Fluence and dose of mixed space radiation by SSNTDs achievements and constraints

The space radiation can be characterized in several ways: considering its origin, particle type and energy or by registration technique. From the point of view of solid state nuclear track detectors (SSNTD) applied for space dosimetry one way of characterization is to distinguish external radiation (primary cosmic ray particles and projectile fragments entering the detector from the surroundings) and internal radiation (secondary particles like target fragments and recoiled ions which are formed mostly by protons and neutrons inside the detector material). The measurable quantities are always the track parameters on the etched surface of the detector sheet, which must be enough to derive the particle fluence, based on reasonable theoretical approach. The “classical” or “conventional” method to obtain the fluence and dose does not distinguish between tracks induced by external or internal particles, and this may introduce systematical errors and generate higher uncertainty, and over- or underestimation of the dose. The latter consequence is demonstrated after the brief description of the classical method. Since the most abundant particles in space are protons, the study deals –as an example- with the determination of the high energy proton induced secondary particle forming events inside the detector, based on experiments.