Waiting for D-Day
While camping in Divonne, a charming little French village about 20 kilometres from the world’s largest and most ambitious accelerator centre in Europe, one can hear the soft beat of a contemporary tune played out somewhere in the valley, while the church bells toll in the distant background of the otherwise tranquil village.
CERN, or the European Organization for Nuclear Research, is on a fast track to commission the mightiest, largest and most energetic accelerator in the world, well surpassing the nearest rival that exists today. For CERN, and indeed for all the countries which have been participating in this incredible adventure, the moment of reckoning is nigh. The Large Hadron Collider is about to go into operation.
Here are some basic statistics. It is a device to facilitate the collision of two protons circling round in opposite direction at an awesome energy of trillions of electron volts (one trillion electron volts is a million times a million electron volts — an electron volt is the energy gained by an electron across a potential of one volt), protons and neutrons along with mesons constituting an atomic nucleus, which harnesses the mystery of nuclear fission leading to either a reactor or even a bomb.
The LHC has cost the European Union and other countries, including India, a little more than $ 8 billion and it took nearly 15 years to build. The tunnel which houses the beam lines is the fanciest pathway for protons going round, one lot in one direction and the other in another, eventually colliding with each other at certain specified points. It takes a proton only forty times a millionth of a second to go around once in the tunnel, a speed very close to the speed of light. The tunnel is 27 kms in circumference — considering that there are two beam lines harnessing the beam (one is talking about 54 kms of most high-tech beam lines in the world).
The temperature is around -267 degree Centigrade — a feat which can be achieved with the most developed form of liquid helium technology, usually referred to as cryogenic technology. These superconducting magnet systems at that temperature suffers virtually no resistance to electric current — and that is precisely why it has been possible to attain such incredible energy. Otherwise the machine would be the most power-hungry machine on this planet. The temperature is even lower than in the coldest part of our universe.
Very soon, however, there will be experiments related to the debris created by two nuclei (somewhat like the protons) colliding against each other after going round in the opposite direction at hundreds of trillions of electron volts.
After Europe was ravaged by World War II, some of the greatest visionaries of Europe in the early Fifties decided to build an accelerator complex, later named CERN. They wanted to create an international set-up of accelerators designed to look into the deepest and darkest mystery of nature; yet, they perceived very clearly that this great effort would create an incredible surge of high technology, unmatched in the world and thus help to put Europe on the way to rapid economic recovery.
The United Kingdom, France, Germany, Italy and other European countries took a leading role. It was more a story of brain than brawn or money. In fact, these great men, so convinced of their enterprise, went out of their way to borrow large sums of money, especially from the United States of America. John Adams of the UK built the first one-of-its-kind accelerator in the world at that time. The ancient workhorse, called Proton Synchrotron is still working, although for a different purpose.
There was no looking back. One by one, accelerators for tomorrow were designed and built — Super Proton Synchrotron (SPS), then electron position collider (LEP), which, after a process of upgradation, led to the LHC. The SPS and LEP put CERN at the top of the world physics chart. The famous prediction of Abdus Salam, Steven Weinberg and Sheldon Glashow — of W&Z bosons uniting electromagnetism (the law that commands ordinary light) and weak interaction (the central force of radioactivity) — were discovered at CERN. The experiments designed to discover these fundamental particles, called UA1 and UA2, eventually led to the discovery of the “web” system of computing, now a household name and used all over world as the “world wide web”. By 1984, Carlo Rubbia and Simon van der Meer got the Nobel Prize for their fundamental contribution to accelerator physics and design. They discovered the famous W&Z bosons. Less than six years after the discovery of Salam, Weinberg and Glashow, W&Z bosons were discovered — an unprecedented feat.
It was about this time that India entered the scene. Before this, only an individual Indian had taken part in these experiments, but there was no collective Indian presence. By the Eighties, there was, however, a paradigm shift in our mindset. We in India began to dream of competing with the rest of the world. A group led by the late P.K. Malhotra of the Tata Institute of Fundamental Research entered the Bubble Chamber effort at CERN. Calcutta, the Variable Energy Cyclotron Centre, along with the universities of Rajasthan, Jammu, Chandigarh and others came to CERN in the mid-Eighties in a big way to design and build a marvel of a detector half the size of any standard room, called the Photon Multiplicity Detector (PMD). The PMD consists of 55,000 plastic scintillator pads, typically (1-2) Cm2 in size. This was designed and built in India, mostly by rather young scientists. For the first time, two novel phenomena took place almost unnoticed. Calcutta’s Cyclotron Centre, in collaboration with the universities of Rajasthan, Jammu and Chandigarh formed a team, sharing the responsibilities. Small but efficient, clean rooms were built in the university premises and work started with much enthusiasm. This kind of collective effort on such a huge scale was the first of its kind in India. Second, two governmental agencies — the department for the development of atomic energy and the department of science and technology were merged for funding.
Meanwhile, my colleagues at the Saha Institute of Nuclear Physics, wanting to participate in the ALICE project, incredibly enough, designed and fabricated an original chip, called Manas. About one lakh of them are hanging right now in the muon arm detector of ALICE. It has not been a cakewalk by any means. The competition was tough, and the battle was keenly fought, but eventually won by us.
One can see the 80,000 Manas Chips, created in the Saha Institute, make up the entire muon arm detector. With another 20,000 chips for the PMD, there are a lakh of them altogether.
Finally, the detector was shipped to CERN and took its position at the end of the beam line of CERN, Super Proton Synchrotron (SPS). SPS till that time was to us just a name with the glamour of the Nobel Prize attached to it. But now we became part of the show. The idea of impending experiments was breathtakingly exciting. By the early Nineties, India became a key player on the world stage and ceased to be only a spectator. Experimental runs started and the PMD was a resounding success, and was rewarded with discoveries. Results from the PMD were presented in all major world conferences.
Within a few years, our status was so well-established that the management of the Relativistic Heavy Ion Collider (RHIC) across the Atlantic at the Brookhaven National Laboratory invited us to participate in the STAR detector to look for photons, as signals of the exotic debris left after the collision of the two nuclei at RHIC — yet another success.
What is the LHC looking for?
With the collision of two nuclei, man will create a speck of energy window, within a very very tiny volume, equivalent to one million times the temperature in the interior of the sun. Indeed, the universe, a microsecond (a millionth of a second) after its birth from the Big Bang, according to conventional wisdom, must have been in this state. So, LHC is having a “peep” into the very early stages of the creation of the universe and, of course, into the history of its evolution through space and time since then. And now, 14 billion years later on this planet, we shall mimic that primordial epoch. Colliding proton with proton, one can trace back to even earlier times of the universe, coming even closer to the Big Bang.
Our workhorses, the PMD and the Manas chip of the muon arm are expected to pick up signals of a plasma of the most fundamental elements of all matter, of quarks and gluons. Quarks are glued together by gluons, the building blocks of our familiar protons and neutrons; three quarks make either a proton or a neutron, and, to remind, protons, neutrons and mesons make up a nucleus. At the primordial epoch, the universe, strange as it may sound, must have consisted of quarks, gluons, electrons and photons (light particles).
There are many more fundamental questions which will be addressed by the experiments designed for the LHC. For instance, the tantalizing possibility of discovering the Higgs Boson, the missing link of the most fundamental theory of particle physics, the standard model of quarks and gluons.
There are three great beasts of detectors — ALICE, our own wonderland of quarks, CMS, and ATLAS, each costing billions of dollars. The whole world is waiting anxiously for the outcome of the experiments, confirming or negating our ideas about the deepest and darkest mysteries of nature. The sense of excitement prevailing here is so infectious that it even gets to the die-hard cynics of the “so what is it all worth?” kind. It is an explosion, a revolution of ideas so fine-tuned that even the greatest masters will be humbled.
On April 5, when CERN was thrown “open” to anybody and everybody, the great Peter Higgs from Edinburgh University came up to see the CMS, ALICE and ATLAS. CMS in particular is looking for Higgs boson. In no time, the website of CMS had the addition, “Higgs was found at CMS”. He was, of course, there in person, going up and down the huge lift at ALICE to see our detectors. An extremely self-effacing person, he is waiting patiently for the Higgs boson.
Some doubting Thomases suggested that the LHC will produce nature’s most bizarre yet perfectly structured objects, the black holes. And the black holes, they claim, created in the LHC will eat up not only CERN but entire Europe, and eventually our planet. Black holes are known for their bottomless capacity to gobble because of their infinite gravitational attraction.
Cosmic rays consisting of fundamental particles hit the earth from all over the cosmos with energies even upto a million times the energy of the LHC. But nothing like the black hole phenomenon has happened, proving the physicist’s prediction right. Even if a mini black hole is fleetingly produced, it will “pop” in no time, bursting with finite energy that is easy to handle. Mini black holes (less than a few centimetres in size) do not have the gravitational appetite to “gobble” anything. They “pop” very very fast.
Meanwhile, here in India, the Raja Ramanna Centre of Advanced Technology of the Department of Atomic Research has been participating meaningfully on the machine side of the LHC, by contributing superconducting steering magnets, jacks on which the beam lines stand, and so on. The entire contribution measures up to about $40 million. India’s prestige in the high end of engineering has shot up substantially, while this financial contribution helped the group working with the detectors.
Yet another great leap in application is the entry of the grid computing, an advanced form of collective computing network spread across the world. As I have said, the world wide web was discovered at CERN and now, comes the “Grid”, a quantum jump from www. The load of data expected to come out of the experiments will be so huge that computers set up in Europe and other participating countries will become part of the network. In this revolutionary breakthrough, a fantastic software, somewhat like the electric grid, distributes the data load across the world at once keeping all the computers in the world busy all the time. Just as www has ushered in a neo-revolution in the world of communication, most of us feel Grid will precipitate a mighty revolution. Its power is almost limitless. With nano chips round the corner, tomorrow will not recognize yesterday.
Thus the great farsightedness of the founding father’s of CERN has been more than vindicated. October 21 is the D-Day, when heads of states will assemble here to witness man’s greatest creation so far in science and technology. That is the day the LHC goes into operation and is dedicated to all the participating nations — in short, the world. CERN is where the world exists in perfect harmony and order, effortlessly crossing the barriers of countries, cultures, languages and religion. If there be an utopia on Earth, it most certainly is CERN. It is almost a perfect demonstration what man can do, what he can achieve, and the heights of beauty, harmony and brotherhood that can be created on this planet.