[en] A new method is proposed to determine the 'effective' linear energy transfer (LET) in mixed radiation fields, by analysing the radiation density dependence of the area of peak 8 in the thermoluminescence glow-curves of MTS-7 (⁷LiF:Mg,Ti) detectors. The dependence of the peak 8 area to the peak 5 area on the 'effective' LET allows the estimation of the LET to be extended to values higher than those estimated by the other methods. Tests of this method, performed for the 'blind' exposure within the ICCHIBAN intercomparison project, resulted in agreement to within 7% with the true LET value and 13% with the true dose value, for a complex mixed radiation field. The limitations of the method are in the uncertainty of the LET estimation of up to 50% for very specific fields and in the difficulty of deconvoluting high-temperature peaks in the glow-curves of MTS-7 detectors after small doses or low-LET irradiation. The newly proposed method, complementary to the high-temperature peak ratio (HTR) method and the method using two different TL systems, can improve estimation of the ionisation density in mixed radiation fields, e.g. in cosmic-ray dosimetry