Volume 13, Issue 10

Fragmentation probabilities and interaction mean free paths for the interaction of heavy nuclei (Z > 2) of the primary cosmic radiation with target nuclei of emulsions (Ilford G 5) have been obtained. The experiment has been carried out in Northern Italy, at a geomagnetic latitude of 46° N. The values are in good agreement with those reported previously by Fowler, Hillier, Waddington and Rajopadhye, Waddingto and Cester, Debenedetti, Garelli, Quassiati, Tallone, Vigone. Values are derived for the fragmentation probabilities in air by a geometrical model introduced by Noon and Kaplon. Assigning both to the incident particle and to the target nuclei a radius R = R 0 · A ⅓ , one obtains an effective nuclear radius R 0 =1,2·10 -13 cm. Using our values for the fragmentation probabilities instead of the lower values found in an experiment by KAPLON et al., their ratio for the fluxes of L-nuclei to M-nuclei at the top of the atmosphere is increased from 0.46 to about 0.80.

Experimentelle Untersuchungen des Verhaltens der 6,14 MeV-γ-Strahlung bei F 19 (p, α γ) O 16 ergaben folgende Winkelverteilungen: l γ (669) ∼ isotrop, l γ (598) ∼l +0,17 cos 2 θ, 1γ(340) ∼l-0,035 cos 2 Θ. Das im letzteren Falle gegenüber früheren Messungen abweichende Ergebnis steht in bester Übereinstimmung mit der begründeten Annahme, daß neben den s-Protonen auch etwa 1% d-Protonen an der Reaktion bei E p = 340 keV beteiligt sind.