In the end of 60s, the study of the global characteristics of the hadron interactions was of common interest.
The behaviour of the total cross sections for the hadron interactions and the shrinkage of the diffraction cone with the energy increasing were hot topics at that time. In particular, the theory of Regge poles predicted constancy of the total cross sections in the asymptotic region of high energies accompanied by the logarithmic shrinkage of the diffraction cone. Also, it was a question whether the dispersion relations between the real part of the forward scattering amplitude and the total cross section remain valid.

In 1969, a new experimental method was suggested and worked out at PNPI for studies of the small-angle scattering of high energy hadrons. A hydrogen-filled ionization chamber (IKAR) used as a recoil detector was the base of the method. This method provided precise measurements of the differential cross sections for small-angle scattering of various hadrons with the absolute normalization at the 1% precision level.

First experiments using this method were carried out at PNPI in 1972. The pp scattering in the energy internal from 600 to 1000 MeV was investigated. In these experiments, the "puzzle of Dutton" was solved, and the validity of the dispersion relations in pp scattering at this energy was restored. Then, pp scattering at the energy of 40 GeV was studied at IHEP (Serpukhov). Later, pp scattering was studied at the energy up to 140 GeV (CERN, WA9 experiment), and at the energy to 400 GeV (CERN, NA8 experiment). These experiments yielded important results concerning the hadron interaction at available at that time energies. The most important results are the observation of the universal rise of the total cross sections and the universal shrinkage of the diffraction cone with the energy increasing.

(For more detail review see article "Diffraction scattering of high energy hadrons" in PNPI report of the High Energy Physics Division "Main Scientific Activities 1971-1996").