Alcune proprietà delle esplosioni nucleari nella r

Authors: A Lovati A Mura G Salvini G Tagliaferri

Publish Date: 2008/05/18

Volume: 6, Issue: 3, Pages: 207-216

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Abstract

Si riferisce su una ricerca eseguita a 3500 m sul livello del mare con contatori e camera di Wilson intesa allo studio delle esplosioni nucleari nella radiazione cosmica L’esame delle esplosioni nucleari ha messo in evidenza la presenza contemporanea di particelle fortemente ionizzanti e di particelle penetranti quest’ultime capaci di dar luogo a successive esplosioni nucleari Sono state studiate in particolare la diffusione nel piombo delle particelle penetranti di queste esplosioni che non ha messo in evidenza alcuna interazione non coulombiana e la sezione d’urto media per la produzione di successive esplosioni nucleari nel piombo che è invece risultata ∼ 10−24 cm2 per nucleo pari ad un cammino libero medio di ∼ 330 g/cm2 Quest’ultima interazione ci permette di concludere che le particelle penetranti delle esplosioni nucleari non sono di massima mesoni μ ma piuttosto protoni o mesoni πWe report the results of a research in which we studied nuclear bursts in cosmic rays developed with a countercontrolled cloud chamber at the Laboratorio della Testa Grigia 3500 m asl The arrangement used is shown in fig 1 The cloud chamber expanded whenever one counter at least was discharged in each of the groupsA1A2B1B2 or in each of the groupsB1B2C1C2 and for this two particles at least were necessary In 12200 minutes 801 photographs were obtained from which we selected 120 which containa groups of particles originating from a common point in the leadS or in the three plates inside the chamber and in which penetrating particles recognisable for not generating secondaries in any plate or heavy ionizing ones were presentb showers with no evidence of penetrating particles but surely descending fromS so that the showers appeared under 23 cm of lead referred to as electron showersc some other events that were worthy to be noted Thirtyeight photographs present showers of penetrating particles only produced in the leadS 9 present mixed showers and 16 electron showers Twentytwo photographs present nuclear bursts produced in the lead plates of the cloud chamber Tabella II Penetrating showers observed by us are nearly all produced in the deeper region ofS We observe moreover that the penetrating particles of a penetrating shower which we see in the cloud chamber are normally not the same which have dischargedA1 andA2 This is in accord with the hypothesis that socalled penetrating showers are due to the more energetic bursts and contain a large number of short range particles too in agreement with a recent suggestion ofPowell and coworkers We have measured the scattering angles through the three plates of 38 penetrating particles associated in bursts produced inS The scattering observed Tabella I is never larger than 6° except in one case 9° and can be explained with Coulomb scattering alone without any anomalous scattering The examination of the nuclear bursts produced in the plates of the cloud chamber with particular regard to those produced by ionizing particles of nuclear bursts from the leadS lead us to a sort of cascade representation in which the most energetic of the produced particles may successively give rise to new bursts The mean cross section for new bursts production by ionizing particles of nuclear bursts has resulted of the order of 10−24 cm2 per nucleus This rather strong nuclear interaction confirms that the particles produced in nuclear bursts are not generally μmesons but rather protons or πmesons

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