The aim of this work was to determine energy dependence characteristics in terms of values of the personal dose equivalant, H_p(10). The following types of thermoluminescent detectors (TLDs) were investigated: (a) two new types based on lithium borate Li₂B₄0₇:Cu,In and Li₂B₄0₇:Cu,In,Ag; (b) two types based on the highly sensitive material LiF:Mg,Cu,P, TLD-700H and GR 200A; (c) two well-known types of LiF:Mg,Ti detectors, TLD-100 and TLD-700 and (d) highly sensitive Al₂0₃:C detectors. TLDs previously calibrated with ¹³⁷Cs gamma rays were simultaneously irradiated with X ray beams in the range of mean energies between 33 and 116 keV. The irradiations were performed with detectors in polymethyl methacrylate (PMMA) holders placed on a 30 cm x 30 cm x 15 cm water phantom with PMMA walls (ISO phantom). Measured energy responses were compared with calculated data for H_p(10) values. The results confirmed the satisfactory tissue equivalent characteristics of all investigated TLDs except Al₂0₃:C, which (due to its large energy dependence) is suitable for personal dosimetry only with an appropriate filter.