CERN pioneers
I read with great interest the article devoted to the role played by American physicists in the creation, launching and development of CERN (CERN Courier April).
You will, perhaps, allow me to point out that the first American initiative in this area was the work of Robert Oppenheimer.
I first met Oppenheimer and Isidor Rabi in the course of my duties as representative of France to the United Nations Commission for international control of atomic energy (1946-1948).
I quickly became friendly with Oppenheimer and his wife, and my wife and I spent many weekends at their Princeton house. Here in substance is what he told me in the course of these get-togethers: "What we know we have learnt in Europe, but henceforth fundamental research in particle physics will demand large resources which are beyond the scope of European countries taken individually. It would be basically unhealthy for the Europeans to have to go to the US or the USSR to be able to continue contributing to fundamental research. It is therefore necessary for the Europeans to pool their human and financial resources to give themselves the tools needed to pursue research".
I organized meetings between Oppenheimer, Pierre Auger, Francis Perrin and Lew Kowarski, who came to New York as scientific advisers in my delegation to the UN Commission. Naturally, Rabi was in complete agreement with Oppenheimer on this matter.
On my return to Paris, I undertook a tour of European capitals with Francis Perrin to see what sort of reception would be given to Oppenheimer's idea.
I must say that these approaches, made in 1949 and 1950, aroused little enthusiasm except on the part of Amaldi in Italy, Scherrer in Switzerland and Niels Bohr in Denmark.
This lack of interest was largely due to a twofold reticence, on the one hand that shown by governments who, having not the slightest idea of what was involved, thought in terms of a European atomic bomb project; and on the other hand that shown by the many researchers for whom the plan would have the effect of drying up the already meagre resources allocated to their own laboratories. It was, as you quite rightly say, the intervention by Rabi at the 1950 UNESCO conference in Florence that set things in motion.
If, then, Oppenheimer was the spiritual father of CERN, it was Rabi at Florence and Pierre Auger afterwards who were the midwives.
Gordon Fraser's articles showing the intensity of co-operation that has been established between European and American researchers in the framework of CERN, and the fact that many American teams work there, would have deeply delighted Oppenheimer as well as Rabi. Their wish was that Europeans would not be constrained to cross the ocean to carry out advanced research: it seems to me that the co-operation as Fraser describes it is established on a footing of perfect coherence and complementarity between researchers on the two sides of the ocean.
François de Rose, president of CERN Council 1959-1962.
Intellectual atmosphere
Maury Tigner's article (CERN Courier May) rings true. In a time of belt-tightening in particle physics, it is interesting to look back to the late 1970s when CERN actually had slightly more money than it needed to carry out its approved programme. This allowed the laboratory to foster the intellectual atmosphere in accelerator physics that Tigner speaks of, and to act on one particularly imaginative idea - Carlo Rubbia's proposal for converting the newly commissioned Super Proton Synchrotron into a proton-antiproton collider. This was a daring suggestion. Antiprotons are hard to make and you need a lot to get any useful luminosity, so the first thing you need is an antiproton factory. Moreover, experience from CERN's intersecting storage rings showed that it could be difficult to extract interesting physics at a hadron collider. The first problem was solved by Simon van der Meer's beautiful idea of stochastic cooling - a prime example of the sort of intellectual creativity Tigner calls for - which allowed antiprotons to be stacked and the beam phase space to be reduced so that "dense" bunches of antiprotons could be produced.
Stochastic cooling worked superbly, and even more surprisingly, the signals from both Zs and Ws turned out to be very clean. The W events were so clean because of the novel technique of missing transverse energy used to identify and measure the Ws. This was a revolutionary discovery because it killed off the old prejudices about hadron colliders being "dirty" and pointed the way to the future. The quickest and cheapest way to achieve the highest-energy collisions was with hadron colliders. Fermilab's Tevatron took over from the CERN collider and went on to discover the top quark - it may well make many more discoveries. The next big exciting steps in particle physics will come when CERN's 14 TeV proton-proton collider, the LHC, starts operating in 2007.
We can only speculate where our field would be today had CERN not been in a position to foster and exploit intellectual activity in accelerator physics back in the 1970s. I will leave that question to historians of alternative histories.
Tony Weidberg, Oxford University.