Questions? Call Us 1-773-271-0318 9am to 2pm Central Time Mon.-Fri.
Cambridge celebrates "small wonders" 75th anniversary
THRee-QUARTeRS of a century ago, two young Cambridge physicists narrowly beat their American rivals to become the first scientists to split the atom.
John Cockcroft, 35, and ernest Walton, 29, achieved their breakthrough experiment at the old Cavendish Laboratory in Free School Lane in Cambridge. But neither could have foreseen the staggering repercussions of their scientific success.
Seventy-five years later, the work of Cockcroft and Walton continues. Husband and wife team Prof Andy Parker, 50, and Dr Val Gibson, 43, of Huntingdon Road, work in high energy physics - small bits of atoms, to the rest of us.
"Cockcroft and Walton are the founders of this field and they did it purely out of interest," says Val. "Unfortunately, 10 years after their experiment, others began developing the technology to invent the atomic bomb.
"Cockcroft and Walton were disappointed by what came after but if they hadn't done it, someone else would have, so I don't think they regretted it.
"they were just trying to push the field of science forward, like we are today (Monday, 16 April)."
From the late 19th Century onwards, four future Nobel Prize winners worked at the Cavendish to unlock the secrets of the atom.
"The atom is made up of electrons, protons and neutrons," explains Val. "J J Thompson discovered the electron in 1897. Then, in the 20s, ernest Rutherford suggested it span around a nucleus made up of protons and neutrons.
Rutherford pushed his staff, Cockcroft and Walton, to confirm exactly what this hard centre was made of and this goal became known as splitting the atom. People called Rutherford the crocodile because he was very forthright with his team, but he made things happen!"
Says Andy: "To look inside an atom you need to accelerate particles of energy. They built a machine to do this which became known as 'The Cockcroft-Walton'. We're carrying on in the exact same direction. But whereas they had only a small machine, we've got much bigger one."
On April 14, 1932, the two young scientists bombarded protons onto a piece of Lithium 7. By counting the resulting flashes of light, they worked out that the neutrons and protons had redistributed themselves - proof that the atom had been split.
Val continues: "When Cockcroft and Walton were developing their apparatus there was competition from the Americans. In San Francisco they were trying to build something called the Bevatron.
"Cockcroft and Walton were tweaking their machine, trying to make it perfect and eventually Rutherford told them to get on and do the experiment because they were running out of time."
The Cambridge scientists may have been in competition with the Americans back then, but 75 years later the international scientific community is now working together.
"For the last 17 years we've been working on the Large Hadron Collider; the highest energy particle accelerator there's ever been," says Andy.
Val adds: "It's a world project involving thousands of physicists - not just one box and two men."
Andy continues: "In October we will use it for the first time to look deep inside protons and discover new phenomena. The proton is the particle that Cockcroft and Walton used as bullets to smash bigger atoms and now we're smashing their bullets."
Val and Andy met in CeRN - the world's largest particle physics laboratory - in Geneva in 1983.
they moved to Cambridge in 1989 and now have two daughters, Milly, nine, and Lucy, four.
"We're both from Britain originally," says Val.
"I met Andy when he was in Geneva working on a bubble chamber experiment and I was there as a summer intern. So, for more than one reason, I decided I very much liked particle physics and we got married 10 years later. Eventually we both got jobs at the new Cavendish Laboratory in Cambridge on Madingley Road. It's very rare for a couple working in this area of science to find two jobs in the same place so now we're here for good!"
The Large Hadron Collider will accelerate protons to the speed of light. Andy and his fellow scientists will then use magnets to make them go round in a circle and cause them to smash into each other. It is from these collisions that they will be able to see the fundamental particles inside the protons and study how they interact.
"The particles collide at 25 nanoseconds - 40 millions times a second," says Andy. "When they collide they produce showers of particles and millions of flashes of light which you can't count with the naked eye. We need to detect what happens when they smash into each other, so we've built huge detectors which have millions and millions of electronic sensors inside. All the technology is very big and sophisticated which is why we've been working on it for such a long time."
By contrast, Cockcroft and Walton had a piece of plastic that would make a flash of light when the particles collided.
"they just sat in their box and counted the flashes," says Andy. "That seems a lot easier to me!"
...source, cambridge-news
A Gather of News of Atoms, elements, and Periodic Tables