Summary
Attenuation coefficients of the nucleonic component of cosmic rays in the lower atmosphere are obtained both by measurements with a mobile monitor in summer 1963 and by statistical regression analysis on 1962 and 1963 data of 25 IGY neutron stations; the advantages of using the successive differencing method in this regression analysis are studied. The latitude dependence of the coefficient is clearly established at least for the stations at sea level (more than 10% difference between pole and equator values). An altitude dependence of the attenuation coefficient opposite to the one existing in the upper atmosphere is found in the lower atmosphere; here the coefficient decreases with increasing atmospheric depth, showing a hardening of the « nucleonic » component which is tentatively attributed to the increasing contribution of muons to the star-producing radiation in the IGY neutron monitors.
Riassunto
Si sono ricavati i coefficienti di attenuazione della componente nucleonica dei raggi cosmici nella bassa atmosfera negli anni 1962 e 1963, sia per mezzo di misure con un rivelatore mobile, sia con un’analisi statistica di regressione sui dati di 25 stazioni di neutroni della rete stabilita per l’A.G.I.; e si discutono i vantaggi ottenibili se si usa in tale analisi il metodo delle « differenze prime ». Risulta chiaramente stabilita, almeno per le stazioni al livello del mare, la dipendenza dalla latitudine del coefficiente di attenuazione (con differenza maggiore del 10% fra i valori al polo e all’equatore). Si trova inoltre nella bassa atmosfera una dipendenza dell’attenuazione dall’altezza opposta rispetto a quella dell’alta atmosfera; alle quote da noi studiate il coefficiente diminuisce al crescere dello spessore atmosferico mostrando un indurimento della componente « nucleonica » che potrebbe essere attribuito al crescente contributo dei muoni alla radiazione che produce stelle nel rivelatore AGI di neutroni.
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This work has been supported partly (mobile monitor project) by the NATO Research Grants Programme and partly by the Consiglio Nazionale delle Ricerche, Commissione Italiana per la Cooperazione Geofisica Internazionale.
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Bachelet, F., Balata, P., Dyring, E. et al. Attenuation coefficients of the cosmic-ray nucleonic component in the lower atmosphere. Nuovo Cim 35, 23–35 (1965). https://doi.org/10.1007/BF02734822
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DOI: https://doi.org/10.1007/BF02734822