Preliminary study on estimating the energy and angle of incident protons based on the nuclear track morphology on CR-39 / 中华放射医学与防护杂志

ABSTRACT

Objective:To explore the method for estimating the energy and angle of incident protons based on the nuclear track morphology on CR-39.Methods:The CR-39 was irradiated with different energies and angles of incident protons and the morphology of nuclear tracks was scanned and read out by both the atomic force microscope and optical microscope after chemical etching. Through out quantitative analyses of the two-dimensional morphology of the nuclear tracks, an attempt was made to establish the method for estimating the energy and angle of incident particles.Results:As the increase of incident proton energy, the nuclear track became smaller and shallower. In the case of vertical incidence, the track opening was close to a circle. As the incident angle increases, the track opening gradually changed into an ellipse shape. The diameter of the circular nuclear track and the minor axis or the equivalent diameter of the elliptical nuclear track both decrease exponentially ( E= Ae - Bx) with the increase of the incident energy of protons. The fitting coefficients A and B were 15.763 and 0.305, and 15.886 and 0.320 by using the diameter/equivalent diameter and the minor axis of tracks. There also existed a relatively fixed quantitative relationship between the angle of the incident particle and the ratios of the major and minor axes of the elliptical nuclear track. For protons incident at 10° and 20°, the average ratios of the major and minor axes of the nuclear track were 1.10-1.15 and 1.35-1.37, respectively. Conclusions:Based on the diameter or minor axis of the nuclear track formed on CR-39, the energy of incident particles can be estimated, and the angle of incident particles can also be estimated by using the ratio of the major and minor axes of the nuclear track.