of geological samples.
A substance frequently used in SSNTDs is polyallyl diglycol carbonate (PADC), also known as Tastrak,
CR-39. It is a transparent, colorless, inflexible plastic with the chemical formula C12H18O7. Etching to
expose radiation damage is typically performed using solutions of caustic alkalis such as sodium
hydroxide, regularly at high temperatures for a number of hours.
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