PoS(CRA School)032

http://pos.sissa.it Licence. Licence. rch activities in . Due to the introduced this field in the country this research area. Although many ttes to making this one of Brazil’s most edicating their efforts building detectors, built built and over the past eighty years there and Lattes are the main protagonists of the physics in Brazil, one must acknowledge the tadualde reative Commons Commons reative Attribution-NonCommercial-ShareAlike

1 [email protected] Speaker Speaker have have always been one or more groups of scientists d around 1930, a tradition in cosmic ray physics was performing experiments and obtaining physicists spent their lives top working in cosmic ray results in enormous contribution of and Cesar La story of cosmic ray physics in Brazil. Cosmic rays have long been a topic of intense resea contagious enthusiasm and excellence of the men who traditional areas of research in Physics. Wataghin 1 Copyright owned by the author(s)of the owned terms by Copyrightthe C under

Cosmic Ray Physics in Brazil Brazil in Physics Ray Cosmic Carola Dobrigkeit Campinas, Brazil E-mail: 4th School on Cosmic Rays and Astrophysics São Paulo,Brazil August 25- September 04, 20 Instituto de Física Gleb Wataghin – Universidade Es

PoS(CRA School)032 y, with with y, igures. igures. ting parallel ting eds germinated eds germinated Carola Dobrigkeit ents of cosmic ray interactions induced ibuted to the creation ar emulsions exposed exposed emulsions ar . . One of the scientists l were responsible for n developments which lel in these two cities, to the development of rticularly rticularly of cosmic ray ierre Auger Collaboration s was abroad, it strongly rty rty years this collaboration od is characterized by the asileiro asileiro de Pesquisas Físicas limits of these periods are São São Paulo, where a group of n almost simultaneously by support support agencies in the fifth , in Rio de Janeiro and in São story of cosmic ray physics in almost almost eighty years can be best hysics, and with the creation of in was Bolivia, which to be used eV. The fourth period is the h one has its own characteristics rn science in Brazil started much from from 1916, it was the creation of 17 n the first observation of artificially ientists ientists involved in cosmic ray physics and 10 13

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The The story of research in cosmic ray physics in Brazil over and bears an interes 1933-34 in starts in physics Brazil ray of cosmic story The Two European physicists arriving almost simultaneously in Brazi followed followed by telling it over four successive sometimes periods. blurred in time and Even part of the if periods overlap, eac the and peculiarities. The seeds of cosmic in Those inse Janeiro andBernhard by Gleb Wataghin, Rio de Gross, São Paulo. ray research were sow around the two pioneers, grew and became particularly strong in young and dedicated scientists built detectors showers at the and ground, in a mine, in a performed tunnel, on a mountain or in measurem a plane the stor of the period second began and his work him With Lattes. Cesar was group in the in nucle of the pion discovery and the research of the results the major first to cosmic radiation. Although the discovery was made influenced while the Latte future development of the research in physics, and physics, pa in Brazil. Returning to Brazil after participating i produced pions, Lattes participated in the creation of the Centro Br in 1949 and of the Conselho Nacional de Pesquisas in 1951. He also contr of thede Cósmica at Física Laboratorio the Mount Chacaltaya, by physicists of many countries in their research done by research. the Brazil-Japan Collaboration. Over more than The thi third peri exposed emulsion chambers at Mount Chacaltaya and studied high energy by cosmic ray particles at energies between 10 1. Introduction contemporary one, in which Brazilian physicists are involved in the P to study cosmic rays of the highest energies ever observed. The Brazil will be told here with focus on recent years. the most of success and the progress enabled the beginning and on the mai (1934-1949) The beginning: pioneers the 2. with the story of the development of systematic research in P universities and research institutions in Brazil. Although mode earlier, with the support of the Brazilian Academy of Science universities in the third decade and of research institutions and decade of the last century that provided conditions and gave Science in Brazil. In all impulse these steps the contribution of sc was of great importance. importance. ofwas great introducing introducing cosmic ray physics to scientists working, respectively Paulo. So it happened that research on f inspiring two the around gathering students of young groups with two schools forming this topic developed in paral Cosmic Ray Physics in Brazil PoS(CRA School)032 the the he Gross . osphere. osphere. Gross Carola Dobrigkeit theoretical and s of Physics and la Politécnica in São y of Sciences in Brazil Brazil in of Sciences y ing ing aspects of those ão Paulo in 1934. The cosmic cosmic ray physics in words of some of his lecturing in São Paulo. himself to research in esults esults of experiments he at 250 m depth at Lake unidirectional unidirectional beams of 1]. 1]. s in Europe to attract them intensity of cosmic rays in my of Sciences [4-10]. of Sciences [4-10]. my hed in 1934 and so Gross er [14]. It is also interesting

s, landing in Rio de Janeiro in had started in Europe with his ts in glasses and polymers. His a, a, had created the Faculdade de radiation. This work was done mportant mportant influence of Gross and the development of Physics in integral (omnidirectional) rate of to gradually change the subject of ntensity ntensity of a certain radiation per ticity ticity and rheology. He was also Fantappié and the Russian-Italian rious rious materials, like carnauba wax tarting tarting points of the Universidade de nd nd at the Instituto de Tecnologia (later ure dependence of the ionization caused

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Gross is best known in the cosmic ray community for his work on t In the following years, Gross worked at the INT and dedicated His interest in the interaction of radiation with matter that Gross was a complete scientist, analyzing phenomena both from the The The first cosmic ray physicist to arrive was Bernhard Gros The second scientist to arrive was Gleb Wataghin, who came to S named named Instituto Nacional de Tecnologia (INT)), presenting interest 1933 just after his finishing PhD in Gross Germany. brought with him r had performed there with the group of Erich Regener, measuring the the stratosphere and under water. These measurements had been made Constance and with probes on balloon flights up to almost 20000 m in the atm held seminars and gave talks at the Escola Politécnica a measurements. A short version of these presentations [ rays cosmic about in Brazil publication first the of author the became was publis Transformation [2], which relates the absorption radiation. Using of this transform one isotropic can obtain and the vertical i unit solid angle at a certain atmospheric depth in terms of the that radiation at this depth. He applied this relation to cosmic prior to his arrival in Brazil, as was a study of the press [3]. radiation cosmic by cosmic rays and metrology. He published the Acade Brazilian the results of Annals the in as as well journals international of his work in early studies of the ionization caused by cosmic rays led him his research and he later studied dielectric properties of va on topics such as he worked mostly interests, his multiple by motivated [11, 12]. 1940, After theory of dielectrics, the thermodielectric effect, viscoelas responsible for the discovery of important charge storage effec research. in electret progress for important most were contributions experimental experimental perspectives. He was one of the key players Brazil. His students and in collaborators often theacknowledged i his contribution to the development of Physics, as can be found in many students and colleagues, the S. Mascarenhas [13] and G. M. Sessl Histor on the projectfor a in an interview testimony own Gross’ to follow [15]. Governor of the state of São Paulo, Armando Salles de Oliveir Filosofia, Ciências e Letras (FFCL), that was one of the s São Paulo (USP). He gave Teodoro Ramos, then professor of Paulo, the mission the of inviting eminent mathematicians Esco and physicist to settle in São Mathematics Paulo at the FFCL. and The Italian mathematician contribute Luigi to physicist develop Gleb Wataghin accepted the invitation and by the1935 they were new Department Enrico Fermi from came to São Paulo tocome Wataghin invite to suggestion The Cosmic Ray Physics in Brazil PoS(CRA School)032 published in he coincidence he coincidence s of particles in Carola Dobrigkeit ts ts of a series of who, inspired by h his characteristic iod iod 1931-1934 with ted to work with him scola scola Politécnica, the n physicist Giuseppe l group in São Paulo. São Paulo. in l group tive tive with those used in At the very beginning had worked together in together had worked ributions ributions to astrophysics, relativity. relativity. He also talked m m to express himself in of of the positron in cosmic esearch esearch activities both in t ground level, in a tunnel, by Wataghin’s group. The The group. Wataghin’s by he vanguard of cosmic ray o learn the language just to er er joined by Paulus Aulus t t he had met in Europe and measurements were done in amy amy and Wataghin published ating ating particles in cosmic ray f Morro Velho, in the state of São Paulo in 1937. As early as y y have applied the coincidence d to the new university. Students earch. earch. The coincidence circuits that insight insight and creativity made a strong xisting xisting in those days and enabled the theory theory of multiplicative showers and

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With With the creation of the Universidade de São Paulo (USP), the E Although he himself was a theoretician, Wataghin initiated r Mario Schönberg was one of Wataghin’s first students and soon star theAmong students of was engineering Marcello Damy de Souza Santos of Systematic measurements the radiation cosmic instarted In the following decade many experiments detecting penetrating shower In 1938, Wataghin and Marcello Damy published the preliminary resul In the following year, having been joined by Paulus Aulus Pompeia, they Faculty Faculty of Medicine and the Faculty of Law were incorporate of Engineering attended lectures together with Wataghin those held lectures in of Italian and some the of his students FFCL. began t follow these lectures. But his gift Portuguese. for He languages introduced soon the allowed students hi to enthusiasm about modern the birth physics, of quantum talking mechanics or wit the theory about the of great physicists responsible for these breakthroughs tha friends. his had become who theoretical and in experimental physics. In to Occhialini Wataghin toand theOcchialini join São Paulo department. 1938 he invited the Italia Enrico Fermi’s group in Rome. Occhialini had Patrick Blackett at the Cavendish also Laboratory in Cambridge. The worked in the per counter technique to a cloud chamber and confirmed the discovery rays. His extraordinary experimental skills, acute intuition, experimenta of the capability and expertise the increasing to contribution on theoretical problems. Although he is best remembered for his cont he also worked in cosmic ray physics, particularly in the [16-20]. radiation cosmic of components ultra-soft and hard on the the enthusiasm of Wataghin, became t building for responsible and were keen Both were on electronics, very Pompeia. his assistant. He was lat done radiation cosmic to explore experiments first in the circuits used instrumentation and electronics developed by this group were competi Europe and USA at the time, as were the results of their res were built by the group were ten times faster than others e measurement of penetrating showers, experiments which were at t time. the at physics this, while preparing an experiment for measuring cosmic rays, D [21]. counters of types new in building progress their experimental cosmic radiation by were Wataghinperformed and collaborators his a altitudes. at mountain or underground measurements of the cosmic shower intensity in the gold mine o [22, 23]. m 400 200 and of depths water-equivalent at Minas Gerais, Physical Review the results of observations of groups of penetr showers which arrived simultaneously at the detectors [24]. Those Cosmic Ray Physics in Brazil PoS(CRA School)032 enezes, enezes, Mario [26]. [26]. In those construction at Carola Dobrigkeit hialini hialini and the ess, ess, the results of below below 30 m of clay had to work with ]. A more complete [26]. In follow-up rg rg and Wataghin in with with the purpose of 2 become become his assistant. onal journals [32]. [32]. journals onal asurements, asurements, the group Schützer Schützer involving the lished in [34]. in lished l. A group of American used [27]. used [27]. ficulty ficulty in handling the Aulus Aulus Pompeia. Most of ions ions on the abundance of eoretical eoretical and Mathematical n Academy of Sciences in f the shielding around the timate a lateral spreading of ed ed by him some years later on, a symposium on cosmic also in this Symposium that onfessed onfessed that what had made cloud chamber, but without e of showers with at least two e with least of two at showers national national journals and only the São Paulo, also as a student of ed groups of particles that had Joaquim Joaquim Costa Ribeiro, Yolande azilian azilian Academy of Sciences. The nce nce in theoretical andphysics what symposium symposium were outstanding. The the the University of São Paulo. In his es having es having a range larger than 17 cm of [28].

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Results of other measurements were reported to the Brazilia By 1940 [25] the results of measurements made in the tunnel then under The year of 1941 was exceptional for cosmic ray physics in Brazi In 1941 Cesar Lattes hisstarted studies at the University of During 1945, Lattes was very interested in the activities of Occ São Paulo at about 800 m above sea level. The counters register of lead. cm of 16 a layer through coincidences fourfold produced 1940 [25] and published was Damy by built been that had circuit multivibrator the measurements in the following year in the Physical Review the Avenida 9 de Julho, in São Paulo were presented. Measurements done the existenc tunnel in confirmed the (about water 50 m equivalent) associated particles penetrating 20 cm of counters) even underground. In lead the next publication (the of this series thickness of me o reported the existence of showers with at least two particl measurements, a fifth counter was added which allowed them to es 1 m of an area over shower core the penetrating physicists led by Arthur Compton measuring visited cosmic rays in the the southern hemisphere. On country this occasi on a rays was mission held in Rio de Janeiro, under the auspices of the Br contributions of the Brazilian cosmic ray physicists at this list of authors includes Bernhard Gross, his former student Monteux, , Gleb Wataghin, Marcello Damy, Adalberto Schönberg, M Francisco Xavier Roser, J. A. Ribeiro Saboya and Paulus the presentations at this symposium were also published in inter reference to the annals of the symposium is given here [29]. It was Wataghin presented the hypothesis of multiple production of mesons [30 treatment of the multiple production of mesons was to be present [31]. Wataghin. Wataghin recognized his potential and soon invited After him to graduating in 1943, Lattes started Theoretical Physics. In 1944 working he was designated third assistant in with Th Mario Schönbe Physics at the Faculdade de Filosofia, Ciências e Letras of first work he studied the influence of extreme thermodynamic condit in internati publication first his produced work This universe. in the nuclei experimental group. Occhialini was trying very hard to install a success. Lattes very liked to much talk about his experie first had been the reason for tohim move to physics. experimental He c him change from theoretical to calculations. Then experimental he physics would add was with his consisted a smile dif of that 99 the Langrangean terms. he He calculations he had talked done with Schönberg about in collaboration with this Walter choice were pub moments dipole with point-particles of charged theory classical in [33]. Nonethel lead and with a size of the penetrating core of the order of 0.2 m Cosmic Ray Physics in Brazil PoS(CRA School)032 s s s. leus leus ion of ion of hin. Meyer hin. Meyer stratosphere. In In stratosphere. Carola Dobrigkeit and been been done with ghin ghin was given measurements at nerate nerate penetrating nd around 7000 m s s 10 mm and also the mean absorption performed by Cocconi scientists doing those al apparatus al was apparatus similar he he data revealed that the urements urements of the variation s, he concluded that the an an absorber layer of water ons ons seem to indicate that ative ative studies of showers of ure ure of the primary particles type type of balloon was usually s Lattes: Oscar Sala. During d in a layer of water of only sumption sumption of an exponential s explained their experimental showed that the intensity of at an 1750 above altitude of m ded that “this layer as functions resulting resulting showers depended on ltitude ltitude of 22000 feet and 26000 . He decided to study Physics in irst irst series of measurements with ed very rapidly with atmospheric ndicating ndicating that either the absorption erials erials at altitudes of 1750 m and 750

6 [37]. 2 cm -25

. Wataghin even reported an estimate of the cross sections per nuc 2 Further experiments were done in the group to study the cross section for the for product section cross the to study done in group the were Furtherexperiments In In later years two more papers appeared investigating the nat Another Another student initiated his studies at about the same year a In the following year, Wataghin published further results of meas A A thorough study of the frequency of penetrating showers was done by A second paper by Sala and Wataghin [36] also reported comparative of the frequency of showers during flights in air plane at an a feet. With the inclusion of these two observed altitudes to variation the with previous altitude one was in absorption law agreement for with the the shower producing as primary radiation, length around 101 estimating g/cm 2.5 x 10 around or nitrogen of oxygen penetrating showers in various materials. The results of the f water and iron as shower-producing materials were reported in [38]. T cross section per nucleon was larger in water than in iron, i coefficient of primaries or the constitution and multiplicity of Watag son of Gleb Andrea, was of the this work authors of One structure. the nuclear and Schwachheim also published an interpretation of the measurements [39], considering possible exchange phenomena [40]. showers of the nucleons that ge showers thepenetrating generating from ofresults measurements sea level at Campos de Jordão. In the first paper [41] the author Compton’s Compton’s mission in 1941, measurements of balloons launched from some cosmic cities in the state of ray São Paulo. This intensities had andup reached into measurements 20 employed meteorological into 30 thekm Bauru, a young student whose family lived experiments and in got inspired and excited: this this was Oscar city Sala watched the shower ray cosmic and measuring Wataghin with working also he began soon and São Paulo different altitudes, at São Paulo (750 m) and Campos do Jordão (1750 m), a with measurements done in three airplane flights. particles The generating the results showers of penetrating rays decreas depth, probably following an exponential (FAB). Air Force the Brazilian by assistance law. For this experiment Wata Wataghin Wataghin [35]. In this work the authors presented results of compar penetrating particles at various altitudes with different mat in m, Campos de Jordão and inThe São experiment Paulo, respectively. wa and coincidence Fourfold his Wataghin group. by done experiments to previous used that in observed between counters fully surrounded by lead of minimum thicknes separated by 10 cm of lead. Further measurements were done adding of 80 thickness.their cm the From authors conclu measurements an absorber and as a source of secondary groups of radiation. particles penetrating more than Our 30 cm of observati Pb are produce 80 cm”. Cosmic Ray Physics in Brazil PoS(CRA School)032 ion on the on the ion Carola Dobrigkeit finally succeeded, ulsions. decay of samarium. c ray physics. He did diation diation producing the α about about the production of i in Bristol and received ame ame to work with Cecil th a higher concentration es es in the showers as “µ- enthusiasm while telling the the samarium decay time ber and trying to put it to in Campinas and a new 42] 42] the mean range of the the the Physics Institute of the tons and alphas in the new ferred. ferred. In recognition to his sions produced by by sions Ilford produced Ltd. egration products. Occhialini rking rking with these new plates. al al of this type of detector and s idea, opening his arms and the the atmosphere and in water, to the publication of Lattes, rators and friends rators he and friends had made n Bristol in 1946. Shortly after n this paper the transformation so dear to him. Then he would ation ation obtained in the study of d- study study the or or of the Physics Institute and to o Campinas, to the recently founded

7 , respectively. No waseast-west asymmetry ofobserved 2

and ~ 55 g/cm 2 reactions, Lattes and Peter Cuer were able to determine α When Occhialini arrived in Bristol at the end of the war, he c At the same time Lattes was working at USP on a cloud cham One of the first tasks Lattes was given in Bristol was to Wataghin Wataghin returned to in 1949 and continued working in cosmi not collabo ties his students, the break and country with the many during the years in Brazil. He returned in the seventies t , where Marcello Damy was the direct where Cesar Lattes and his group of cosmic ray physics had trans extraordinary contribution to the development of Physics in Brazil, new university was named after him. Wataghin generation also of students could held learn from him and lectures be influenced by his about the birth of Quantum Mechanics, about General Relativity and fireballs in high energy interactions of cosmic rays, which was always repeat the comment of his friends at that time are dreaming….”. you “Wataghin, them: imitating about thi of (1946-1959) The pion and discovery the its consequences 3. Powell. and time At that emul Powell group nuclear his were using radiat to cosmic emulsions had also group The exposed nuclear reactions. for studying Jungfraujoch, in the Alps, at 3500 m and looked for nuclear disint soon started to work with these emulsions and with some new ones wi Ltd. by Ilford experimentally been produced had which bromide of silver work in collaboration with Ugo Camerini and Andrea Wataghin. When they Lattes sent some photographs obtained with this chamber to Occhialin in return some positive prints of photomicrographs of tracks of pro recognized theLattes immediately emulsions. concentrated potenti demonstrated his interest in joining the group in Bristol and Occhialini and wo Powell then invited him to come and he arrived i em with new the work to and group the join to Camerini invited he his arrival results results considering two different types Occhialini of and Powell in mesons, 1947, and referring identified the penetrating particl mesons”, as muons were called at that time. In the second radiation paper [ that generates penetrating showers was determined in inresulting ~ 120 g/cm this radiation within the experimental errors. As a curiosity, i proposed by Gross [2] was used in the study of the absorption of the showers. penetrating ra Using the new concentrated emulsions and the relrange-energy p and d- [43]. Cosmic Ray Physics in Brazil PoS(CRA School)032 the new new the nt image nt image beams beams of larger multiple Carola Dobrigkeit es at high altitude. ents than the normal through the reaction in Nature [47]. In the rmal rmal plates and those an Andes, only 20 km emerging from itsemerging end, a a meteorological station ssary, ssary, Lattes went to the ccelerator ccelerator at Cambridge) e processed and scanned. only only a few days a second emulsions. The protons he ingle ingle charged particles [44, ained. After recovering the or or of the new concentrated ticle ticle tracks were registered tracks in the borax-loaded of energy and direction of ench ench Pyrenees and exposed sity sity with the range made it ogeneous ogeneous groups of protons lation lation between the energy of one that he chose to fly with ts found an unusual event. In involved it was possible to ain ain a range-energy relation for x x to the emulsion. His intention asuring asuring neutron energy became ini ini that he fly to South America passengers [46]. The rest of the of of the same order as in the first ide ide the emulsion. Measuring the choice saved his life, because the

8 particles used in the experiment were from natural α C C to produce a beam of neutrons with an energy distribution 12

B B (d, n) 11 H. H. 3 particles and other light nuclei and their range in the new ) α α Lattes was also given the task of obtaining the shrinkage fact Lattes and Occhialini then decided to expose some emulsion plat When it became clear that a larger number of events was nece B (n,B 2 used were produced in well-known primary nuclear deuterons of reactions 900 keV induced (produced in by the homogeneous Cockcroft-Walton a falling on five targets of light elements. calculate the energies of Knowing the protons. The the masses Department of Geography of the University and found that there was operating on Mount Chacaltaya, at 5200 m above sea level in the Bolivi far from the capital La Paz. He proposed to Powell and Occhial and expose the borax-loaded emulsions. Lattes liked to tell every the Brazilian company instead of the British one and that this flight he were supposed to be in crashed in Dakar allkilling the story is well known. When he returned to Bristol, the emulsions wer decay decay of radioactive elements. Measuring the mean range of hom emulsions emulsions and to calibrate them. He decided to investigate the re protons, and alphas, Lattes, Peter Fowler and Peter Cuer were able to obt protons up to 10 MeV which would be useful in future research on s 45]. In this process he asked the fabricant Ilford Ltd to add bora was to use the reaction peaked at 13.4 MeV and obtain the energy and momentum of the neutrons 10 Occhialini took the plates to the Pic-du-Midi (2800 m), in the were of all but withloaded borax, of the plates some had been for Only sixthem weeks. Fr concentrated type, for which the range-energy relation had been obt emulsions, Occhialini developed them and a difference between the no loaded with thehadborax appeared: evmore emulsions many borax-loaded and the late to fading the resistant more emulsion had made borax The of ones. addition was kept for a longer time. Consequently a greater number of par compared to the normal plates. The number and the variety of the emulsions were so impressive that the original intention of me secondary. After a few days of scanning, one of the microscopis Lattes own words, he this describes event as “one and,stopping meson new meson of about 600 µ range, scattering all shown contained by in that the track and emulsion” the [46]. variation The of the possible grain to distinguish den the observed particle from a proton. Within event was observed, but the secondary particle did not stop ins grain density, it was possible to obtain the extrapolated range event, around 610 µ. The observation of these two events was published same volume Lattes and Occhialini published the [48]. emulsions of such means by obtained neutrons, ray cosmic determination Cosmic Ray Physics in Brazil PoS(CRA School)032 ed ed

attes believed in the centre- Carola Dobrigkeit to be detected. be detected. to d artificially d atartificially the t to look for. Two d been exposed to ina [57]. [57]. ina results. results. The first one nológico. nológico. CNPq is a expectation was that ation. Lattes tells that eson with the particle ounting ounting of the tracks it tists tists created the Centro as as leaving Berkeley in rica. He presented the observation of positive ars research activities in the Rockefeller Foundation he one detected in 1937 by hese observations hese were observations never ogy, ogy, for fostering research in t the decay mode resulting in muons [56]. Another simple South America. Cosmic ray he internal momentum of the and lecture at the Faculdade onselho onselho Nacional de Pesquisas rkeley, rkeley, which were offered by d referred to pions produced in cond cond meson. The results were plates which had arrived from applied applied magnetic field, the mass Ilford. Ilford. Using the measured range k on these emulsions. This gesture This k on gesture emulsions. these was able to find pion tracks in the arly arly years. The first scientific work e left USP and to transferred Rio de isa isa Frota Pessoa and Neusa Margem

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particles of 380 MeV had insufficient energy to produce pions. L α Lattes left Bristol at the end of 1947 with a scholarship from Lattes reported another curious fact in [46]. Just before he w Lattes returned to Brazil in 1949 and with other Brazilian scien In 1951 Lattes also participated in the effort to create the C Thirty Thirty events were found showing the double meson decays. From the c was also possible to obtain the mass ratio published of immediately the [49, first 50]. and The se authors identified predicted the by heavier Hideki m Yukawa [51] and the secondary particle as [53]. and Stevenson Street by t independently and [52] and Neddermeyer Anderson with theforwith intention looking of Eugene Gardner working pions produce 184-inch cyclotron which had begun to operate at Berkeley. The general the beam of that the energy could be sufficient in those collisions in which t nucleon was aligned with the momentum of the beam, providing enough energy of-mass system. Only one week after arriving in he Berkeley, emulsions. This rapid discovery points out the importance of knowing wha papers were published describing the method which had been used and the described the observation of negative pions [54] and the second, pions being produced the [55]. Most of the results that were reporte carbon targets. The photographic plates used were those from of the pions in the emulsion and the radius of curvature in the masses. electron 300 be about to estimated was pions of the February February 1949, Edwin McMillan asked him to look at some plates that gamma rays produced at ha the 300 MeV- electron synchrotron, then in oper he deliver and that in next pions, the morning adetect dozen about in to he one able was night the plates to McMillan with maps informing where to find them. T pions photoproduced first the be would these Lattes, to according but reported, Brasileiro de Pesquisas Físicas (CBPF) in Rio de Janeiro. H Janeiro to become the first director of the new Nacional research centre de Filosofia, Universidade do Brasil. In Physics the at following CBPF developed ye and attracted students from all over physics has been one of the main research fields since the e done by physicists in CBPF reflects the legacy of Lattes. El employed nuclear emulsions irradiated at the accelerator of Be Lattes, for studying the decay of positive pions and concluded tha electrons was at least hundred times less frequent gesture than that of in Lattes impacted on Argentinian Estrella Mazzolli cosmic de Mathov ray with some emulsion Physics in formed a toBristol. Estrella students group and started of wor South Ame in Argent physics ray cosmic of development future the for an impulse gave (CNPq), now Conselho Nacional de Desenvolvimento Científico e federal agency, connected Tec to the Ministry of Science and Technol Cosmic Ray Physics in Brazil PoS(CRA School)032 and the a that had a thathad Carola Dobrigkeit es, as Research constructing a e there. A very

y y of Chicago. The aboratory aboratory of cosmic porting to porting Chacaltaya chnicians. Apart from from Apart chnicians. ira, Fernando de Souza nvolved nvolved in cosmic ray osmic osmic ray physics was yor yor de San Andrés and al was approved by the studying studying the dependence rts. rts. Such expeditions are s at Chacaltaya. They also tors tors to cosmic radiation at d as detectors and exposed livia livia and in various other nd nd personnel to and from Bolivia, just to name a few. r possible, the transportation mica mica at Chacaltaya over the o CBPF, Roberto Salmeron, son son responsible for installing not not published in international easuring easuring the mean of life time Chacaltaya. In the following technological technological development of The emulsions. importance of Correio Aéreo Nacional of the ttes, Occhialini and Powell had was impossible, transportation nd meetings were organized and r. Even before approval, scientists es of the decays of pions produced s of the University of Chicago and

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In In the same period, work began on the construction of a permanent l In the early fifties the main instrumentation for research in c Between 1955 and 1956 Lattes spent a sabbatical in the United Stat Brazil and has been of utmost importance for the scientific and years. last sixty in the the country ray physics at Mount Chacaltaya. Ismael Escobar had been the per the one on Mount Chacaltay including in stations Bolivia, ofa meteorological network drawn Lattes’ attention when looking for a place for hisexposing the discovery of the pion and the observation of its decay by La worldwide repercussion and inspired permanent Escobar cosmic ray to laboratory at present Chacaltaya in the 1949. Universidad His proposal propos Mayor of de San Laboratorio de Andrés Física Cósmica was created in and this same yea by the from various countries Bolivian came to Bolivia in Government missions to expose detec in 1951 this special site. In 1952 an agreement between the CBPF was Universidad signed Ma and Brazilian physicists also came to work at years scientific expeditions from various countries arrived a held in Bolivia giving an enormous impulse detailed report to about the the history of development the Laboratorio of de Fisica Cos Scienc decades and its relevance for the development countries of can Science be in found Bo in [58]. te and physicists Bolivian with in collaboration the at Laboratorio research Various Brazilian physicists were i Lattes, also Occhialini and Camerini, both returned from Bristol t Hervasio de Carvalho, Alfredo Marques, Rudolph Thom, Ricardo Palme Barros worked there with Ismael Escobar and Alfredo Hendel from Georges Schwachheim and Andrea Wataghin developed a project for of penetrating shower creation on altitude, but their results were journals. available at CBPF and subsequently taken to Chacaltaya. Wheneve from Rio de Janeiro to La Paz was done in regular flights of the Brazilian Air Force, which assisted in Bolivia. For larger transporting or heavier detectors, when equipment the use of a planes was done by train and small trucks. Rivers described and in documented [59]. One expedition organized was for trans were crossed in ox ca a cloud chamber donated to CBPF by Marcel Schein, intention of towas Lattes and collaborators usefor the chamber m from the Universit the pion and investigating the density and energy spectrum of shower showers. the in detected particles unstable and mesons other study to intended Associate at the Enrico Fermi Institute for Nuclear Studie later at the University of Minnesota. He participated in studi in high-energy cosmic ray interactions. Nuclear emulsions were use 61]. [60, publications came this period From altitude. 30 km at on balloons Cosmic Ray Physics in Brazil PoS(CRA School)032 Carola Dobrigkeit n 1949 after the ray research was eV. eV. 17 national national Cooperative of research activities of research activities invited him to return years years later. Japanese o o of Tanikawa [63]. It epting the invitation at at invitation the epting particle predicted by ic ray physics in Brazil nteractions nteractions at energies smic radiation smic inradiation balloon ching ching activities at CBPF community community of Japanese azil-Japan azil-Japan Collaboration. mulsions mulsions were distributed early early sixties, when Lattes ant ant results about nuclear hambers hambers to be exposed at vour vour of it being a fermion, and 10 and Lattes in USP was one of of Chicago. The balloons 51] and was consistent with 13 he he discovery of the pion and higher higher energies. Research in theories in Japan in 1942, the in 1947 gave decisive evidence ted in this fruitful collaboration le responsible for nuclear forces nt to invite Yukawa to São Paulo ith ith nuclear emulsions exposed at ant event for Japan at that time still nd initiated a research group at USP

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Returning Returning to Brazil in 1957 Lattes resumed his research and tea Between 1960 and 1962 Lattes also participated in the project “Inter A new period of intense experimental activities started in the At the end of the second period the pressure on the field of cosmic In the third period the majority of physicists dedicated to cosm It It is interesting to remember the circumstances that resul and at the Universidade do Brasil in Rio de Janeiro. In 1960, Schoenberg to the University of São Paulo. He accepted the invitation a for investigating cosmic ray interactions at high energies w Chacaltaya. Emulsion that Flight”, with chambers emulsion tohad been exposed co flights by Marcel Schein and his co-workers from reached an the altitude of around 30 km. After University chemical processing, the e among various laboratories in 15 different countries. The group of those. and collaborators prepared the construction of the first emulsion Collaboration. Brazil-Japan the by Chacaltaya, Mount c ) - The (1959 Brazil-Japan Collaboration 4. growing, with more accelerators being built and attaining even cosmic rays gradually changed time. the at accelerators in unobtainable the focus to studying nuclear i were participating in the emulsion chamber experiment with the This Br collaboration lasted over thirty 10 between at energies particles ray cosmic by induced interactions years and produced signific and the ties that connected physicists from those two countries. T its decay into the lighter muon by Lattes, Occhialini and Powell of the existence of mesons predicted in 1935 by Hideki Yukawa [ the hypothesis of the two-meson theory of Sakata and Inoue [62] and als is worth mentioning that although these authors presented their corresponding papers were published in physicists had international also journals participated only in discussions Yukawa. While about Marshak and Bethe the [64] presented arguments in spin fa of the Taketani and his collaborators defended the idea that the partic should be a boson [65]. confirmation of existence of mesons. This was Yukawa a very import received the Nobel Prize recovering in from Physics the i war. In immigrants in Brazil recognition and their descendants started a moveme of this importance, acc from him health prevented visit. Yukawa’s his for funds and collected the this occasion, so the that funds were tosent Japan to be used in the support Cosmic Ray Physics in Brazil PoS(CRA School)032 , 2 apanese apanese and 33 m 2 s lead plates, at s lead at plates, as successful in in as successful altaya altaya was of a Carola Dobrigkeit o known in Japan . llaborative llaborative research altaya, where altaya, Lattes in level, 1958. Since experimentalists experimentalists for a apanese apanese scientists and ted ted Japan to attend the n. n. Fujimoto also reports d organized in 1954 and . In . orderIn to attain higher chamber. chamber. In this way the ount ount Chacaltaya. Yukawa informing him about the on between Japanese and il-Japan il-Japan Collaboration over n [66] about the importance a faster scanning by naked atory atory at Mount Chacaltaya, egularly egularly at the International carbon. carbon. The lower chamber es. es. In more than thirty years were were composed of nuclear n Japan. These X-ray films ayer. ayer. The air gap provided the atmospheric gamma rays and the gamma rays in the lower multi-layered sandwich of lead of nuclear emulsion plates and . This was the birth of a long- hambers hambers consisted of an upper inguishable inguishable to the naked eye for ays ays produced in local interactions ion chamber, as the detector was stimony, stimony, he describes the progress ca ca Cósmica, so the idea of collaboration

12

An An excellent review of the main results obtained by the Braz So So it came about that in 1959 Yukawa wrote a letter to Lattes The basic structure of the emulsion chambers exposed at Mount Chac respectively. The average time of exposure of a chamber was around 500 days 500 around was a chamber of of exposure time average The respectively. the years up to 1980 is given in [67]. Results were also presented r there. In particular, part of the money was given to study a of cosmic rays using nuclear emulsions. group Y. Fujimoto reports i of young of this support and the influence it had on activities the between future scientists development of of Brazil co and Japan. In his te achieved in producing nuclear emulsion plates of good quality in Japa about a project to a develop new type of detector ofconsisting a plates and photosensitive material. emulsion The plates photosensitive and layers highly sensitive X-ray recorded electromagnetic showers as a films black spot which is dist also made i showers of 1 TeV or above. The X-ray films were added to enable and w in flight 1956 in a balloon tested was a detector large areas. Such over eye the of observation mesons produced in cosmic energy interactions high energies, it was planned to increase the area of itexposing named, to cosmic at at rays Mount above Norikura, sea2800 m this emuls J the to be observed, of flux events be toofound a reasonable for low to this altitude was group considered the of possibility suchexposing a at chamber Mount Chac had exposed the emulsions in which the pion had been discovered. It was als that Lattes was still working at the Laboratorio de Físi natural. was Cooperative Emulsion Group of Japan that experimental physicists ha presenting the intention of this group to carry out an experiment at M also suggested that this experiment should be done in a Brazilian groups. collaborati Lattes responded positively and in 1961, when he visi International Cosmic Ray Conference at Kyoto, he met the group together of they J planned the steps to turn the project into reality lasting and fruitful collaboration among institutions in both countri twenty five emulsion chambers have been assembled at the Labor 1993. in last one the and in 1962 one firstthe multi-layered sandwich of lead plates and photosensitive layers X-ray films of high sensitivity. A typical chamber, assembly a target of layer the of pitch, c an air gap of 150 cm in it or in the atmosphere initiated to detect showers intended was upper chamber and a lower the same time working as shield for the lower chamber against electrons. The pitch layer was almost transparent to gamma r due to its thickness and the low atomic number of the constituent recorded showers produced in nuclear interactions at the target l traveling distance necessary for sufficient separation chamber. among Typical dimensions of the upper and lower chamber are 44 m Cosmic Ray Physics in Brazil PoS(CRA School)032 Carola Dobrigkeit om om CBPF to get V. Guaçu jets were the Symposium on Kotaro Kotaro Sawayanagi, led mirim, açu and positive correlation the pioneer work of isited isited Brazil. Yoichi Rio de Janeiro and te te the community of riment. riment. cosmic-ray experiment experiment cosmic-ray by by the Collaboration at 1000 TeV. The gamma and in the atmosphere azilian azilian Indian language, interaction interaction has never been vent vent was the almost total Mantovani, José Augusto orked orked with Lattes over the nd the presence of a large Neusa Margem Amato andNeusa Margem on was the observation of multiplicity multiplicity increases more racterized racterized by rest energies cation cation of the Collaboration sity sity of Campinas, to where zed zed by increasing average ntum ntum was observed. Three detailed detailed studies of particles tem, tem, which to correspond the from 1964 on, and latter also onsible onsible for the scaling breaking, tector, tector, which is part of the CMS ies ies were from institutions in the Luksys, José Bellandi, Valdir tions tions such as those observed in e scaling extrapolation from the he he very forward region. Brazilian

13

Systematic Systematic studies of nuclear interactions in the carbon layer Among the interesting results of the Brazil-Japan Collaborati It It is worth mentioning that in one of the first lines of a publi In the thirty years of collaboration many Japanese physicists v In Brazil, physicists participating in the research activit Cosmic Cosmic Ray Conferences which occur every worldwide. physicists ray cosmic two years and congrega revealed three phenomenological types of pion multiple guaçu production, cal (meaning small, large respectively). Mirim and jets were very those consistent large accelerator region around 1 TeV. with Açu jets were considered resp in simpl the native and their frequency showed an increase with energy, being Br ~50% by 100 Te found in the atmospheric interactions at even higher energies, around rays produced in those three transversal and momentum, increasing rapidity density. Further, the intermediate states are characteri quickly with energy than predicted by a between logarithmic dependence the and rapidity a density and the fireballs were average supposed transversal to correspond mome the three types respectively. GeV, 100~300 and GeV of 15~30 2~3 GeV, around jets, cha events named Centauro. The main characteristic of absence this of type gamma rays of that originated e from neutral pion decays, a number of decays attributed to hadrons. The observation was reported the International Cosmic Ray Conference of 1973 [68]. This type of observed in accelerator experiments. thePresently CASTOR de experiment at the Large Hadron Collider at in produced sys at TeV inenergies collisions the14 centre-of-mass CERN, will allow cores of cosmic ray showers. The search cosmic for rays is exotic one interac of the motivations for this expe the detector in participating are Santoro A. of leadership the under physicists in t concerning concerning fireballs in pion multiple production [69] one can read “about in idea his a in the Wataghin of he introduced from 1941, fire-ball which on penetrating showers…”. That had been the contribution of Wataghin at [30]. 1941 Janeiro in de Rio held in Rays Cosmic Fujimoto, Shunichi Hasegawa, Akinori Ohsawa, Toru Shibata, Kei Yokoi, Naoyuki Arata and many others stayed colleagues. Brazilian the with together working Campinas, for long and short periods in states of São Paulo (first at USP and from 1967 on at Lattes and the his Univer group had transferred) and Rio de Janeiro (CBPF Universidade Federal Fluminense). In Campinas, many physicists w years, as Edison Shibuya, Armando Turtelli, Claudio Santos, Marta Chinellato, Margarita Ballester, Carola Dobrigkeit, Rodrigues, Marcio Miguel Menon and many others. ininvolved was the Anna collaboration joinedMaria Freire, soon In by Rio, the first physicist fr Cosmic Ray Physics in Brazil PoS(CRA School)032 is ° igin, igin, and data data taking significant n cosmic ray Carola Dobrigkeit assembling and so been published. took over the work physicists in Brazil. in Brazil. physicists tors tors and fluorescence to detect air showers n in [70, 71]. n in [70, the town of Malargüe, ed later on working in Observatory. e Auger luorescence luorescence telescopes, chmidt chmidt optics is adopted Results involving limits on a hexagonal grid with ank ank by shower particles is 2 bservatory bservatory is comprised of ng ng more than 350 scientists tank filled with pure water, ow ow of electrons, photons and highest energies observed so description of the detectors of Pierre Pierre Auger Observatory were tector ever built and is the result a that collects light falling on an y y films and emulsions, and in the he electronics, an antenna for data array. array. The telescopes measure the nd nd Regina Maldonado from UFF. ecules excited by showers particles the energy spectrum [72], the arrival val val of the shower at particles the detector.

eV a shower arriving at an angle below 60 18 14

eV - to get clues about their composition, energy spectrum, or 18 spherical mirror. The camera consists of 440 photomultipliers. S The Auger Observatory is located in the Argentinian pampas, near Many Many students were also involved in the experiment, working in the In the beginning of the nineties, a new and challenging idea to focus The o Pierre Auger is Observatory the largest cosmic de ray Although the construction of the Auger Observatory was completed in 2008, 2 acceleration mechanisms. mechanisms. acceleration at 1400 m above sea level. It explores two induced complementary techniques by cosmic rays of extreme telescopes. A water-Cherenkov detector energies: consists of a polyethylene water-Cherenkov detec three photomultipliers, solar panels and batteries for driving t transmission and a GPS toreceiver fix the time of arri The water Cherenkov detectors are used to measure the energy fl Francisco Francisco de Oliveira Castro, and later by Carlos When Navia a Lattes retired from the University of Campinas, team. the Brazilian leading Edison Shibuya disassembling of the chambers, in the of development the X-ra analyses of the results. Most of them obtained their ray cosmic of third generation the form PhD These students physics. ray cosmic and continu Observatory (1992 ) - Auger The Pierre 5. Pierr the of inception the motivated region energy highest the in research of an ongoing effort of a major international collaboration involvi from 17 countries. Its main goal is the study of cosmic rays of the far - above 10 muons in the air shower. Cherenkov light produced in the water of a t collected by the photomultiplier tubes. The surface array of the O 1660 water-Cherenkov detectors deployed over the area of 3000 km 1.5 km side. The volume over the installed surface in four array buildings is on the covered perimeter by of 24 the surface f faint fluorescent light emitted isotropically by nitrogen mol traversing the atmosphere. Each telescope consists of a camer 11 m to eliminate coma aberration. Above 3 x 10 detected by the surface array with 100% efficiency. A detailed give is and performance operation and their Observatory Auger the Pierre has been continuous since January 2004, even during the results construction. published by the Pierre TheAuger Observatory refer to most direction distribution [73-75] and composition of the cosmic rays [76]. on the neutrino fluxes [77, 78] and on the photon fraction [79, 80] have Updates al of the most important results obtained recently by the [81]. Proceedings these to a contribution offocus the Cosmic Ray Physics in Brazil PoS(CRA School)032 Carola Dobrigkeit bility to produce to produce bility ious analysis tasks. tasks. analysis ious er Observatory was construction of the orrector orrector ring for the the the first complete set of data data taking and in the nterprise Schwantz Ltd, eceived eceived the continuous astyc astyc and Alpina. Also a uction. Diamond uction. grinding Diamond ses ses for the fluorescence hape hape of the ring. The next razil razil (FAPESP, FAPERJ, ll the 24 telescopes of the te of São Paulo there are ractically ractically half of the 1660 chairman of the Finance the community of cosmic erre erre Auger Observatory in the the axis São Paulo - Rio de llaboration, llaboration, respectively, for f Carlos and Escobar Ronald cant cant loss in resolution. The ts performance with different about about the manufacturing of the on Auger Telescopes (HEAT) nators nators and conveners of Physics io Janeiro, de are institutions the f 85 cm and outer radius of 110 dial dial part of the diaphragm was of the aperture box, shutters and are involved in the operation of tries in Brazil were also involved dade dade Católica, Universidade Federal lection lection area of the telescope and also the the data acquisition is Brazilian, from

15

The contribution for the surface detector was also significant. P Presently there are physicists from Brazil acting as coordi The participation of Brazilian institutions and physicists has r It is worth mentioning that with the Pierre Auger Observatory Cosmic Cosmic ray physicists in Brazil have participated in the Pi Brazilian physicists participated in the stages of construction, One of the major contributions of Brazilian collaborators to the There was also Brazilian participation in the first design safety curtains for the fluorescence telescopes. telescopes. fluorescence thefor curtains safety tanks of polyethylene were produced by Brazilian industries Rotopl large fraction of batteries which power the electronics for Moura. var the in participants many and also Tasks Performance and Detector Tasks support of the agencies fostering the development of Science CNPq, in FINEP B and MCT). The scientific director of two mandates. in Collaboration Auger the Board of FAPESP was ray physicists in the country expanded and exceeded the limits of Janeiro. Presently physicists from eleven institutions in Brazil and the in the Observatory analysis of the the In data. state of R Centro Brasileiro de Pesquisas Físicas, Pontifícia Universi do Rio de Janeiro and Universidade Federal Fluminense. In the sta Argentina since the beginning of Argentina since thethe beginning project, the under leadership o Shellard. Both acted as chairman and co-chairman of the Auger Co mandates. two successive analyses of the data. Their contribution to significant both for the surface array the and the telescopes. Indus construction of the Aug Observatory. Auger thefor Pierre the detectors of development in the Observatory was in the telescopes. production The process inclusion of of a corrector the ring in motivated corrector by the the idea of increasing len the outer effective light col ra increasing the signal to noise Brazilian ratio, group studied the optical without system doing simulations causing of i a signifi designs of the corrector ring, and concluded about the most suitable s and capa the expertise had in the Brazil industry which in finding step consisted the ring and develop the machinery necessary for the production. The e in the city of Indaiatuba, Observatory and designed and accepted built the proper formachinery the prod the challenge of producing tools the were used to shape the c ring of lenses with inner radius o cm, divided in 24 of segments aspherical shape. the After production of segments, the prototype was tested and the performance approved. A Observatory and also the three telescopes of the extension High are equipped with such corrector rings. The full report Elevati [82]. in presented is lenses corrector Schmidt Cosmic Ray Physics in Brazil PoS(CRA School)032 ith Oscar Oscar o work went went to ientists ientists of the Carola Dobrigkeit sors. sors. ray physics in Brazil centres in Physics. He n this atmosphere of in Brazil. in Brazil. by by him and his students. Federal do ABC and Universidade Universidade Federal da aulo aulo and in São Carlos) worked worked at the frontier of that are presently working the the tradition and keeps the king king in cosmic ray physics nts in mainstream Physics. nts nts to work with the most ration ration with physicists from nt physicists worldwide and difficult than nowadays he tion tion in cosmic ray physics are vel. vel. l prediction of Wataghin about main centres of Physics at the work work of Gleb Wataghin and his cal cal Review, so the results could ented ented in international journals and at lso involved: Universidade Estadual de de Estadual involved: lso Universidade e e to work with William Bragg, Paulus Aulus

d with John Wheeler and Eugene Wigner Princeton,in rge Herb and finally Cesar Lattes and Ugo Camerini to work with Paul Dirac, Walter Schützer was sent t Compton, Compton, Mario Schoenberg went to Rome and worked w 16

This tradition also facilitated the exchange of ideas with sc 1 In In all those institutions young scientists of the fourth genera What is common in all four periods is that the work done in cosmic Particularly important in the first period was the pioneer Wataghin and Lattes left a legacy for the new generations wor The new generation of cosmic ray physicists in Brazil follows Just to name a few: Marcello Damy went to Cambridg 1 with with Eugene Wigner in Princeton, Jayme Tiomno worke Sala was sent to Wisconsin to work with Raymond Geo Powell. Cecil Bristolwith work to Pompeia Pompeia was sent to Chicago and worked with Arthur Enrico Fermi, Sonia Aschauer was sent to Cambridge physicists physicists from Universidade Estadual de Universidade de Campinas, São Universidade Paulo (both the the In are state participating. of a Bahia three universities Physics Institutes in São P Feira Feira de Santana, Universidade Estadual do Sudoeste da Bahia and

Bahia. initiating new groups working in cosmic ray physics. The students physicists ray cosmic of the fifth generation form supervision their under 6. Conclusion le international the at competitive and level top at been has always group in São Paulo, both from the point of view of the theoretica multiple meson production and from the experimental results obtained It is worth mentioning that all the work was done far from the time. Wataghin always took care that the results were pres a time when the access to international journals was much proved to more be well aware of the latest achievements and developme Wataghin knew how to overcome the isolation of Brazil from the main published many of the results in Letters to the Editor of Physi become public faster. He cultivated good withrelationships importa made it a tradition to send his students abroad. famous He scientists. sent his stude Brazil. in of Physics the development to and contributed level highest in Brazil. They both set international standards in knowledge their in work their and fields. They always worked in intense collabo countries. other strong international cooperation alive. predeces their left by tradition the continuing and vanguard, internationalism It is up to them to sustai Cosmic Ray Physics in Brazil PoS(CRA School)032

78

29 (1999) 29 ctric ctric (1939) 43-58. (1936)75-77. (1938) 607-607. Carola Dobrigkeit 11 8 53 sio sio Leite Vieira, for (1934) 6-12. , Braz.J.Phys. chool. The support of of Thechool. support 27 (1937)334-340. , Braz. J. Phys. (1939)112. , Zeitschrift für Physik (1935) 287-300. author author would also like to 7 ortunity ortunity to know many of 55 (1933)214-221. 105 ng ng cosmic ray physics over (1945) 253-259. oss, oss, and Roger Clay for his razil r the invitation to give a talk al al document. Therefore it is 83 , Phys. Rev. research 67 he Pierre Auger Collaboration, Collaboration, he Pierre Auger ahlung hard Gross, no anfiteatro de física (1936) 1188-1189. ace Charges and Transient Currents 50 mic rays , Phys. Rev. , An. , An. Acad. Bras. Cienc. , An. Acad. Bras. Cienc. , Phys. Rev. , Phys. Rev.

, Zeitschrift , PhysikZeitschrift für , An. , An. Acad. Bras. Cienc. , Zeitschrift für, Zeitschrift Physik 17 , Revista Brasileira, Revista de Engenharia (1949)866-872. 17 On Permanent ChargesSolid in Dielectrics. I. Diele

, J. Chem. Phys., J. Chem. Bernhard Gross and his contribution in toB physics Bernhard andGross the evolutionof modern electret Zur Druckabhängigkeit der Ionisation durch Ultrastr Raios Raios cósmicos: resumo das conferências do Dr. Bern On hardthe component of cosmic rays Sobre o efeito de transição dos raios cósmicos Zum Breiteneffekt der Ultrastrahlung Zur AbsorptionUltrastrahlung der Pour l'analyse des rayons cosmiques On the latitudeof effect the soft component of cos A Remark on the Latitude Effect of Cosmic Rays Sôbre o efeito da latitude da radiação cósmica On Permanent inCharges Solid Dielectrics. II. Surf The The author would like to thank Marcelo Leigui de Oliveira fo This report is a personal recollection, rather than a historic da Escola Politécnica do deRio Janeiro B. Gross, B. Gross, B. Gross, B. Gross, B. Gross, B. Gross, (1932) 271-278. B. Gross, B. Gross, B. Gross, B. Gross, B. Gross and FerreiraL. Denard, Absorption and TemperatureEffects in Carnauba Wax B. Gross, in Carnauba Wax S. Mascarenhas, 217-219. G. M. Sessler, (1999) 220-225.

[5] [6] [7] [1] [2] [3] [4] [8] [9] [10] [11] [12] [13] [14] 7. Acknowledgement Acknowledgement 7. physics this S ray for in of participants in cosmic the Brazil about story the FAPESP, CAPES and CNPq is acknowledged. The author also thanks Cas his help in finding some of the earlier publications of Bernhard Gr help. valuable strongly biased by the reminiscences of the author, who had the opp the protagonists and to work on cosmic rays over many years. The and in t inCollaboration thank the the all Brazil-Japan colleagues with whom she had the pleasure of sharing the adventure of explori last decades. the References Cosmic Ray Physics in Brazil PoS(CRA School)032 11

(1940) (1940) , Il , An. , An. , An. , An. 69 12 , Phys. I II , An. Acad. , in Academia , La ,Ricerca La Carola Dobrigkeit (1940) 281-299. , An. Acad. Bras. (1940) 179-189. 12 , Phys. Rev. 12 de História Contemporânea , An. , An. Acad. Bras.Cienc. ergy collisions , Imprensa Nacional, Rio de (1948)975-976. , An. Acad. Bras. Cienc. 74 Cesar Cesar Lattes, a descoberta do méson , talk held in Rio de Janeiro at October Showers of Penetrating Particles Simultaneous Penetrating Particles in the Simultaneous Penetrating Particles in the , Imprensa Nacional, Rio de Janeiro (1943) ew given to R. Guedes and T. Franken (in , An. Acad. Bras. Cienc. a, Penetrating cosmic-ray showers (editors), , An. , An. Acad. Bras. Cienc. , Phys. , Phys. Rev. of the Conselho Nacional de Pesquisas (CNPq)

Sopra un nuovo tipo di contatore di corpuscoli 18 Sulla produzionedegli sciami in profondità Cosmic-Ray Showers at Great Depths (1940)339. Symposium sobre Raios Cósmicos On the Abundance ofin Nuclei the Universe (1940) 61-61. Sobre uma componenteultra-mole da radiação cósmica Sobre uma componenteultra-mole da radiação cósmica 57 57

Symposium sobre Raios Cósmicos (1939)351. (1940)197. A multivibrator counter circuit , Phys. Phys. Rev., (1937)104-107. , CBPF, Rio Janeiro,de 1999. 11 12 , Rio de Janeiro, Centro de Pesquisa e Documentação , Phys. , Phys. Rev. O Nascimento das Partículas Elementares 15 (1940)229-232. Sobre uma componente ultra-moleda radiação cósmica Origem da componente dura da radiação cósmica On the theory of multiplicative showers, On the production of groups of mesotrons by high en On the multiple productionof mesons 12 (1938)1-4. 2 (1939) 1-9. B. B. Gross (1941) 902-903. 11 59 e outras histórias π Rev. Rev. M. D. Souza Santos, B. Gross, (1939) 149. M. Schönberg and G. Occhialini, 33. M. Schönberg and G. Occhialini, Bras. Cienc. portuguese), 92 pages. M. Schönberg, M.de Damy Souza Santos, Pompeia,P.A. G. Wataghin (CPDOC) da Fundação Getulio Vargas, (1976), Intervi Acad. Bras. Cienc. M. Schönberg, Acad. Bras. Cienc. Scientifica G. Wataghin, M. D. de Souza Santos, P. A. Pompeia, M. Schönberg, G. Wataghin, M. Damy de Souza Santos, Cosmic Radiation P. Pompeia, A. M. D. de Souza Santos, G. Wataghin, Cosmic Radiation II M. Damy M.de Damy Souza Santos and G. Wataghin, Nuovo Cimento Cienc. G. Wataghin, M. D. de Souza andSantos P. Pompei A. Academia Brasileira de Ciências, Janeiro (1943). G. Wataghin, Brasileira de Ciências, C. M. G. Lattes and G. Wataghin, (1946) 237. C. M. G. Lattes, G. Wataghin, M. Damy de Souza Santos, 129-136. G. Wataghin, 11, 1996 at the celebration of the 45th anniversary and reproduced in F. Caruso, A. Marques, A. Troper

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