Measurement of bulk etch rate of CR-39 with atomic force microscopy

For atomic force microscope (AFM) observations of minute tracks ( ⩽1 μ m) in the CR-39 track detector, an accurate method to measure an extremely small amount of bulk etch is required. A simple method for direct measurements of the bulk etch using AFM was developed. Before the etching, a part of the CR-39 surface was covered with epoxy adhesive resin. The amount of bulk etch was measured as a level difference between the etched surface and the unetched original surface which has been covered with epoxy resin during its chemical etching processing. The details of this method are reported and its limitations are discussed in comparison to a conventional measuring method using tracks of fission fragments.