[en] (full text) As reported in previous annual reports, in 1997 the research activities of the Department were concentrated on tbe following areas: Dosimetry and Microdosimetry; Numerical modelling of interaction of radiation with matter; The main achievements in 1997 can be summarised as: -DOSIMETRY: Our activities in metrology of absorbed doses were focused on absorbed dose standardisation problems connected with use of ¹⁰⁶Ru and ¹²⁵I applicators for ophthalmological purposes. The metrological chain for absorbed dose determination in water phantom for a ¹⁰⁶Ru applicator is based on the use of a small size, parallel plate, ionisation chamber calibrated against Co in a SSDL laboratory and a scintillation detector NE1O2A. The scintillation detector (4mm³ size) is used for relative dose depth determination. Measurements of depth dose in water phantom for 14 seeds of ¹²⁵I (ropes applicator) were carried out using the same scintillation probe as for Ru applicators. -MICRODOSIMETRY: Works to optimise a JET Counter device for nanometric experiments have been progressing. The time of flight spectra of nitrogen ions for a wall-Iess condition were measured. The new method for absolute counting efficiency of the channeltrons for electrons with 50-1500 eV has been devised. The absolute efficiency of B419BL and KPE 07 channeltrons was determined. The preliminary results of ion cluster formation in a nanometre nitrogen cavity irradiated by 100 eV electrons were obtained. Activities in this field were supported by IV CEC Framework Programme as well as by the Polish State Commission for Scientific Research. - THE ENERGY RESPONSE of a HPGE detector was calculated using the MNCP code with MNCPDAT, 6 libraries for gamma photons emitted by ¹³⁷Cs and ⁶⁰Co isotopes. The calculated spectra were compared with measured ones as tests of the quality of the calculations. The MNCP code was used for modelling the influence of a large mass of scattered material, placed in the vicinity of this detector in the energy spectrum. - EVALUATED CROSS SECTIONS for high-energy transport codes for neutrons above 10 MeV, calculated by FLUKA, LAHET and CROSEC codes, have been compared with experimental data. Rather large differences were observed and, not surprisingly, this has led to further research recommendations. Work was done with Royal Institute of Technology in Stockholm (Sweden) and Joint Institute for Nuclear Research in Dubna (Russia). (author)