Measurement Of The Thickness Of The Removed Active-Layer Of Cellulose Nitrate Cn-85(Lr-115, Type Ii) Solid State Nuclear Track Detector

The measurements of the thickness of the removed active layer of a cellulose nitrate-85 (LR-115, type II) detector have been carried out by using surface profilometry method through Fourier transform infrared (FTIR) system with the spectroscopic wave number at 1598 cm−1 corresponding to the O–NO2 bond of a CN-85 (LR-115, Type II) SSNTD. Due to chemical reaction between the etching solution (etchant) and the detector material, some molecules of the detector are removed. The final effect is the removal of the material from the detector surface. During etching, the material is removed layer by layer and the thickness of the detector becomes smaller and smaller. It was found that the bulk etch rate or removed active layer of CN-85 (LR-115, Type II) detector could not controlled by temperature easily during chemical etching and is significantly affected by the presence and amount of stirring. Therefore actual layer monitoring of the active layer thickness is necessary when using CN-85 (LR-115, Type II) solid state nuclear track detector (SSNTD). For the standard etching condition of CN-85 (2.5 N aqueous solution of NaOH kept at 60 0C temperature) detectors, the bulk etched rate under magnetic stirring and no stirring condition was found respectively 6.61± 0.33 µm h−1 and 3.59 ± 0.12 µm h−1. Also there is some variation have been found in the initial thickness of the active layer in CN-85 (LR-115, type II) detector of 12 µm.