Physics is Fun Memoires of Richard Wilson Version of September 25th 2009

Scientific autobiography
In this part of my reminiscences I do not repeat all the contents of the many papers I and my co-authors have written for scientific journals. I mostly describe here the context in which they are written and merely provide references. These reference numbers refer to the number of the article in my collected list of references which may be found in the webpage: http://physics.harvard.edu/~wilson/publication/published_papers.html
Beginnings
As I reviewed recently a paper for possible publication in an epidemiology journal my mind went back to an event when I was a 6 year old. I had been weighed with great precision in pounds and ounces probably by a nurse. I enquired of someone, my aunt Mabel (May) I believe, whether it would make a difference whether I had just had a bowel movement or not. The answer came back, incorrectly, that it would make no difference. I pondered this for a long while (maybe even an hour) and decided that it would make a difference of an ounce or so. But I did not want to contradict or correct my aunt who I loved, and kept my own counsel. What does that have to do with epidemiology? The hopeful author of a typical epidemiology paper gives a table of upper 90% confidence limits to 4 significant figures! Yet only the first digit had any meaning. This childhood experience may be the subconscious reason why I tell my students: “Never quote more figures than are significant; to do so only displays your own ignorance of the meaning.” As computers have simplified calculations, they also enable a table to be prepared with numbers unedited straight from the computer. Maybe the hopeful author understood that most of the digits in the table had no meaning, but if so, he was wasting the time of his readers by asking them to figure out for themselves what numbers were significant.
My first technical interest came in 1939 when we were evacuated from London to Crowthorne, Berkshire. In our billet in the billiard room of Alderbrook, we had no radio. So I undertook, at age 13, to build one. It was put in a box by my Uncle Gilbert and picked up the two important stations; the regional and the national BBC stations. On vacations back home I worked on radio and gramophone (phonograph) systems following my father’s lead. One of the first moments was when I had built my first audio amplifier at age 14 and my father came to inspect it and pulled apart several dry soldered joints. I was in tears. But I learned the judicious use of flux and “tinning” the surfaces in advance I soon graduated to fixing radio sets for friends and neighbors. One problem took me 3 hours to discover and fix. It was a leaking electrolytic condenser (capacitor). By the time it was fixed there was a big mess on the floor for me to clear up. I was proud of myself for finding the obscure problem. But the neighbor thought I was dumb. In contrast when I had traveled all the way to Edgeware in 1946 on the underground (Northern Line) to fix our friend Joe Newton’s radio, I was a genius for pointing out that the AC plug, behind the sofa, had pulled away from the socket! Our physician Dr Kelley, who had diagnosed my father’s appendicitis when others had failed, bought an X ray set - mostly for radiation “treatment” I believed. It was professionally installed. But people got electric shocks from it. So my father volunteered my help. I found that the electrician had properly changed a 2 pin socket to a 3 pin one, but had connected nothing to the ground socket! Although my children sometimes are concerned that in our old house some of the wring is not up to modern code standards, I am sensitive to the need for grounding.
I read extensively about electronic circuits. Of special interest to me at the time was an article on negative feedback in the RCA technical review about 1936, discussing an audio amplifier with feedback. I built one with modified circuitry, buying the parts from a junk store on Lisle Street just north of Leicester Square and near Piccadilly Circus. I was also interested in an interest of my father - in gramophone reproduction. He had a couple of turntables in his radio console and had special “pick ups” to paly the 78 rpm records. A couple of his patents were on pick up design. I decided that the crystal pickup was better than the magnetic pickups my father had used, but they needed damping so I rebuilt a few with rubber damping. This got rid of a few objectionable resonances. My father had a collection of 20 - 30 constant frequency records to test his equipment and I was able to show that my pickups were not only high quality but gave less wear on the records - especially with fiber needles.
I remember Joe Newton questioning me about going to this district around Lisle Street and Piccadilly circus where hookers abounded.. So I told him I was interested in valves (vacuum tubes) not pick ups! I built an RF tuner with automatic tuning to the right frequency. The circuit I built was copied from, I believe, and article in the “Wireless Magazine”. It was the forerunner of an FM receiver. All of this served me in good stead, firstly when I had to study radar and electronics during the war to satisfy the recruiting board. I knew at the time more than the instructor! My first paper (1A on my list) was on a piece of equipment I first tested at the undergraduate lab and then built at home. It was on an electronic device for selecting random numbers The idea was to use it for experiments in “Extra Sensory Perception” (ESP) to avoid many of the statistical and other pitfalls. I had been impressed by experiments on “Precognitive Telepathy” by the mathematician SG Soal and M (Molly) Goldney, with the subject Basil Shackleton. The idea was simple. If no one knew what was coming till the button was pressed, the possibility of cheating or collusion would vanish. But it was never seriously used. But the development was fun. It led me to the fundamental realization that there exists no such thing as a table of random numbers. Once a series of numbers is written down it is merely a sequence. What can be random is the procedure for finding the next random number. I think that this is a fundamental point, but not many others seem to agree with me. But I do remember discussing this with Ed Purcell about 1957. I was explaining the limits of the random number procedures given my the resolution time and the frequency of circulation in my device. He showed me a book - prepared by the Rand Corporation - of 10,000 numbers. I think they were prepared by a method similar to mine and I was able to show that they showed a small non-random property in sequence preferences, about the same as in my early device. But Ed Purcell discussed randomness in a characteristic way He held up the Rand book in his hand and tore it in two. “This is the only book that I know where half the book is worth half of the whole!”
Nowadays one uses a more complex computer based procedure. But not all commercial programs work alright. In about 1992 I gave my freshman seminar tables of ransom numbers produced by Miscrosoft EXCEL but they were far from random. I have not looked recently at the EXCEL program but the Open Office random number procedure seems to be fine. I have realized since in my instructional work that a basic understanding is rare. Physical scientists are better off than others. We know that the physical universe is governed by random motions of atoms and molecules. The derivation of the basic gas laws illustrates this. We also know that rare events occur. As molecules rise to the surface of a liquid, most of the time they are turned back by the attraction of other liquid molecules that create the surface tension. But a few in a million get through and evaporate. This rate process can be calculated precisely and leads of course to the vapor pressure laws.

In mathematics at St Paul’s School I had learned about “Cause and Chance” with examples from card games. This leads naturally of course to a “frequentist” approach to statistics and expression of scientific results. When I left St. Paul’s school I was asked to select a book as a prize for being head of the class. I selected RA Fisher’s “Statistical Methods for Research Workers”. This is a bible for biologists and medical people but overly simplistic for physicists. Nonetheless I keep it and refer to it when I am involved with epidemiology. I suppose it was about then that I developed a basic understanding of statistics. This was not merely on theorems useable for biomedical studies but what they might mean. I was explaining a fundamental point to a student who I had hired for a summer job. She said: “ I got an A in the statistics course but no one ever explained this to me.” Indeed I think that an understanding of statistics and its limitations should be a prerequisite for a public policy position of any sort. By implementing such a requirement for employment now, that would have the additional benefit of reducing the federal bureaucracy one hundred fold!

I started my D.Phil work at the Clarendon Laboratory, Oxford, in 1946. I note that Oxford uses the genitive rather than the dative most Universities use) in 1949. The thesis was on the cross section for photodisintegration of the deuteron (1,2,3,9). I first measured the absolute cross section, for both the 2.62 MeV gamma ray from Th C’‘, using a 250 millicurie thorium source, and then for the 2.76 MeV gamma ray from Na 24. We calibrated the radiothorium source using the procedures from Dr LH Gray, then at Hammersmith Hospital, and the sodium source using the beta gamma coincidence method suggested by Sam Devons in 1939. Unfortunately the measurement of the croissection, particularly with the radiothorium source, was too high. I was disappointed at the time, and still am, in both Collie and Halban who never went over the data with me to see whether, or what, mistakes I had made. The meeting with LH Gray at Hammersmith hospital was very informative and influenced me later. He was a physicist with no formal medical training yet all the physicians treated him as an equal and some thought he had a medical degree. He had a young assistant measuring sodium (using radioactive sodium 24) though the blood.
There was a slight argument about the radiothorium source. There was only one in UK. Who was to have it? Brian Flowers, a young physicist at Harwell wanted it but Hans Halban prevailed. After that Brian switched firstly to theoretical physics, and then to public policy in which he was very effective ending up in the House of Lords. I remember him most by a letter he wrote to Sir John Cockroft, head of AERE And his boss. What should one do with scientists when they get too old? Not till the end of the second page did he say that too old meant over 30!. In view also of some frustration I got between 25 and 30 I remember also the comment of the Russian born physicist, Professor Nicholas Kemmer at Edinburgh. “While there is death there is hope”. I hope I am not too much in the way of my younger colleagues and do not propose to die yet (at age 83)
To return to my main narrative, I then used these techniques for a variety of small measurements: such as a search for the “cross over” J=4 to J=0 transition in Na 24 at 4.14 MeV (present at the level of 10^-7) almost all suggested by myself, and moving equipment to the Harwell “BEPO” research reactor I measured the capture gamma ray in carbon. Alas I also found some gamma rays which were not there. I should have been alerted by the fact that the width of the peaks was a little too narrow.
The photodisintegration of the deuteron, is a problem in the interaction of two nucleons. I read about the work of Bethe and Peirls in 1934 “the quantum theory of the diplon, (as the deuteron was at one time called)”. I was to meet Peirls at my D.Phil. oral where he was asked to be the external examiner. I met him later in 1953 at a conference in Birmingham where he was a Professor, and again when Birmingham offered me a job as Professor in 1956. I came across Eugene Wigner’s 1935 paper on neutron-proton scattering, and his work with Gregory Breit, also from eastern Europe. Valentine Telegdi reminded me later that he and I first met at a nuclear physics conference in Oxford in 1948 and we both met Eugene Wigner at that time. I was probably introduced by Dr Nicholas Kurti, a low temperature physicist in the Clarendon Laboratory who, like Wigner, was from Hungary.
I found difficulty in getting ideas in Oxford. So probably at Hans Halban’s suggestion, I went down to Harwell, 15 miles away, on the number 13 bus. There I met Bruno Pontecorvo who I got to know and was always Ponte to me. Ponte was an Italian who had worked with Enrico Fermi in Rome, and later in 1938-1939 in Joliot-Curie’s laboratory in Paris. Ponte left Paris by bicycle in May 1940 with, I believe, Dr Franzinetti and Dr Benedetti. Crossing the Spanish frontier 6 hours ahead of the Nazi armies, they went to Lisbon, and worked their passage to the USA on a freight boat. Ponte then explored for oil in the west before being tapped by Hans Halban to join his team in Montreal on back up work for the bomb project. After the war, he spent a coupe of years in the Atomic Energy Of Canada Laboratory in Chalk River and came to Harwell in 1948 or 1949. I had already read about his famous measurement, performed in Chalk River, of the decay spectrum of tritium, obtained by filling a proportional counter with tritium gas. That showed that it was indeed a three body decay and he looked at the end point of the beta spectrum and hence found the decay energy. By comparison with mass measurements, this suggested a neutrino mass close to zero.

There was another paper on tritium decay about the same time by Curran, Angus and Cockeroft (not Sir John) from Glasgow University. In that paper they made a calibration with K X rays and succeeded in separating the two x ray peaks. While that measurement was basically correct, Ponte pointed out that the separation could not have been achieved.. The resolution of the apparatus was inadequate! I was alerted then and am alert since, to many times when an experimenter has described incorrect results by selective use of data. It especially happens when he thinks he knows the “right” answer. In 1938 Kopferman’s student selected data and found a hydrogen fine structure in agreement with the then theory. When these data were reexamined some 7 years later, it was realized that there was a statistically significant shift from the theory, measured later by Willis Lamb using radio-frequency spectroscopy and appropriately called the “Lamb Shift”. The 2 Mev neutron capture gamma ray “discovered” in the “cold fusion” experiment of Pons and Fleischman can quickly seen to be bogus as it was too narrow for the resolution. I also read with interest Fisher’s paper about 1919 that showed that the experimental results that Mendel relied on for checking his Mendelian theory of heredity could not have been derived from data. They were too precise! No one knows what happened but one suspects that Mendel’s gardener doctored the results to produce numbers that he thought that his boss wanted! I always remember the Mendelian theory by the limerick:

There was a young fellow called Sarky

who had an affair with a darky.

The results of his sins were quadruplets not twins,

One white, one black and two khaki”

The controversy about whether electromagnetic fields cause cancer is full of such problems. It is easy to identify them but, as noted later, not so easy to describe the problem to a judge and jury in a courtroom.
One day Ponte gave me and another student a lift back to Oxford in his car. He parked his car just outside the post office in St Aldate’s where no parking was allowed. A burly “Bobby” came up and reproved him. Ponte let off a string of very rapid Italian and the Bobby retired in disorder!
As I left for the USA at the end of June 1950, Hans threw a farewell party for me. I am not sure whether it was at this party or another, but Ponte showed up with his Swedish born wife and children. “We are just going on vacation and we want to say good bye”. We found out later what he did but not why he did it. He emigrated to the Soviet Union secretly. Ponte and his family first went to see Ponte’s brother, an Italian film producer and communist, in Italy. Then Ponte and his family, wife and two children, flew to Stockholm to see his wife’s family. Then a Russian freight boat took them to Leningrad and he went to Dubna. His portrait hangs in the lecture room in Dubna as one of the founders of that laboratory. This secret departure from England leaves us with a difficult question which for me is unanswered. Why did Ponte go to USSR? I do not believe he could have known that he would be accepted, well treated and even honored. I think the Soviets had “something on him”. I don’t believe he ever betrayed secrets, but he could have been a “sleeper”, and once away from Harwell he would have been of no use to the KGB. They could well have betrayed him. So most of us suspect he was giiven the choice of working in the USSR or spending 7 years in jail as Alan Nunn May and Klaus Fuchs did. Dr Alan Nunn May had been arrested as a spy in Montreal in December 1949 and spent time in a UK jail. Klaus Fuchs was arrested in Harwell in February or March 1950. I remember that I was in Harwell at the time and the police at the gate told everyone coming out at 5 pm (to catch the 5.10 bus) “don’t talk to the press”. I did not know what not to talk to the press about! The UK government then felt that the only way to be sure about someone was if he was born, and his grandfathers were born, in the USA. Ponte was told that he had to take the first University position available where he would not be a security risk. He was immediately offered, and accepted, a lectureship at Liverpool where they were just finishing a 350 MeV cyclotron. I remember Gerry Pickavance saying at a dinner party in April 1950 or so, “I will believe that the government procedure makes sense when Pontecorvo is arrested”. Ponte was never arrested in UK but was arrested (by mistake) in summer 1951 in the Ukraine as noted later. Although as noted later I met him in the USSR it was not possible to ask him directly and his colleagues in the USSR have told me since that they were also puzzled. But Ponte died before the fall of the Soviet Union so it will always be a mystery.
In a post doctoral year in Rochester New York, I learned a lot of theoretical particle physics and had great experimental opportunities. I arrived in late June 1950. John Tinlotkindly drove me (and David Ritson also going to Rochester) up to Rochester in his car. We stopped at Ithaca on the way to call on Norman Kroll, a theoretical physicist who was a personal friend. That also was my first meeting with Robert R. Wilson, the great accelerator man, and Hans Bethe, the outstanding theoretical physicist. I knew a lot about Bethe’s work. Firstly his work on nucleon-nucleon reactions starting with his paper with Rudi Peirls on “The Quantum theory of the Diplon (now the deuteron)” in 1934. When I was supposed to be studying for my final examination in 1946, I came across Bethe’s paper on “Order-Disorder” reactions and got very excited about it. It was the beginning of Hans famous work on condensed matter physics. The net effect, as noted before, was I neglected the studies for the exam and that perhaps was the reason for my second class honors. It was one of many examples of my tendency to get excited about something and diverge from the straight and narrow path. That makes me admire those who can focus better than I can, such as my friend Klaus Roth.
. Arriving in the University of Rochester we (John Tinlot, David Ritson and I), were immediately herded into a seminar by Frank Yang from Chicago. That July (1950) I began to learn the latest meson theories and their consequences from Bob Marshak who had a very clear understanding of as much of the meson theory as could be derived from the first Born approximation. He had been one of the first, if not the first, to suggest (with Hans Bethe) the "two meson" (B meson and µ meson) hypothesis and had since described the selection rules that govern the measurements of capture on hydrogen and deuterium. He was excellent at explaining it all to the novice. A review paper was in draft as I arrived which we read greedily. It was exciting stuff to a visitor from the old world.
I learned that it is easy to understand things in first Born approximation - and it is often not worth the trouble to understand more details. Selection rules often govern what can be observed. But it is not always the case, and this led me astray. Bob and a student had suggested that the angular distribution of ( rays from proton bremsstrahlung would be very different for a scalar meson theory and a pseudoscalar meson theory with the ration of intensities at 90 degrees and zero degrees being 230 for pseudoscalar mesons and 0.8 for scalar mesons. We now know, of course that this Born approximation does not hold. It seemed here that even a very crude measurement could give interesting information. I set up and performed such a crude measurement, using a lead radiator and counter telescope to detect the gamma rays. The angular distribution was usually isotopic (in the center of mass) - indicating a scalar theory, but I soon realized that the large theoretical differences were not real; and that corrections to first Born approximation are all important in this case. The bremsstrahlung cannot be described in Born approximation; to first order it follows merely from the acceleration of the charged particles and is nearly isotropic in all models. Differences might arise from off shell effects may arise but are harder to find. I did not forget nucleon-nucleon bremsstrahlung and had it “on my list” to attempt when I got to Harvard , but it was over 10 years before good measurements were made by my colleague Bernie Gottschalk at Harvard and a former student, Ed Thorndike in Rochester.

I reported on my bremsstrahlung experiment at an APS meeting in Chicago. I went by the Commodore Vanderbilt, one of the last steam trains, and stayed near the University of Chicago. One afternoon I called on William (Bill) Libby Professor of Chemistry, who I had met in Christ Church the previous March, when he, as an Atomic Energy Commissioner, was in UK for a declassification conference. Strangely that was just after Klaus Fuchs was arrested. I wanted to see his carbon 14 dating system - which won him the Nobel prize. Like all the great scientists I called on he was gracious and spent an hour with me.

Marshak was very supportive of me as a young physicist. He was also introduced me to better eating. After the weekly physics colloquium the speaker was always invited to dinner and perhaps a party at his house. There I met Maurice Goldhaber, whose name I had known from his first measurement of the photodisintegration of the deuteron in 1934. Maurice had just arrived in Brookhaven National Laboratory and was enthusiastic about understanding the nuclear shell model which had Maria Goeppert M ayer the Nobel prize a few years later (1963). Maurice and his wife Gertrude (Trudy) had been at the University of Illinois but the University had a nepotism rule. It was not permitted for a second member of the family to have a paid job at the University. Trudy wanted to return to physics research after two youngsters were 5 years old or so, so they moved to BNL where they stayed. I followed the physics careers of both Trudy and Maurice. When their sons got to college age they came to Harvard and they suggested that I be their faculty advisor. That was a privilege of mine. Alfred (Freddie) became a Professor of Physics at Stoney Brook. Freddie’ son David, Mauric’s grandson also came to Harvard. I was not his advisor but I remember him in the undergraduate physics laboratory. David is now Professor of Physics at Stanford. It was at one of these dinners, though not at Marshak’s house that I first ate a boiled lobster. It was a pleasure that I have often repeated.
In August I went down to Princeton to call on Robert (Bob) Hofstadter and see how he arranged his Sodium Iodide (NaI) scintillation counters, followed by a brief trip to Brookhaven National Lab in Upton, Long Island to see what they were doing. In those days there were not very many high energy physicists. Remembering the Shelter Island conference of 1947, where he had gotten the idea that there might be two mesons, Bob Marshak decided to organize a high energy conference of his own. He persuaded Rochester industry to provide the funding and thus began the Rochester conferences. The first one, in December 1950, was attended by less than 100 people - fewer than participate in a group meeting of one of our modern experiments! Yet, so far as I can remember, everyone in the U.S. came, and several from overseas. It was probably the first presentation by Butler of the particles (now known to be 7₀ and K₀) which had been seen in cosmic rays using Manchester's triggered cloud chamber. I remember discussing them, sotto voce, with Bob Wilson - we were not sure we believed them and he suggested taking a vote!

I recollect meeting at that conference Jack Steinberger, Bob Oppenheimer, Bob Wilson, Lois Alvarez and Pief Panofsky. Pief stayed a full week in Rochester and told us about his classic experiments on B? meson capture in hydrogen and deuterium. This led me to desert Rochester the next year and join Pief at Stanford - where I carried out the most important and enduring research of my life - finding a wife.

In 1952 I began work in earnest on what was probably the most important experiment I did in Rochester. Since my Ph.D. thesis was on the measurement of the disintegration of the deuteron; (+D÷N+P (Reference 17on my publication list). I wondered (before I even got to Rochester) whether the disintegration by a B meson B⁺+D÷P+P would have a similar (or greater) interest. It seemed to me that each of the two protons would have a high energy and be easily detected in a scintillation counter. I had not expected that this was in fact an interesting, as well as being a possible, experiment. I asked Bob Marshak. Was the experiment interesting?. Bob was discouraging. He could find no important interpretation. He and a student, Warren Cheston, had already been studying the proton reaction P+P÷B⁺+D which had just been studied at Berkeley by Crawford and Stevenson. The grapevine was fast in those days.
The next day when I met Bob at lunch, where he always tried to talk to students and research fellows in the department, Bob was excited. He pointed out that a measurement of the cross section - even to an accuracy of 50% - could distinguish between two possibilities for the spin of the B meson. Far from merely repeating the experiment at Berkeley we would compliment it. The two experiments were related by the principle of detailed balanced, but the relationship contained the all important statistical factor (2S + 1). This statistical factor would be 3 if S = 1 and 1 if S = 0. We would have a simple measurement of the spin of the B⁰ meson.
At Rochester we (Arthur Roberts, Donald Clark and myself) had to build a meson beam with an energy higher than before (40 MeV). We also had to build the detectors. In those days counting electronics had to be built in the laboratory, not bought from industry. Even if the industry had existed, funding did not; and we had not yet acquired the habit of spending money. We still believed in the words of Arthur Roberts popular song "It ain't the money, it's the principle of the thing."
I proposed to detect the protons using liquid scintillation detectors using a solute - diphenylhexatriene - in xylene. Diphenyl hexatriene was a wavelength shifter - absorbing the scintillation ultraviolet light from the xylene and re-emitting in the green where a photomultiplier could detect it. This idea was the brainchild of Professor Helmut Kallmann when in Berlin and then at New York University. He had asked Pilot Chemicals to make the diphenyl hexatriene. Kallman paid $1,000 for 10 grams. I was the second purchaser - also 10 grams for $1,000. Of course this second $1000 was all profit for Pilot Chemicals . But then I made a major mistake. I thought that one could collect the light from each 10 cm square surface of the scintillator by a tapered light guide onto a 1 inch diameter lucite guide. I had forgotten Liouville's theorem and Richard Garwin's letter in Physical Review on how to design light guides had not yet appeared. Not enough light got to the phototube, so we had to scrap the counters. I still keep the light guides as an ornament on a chest in my bedroom to remind me of how stupid I can be. We then spent a lot of money on two sodium iodide crystals which had higher efficiency than the organic scintillators, and also higher density and therefore a smaller area from which to collect the light. The apparatus was tried out in mid March 1951. In the first two day run we found the reaction, and had a measurement of the cross section to the requisite 30% accuracy. It was reported by Arthur Roberts at a meeting of the National Academy of Sciences in early April and by me at the American Physical Society meeting again Washington at the end of April.
Bob had spent some of the summer 1955 lecturing on meson physics at Columbia's Nevis Laboratories, which had better capability for meson beams). He mentioned my idea to scientists at Nevis and Jack Steinberger decided to compete. In early April we submitted a 10 minute post deadline paper (which I gave) to the April APS meeting in Washington and Arthur Roberts talked about the results at a meeting at the National Academy of Sciences the week before. In those days, APS did not have computers to slow down the process, so that only 3 weeks notice was necessary for an abstract! At that time, the APS offices were at Columbia University, and naturally the abstracts could be seen by anyone interested. Jack Steinberger, seeing the abstract, decided to modify the accelerator schedule on B? meson physics, to immediately repeat and confirm the result, and put in a "post-deadline" paper which was scheduled just after ours. Unfortunately for them, the Columbia cyclotron had some temporary problems and at the Washington meeting Jack had no results. We delayed publication to take one more measurement of the energy dependence of the reaction, and submitted a letter to Physical Review. By that time the Columbia group had got their apparatus to work and had superior results (which fortunately agreed with ours). Jack persuaded Physical Review to publish both experiments in the same issue, holding ours up for a week. Alas our small “priority” was widely forgotten and in an article by Pief in the book on a century of physics published by the APS some 50 years later, Steinberger is credited with the discovery. I had got used to being ignored by that time but that Pief forgot made me especially sad.
In a real sense as much credit for the experiment belonged to Lynn Stevenson of Berkeley as anyone else; he had done the first experiment. The idea of using detailed balance for measuring the spin was not unique with Bob either. MH Johnson had written suggesting it. We referred to the letter in our publication but I cannot remember who Johnson wrote to. But Louis Alvarez, in whose group Lynn Stevenson worked at Berkeley, was incensed and extracted a promise form the APS officers never again to allow competitors to see abstracts or papers. I found out some 57 years later, in 2008, that Lois Alvarez had been very unfriendly to Jack Steinberger in summer 1950, less than a year before, and seemed to have taken a dislike to Jack. That may have contributed to his vigorous attack on Jack in May 1951. I was not as worried about it myself. Indeed I might not otherwise have become friendly with Lynn and Louis! In all of this Bob Marshak's role as an enthusiastic catalyst was characteristic. Although I have since become good friends with Jack Steinberger I never discussed this experiment with him. When Jack was invited to give a colloquium at Harvard in 1969 (on K decay) I broke with the tradition of expecting the speaker to fend for himself and arranged a dinner at the faculty club. When Andrée and I spent 6 months in CERN in 1981, he and his wife were the only scientists at CERN to invite us to dinner. When I visit CERN and call on him in his office, he comments that I am one of the few who do.
I left Rochester in July 1951, and traveled across Canada, as described earlier, to Vancouver and Palo Alto. During this second post doctoral year in Stanford University in 1951-2, where I married Andrée Desirée DuMond, I carried out a small experiment comparing photodisintegration and electrodisintegration. I thought at first as the inverse of internal conversion. The internal conversion of a gamma ray into an electron depends on the multipolarity of the gamma ray transition. With electro disintegration I thought that I could find the multipolarity of the transitions. This would have been true if I had looked at the scattered electron and seen the scattering peaks. I had yet to realize the power of the Weiszacker - Williams work which I understood later when making radiative corrections to electron and muon scattering. I did not completely realize the incorrectness of the multipolarity approach at any appreciable momentum transfer for another 15 years when I had been looking at the excited states of the proton by electron scattering at the CEA.
I had hoped that I would be able to carry out, with Pief, some experiments on The Mark III accelerator. But that was not possible. The accelerator itself had problems and no one had completely understood how to work with the pulsed electron beam. But I met and discussed physics with many interesting people. Of course I talked a lot with Pief, but I talked also with Ed Jaynes in the microwave laboratory who is now well known for his work on fundamentals of statistics. Also Hans Motz, a Viennese who had left in 1933 during the depression. He had gone to Kiev hoping that he could establish a life in that communist country and bring his lady love from Vienna. He stayed in an apartment building with Landau and others. He became disillusioned and ended up in UK as a lecturer in Engineering with, so he said, inadequate resources to be married. He became a British subject in 1939 and announced to his colleagues “Now I am English too!.” “No, Hans” was the precise response that he enjoyed hugely. “You have become British, but you will never be English” Hans had been in Stanford for a year or so and had already invented in theory and then experimentally tested, the “Undulator” or wiggler where an electron beam is wiggled between magnets and emits X rays in consequence. An undulator is now used in all dedicated synchrotron radiation devices. Hans remained unmarried, but had met Andrée the previous summer. We became good friends and I saw him after he returned to Oxford about 1956 and got married. He was always a friendly man but never seemed happy. He was thought of as a dilettante in science, but no critic can take away his invention of the undulator.