{"references": ["Jensen, P.K.: Age versus length of horizontal fission tracks represented by 2D-Histograms,,doi: 10.5281/zenodo.4553144, 2021.", "Jensen, P.K., Hansen, K.: Age distribution of horizontal fission tracks, submitted to Geochronology.", "Jensen, P. K., Hansen, K., and Kunzendorf, H.: A numerical model for the thermal history of rocks based on confined horizontal fission tracks. International Journal of Radiation Applications and Instrumentation, Part D. Nucl. Tracks Radiat. Meas., 20, 2, 349-359, doi: 10.1016/1359-0189(92)90064-3, 1992.", "Jensen, P. K. and Hansen, K.: Identifying the post-sedimentary part of fission track length histograms with inherited tracks, Thermo 2018, 16th International Conference on Thermochronology, Quedlinburg, Germany; 16-21 September 2018, https://doi.org/10.1002/essoar.10500031.1, 2018."]}

The code calculates the age distribution of horizontal fission tracks versus their lengths. The code is for tracks measured in the modern way where the angles to the c-axis are considered. 3D-histograms of track length versus angle is the basis for inversion. Equations relating track length histograms and associated surface track densities to track ages are given in an early version in Jensen et al. (1992) and illustrated in a poster (Jensen and Hansen, 2018). The present code is based on further development (Jensen, 2021) and inversion is now performed using a probabilistic theory (Tarantola, 2005). The code is developed for the examples given in Jensen and Hansen (2021). A code for 2D-histograms where the angles to the c-axis are not considered is given by Jensen (2021).