By Martin Weil
Washington Post Staff Writer
Thursday, March 10, 2011; 10:40 PM
Nobel laureate Simon van der Meer, a Dutch-born engineer and scientist whose precise, ingenious technique for controlling beams of subatomic particles was vital to the success of one of the landmark experiments of modern science, died of undisclosed causes March 4 in Geneva. He was 85.
Scientists have concluded that all of the activity in the known universe results from the play of four fundamental forces, and Mr. van der Meer's technique proved essential to revealing the link between two of them.
The experimental technique has entered the annals of science under the name of "stochastic cooling." In that perhaps-opaque phrase, "cooling" refers to imposing order on a swarm of unruly particles - antiprotons - required for the experiment. "Stochastic" refers to the role of probability and randomness in the technique.
Mr. van der Meer's Nobel Prize, awarded in physics, was given for an experiment completed in 1983 at Geneva-based CERN, the European nuclear research center.
A new theory uniting the weak force with electromagnetism had called for the existence of new particles that mediate the unified "electroweak" force. Before the experiment, those particles had never been detected.
At CERN, the Italian-born physicist Carlo Rubbia and Mr. van der Meer produced the particles, confirming the theory. (The particles are known as the W and Z intermediate vector bosons.) Behind the abstruse terminology lay one of the peak accomplishments of physics.
In testimony to the enthusiasm about their results, Rubbia and Mr. van der Meer received the Nobel the year after their discovery, an unusually brief interval.
The road to the scientists' triumph involved the crashing of a beam of protons head on into a beam of antiprotons. Antiprotons, the relatively exotic antiparticles of the proton, are difficult to create and were not to be squandered.
After creation in an early stage of the experiment, the antiprotons streak wildly about, with a huge spread in speed and direction that makes them essentially unusable for the experiment. Mr. van der Meer developed the apparatus that created a carefully controlled beam of these invisible subatomic particles.
The experiment "would have been totally impossible without this," said John Marriner, a scientist at Fermilab, the government's high-energy physics laboratory in Illinois. The difference between trying the experiment with and without the technique was "like night and day," he said.
Many advances in science are incremental improvements over what had come before. This, Marriner said, was "breakthrough technology."
Particle beams race around accelerators at speeds approaching that of light. At the same time, the electromagnetic detection equipment incorporated in Mr. van der Meer's devices were sensitive to trillionths of a watt.
Simon van der Meer was born Nov. 24, 1925, in The Hague. While growing up, he was an enthusiastic gadgetmaker, but his technical education was suspended during the WWII Nazi occupation of the Netherlands.
After getting a degree from the Delft University of Technology in 1952, he worked in industry before joining CERN in 1956, two years after it opened. He retired in 1990.
He married Catharina Koopman, whom he met in 1966 while skiing with friends in the Swiss mountains. Besides his wife, survivors include two children, Esther and Mathijs; a sister; and a granddaughter.
In a statement issued after his death, CERN described Mr. van der Meer as "a true giant" of modern particle physics.
"When confronted with a problem," the statement said, "he would sink into deep reflection, rarely emerging until he had a solution."
One co-worker recalled him as a taciturn man who "would never use two words where one would suffice."
But, according to CERN, "that one word would invariably be the right one."