by V N Gribov, Cambridge University Press. Hardback ISBN 0521818346, £65 ($95).
Published as part of the series of Cambridge Monographs on Mathematical Physics, this is an English translation of the lectures given by Gribov in 1969, when the physics of high-energy hadron interactions was emerging. It provides a rigorous introduction to the theory of complex angular momenta based on the methods of field theory. The approaches developed are useful for analysing high-energy hadron scattering in many contexts, including future analysis of electroweak processes at the Large Hadron Collider.
Jeremy Bernstein, theoretical physicist and erstwhile science writer at The New Yorker, targets “readers whom I do not assume to be scientists, but whom I do assume to have intellectual curiosity”. With Oppenheimer: Portrait of an Enigma he aims true. Portrait is an engrossing collection of vignettes of the great and the good (and the not so great and not so good) who took part in a scientific project that changed the world like no other: building the atomic bomb. Woven into the story are lucid exposés of those 20th century sciences that informed the project, as well as many insights into the geopolitical upheavals that were provoking and being provoked by it.
Portrait is less fraught with witch-hunting and soul-searching than earlier accounts of the same events. After passing sensitively through Oppenheimer’s somewhat strange and sad childhood, Bernstein treats his readers to splendid tales of “Oppie” as sartorial aesthete, polyglot, poet, lover, homicide manqué, “leftwanderer”, brilliant physicist, serial show-off and cruel critic, an insecure genius with a profound need to be admired. The supporting cast includes military and political stars, and most of the glitterati of early quantum, atomic and astrophysics, from Alvarez to Zwicky.
Though firmly in the Oppie fan club, Bernstein remains even-handed in drawing a fascinating profile of a complex man. The fellow he depicts is not particularly nice but undeniably charismatic, a magnet with both poles fully exposed, admired and hated equally. Unfortunately for Oppie, times were such that his enemies could be dangerous. Pivotal episodes are his unlikely appointment as director of the Los Alamos Laboratory in 1943 – “he had never managed anything” and “had a ton of left-wing baggage” according to Bernstein – and his almost self-induced downfall during the following years. His disgraceful testimony to the House Un-American Activities Committee in 1949 and bizarre conduct during his own “trial” before the Atomic Energy Commission (AEC) in 1954, when he finally lost his security clearance, are candidly presented and carefully analysed. In 1947 Oppenheimer was made director of the Institute of Advanced Study in Princeton, where Bernstein was later to meet him. The cold-war arms race proceeded without him.
Though not mentioned, in CERN’s 50th birthday year it is fitting to recall that several “men of science” who came out of the Manhattan Project with a feeling of “blood on their hands” were determined that things would be different for future generations of researchers. While Oppenheimer was being investigated by the AEC, his close friend Isidor Rabi and others were working through UNESCO to create CERN, a European laboratory where physicists could conduct “nuclear research of a pure scientific and fundamental character…[having] no concern with work for military requirements.”
Portrait prompts other sobering reflections on “then” versus “now”. For example, in July 1945 the Franck Report premised that bomb technology could not be kept secret and that it was only a matter of time before other nations would have nuclear weapons. A scant four years later Russia exploded its first nuclear bomb. In June of this year Mohamed El Baradei, director-general of the International Atomic Energy Agency, speaking at a conference hosted by the Carnegie Endowment for International Peace, said: “we are actually having a race against time…not only with regard to countries acquiring nuclear weapons but also terrorists getting their hands on some of these materials, uranium and plutonium.”
Portrait is full of personalities and is entertaining and thought-provoking. If cavils there must be, there is a brief lapse of clarity concerning fusion, later redressed, and the timeline is sometimes confusingly broken or looped, but these are minor quibbles not major complaints.
by Q Ho-Kim, N Kumar and C S Lam, World Scientific. Hardback ISBN 9812383026, £76 ($103); paperback ISBN 9812383034, £30 ($41).
This is a completely revised second edition of a book that presents 10 of the most important areas of modern physics. It ranges from lasers and superconductivity to particles and cosmology, and includes three new chapters on Bose-Einstein condensation, nanostructures and quantum computing. Of interest to students and teachers, the emphasis is as much on describing natural phenomena as on explaining them in terms of basic physical principles.
by R Aldrovandi, A Santoro and J M Gago (eds), AIAFEX, Rio de Janeiro. ISBN 8585806028, €40. Available from Livraria Leonardo Da Vinci, Rio, Brazil, fax: +55 21 2533 1277, e-mail: info@leonardodavinci.com.br.
This book is a token of the admiration and friendship felt for Roberto Salmeron on the occasion of his 80th birthday. Some of the authors regard him as both their teacher and mentor, and others as a respected colleague and friend. The book is thus a tribute to the scientist, the professor and the friend.
There is scarcely a domain in Brazilian science and culture where Roberto has not played an important role. He is remembered for example by his support for the Instituto de Fisica Teorica in Sao Paulo in the 1950s. He also proposed the establishment of the first ICFA Instrumentation School in Brazil, as well as the creation of a synchrotron light laboratory in Campinas. Then came his support for the development of instrumentation to be used in experiments both at CERN and at Fermilab.
The 32 contributed papers cover a wide spectrum of topics, from general relativity and cosmology to the interaction between science and society. They touch in turn upon the physics of neutrino masses and mixings, the study of cosmic rays and particle physics, and the search for the quark-gluon plasma, the origin of masses, the development of nanotechnology and several quantum-physics issues.
They also provide vivid glimpses of Roberto’s personality, such as his enthusiasm for teaching physics, the desire to develop science for the benefit of all society, and his awareness of the social responsibilities of scientists. A dramatic article by Michel Paty evokes their common struggle, in 1963-1965, in building the Institute of Physics of the University of Brazilia and defending its freedom against the intervention of the dictatorial regime. This was a fight that ended in the resignation of most of the faculty members and Roberto’s exile – an example of his courage and determination in defending the dignity of science. Long live Roberto!
Sitting in an undergraduate lecture, being introduced to the Dirac equation for the first time, I found myself wondering “How on earth did he come up with that?” My hope for this book was that it might provide some insight into what made Paul Dirac such a great physicist. I think that it was satisfied to some extent.
2002 was the 100th anniversary of Dirac’s birth and this book constitutes the proceedings of a symposium held at Florida State University, where Dirac held a faculty position during his last 14 years. There are 13 contributions from the speakers, more-or-less centred around areas of Dirac’s interest. The anecdotes sprinkled throughout are particularly entertaining to read, especially for younger readers who may not have heard many of them.
Dirac’s daughter, Monica, writes an endearing account of her father, the family man, with obvious warmth and affection. Memories such as Dirac measuring the length of the cat’s whiskers to make sure he’d fit through the cat-flap warm the heart. His love of walking, swimming outdoors and classical music also shines through.
Despite not being able to attend due to a snow storm, Frank Wilczek contributed an outstanding essay (contrary to some speakers who are named and shamed for not contributing). It starts with a discussion of the Dirac equation and leads in sometimes surprising directions: considerations of the possibility of artificial intelligence, for instance. Wilczek’s views on what one may learn from Dirac’s approach to physics is interesting, and we see from various contradictory quotations that Dirac sometimes changed his mind. In particular, there are several quotes about Dirac apparently not worrying too much about experimental results, but Wilczek exposes Dirac’s delight when the prediction of his equation that the ratio of the magnetic moment of the electron to its spin equals two was supported by data. William Marciano follows with a nice and succinct review of this latter topic. Later, Dirac also lost faith in “his” monopole due to the lack of experimental evidence.
There are good introductions to time variations of fundamental “constants” by Paul Langacker and neutrino physics by Vernon Barger, which will appeal to those of a more phenomenological bent. Some of the M-theory/brane and string-oriented contributions by Pierre Ramond, Roman Jackiw and Joe Polchinski will probably appeal to the more mathematical physicist. The contribution of Leopold Halpbern is frankly annoying, however, after he starts discussing his own work in general relativity, and I found Maurice Goldhaber’s resolution of the fermion mass problem bizarre and too heuristic.
So how did Dirac contribute so much important work? It seems by doggedly hanging on to an elegant idea that solves a difficult problem, then frequently changing methodology; certainly by looking for mathematical beauty but also by taking note of other theorists’ work and experimental data. Oh, and plenty of long walks.
CERN’s director-general Robert Aymar presented a seven-point scientific strategy for the organization at the 128th session of the CERN Council on 18 June. Completion of the Large Hadron Collider (LHC) project, with start-up on schedule for 2007, heads the list. This is followed by the consolidation of existing infrastructure at CERN to guarantee reliable operation of the LHC. The third priority is an examination of a possible future non-LHC experimental programme.
Fourth on the list is a role for CERN in the growing coordination of research in Europe. Aymar cited as examples the Coordination of Accelerator Research in Europe (CARE) project, which could contribute to an LHC upgrade by around 2012, and the EUROTEV project through which CERN will participate in generic R&D issues related to a possible future linear collider. Both of these projects are partly financed by the European Union.
The fifth priority is the construction, starting in 2006, of a linear accelerator injector at CERN to provide more intense beams for the LHC, followed by an intensified R&D effort towards a compact linear collider, or CLIC. This novel accelerator technology under development at CERN could open the way to much higher energies than are available today. Aymar is appealing to laboratories around the world to join the project, and has so far received 18 expressions of interest.
The seventh and final point in the new strategic plan is to prepare a comprehensive review of CERN’s long-term activity, to be available by 2010 when results from the LHC will have given a first description of the landscape of particle physics for years to come.
The current status of the LHC project was the subject of a report at the same session by Lyn Evans, the LHC project leader. The programme for installation of the LHC is currently being reviewed, following a delay in installing the distribution line for the cryogenic liquids that will cool the machine to 1.9 K. Difficulties have been solved, and the contractor has delivered a new schedule that foresees completion of the distribution line by February 2006, with two octants fully installed by the end of 2004. This compresses the overall schedule, which now requires the installation of two octants at a time to make up for the delay. However, Evans strongly reaffirmed the intention to start up the LHC in 2007, with first collisions in the summer. He also drew attention to the global collaboration that is making the LHC a reality. Most of the components from non-member states are now complete.
The bubble-chamber programme at CERN began in an atmosphere of enthusiasm soon after the foundation of the organization. The then recently invented bubble chamber was marvellously appropriate for exploiting the new CERN accelerator, the Proton Synchrotron (PS), which could reach energies where new phenomena were expected. The emergence of the electronic computer around the same time also provided a means of dealing with the large numbers of bubble-chamber pictures. New instruments would be built to measure the thousands of metres of film, and so began a period of intense activity at CERN.
The bubble chamber, which was invented in 1952 by Donald Glaser in Michigan, played an important role in experimental physics at particle accelerators. Glaser showed that the trajectories of energetic particles could be made visible by photographing the bubbles that form within a few milliseconds after particles have traversed a suitably superheated liquid. For three decades bubble chambers were to dominate particle physics, especially research on strange particles, until the mid-1980s when developments in electronics and new wire chamber detectors, together with the start of a new era of collider physics, brought an end to the bubble-chamber programmes.
The early bubble chambers were very small, but over the years they increased in size with the largest containing 20 m3 of liquid. More than 100 bubble chambers were built throughout the world, and more than 100 million stereo pictures were taken (“30 years of bubble chamber physics” 2003). More than half of these pictures were taken at CERN by the 30 cm hydrogen bubble chamber, followed by the 81 cm Saclay chamber, the 2 m CERN chamber and finally the Big European Bubble Chamber (BEBC).
In the 1960s bubble chambers became the main tool at CERN for the study of resonances and strange particle physics, keeping hundreds of physicists busy for a decade. The 30 cm hydrogen chamber came into operation at CERN in 1960, followed four years later by the 2 m hydrogen chamber. From the early 1960s CERN also pioneered the use of bubble chambers for the study of neutrino interactions, and it was the great interest in this field that led to the conception and construction of giant bubble chambers such as Gargamelle and BEBC.
In 1966 CERN, France and Germany launched the BEBC project – a giant cryogenic bubble chamber surrounded by a 3.5 T superconducting solenoid magnet that operated at CERN in the West Area neutrino beam line of the Super Proton Synchrotron (SPS) until 1984. Gargamelle, a very large heavy-liquid (freon) chamber constructed at the Ecole Polytechnique in Paris, came to CERN in 1970. It was 2 m in diameter, 4 m long and filled with 10 tonnes of liquid at 20 atmospheres. With a conventional magnet producing a field of almost 2 T, Gargamelle was the tool that in 1973 allowed the discovery of neutral currents.
The contacts between the American laboratories and CERN were very close. The physicists at the time were inspired by the example of the Lawrence Berkeley Laboratory, where bubble-chamber experiments using beams from the Bevatron were available before CERN’s PS started operation. In particular there was close collaboration on the technical side between CERN and the Brookhaven Laboratory. It was during these early years of CERN that the first international collaborations on experiments began, thanks to the distribution of bubble-chamber film and joint analysis efforts. Among the first of the groups measuring film from CERN to start a collaboration were those from Bologna and Pisa, who already had experience analysing film from the 30 cm propane chamber at Brookhaven (Eisler et al. 1957). A group from Warsaw with experience in nuclear emulsions, along with other groups who had worked previously with cloud chambers, also soon joined the collaborations with CERN to analyse bubble-chamber film.
The bubble-chamber exposures in beams at the PS were based on physics proposals, often hotly debated in the experimental committees at CERN. The results obtained by the many collaborations using film from the laboratory contributed to establishing bubble-chamber physics at CERN on the world stage. For example, many of the major verifications of SU3 symmetry – apart from the discovery of the Ω– particle – came from bubble-chamber experiments at CERN during the 1960s and 1970s. The success of SU3 not only illustrated the importance of group theory in contemporary high-energy physics, but also became a vital ingredient of the modern Standard Model of particle physics.
One of the most important highlights of the bubble-chamber era – and an outstanding success story for CERN – was the discovery of weak neutral currents in Gargamelle, the giant heavy-liquid bubble chamber. The chamber was first exposed to the neutrino beam at the PS, where the decisive detection was made. Parallel with the operation of the chamber and the evaluation of the photographs from the PS exposure, detailed background calculations were made on neutron-induced events, which could simulate neutral currents. It turned out that this background was only 15% of the signal and so neutral currents were established. Later, Gargamelle was transferred to the neutrino beam at the SPS and equipped with an external muon identifier.
Beyond physics
The results of the bubble-chamber programme at CERN extended well beyond the intrinsic interest of the physics. Bubble-chamber studies played a major role in the reconstruction of physics in post-war Europe and had a great impact on its further development. Bubble-chamber pictures could be easily transported, and efforts were made to persuade industry to construct measuring instruments that became commercially available. As had happened for nuclear emulsions a few years earlier, many new groups formed in research centres and universities, where young people were trained. These collaborations produced much of the significant physics. At CERN the use of digital computer and data-handling techniques for experiments began with bubble chambers, and their use in other fields of high-energy experimentation followed later.
Bubble-chamber physics became a training ground for physicists, engineers, technicians, and for specialists in computers and data handling. A great number of new techniques were developed to improve particle identification both inside and outside the track-sensitive volume of the bubble chambers. There was the question, for instance, of how best to convert photons resulting from π0 decays inside a hydrogen bubble chamber. This led at CERN to the operation of track-sensitive hydrogen targets, surrounded by neon-hydrogen mixtures, to improve the photon-conversion efficiency.
Over the years there were many other technical developments (Mulholland and Harigel 2003). Proportional wire chambers surrounding the bubble chambers allowed the identification of muon tracks escaping from the inside through the tanks and magnets of the bubble chamber.
Special fish-eye optics, stereo photography and holography were developed to optimize the recording of the particle tracks. Finally, rapid-cycling bubble chambers and hybrid systems, which combined bubble chambers with spectrometers and counters, were constructed. Interaction triggers, in particular for signals of charm events, were used to fire the flash so as to take photographs only of interesting physics events in order to improve on the slow data-taking rate of bubble chambers. CERN’s competence in engineering and cryogenics, which was developed in the Track Chamber Division through the building and exploiting of bubble chambers, later benefited the construction of the detectors for the Large Electron Positron collider and the experiments for the Large Hadron Collider (LHC).
A whole generation of physicists wrote their PhD theses based on bubble-chamber data. Perhaps because of the large numbers of young people who were working in the field of bubble chambers and film analysis, many are to be found today as leaders of experimental teams or laboratories, and indeed in many other diverse areas.
Lastly, and arguably most importantly, bubble-chamber physics initiated on a large scale the symbiosis between CERN and its community of users. Laboratories that at first limited their activities to measuring pictures and analysing the results soon diversified their activities and links with CERN expanded. This became one of the ingredients of CERN’s success. Bubble chambers had initiated the international collaborations for performing experiments that are now extending to the worldwide collaborative efforts for the LHC.
The bubble-chamber era has now ended and the remains of the major CERN bubble chambers are today exhibits in science museums – BEBC and Gargamelle are in the garden outside the Microcosm exhibition at CERN and the 2 m chamber was donated to the Deutsches Museum in Munich. However, bubble chambers live on in other ways, not only through the many beautiful postcards and books showing bubble-chamber tracks, but also through many of the original ideas and the “bubble chamber philosophy” that continues to play an important role in physics today.
Acknowledgments
The author would like to acknowledge some valuable sources of material. Much of this article is based on a memorandum written in 1987 by the late Yves Goldschnidt-Clermont to the CERN history committee (Goldschnidt-Clermont 1987). The proceedings of the “Bubbles 40” conference, held at CERN in 1993 to commemorate the 40th anniversary of the invention of the bubble chamber, document the evolution and impact of bubble chambers on particle physics and physics discoveries and outline their technological, sociological and pedagogical legacies (“Bubbles 40” 1994). Jack Steinberger from CERN recounted his time with bubble chambers in memories of his early life (Steinberger 1997), and the impact of Charles Peyrou on the bubble-chamber programme at CERN is recalled in a tribute published after his death in 2003.
Ettore Majorana was the Vincent van Gogh of theoretical physics, endowed with phenomenal talent but tortured by his own personality; both were geniuses whose unconventional epic work was first recognized by only a few contemporaries, but whose fame ultimately came only after a premature death, by suicide for van Gogh, and possibly so for Majorana too.
Enrico Fermi once said: “Few are the geniuses like Galileo and Newton. Well Ettore was one of them.” Appointed professor at the University of Naples in 1937, Majorana mysteriously disappeared in March 1938 after a brief trip to his native Sicily. After having cabled “I shall return tomorrow”, he was not aboard the ferry from Palermo when it docked at Naples. Despite extensive searches, no trace of him was ever found. The only clue was an enigmatic remark “The sea has refused me (il mare mi ha rifiuato)” in the same cabled message from Sicily, suggesting that his plan to jump overboard unseen on the outward trip had failed and so he had opted for another attempt on the return journey. It was a major loss for Italian physics, compounded later that year when Fermi emigrated to the US.
After having first studied engineering, Majorana graduated in physics with Fermi in 1928 and went on to become a key member of Fermi’s newly established and subsequently famous Rome group of the early 1930s (which included, among others, Edoardo Amaldi, Ugo Fano, Bruno Ferretti, Bruno Pontecorvo, Giulio Racah, Emilio Segrè and Gian Carlo Wick).
Majorana was chronically diffident, and this shyness extended to his own publications. He formally published just nine papers in his lifetime, including his 1932 relativistic theory of particles with arbitrary spin. His final paper in 1937 was called “A Symmetrical Theory of the Electron and the Positron” and introduced the revolutionary concept of what became known as a “Majorana particle” – a neutral spin 1/2 particle that is its own antiparticle – now of vital importance for neutrino physics. However, Majorana’s archived papers in the Domus Galileana in Pisa show that he had already formulated these ideas in 1933, soon after the positron had been discovered.
This book looks instead at Majorana’s first steps in physics research, carefully documented by him in five notebooks (Volumetti) from 1927-1932, about one notebook per year, and extending from his formal coursework to original research covering topics ranging from the effect of a magnetic field on melting point to solutions of the Fermi-Thomas equation. These papers are translated into English but retain Majorana’s original format and conventions.
As Majorana’s contributions to physics have increased in value, several other collections of his work have appeared. There is also Recami’s excellent biography Il Caso Majorana (Mondadori), but the volume now published by Kluwer is the first rendition of any of Majorana’s work into English. This book is the outcome of some dedicated and painstaking work by the editors in translating a wealth of difficult material and reproducing Majorana’s original presentation. It was commendably supported by the Italian Embassy in the US and by the Italian government. After this effort, the highly motivated editors are looking towards a new volume of Majorana’s subsequent research notes.
The “fly” in question is the nucleus and the “cathedral” is the atom, and this is the account of “how a small group of Cambridge scientists won the race to split the atom”. The story begins in 1909, after Ernest Rutherford’s student, Ernest Marsden, found that when alpha particles are scattered by a gold foil the Rutherford formula is not exactly satisfied. There is therefore evidence that the nucleus is not just a point, but a “fly”. After moving from Manchester to Cambridge, Rutherford and his collaborators wanted to know more about what is inside the “fly”.
In the Cavendish Laboratory at Cambridge in 1927 there were two lines of approach to the study of the nucleus: the traditional one using naturally produced particles such as alphas, gamma rays, etc, and another that was trying to accelerate particles artificially in the laboratory.
James Chadwick was following the first approach, and this led him to the discovery of the neutron in 1932 and to the Nobel prize in 1934. In 1930 two German physicists, Walther Bothe and Herbert Becker, had reported that by bombarding beryllium nuclei with alpha particles from a polonium source they had registered the emission of a powerful neutral radiation. Later, the Joliot-Curies reproduced the phenomenon and proved that the mysterious radiation could knock protons out of a block of paraffin – something that gamma rays of available energies could not have done. When their “Note aux comptes rendus de l’Academie des Sciences” arrived in Rome in January 1932, according to what Gian-Carlo Wick, who was present, told me, Ettore Majorana exclaimed: “Stronzi (idiots), they have not understood that it is the neutron.” Soon after, Chadwick proved by careful experimentation that it really was the neutron, with a mass close to the proton. Another important experiment belonging to the same category, but not mentioned in the book, is the photodisintegration of the deuteron into a proton and a neutron by Chadwick and the then young Maurice Goldhaber (who is now 93 years old). They showed that the neutron was slightly heavier than the proton.
The other approach, trying to accelerate particles, marked the beginning of a new era that CERN continues, through its past achievements and its future projects. This is why the detailed account given in this book, including the successes and failures and the personal lives of the protagonists, seems so interesting.
The main protagonists were a young Irishman, Ernest Walton, a Briton named John Cockcroft, their friend Thomas Allibone from the Metropolitan-Vickers laboratory, and naturally Rutherford himself, who said in his address as president of the Royal Society in November 1927: “It would be of great scientific value if it were possible in laboratory experiments to have a supply of electrons and atoms of matter in general, of which the individual energy of motion is greater even than that of the alpha particle. This would open up an extraordinary new field of investigation that could not fail to give us information of great value, not only in the constitution and stability of atomic nuclei but also in many other directions.”
Cockroft and Walton worked very hard within the limits allowed by the rules of the Cavendish Laboratory, which closed at 6 p.m. and during holidays. But the friendly competition between Europe and the US was already fierce, a little like we see today! In the US Lawrence and Livingstone were working on their cyclotron, Van de Graaf had the machine that bears his name, and Lauritsen had his X-ray machine. There were also competitors in Europe, such as Greinacher, who independently of Cockcroft and Walton had the idea of voltage multiplication.
At this point it is necessary to mention a theoretician of Russian origin, George Gamow, who, as the author explains very well, played an important role in predicting that the attempts of Cockcroft and Walton would be successful. Gamow was probably the first to realize that quantum mechanics applied not only to the electrons running around the nucleus but also to the constituents of the nucleus. Before the discovery of the neutron he was extremely unhappy at having electrons inside the nucleus because their wavelength was much larger than the size of the nucleus. He produced a beautiful explanation of the alpha decay of nuclei by the tunnelling of alpha particles through the Coulomb barrier of the nucleus, a typical quantum mechanical effect. The alpha particles don’t need to have an energy as high as the classical barrier but can “borrow” energy for a short time to cross it. This was very important for the Cambridge machine builders because it meant that protons can penetrate inside the nucleus without having the full energy to cross the barrier. Even Rutherford, who had some repulsion for theory, liked this.
The Cockcroft-Walton accelerator finally started working at the beginning of 1932, but the protons they directed at beryllium and lithium targets did not seem to produce any clear effect. They were looking for gamma rays and saw practically none. This was a serious disappointment and they feared that Lawrence, with a higher energy, would win the race. Rutherford was beginning to get irritated. So they tried using a scintillation detector of zinc sulphide that had been used in the past to detect alpha particles and then they saw a beautiful signal, which was immediately interpreted by Rutherford to be a pair of alpha particles. This was at 800,000 volts, clearly below the classical Coulomb barrier. Then in complete agreement with Gamow’s theory, they lowered the voltage to 150,000 volts and still saw the effect. In this case Rutherford broke the rule of closing the laboratory at 6 p.m. The time of the “night shift” was approaching.
The reaction observed was p + 7Li → α + α with a kinetic energy release of 8 MeV. It was a tremendous success and as the subtitle of the book says, they “won the race to split the atom”. The press jumped on that, but Cockcroft and Walton disliked the statement that this could be “a new source of energy”. In fact the press was right. The discovery of the fission of uranium was not too far away and this kind of proton-induced fission, except for the fact that it uses light elements, is not fundamentally different from what is proposed now by Carlo Rubbia as a new source of energy. Later, long after the unfortunate death of Rutherford due to delays with a hernia operation in 1937, Cockcroft and Walton received the Nobel prize in 1951.
There are also many other people who are rightly quoted in the book, such as Kapitza, who after spending several years in Cambridge was forced by Stalin to stay in the USSR; Blackett, who started cosmic-ray research with Occhialini; and the theoreticians – Dirac of course, but also Mott, Massey, Hartree and so on.
To end this review I would like to complete the postscript of the book, in particular regarding the links of Cockcroft with CERN. A biography of Cockcroft by Ronald Clark says (on page 101) that he “loaned someone from Harwell to build one of the accelerators of CERN”. This accelerator was the Proton Synchrotron (PS), and the “someone” was John Adams. Cockcroft directed radar research in Malvern during the Second World War and one of the people he hired was an engineer called John Adams (once, John complained to me that journalists thought he was originally a “mechanic”). Another was Mervyn Hine (who died very recently, see his obituary in “Faces and Places”). When the war was over Cockcroft retained these two people at the Atomic Energy Research Establishment at Harwell, where they worked on accelerator research; they then moved to CERN with the fantastic success that we all know. Until 1992 the pre-injector of the PS was a Cockcroft-Walton accelerator, and Cockcroft was a member of the CERN Scientific Policy Committee from 1956 until 1961. So there is a link between Rutherford, Cockcroft and Adams for which we must have a great deal of gratitude.
Canada’s national laboratory for particle and nuclear physics, TRIUMF, has proposed a new five-year plan to take it through to the end of the decade. The plan is ambitious, but realistic, and builds on the laboratory’s past and present accomplishments. It aims to deliver first-rate science in a timely and efficient manner and will ensure that TRIUMF remains competitive at the highest international level.
TRIUMF is funded by the Canadian government on a five-year cycle; the current one running from 2000 to 2005. Over the past two years scientists and staff at TRIUMF and its associated universities have been discussing the plan to be forwarded to the government for funding in 2005-2010. The plan was peer-reviewed by two international committees in the latter part of 2003 and presented to the National Research Council of Canada in February 2004. Council recommendations will be transmitted to the higher levels of government for funding decisions later this year.
The underlying theme is to provide Canadian scientists with access to world-class subatomic facilities at TRIUMF, and to provide scientific and engineering support to enable Canadian particle-physics groups to lead or significantly contribute to various experiments worldwide. For facilities at TRIUMF, which are freely open to the global community, the plan includes:
•completion of the ISAC-II radioactive beam post-accelerator, which will extend the maximum ion mass from 30 to 150 and the beam energy from 1.5 to 6.5 MeV/u;
•a new proton line and targetry for the development of new radioactive beams;
•major upgrades to the muon beam lines for materials science and chemistry research;
•greater throughput of radioisotopes for research in the life sciences.
To support external experiments, the plan includes the development of a data hub at TRIUMF for data analysis for the ATLAS experiment at CERN’s Large Hadron Collider; contributions to the T2K long-baseline neutrino experiment in Japan; and to the KOPIO (K0→π0+ν+νbar) kaon rare-decay experiment at Brookhaven; and research and development for the Next Linear Collider. The plan also identifies the importance of transferring the technical knowledge developed at TRIUMF to the commercial sector, and that of educational outreach to the general public and students.
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