Bruno Rossi

Early days in cosmic rays

Early in 1928, shortly after receiving my PhD at the University of Bologna, I was offered the position of assistant at the Physics Institute of the University of Florence. The Institute rose among olive trees, on the hill of Arcetri, a short distance from the villa where Galileo had spent the last years of his life as a political exile. The chair of physics was held by Professor Antonio Garbasso who, in earlier years, had done some creditable scientific work. But the first world war and subsequent events had diverted his interests toward politics. He was now a senator and the mayor of Florence. However, he still went to Arcetri three times a week to deliver his lectures, and he still had a strong desire to see the Institute, which he had built, become an important center of research.

Evidence for heavy mesons with the decay processes Kπ2 → π + π0 and Kμ2 → μ + ν from observations with a multiplate cloud chamber→ μ + ν from observations with a multiplate cloud chamber

SummaryAnalysis of the data on S-events observed in the M.I.T. multiplate cloud chamber shows that these events represent the decay processes of two kinds of heavy mesons. The decay processes are of the type: Kμ2 → μ + ν and Kπ2 → π + π0RiassuntoL’analisi delle fotografie ottenute colla camera di Wilson a setti del Massachusetts Institute of Technology mostra che i cosidetti « eventi S » rappresentano processi di disintegrazione di due diversi tipi di mesoni pesanti, secondo gli schemi: Kμ2 → μ + ν e Kπ2 → π + π0.

The decay of 'mesotrons' (1939-1943), experimental particle physics in the age of innocence

An account is given of the experimental work carried out by the author and his associates during the years 1939 through 1943, which produced the first unambiguous evidence of the spontaneous decay of “mesotrons,” showed that this decay occurred according to an exponential law, as expected, and measured the mean life with a 3% accuracy. A by product of this work was a verification of the relativistic equation for the dilation of time intervals.

Cosmic Ray Bursts

During a period of over a year a number of experiments have been carried out, partly on the ground and partly aboard a B‐29 aircraft.

Ricerche sull’azione del campo magnetico terrestre sopra i corpuscoli della radiazione penetrante

SuntoSe la radiazione penetrante giunge al limite dell’atmosfera come una radiazione corpuscolare avente un’energia di alcuni miliardi di volt-elettrone, il campo magnetico terrestre dovrebbe dar luogo ad una forte dissimetria nella sua distribuzione di intensità rispetto al piano del meridiano magnetico. L’esperiema eseguita per mettere in evidenza questa dissimetria ha dato esito negativo.

Arcetri, 1928 – 1932

Early in 1928, a short time after receiving my doctorate at the University of Bologna, I was offered a position of assistant at the Physics Institute of the University of Florence. The Institute rose among olive trees, on the hill of Arcetri, a short distance from the villa where Galileo had spent the last years of his life as a political exile. The chair of physics was held by Professor Antonio Garbasso (Fig. 1) who, in earlier years, had done some creditable scientific work. But the first world war and the events of the post-war period had diverted his interests toward politics. He was now a senator and the mayor of Florence. However he still went to Arcetri three times a week to deliver his lectures and he still had a strong desire to see the Institute, which he had built, become an important center of research.

Moments in the Life of a Scientist

List of plates Foreword Preface Prehistory 1. Arcetri (1928-32) 2. Padua, Copenhagen, Manchester 3. Physics of elementary particles in the Age of Innocence (1939-46) 4. Los Alamos (1943-46) 5. Cosmic rays at MIT (1946- ) 6. Physics in space Postscript As for me ... Nora Rossi Index.

Breve descrizione dello stato attuale della X-astronomia

RiassuntoVengono passate in rassegna le linee di ricerca seguite nello studio di sorgenti localizzate di RaggiX nella volta celeste e sono esaminate le informazioni esistenti su alcune delle sorgenti meglio conosciute, con particolare riferimento al problema della loro identificazione con oggetti ottici. Viene inoltre studiata la distribuzione delle sorgentiX nella nostra Galassia ed esaminata la possibilità di osservare sorgenti extragalattiche.SummaryThe main lines of research in the study of localised sources of extraterrestialX-rays are reviewed. The existing data on the better-known sources are analysed, particular attention being paid to the problem of their identification with optical objects. The distribution ofX-ray sources in our Galaxy is studied, and the possibility of observation of extragalactic sources examined.