We have investigated the time profiles of flare heating function for selected flares based on the analysis of their evolutionary paths in the Emission Measure - Temperature diagrams. The emission measures and the temperatures werederived from the Ca XIX soft X-ray spectra observed by the Bent Crystal Spectrometer aboard the Solar Maximum Mission satellite. Interpretation of these diagrams allows to study the rate of energy deposition during both rise and decay phase of flares. The investigation of (EM-T) diagrams during
the decay phase allows furthermore for determination of effective length/cross-sectional area ratio of the flaring loop. We háve used the value of this ratio to derive the effective loop cross-sectional radius and the plasma density from deconvolved Fiat Crystal Spectrometer soft X-ray images.
We have analysed the relations between basic physical parameters In the flarlng loops. Based on the results of the "Palermo Code" hydrodynamlc flare modellng, we have checked that even for transient energy Input, the energy deposltlon rate can be adequately expressed In terms of the actual maximum temperature of the plasma in the loop. Taklng thls Into account, we have used a slmple equatlon governlng the energy balance In the flarlng loop. Thls
equation relates the basic characterlstlcs such as: the maximum temperature, the mean temperature and the emlsslon measure wlth the loop's length and cross-sectlon as the parameters. Except the geometry parameters, the other characterlstics can be determined based on the soft X-ray spectral analysis. In the paper, we describe the diagnostic procedure called LEBAN which may be helpful In deriving basic geometrlcal loop parameters. Palermo model calculations have been used to test reliabillity of the procedure.