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) uncovered 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 and CR39. 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.