Observation of heavy cosmic-ray primaries over the wide energy range from ∼100 GeV/particle to ∼100 TeV/particle: is the celebrated knee actually so prominent?

We have exposed a new type of emulsion chamber of area 1.53 m 2 at an atmospheric depth of 11.7 g/cm 2 for 22.2 h. The chamber makes extensive use of screen-type x-ray films, which have recorded the tracks due to over 100 000 cosmic-ray heavy primary nuclei of Z ≥ 8. With this experiment we have succeeded in determining the absolute intensities of the heavy primaries over a pretty wide energy range from a few GeV/nucleon up to ∼ 1 TeV/nucleon, using a single detector and a unified charge-and-energy determination method. In the present paper we give a report of our results on silicon and heavier components, accompanied by a detailed account on our newly adopted energy determination method and a discussion of its accuracy