Uncertainties in linear energy transfer spectra measured with track-etched detectors in space

Polyallyldiglycol carbonate-based track-etched detectors can measure linear energy transfer (LET) spectra of charged particles. Accuracy of the spectra is affected by many factors whose effects are difficult to quantify. Typically, only uncertainty arising from the randomness of particle detection is reported in scientific literature. The aim of this paper is to classify the sources of uncertainties of an LET spectrum measurement and provide a simple model for the calculation of the combined uncertainty. The model was used for a spectrum measured with the track-etched detector (Harzlas TD-1) on board of the International Space Station from May–October 2009. For some spectrum bins the largest contribution to the combined uncertainty came from the uncertainty arising from the randomness of particle detection. For other bins it came from the uncertainty of the calibration curve. Contribution from the cross talk between bins was small for most of the bins as the width of the bins was relatively large compared to the intrinsic resolution of the track-etched detector. The analysis showed that sources of uncertainties other than the randomness of particle detection should not, in general, be neglected.