The phrase "Large Hadron Collider" is so deeply entrenched in the mass media that the overwhelming majority of people know about this installation, including those whose activities are in no way connected with the physics of elementary particles, and with science in general.

Indeed, such a large-scale and expensive project could not be ignored by the media - a ring installation almost 27 kilometers long, at a cost of tens of billions of dollars, with which several thousand researchers from all over the world work. A significant contribution to the popularity of the collider was made by the so-called "particle of God" or the Higgs boson, which was successfully advertised, and for which Peter Higgs received the Nobel Prize in physics in 2013.

First of all, it should be noted that the Large Hadron Collider was not built from scratch, but arose on the site of its predecessor, the Large Electron-Positron Collider (LEP). Work on the 27-mile tunnel began in 1983, where it was later planned to locate an accelerator that would collide electrons and positrons. In 1988, the ring tunnel closed, while the workers approached the tunnel so carefully that the discrepancy between the two ends of the tunnel was only 1 centimeter.

The accelerator operated until the end of 2000, when it reached its peak - an energy of 209 GeV. After that, its dismantling began. Over the eleven years of its work, LEP has brought a number of discoveries to physics, including the discovery of the W and Z bosons and their further research. Based on the results of these studies, a conclusion was made about the similarity of the mechanisms of electromagnetic and weak interactions, as a result of which theoretical work began on combining these interactions into the electroweak.

In 2001, the construction of the Large Hadron Collider began on the site of the electron-positron accelerator. The construction of the new accelerator was completed at the end of 2007. It was located on the site of the LEP - on the border between France and Switzerland, in the valley of Lake Geneva (15 km from Geneva), at a depth of one hundred meters. In August 2008, tests of the collider began, and on September 10 the official launch of the LHC took place. As with the previous accelerator, the construction and operation of the facility is led by the European Organization for Nuclear Research - CERN.

CERN

In short, it is worth mentioning the organization CERN (Conseil Européenne pour la Recherche Nucléaire). This organization acts as the world's largest laboratory in the field of high energy physics. It includes three thousand permanent employees, and several thousand more researchers and scientists from 80 countries take part in CERN projects.

At the moment, the project participants are 22 countries: Belgium, Denmark, France, Germany, Greece, Italy, Netherlands, Norway, Sweden, Switzerland, UK - founders, Austria, Spain, Portugal, Finland, Poland, Hungary, Czech Republic, Slovakia, Bulgaria and Romania acceded. However, as mentioned above, several dozen more countries take part in one way or another in the work of the organization, and in particular at the Large Hadron Collider.

How does the Large Hadron Collider work?

What is the Large Hadron Collider and how it works are the main questions of interest to the public. Let's consider these issues further.

Collider (collider) - translated from English means "the one who collides." The task of such an installation is the collision of particles. In the case of a hadronma collider, the role of particles is played by hadrons - particles participating in strong interactions. These are the protons.

Obtaining protons

The long path of protons originates in the duoplasmatron - the first stage of the accelerator, where hydrogen enters in the form of gas. The duoplasmatron is a discharge chamber where an electric discharge is conducted through the gas. So hydrogen, consisting of only one electron and one proton, loses its electron. Thus, plasma is formed - a substance consisting of charged particles - protons. Of course, it is difficult to obtain a pure proton plasma, therefore, the formed plasma, which also includes a cloud of molecular ions and electrons, is filtered to separate a cloud of protons. Under the influence of magnets, the proton plasma is beamed into a beam.

Preliminary particle acceleration

The newly formed proton beam begins its journey in the LINAC 2 linear accelerator, which is a 30-meter ring, sequentially hung with several hollow cylindrical electrodes (conductors). The electrostatic field generated inside the accelerator is graduated in such a way that the particles between the hollow cylinders always experience an accelerating force in the direction of the next electrode. Without going completely into the mechanism of acceleration of protons at this stage, we only note that at the exit from LINAC 2 physicists receive a beam of protons with an energy of 50 MeV, which already reach 31% of the speed of light. It is noteworthy that in this case the mass of particles increases by 5%.

By 2019-2020, it is planned to replace LINAC 2 with LINAC 4, which will accelerate protons to 160 MeV.

It is worth noting that lead ions are also accelerated at the collider, which will make it possible to study the quark-gluon plasma. They are accelerated in a LINAC 3 ring, similar to LINAC 2. Experiments with argon and xenon are also planned in the future.

Next, the proton packets enter the proton-synchronous booster (PSB). It consists of four superimposed rings with a diameter of 50 meters, in which electromagnetic resonators are located. The electromagnetic field created by them has a high intensity, and the particle passing through it receives acceleration as a result of the potential difference of the field. So after just 1.2 seconds, the particles accelerate in PSB to 91% of the speed of light and reach an energy of 1.4 GeV, after which they enter the proton synchrotron (PS). The PS has a diameter of 628 meters and is equipped with 27 magnets that guide the particle beam in a circular orbit. Here the protons reach 26 GeV particles.

The penultimate ring for accelerating protons is the Superproton Synchrotron (SPS), which has a circumference of 7 kilometers. Equipped with 1,317 magnets, the SPS accelerates particles to an energy of 450 GeV. After about 20 minutes, the proton beam hits the main ring - the Large Hadron Collider (LHC).

Acceleration and collision of particles at the LHC

The transitions between the rings of the accelerators occur by means of electromagnetic fields created by powerful magnets. The main ring of the collidero consists of two parallel lines in which particles move in an annular orbit in the opposite direction. About 10,000 magnets are responsible for maintaining the circular trajectory of the particles and directing them to the collision points, some of which weigh up to 27 tons. To avoid overheating of the magnets, a helium-4 circuit is used, through which about 96 tons of matter flows at a temperature of -271.25 ° C (1.9 K). Protons reach an energy of 6.5 TeV (that is, the collision energy is 13 TeV), while their speed is 11 km / h less than the speed of light. Thus, the proton beam passes through the large collider ring 11,000 times per second. Before the collision of particles occurs, they will circulate around the ring for 5 to 24 hours.

The collision of particles occurs at four points of the main LHC ring, in which four detectors are located: ATLAS, CMS, ALICE and LHCb.

Large Hadron Collider detectors

ATLAS (A Toroidal LHC ApparatuS)

- is one of two general-purpose detectors at the Large Hadron Collider (LHC). He explores a wide range of physics, from searching for the Higgs boson to particles that can make up dark matter. Although it has the same scientific goals as the CMS experiment, ATLAS uses different technical solutions and a different design of the magnetic system.

Particle beams from the LHC collide at the center of the ATLAS detector, creating colliding debris in the form of new particles that are emitted from the collision point in all directions. Six different detecting subsystems, located in layers around the collision point, record the paths, momentum and energy of the particles, allowing them to be individually identified. A huge system of magnets bends the paths of the charged particles so that their momenta can be measured.

The interactions in the ATLAS detector create a huge data stream. To process this data, ATLAS uses an advanced "trigger" system to tell the detector which events to record and which to ignore. Sophisticated data acquisition and computation systems are then used to analyze the recorded collision events.

The detector is 46 meters high and 25 meters wide and weighs 7,000 tons. These parameters make ATLAS the largest particle detector ever built. It is located in a tunnel at a depth of 100 m near the main CERN facility, near the village of Meirin in Switzerland. The installation consists of 4 main components:

• The inner detector is cylindrical, the inner ring is only a few centimeters from the axis of the passing particle beam, and the outer ring is 2.1 meters in diameter and 6.2 meters long. It consists of three different sensor systems immersed in a magnetic field. An internal detector measures the direction, momentum, and charge of electrically charged particles produced in each proton-proton collision. The main elements of the internal detector are: Pixel Detector, Semi-Conductor Tracker (SCT) and Transition radiation tracker (TRT).

• Calorimeters measure the energy that a particle loses as it passes through a detector. It absorbs the particles arising from the collision, thereby fixing their energy. Calorimeters consist of layers of "absorbing" material with high density - lead, alternating with layers of "active medium" - liquid argon. Electromagnetic calorimeters measure the energy of electrons and photons when interacting with matter. Hadron calorimeters measure the energy of hadrons interacting with atomic nuclei. Calorimeters can stop most of the known particles, except for muons and neutrinos.

LAr (Liquid Argon Calorimeter) - ATLAS calorimeter

• Muon Spectrometer - Consists of 4,000 individual muon chambers using four different technologies to identify muons and measure their momenta. Muons usually pass through an internal detector and calorimeter, and therefore a muon spectrometer is required.

• The ATLAS magnetic system bends particles around the various layers of detector systems, making it easier to track particle tracks.

The ATLAS experiment (February 2012) employs over 3,000 scientists from 174 institutions in 38 countries.

CMS (Compact Muon Solenoid)

- is a general purpose detector at the Large Hadron Collider (LHC). Like ATLAS, it has an extensive physics program, ranging from studying the Standard Model (including the Higgs boson) to looking for particles that could make up dark matter. Although it has the same scientific goals as the ATLAS experiment, CMS uses different technical solutions and a different design of the magnetic system.

The CMS detector is built around a huge solenoid magnet. It is a cylindrical coil of superconducting cable that generates a field of 4 Tesla, approximately 100,000 times the Earth's magnetic field. The field is bounded by a steel "yoke", which is the most massive component of the detector, weighing 14,000 tons. The complete detector is 21 m long, 15 m wide and 15 m high.The installation consists of 4 main components:

• The solenoid magnet is the largest magnet in the world, which serves to bend the trajectory of charged particles emitted from the point of collision. Trajectory distortion allows you to distinguish between positively and negatively charged particles (because they bend in opposite directions), as well as measure momentum, the magnitude of which depends on the curvature of the trajectory. The huge size of the solenoid allows the tracker and calorimeters to be positioned inside the coil.
• Silicon Tracker - Consists of 75 million individual electronic sensors arranged in concentric layers. When a charged particle flies through the layers of the tracker, it transfers part of the energy to each layer, the combination of these points of collision of the particle with different layers allows you to further determine its trajectory.
• Calorimeters - electronic and hadronic, see ATLAS calorimeters.
• Sub-detectors - allow detecting muons. They are represented by 1,400 muon chambers, which are located in layers outside the coil, alternating with metal plates of the "hamut".

The CMS experiment is one of the largest international scientific research in history, involving 4,300 people: particle physicists, engineers and technicians, students and support staff from 182 institutes, 42 countries (February 2014).

ALICE (A Large Ion Collider Experiment)

- is a heavy ion detector on the rings of the Large Hadron Collider (LHC). It is intended to study the physics of strongly interacting matter at extreme energy densities, where a phase of matter called quark-gluon plasma is formed.

All ordinary matter in the universe today is made up of atoms. Each atom contains a nucleus made up of protons and neutrons (except hydrogen, which has no neutrons), surrounded by a cloud of electrons. Protons and neutrons, in turn, are made up of quarks bound together with other particles called gluons. No quark has ever been observed in isolation: quarks as well as gluons appear to be permanently bound together and confined within compound particles such as protons and neutrons. This is called confinement.

Collisions at the LHC create temperatures over 100,000 times hotter than at the center of the Sun. The collider provides collisions between lead ions, simulating conditions similar to those that took place immediately after the Big Bang. In these extreme conditions, protons and neutrons "melt", freeing quarks from their bonds with gluons. This is the quark-gluon plasma.

The ALICE experiment uses an ALICE detector weighing 10,000 tons, 26 m long, 16 m high and 16 m wide. The device consists of three main sets of components: tracking devices, calorimeters, and particle identification detectors. It is also divided into 18 modules. The detector is located in a tunnel at a depth of 56 m below, near the village of Saint-Denis-Pouilly in France.

The experiment employs over 1,000 scientists from over 100 physics institutes in 30 countries.

LHCb (Large Hadron Collider beauty experiment)

- As part of the experiment, a study of small differences between matter and antimatter is carried out by studying a type of particle called a "beauty quark" or "b-quark".

Rather than surround the entire collision point with an enclosed detector like ATLAS and CMS, the LHCb experiment uses a series of subdetectors to detect predominantly forward particles — those that were directed forward as a result of a collision in the same direction. The first subdetector is installed close to the point of collision, and the rest - one after the other at a distance of 20 meters.

At the LHC, a large abundance of different types of quarks are created before they quickly decay into other forms. To capture b-quarks, sophisticated moving tracking detectors were developed for the LHCb, located near the movement of the particle beam through the collider.

The 5600 ton LHCb detector consists of a direct spectrometer and flat detectors. It is 21 meters long, 10 meters high and 13 meters wide, and is 100 meters underground. About 700 scientists from 66 different institutes and universities are involved in the LHCb experiment (October 2013).

Other experiments at the collider

In addition to the above experiments at the Large Hadron Collider, there are two other experiments with installations:

• LHCf (Large Hadron Collider forward)- studies the particles thrown forward after the collision of particle beams. They imitate cosmic rays, which are being studied by scientists as part of an experiment. Cosmic rays are naturally occurring charged particles from outer space that constantly bombard the earth's atmosphere. They collide with nuclei in the upper atmosphere, causing a cascade of particles that reach ground level. Studying how collisions inside the LHC cause similar particle cascades will help physicists interpret and calibrate large-scale cosmic ray experiments that can span thousands of kilometers.

The LHCf consists of two detectors, which are located along the LHC, at a distance of 140 meters on either side of the ATLAS collision point. Each of the two detectors weighs only 40 kilograms and measures 30 cm long, 80 cm high and 10 cm wide. The LHCf experiment involves 30 scientists from 9 institutes in 5 countries (November 2012).

• TOTEM (Total Cross Section, Elastic Scattering and Diffraction Dissociation)- experiment with the longest installation at the collider. Its task is to study the protons themselves, by accurately measuring the protons arising from collisions at small angles. This area is known as the "forward" direction and is not available to other LHC experiments. TOTEM detectors extend for almost half a kilometer around the CMS interaction point. TOTEM has nearly 3,000 kg of equipment, including four nuclear telescopes and 26 Roman pot detectors. The latter type allows the detectors to be placed as close as possible to the particle beam. The TOTEM experiment includes about 100 scientists from 16 institutes in 8 countries (August 2014).

Why is the Large Hadron Collider needed?

The largest international scientific facility explores a wide range of physics problems:

• Study of top quarks. This particle is not only the heaviest quark, but also the heaviest elementary particle. Studying the properties of the top quark also makes sense because it is a research tool.
• Search and study of the Higgs boson. Although CERN claims that the Higgs boson was already discovered (in 2012), so far very little is known about its nature and further research could clarify the mechanism of its operation.

• Study of quark-gluon plasma. In collisions of lead nuclei at high speeds, it is formed in the collider. Its research can bring results useful both for nuclear physics (improvement of the theory of strong interactions) and for astrophysics (study of the Universe in its first moments of existence).
• Search for supersymmetry. This research is aimed at refuting or proving "supersymmetry" - the theory that any elementary particle has a heavier partner, called a "superparticle".
• Investigation of photon-photon and photon-hadron collisions. It will improve the understanding of the mechanisms of processes of such collisions.
• Testing exotic theories. This category of tasks includes the most unconventional - "exotic" ones, for example, the search for parallel universes by creating mini-black holes.

In addition to these tasks, there are many others, the solution of which will also allow humanity to understand nature and the world around us at a higher quality level, which in turn will open up opportunities for the creation of new technologies.

Practical benefits of the Large Hadron Collider and basic science

First of all, it should be noted that basic research contributes to basic science. Applied science deals with the application of this knowledge. A segment of society that is not aware of the benefits of fundamental science often does not perceive the discovery of the Higgs boson or the creation of a quark-gluon plasma as something significant. The connection between such studies and the life of an ordinary person is not obvious. Let's take a quick example from nuclear power:

In 1896, the French physicist Antoine Henri Becquerel discovered the phenomenon of radioactivity. For a long time it was believed that mankind would not move to its industrial use soon. Just five years before the launch of the first nuclear reactor in history, the great physicist Ernest Rutherford, who actually discovered the atomic nucleus in 1911, said that atomic energy would never find its use. Experts managed to rethink their attitude to the energy contained in the nucleus of an atom in 1939, when German scientists Lisa Meitner and Otto Hahn discovered that uranium nuclei, when irradiated with neutrons, split into two parts, releasing a huge amount of energy - nuclear energy.

And only after this last link in a number of fundamental research, applied science came into play, which, on the basis of these discoveries, invented a device for obtaining nuclear energy - an atomic reactor. The scale of the discovery can be estimated by looking at the share of electricity generated by nuclear reactors. So in Ukraine, for example, nuclear power plants account for 56% of electricity generation, and in France - 76% altogether.

All new technologies are based on one or another fundamental knowledge. Here are a couple more short examples:

• In 1895, Wilhelm Konrad Roentgen noticed that the photographic plate darkens under the influence of X-rays. Today, radiography is one of the most used studies in medicine, which allows you to study the state of internal organs and detect infections and swelling.
• In 1915, Albert Einstein proposed his own. Today, this theory is taken into account when GPS satellites work, which determine the location of an object with an accuracy of a couple of meters. GPS is used in cellular communications, cartography, vehicle monitoring, but primarily in navigation. The error of a satellite that does not take into account general relativity would increase by 10 kilometers a day from the moment of launch! And if a pedestrian can use his mind and a paper map, then the pilots of the airliner will find themselves in a difficult situation, since it is impossible to navigate by the clouds.

If today the practical application of the discoveries that took place at the LHC has not yet been found, this does not mean that scientists are “messing around with the collider in vain”. As you know, Homo sapiens always intends to get the maximum of practical application from the available knowledge, and therefore the knowledge about nature accumulated in the process of research at the LHC will definitely find its application, sooner or later. As already demonstrated above, the connection between fundamental discoveries and the technologies that use them may sometimes not be obvious at all.

Finally, let us note the so-called indirect discoveries, which are not set as the initial goals of the study. They are quite common, since to make a fundamental discovery usually requires the introduction and use of new technologies. So the development of optics received an impetus from fundamental space research, based on the observations of astronomers through a telescope. In the case of CERN, this is how the ubiquitous technology emerged - the Internet, a project proposed by Tim Berners-Lee in 1989 to make it easier to find CERN data.

Natalia Demina visited the European Center for Nuclear Research (CERN) on the eve of its 60th birthday. She is confident that after the upgrade, the Large Hadron Collider will be ready for new discoveries.

I never rode a bicycle down the LHC tunnel. Although two dozen bicycles, suspended on a special rack or leaning against the wall, were clearly waiting for those who wanted to. We were just downstairs when a siren sounded. Our group was immediately rushed to the elevator, which took us to the surface, 90 meters up. "If a fire starts in the tunnel, everything will be filled with special foam, in which you can breathe.", - the accompanying, cheerful, calmed us Afro-Swiss Abdillah Abal. "Have you tried to breathe in it?" I asked. "Not!" He replied, and everyone laughed.

To the building where the experiment is taking place ALICE, a few minutes later the fire brigade arrived. The search for the cause of the alarm continued for about an hour - it turned out that the oxygen level sensor had worked in the tunnel, but we were not allowed to go down.

Myself CERN looks like a city, at the entrance you will be greeted by a gate with a security guard who will check the pass or reservation at the local hostel hotel. “It used to be easier, - say the old-timers. - All this appeared only after several unpleasant incidents happened, including with the green ones. "... What other incidents? CERN is open to the world, every day on its territory and in museum ("Sphere of Science and Innovation") schoolchildren, students and teachers come on excursions, who are told about the past, present and future of one of the best physical centers in the world. It seems that CERN has everything: the post office, and a delicious inexpensive self-service restaurant, and a bank, and Japanese sakura, and Russian birches. Almost paradise - for both employees and visitors. But there is also a small number of people who need "incidents" like air, and they need to be able to somehow reasonably resist.

The 27-kilometer ring itself is located at a depth of 50-150 m on the territory of both France and Switzerland. From the center of Geneva you can get to CERN by a regular city tram in just 20-30 minutes. The border between the two countries is almost invisible, and so far I have not been told: "Look, this is the border", I would not have noticed her. Cars and pedestrians travel without stopping. I myself went back and forth, from the hotel to CERN, laughing to myself that I was going to dinner from France to Switzerland.

Before arriving at CERN, I did not know about the role that the Russian defense industry played in the construction of the collider, which remained from the times of the USSR. So, for the hadron end-face calorimeter of the CMS detector, it was necessary to make a large volume of special brass plates. Where can I get brass? It turned out that in the North, at our naval enterprises, a lot of spent cartridges had accumulated, so they were melted down.

“At one time, when the Americans threatened the USSR with“ star wars, ”Academician Velikhov proposed placing laser weapons in orbit. Special crystals were needed for lasers, - Vladimir Gavrilov, head of the CMS experiment from the Institute for Theoretical and Experimental Physics (ITEP), told me. - Several factories were built for this project. But then it all collapsed, the factories had nothing to do. It turned out that the plant in Bogoroditsk, Tula region can make crystals that are needed for CMS ".

EXPERIMENTS ATLAS AND CMS

Four large experiments are underway at the Large Hadron Collider ( ATLAS, CMS, ALICE and LHCb) and three small ( LHCf, MoEDAL and TOTEM). The data flow from the four large experiments is 15 petabytes (15 million GB) per year, which would require a 20-kilometer stack of CDs to record. The honor of the discovery of the Higgs boson belongs jointly to ATLAS and CMS, in the composition of these collaborations there are many scientists from Russia. In just 60 years, more than a thousand Russian specialists have worked at CERN. The ATLAS detector is amazing: 35 m high, 33 m wide and almost 50 m long. Nikolay Zimin, employee of the Joint Institute for Nuclear Research in Dubna and this experiment, who has been working at CERN for many years, compared the detector to a giant nesting doll. “Each of the upper layers of the detectors surrounds the previous one, trying to cover the solid angle as much as possible. Ideally, it should be done so that all the emitted particles can be caught and that “dead zones” in the detector are minimized. ", - he emphasizes. Each of the detector subsystems, "detector layers", registers certain particles, which are produced in the collision of proton beams.

How many “matryoshka” dolls are there in a large “matryoshka-detector”? Four large subsystems, including a muon and a calorimeter system. As a result, the ejected particle crosses about 50 "registration layers" of the detector, each of which collects one or another information. Scientists determine the trajectory of these particles in space, their charges, velocities, mass and energy.

Proton beams collide only in those places that are surrounded by detectors, in other places of the collider they fly along parallel tubes.

Beams accelerated and launched into the Large Hadron Collider rotate for 10 hours, during which time they cover a path of 10 billion km, which is enough to travel to Neptune and back. Protons traveling at almost light speed make 11,245 revolutions per second along the 27-kilometer ring!

The protons emerging from the injector are passed through a whole cascade of accelerators until they enter the large ring. "CERN, unlike Russian centers, managed to use each of its record-breaking accelerators for its time as a pre-accelerator for the next one.", - notes Nikolay Zimin... It all started with Proton synchrotron (PS, 1959), then there was Superproton Synchrotron (SPS, 1976), Then Large Electron-Positron Collider (LEP, 1989)... Then the LEP was "cut" out of the tunnel to save money, and the Large Hadron Collider was built in its place. “Then the LHC will be“ cut out ”, a super LHC will be built, there are already such ideas. Or maybe they will immediately start building the FCC (Future Circular Colliders), and a 100-kilometer 50 TeV collider will appear. ", - continues his story Zimin.

“Why is everything so well organized here in terms of security? Because there are many dangers below. First, the dungeon itself is 100 meters deep. Secondly, there is a lot of cryogenic equipment, ATLAS works with two magnetic fields. One of them is formed by a central superconducting solenoid, which must be cooled. The second is the world's largest magnetic toroids. These are 25-meter bagels in one direction and 6-meter - in the other. A current of 20 kA circulates in each of them. And they also need to be cooled with liquid helium. The stored energy of the magnetic field is 1.6 GJ, so if something happens, the consequences of the destruction of the detector can be catastrophic. There is a high vacuum in the beam chamber of the detector, and if it is violated, an explosion may result. ", - is talking Nikolay Zimin.

“Here is one of the empty (in terms of vacuum) places in the solar system and one of the coldest in the universe: 1.9 K (-271.3 ° C). At the same time - one of the hottest places in the Galaxy "- so they like to say at CERN, and all this is not an exaggeration. The LHC is the largest cooling system in the world, it is necessary to maintain a 27-kilometer ring in a state of superconductivity. An ultra-high vacuum of 10-12 atmospheres is created in the tubes through which proton beams fly to avoid collisions with gas molecules.

REPUBLIC OF COLLABORATIONS

The work at the Large Hadron Collider is taking place under conditions of constant scientific competition between collaborations. But the Higgs boson was discovered simultaneously by the ATLAS group and the CMS group. Vladimir Gavrilov (CMS) stresses the importance of two independent collaborations working on this task at the same time. “The announcement that they had found the Higgs boson was made only after both collaborations produced results obtained in completely different ways, but indicating approximately the same parameters with the accuracy possible for the two detectors. This accuracy is now increasing and the agreement between the results is even better. ". “CERN and collaborations are different things. CERN is a laboratory, it gives you an accelerator, and collaborations are separate states of scientists with their own constitution, their own finances and management. And the people who work on the detectors are 90% not employees of CERN, but employees of institutes, their work is paid by the participating states and institutes, and CERN enters into collaboration on the same grounds as other institutes ", - explains Oleg Fedin from St. Petersburg Institute of Nuclear Physics.

THE FUTURE OF THE BIG HADRON COLLIDER

Already the collider does not work for a year and a half, engineers and technicians check and replace equipment. “We are going to launch the first bundles in January 2015. When the first interesting results will come, I do not know. The energy of the collider will be almost doubled - from 7 to 13 TeV - this is, in fact, a new machine ", - told us CERN CEO Rolf-Dieter Heuer.

What does Rolf Hoyer expect from the launch of the LHC after modernization? “I dream that here at the LHC we will be able to find traces of dark matter particles. It will be great. But this is only a dream! I cannot guarantee that we will find it. And, of course, we can discover some new things. On the one hand, there is the Standard Model - it describes the world amazingly well. But it doesn't explain anything. Too many parameters entered manually. The Standard Model is fantastic. But beyond the Standard Model, it's even more fantastic. ".

On the eve of the 60th anniversary of CERN Rolf Hoyer notes that all these years the scientific center lived under the motto: "60 years of science for the world." According to him, “CERN not only ignored it, but tried to stay as far away from any political issues as possible. From the very founding of CERN, when there was a division between West and East, representatives from both sides could work here together. Today we have scientists from Israel and Palestine, India and Pakistan ... We try to stay out of politics, we try to work as representatives of humanity, as normal people ".

This article uses the LHC brochure The guide. Electronic version - on the website

The Large Hadron Collider is called either the "Doomsday Machine" or the key to the mystery of the universe, but its significance is not in question.

As the famous British thinker Bertrand Russell once said: "is what you know, philosophy is what you do not know." It would seem that true scientific knowledge long ago separated from its origins, which can be found in the philosophical research of Ancient Greece, but this is not entirely true.

Throughout the twentieth century, scientists have tried to find in science the answer to the question of the structure of the world. This process was similar to the search for the meaning of life: a huge variety of theories, assumptions and even crazy ideas. What conclusions did scientists come to at the beginning of the XXI century?

The whole world consists of elementary particles, which represent the final forms of everything that exists, that is, that which cannot be split into smaller elements. These include protons, electrons, neutrons, and so on. These particles are in constant interaction with each other. At the beginning of our century, it was expressed in 4 fundamental types: gravitational, electromagnetic, strong and weak. The first is described by General Relativity, the other three are combined in the Standard Model (quantum theory). It was also suggested that there is another interaction, later called the Higgs field.

Gradually, the idea of ​​combining all fundamental interactions within the framework of “ theory of everything ", which was initially perceived as a joke, but quickly grew into a powerful scientific direction. Why is this needed? It's that simple! Without understanding how the world functions, we are like ants in an artificial nest - we will not get beyond our capabilities. Human knowledge cannot (well, or bye cannot, if you are an optimist) to cover the structure of the world as a whole.

One of the most famous theories claiming to "embrace everything" is string theory... It implies that the entire Universe and our life with you is multidimensional. Despite the developed theoretical part and the support of famous physicists such as Brian Green and Stephen Hawking, it has no experimental confirmation.

Scientists, decades later, got tired of broadcasting from the stands and decided to build something that once and for all should dot the i's. For this, the world's largest experimental setup was created - Large Hadron Collider (LHC).

"To the collider!"

What is a collider? Scientifically speaking, this is a charged particle accelerator designed to accelerate elementary particles for further understanding of their interaction. In unscientific terms, this is a large arena (or sandbox, if you like) in which scientists fight to validate their theories.

For the first time, the idea to collide elementary particles and see what will happen came to the American physicist Donald William Kerst in 1956. He suggested that thanks to this, scientists will be able to penetrate the secrets of the universe. It would seem, what is wrong with colliding between two beams of protons with a total energy of a million times more than from thermonuclear fusion? The times were appropriate: the cold war, the arms race and all that.

The history of the creation of the LHC

The idea of ​​creating an accelerator for producing and studying charged particles appeared in the early 1920s, but the first prototypes were created only by the early 1930s. Initially, they were high-voltage linear accelerators, that is, charged particles moved in a straight line. The ring version was presented in the USA in 1931, after which similar devices began to appear in a number of developed countries - Great Britain, Switzerland, and the USSR. They got the name cyclotrons, and later began to be actively used to create nuclear weapons.

It should be noted that the cost of building a particle accelerator is incredibly high. Europe, which played a minor role during the Cold War, commissioned its creation European Organization for Nuclear Research (in Russian it is often read as CERN), which later took up the construction of the LHC.

CERN was created in the wake of international concern about nuclear research in the United States and the USSR, which could lead to total extermination. Therefore, scientists decided to combine efforts and direct them to a peaceful channel. In 1954, CERN received its official birth.

In 1983, under the auspices of CERN, the W and Z bosons were discovered, after which the question of the discovery of the Higgs bosons became only a matter of time. In the same year, work began on the construction of the Large Electron-Positron Collider (BEPC), which played a primary role in the study of the discovered bosons. However, even then it became clear that the power of the created device would soon be insufficient. And in 1984, it was decided to build the LHC, immediately after the BEPK was dismantled. This happened in 2000.

The construction of the LHC, which began in 2001, was facilitated by the fact that it took place on the site of the former BEPK, in the valley of Lake Geneva. In connection with financing issues (in 1995, the cost was estimated at 2.6 billion Swiss francs, by 2001 it exceeded 4.6 billion, in 2009 it was $ 6 billion).

At the moment, the LHC is located in a tunnel with a circumference of 26.7 km and passes through the territories of two European countries at once - France and Switzerland. The depth of the tunnel varies from 50 to 175 meters. It should also be noted that the collision energy of protons in the accelerator reaches 14 teraelectronvolts, which is 20 times more than the results achieved using BEPC.

"Curiosity is not a vice, but a big disgusting thing."

The 27-kilometer-long CERN collider tunnel is located 100 meters underground near Geneva. There will be huge superconducting electromagnets here. Transport cars on the right. Juhanson / wikipedia.org (CC BY-SA 3.0)

Why is this man-made "Doomsday machine" needed? Scientists expect to see the world as it was immediately after the Big Bang, that is, at the time of the formation of matter.

Goals, which scientists set themselves during the construction of the LHC:

1. Confirmation or refutation of the Standard Model with the aim of further creating a "theory of everything".
2. Proof of the existence of the Higgs boson as a particle of the fifth fundamental interaction. She, according to theoretical studies, should affect the electrical and weak interactions, breaking their symmetry.
3. Study of quarks, which are a fundamental particle that is 20 thousand times smaller than protons consisting of them.
4. Obtaining and researching dark matter, which makes up most of the Universe.

These are far from the only goals assigned by scientists to the LHC, but the rest are more related to related or purely theoretical ones.

What have you achieved?

Undoubtedly the largest and most significant achievement was the official confirmation of the existence of Higgs boson... The discovery of the fifth interaction (the Higgs field), which, according to scientists, affects the acquisition of mass by all elementary particles. It is believed that when symmetry is broken when the Higgs field is applied to other fields, the W and Z bosons become massive. The discovery of the Higgs boson is so great in its significance that a number of scientists gave them the name "divine particles".

Quarks combine into particles (protons, neutrons and others), which are called hadrons... It is they who accelerate and collide in the LHC, which is where its name comes from. During the operation of the collider, it was proved that it is simply impossible to separate a quark from a hadron. If you try to do this, you will simply rip out from, for example, a proton, another kind of elementary particle - meson... Despite the fact that this is only one of the hadrons and does not carry anything new in itself, further study of the interaction of quarks should be carried out precisely in small steps. In researching the fundamental laws of the functioning of the universe, haste is dangerous.

Although the quarks themselves were not discovered during the use of the LHC, their existence up to a certain point was perceived as a mathematical abstraction. The first such particles were found in 1968, but it was only in 1995 that the existence of a "true quark" was officially proved. The results of the experiments are confirmed by the ability to reproduce them. Therefore, the LHC's achievement of a similar result is perceived not as a repetition, but as a reinforcing proof of their existence! Although the problem with the reality of quarks has not disappeared anywhere, because they are simply cannot be singled out from hadrons.

What are the plans?

The main task of creating a "theory of everything" has not been solved, but a theoretical study of possible variants of its manifestation is underway. Until now, one of the problems of combining the General Theory of Relativity and the Standard Model is the different area of ​​their action, in connection with which the second does not take into account the peculiarities of the first. Therefore, it is important to go beyond the Standard Model and reach the edge. New physics.

Supersymmetry - scientists believe that it connects the bosonic and fermionic quantum fields, so much so that they can turn into each other. It is such a conversion that goes beyond the scope of the Standard Model, since there is a theory that the symmetric mapping of quantum fields is based on gravitons... They, accordingly, can be an elementary particle of gravity.

Boson Madala- the hypothesis of the existence of the Madala boson suggests that there is another field. Only if the Higgs boson interacts with known particles and matter, then the Madala boson interacts with dark matter... Despite the fact that it occupies a large part of the universe, its existence does not fall within the scope of the Standard Model.

Microscopic black hole - one of the LHC's studies is to create a black hole. Yes, yes, exactly that black, all-consuming area in outer space. Fortunately, no significant achievements have been made in this direction.

Today, the Large Hadron Collider is a multipurpose research center, on the basis of which theories are created and experimentally confirmed that will help us better understand the structure of the world. There are often waves of criticism surrounding a number of ongoing studies that are branded as dangerous, including from Stephen Hawking, but the game is definitely worth the candle. We will not be able to sail in the black ocean called the Universe with a captain who has neither a map, nor a compass, nor basic knowledge about the world around us.

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I will continue my story about visiting the open day at CERN.

Part 3. Computing center.

In this part I will talk about the place where they store and process what is the product of CERN's work - the results of experiments. It will be about a computing center, although it would probably be more correct to call it a data center. But first, I'll touch on the computational and data storage issues at CERN. Each year, the Large Hadron Collider alone produces so much data that, if written to CD, it would be a stack 20 kilometers high. This is due to the fact that during the operation of the collider, the beams collide 30 million times per second and each collision occurs about 20 events, each of which produces a large amount of information in the detector. Of course, this information is processed first in the detector itself, then enters the local computing center and only then is transmitted to the main data storage and processing center. However, you have to process roughly a petabyte of data every day. To this we must add that this data must not only be stored, but also distributed between research centers around the world, and in addition, it is necessary to support approximately 4000 WiFi network users in CERN itself. It should be added that there is an auxiliary data storage and processing center in Hungary, with which there is a 100 gigabit link. At the same time, 35,000 kilometers of optical cable have been laid inside CERN.
However, the computer center was not always so powerful. The photo shows how the equipment used has changed over time.

Now there has been a transition from mainframes to a grid of conventional PCs. The center currently has 90,000 processor cores in 10,000 servers, which operate 24 hours a day, 7 days a week. On average, 250,000 data processing jobs are simultaneously running on this grid. This computing center is at the height of modern technology and often moves computing and IT forward to solve the problems necessary to store and process such large amounts of data. Suffice it to mention that the World Wide Web was invented by Tim Berners-Lee in a building not far from the data center (tell those alternatively gifted idiots who, surfing the Internet, say that basic science is not useful).

However, let's get back to the problem of data storage. The photo shows that in antediluvian times, data was previously stored on magnetic disks (Yes, yes, I remember these 29 megabyte disks on an ES computer).

To see how things are today, I walk to the building where the computing center is located.

There, surprisingly, there are not very many people, and I walk inside rather quickly. We are shown a short film and then led to a locked door. Our guide opens the door and we find ourselves in a fairly large room, where there are cabinets with magnetic tapes on which information is recorded.

Most of the hall is occupied by these same wardrobes.

They store about 100 petabytes of information (which is equivalent to 700 years of Full HD video) in 480 million files. Interestingly, approximately 10,000 physicists around the world have access to this information in 160 computing centers. This information contains all experimental data from the 70s of the last century. If you take a closer look, you can see how these tapes are located inside the cabinets.

Some racks contain processor modules.

On the table is a small exhibition of what is used for data storage.

This data center consumes 3.5 megawatts of electricity and has its own diesel generator in case of a power outage. I must also say about the cooling system. It is located outside the building and drives cold air under the raised floor. Water cooling is used in only a small number of servers.

If you look inside the cabinet, you can see how the automatic sampling and loading of tapes occurs.

Actually, this hall is not the only hall where computers are located, but the fact that the visitors were allowed in at least here already commands respect for the organizers. I photographed what was on display on the table.

After that, another group of visitors appeared and we were asked to leave. I take one last photo and leave the computing center.

In the next part I will talk about workshops where unique equipment is created and assembled, which is used in physical experiments.

For most of the past week, the news media has been full of reports about CERN, the Large Hadron Collider and the new particle found there. In the end, it really turned out to be the Higgs boson - the particle that confirms the Standard Model - which means that scientists can finally be confident in their views on the structure of the world.

Today FURFUR publishes the diary of CERN researcher Stepan Obraztsov. He spoke not only about the search for the Higgs boson and the work of the hadron collider, but also about the traditions of the life of this city of scientists with their own language, rock bands and festivals.

About the first visit:The first time I appeared at CERN, probably when I was about a year old and later - about five years old - so for me this is my second native place after Russia. Then my father worked there. I absorbed everything that was happening around, my father explained to me some things already in childhood. At CERN, there is a permanent exhibition for tourists, where they clearly show all sorts of simple things: for example, there is a spark chamber - in it a particle flies through a chamber filled with gas and with a live wire and causes a spark. In general, he explained to me which particles are flying from space, why and when they are visible, and so on.

About education: Later I graduated from Moscow State University at the Department of Space Physics. When we were assigned, I went to the laboratory of hadron interactions at the Scientific Research Institute of Nuclear Physics (DV Skobeltsyn Research Institute of Nuclear Physics) at Moscow State University. So I started going to CERN when I was still studying - there is a summer school for students, where about four hundred students gather every summer, and even then I started working with the hadron collider because of the topic of my diploma. And now I go on business trips and accumulate material for a dissertation.

This is what the entrance to CERN looks like at night

About working at CERN: It is worth saying that I am not working on one task, but on several at once - everyone does this. Work at CERN is always divided into research and service. You have to perform service work, because each institution that participates in the collaboration undertakes obligations to carry out these works that are not related to any discoveries. That is, this is a kind of exchange: carry out your experiments at the collider, but for this you will also have to keep an eye on the detectors. This can be called a scientific activity, but it is of a very applied nature: detector calibration, participation in shifts on the detector, data monitoring, and a lot of everything auxiliary for setting up this giant machine. It is believed that we go on business trips mainly to carry out service work.

The Large Hadron Collider at CERN is a giant accelerating ring 28 kilometers long. A radioactive source of particles is placed in its center, which are launched with a beam along a small ring, then along a linear tunnel. Having dispersed, they go to the inner small ring, and then to the main thing. These beams of protons are launched in a ring in two in different directions, observe their movement and collect statistics - I am gaining two gigabytes of data per second, which is a rather large volume per day.

There are four detectors at the Large Hadron Collider: CMS, ATLAS, LHCb and ALICE. I work on a CMS - it weighs about 4.5 thousand tons. And its magnetic field is 4 Tesla (twice as much as the entire magnetic field of the Earth).

CERN itself is located fifteen minutes from Geneva, on the very border of France and Switzerland. It is not a science city (which we know from numerous projects of the Soviet Union), since there are quite a few permanent residents there. Instead, there is a huge hostel where engineers stay if they come for a short time. In general, the territory itself is simply huge, because a huge number of people are involved in research: in one experiment alone, in which I participate, there are four thousand people. And each of these four thousand is constantly doing something.

CMS detector, side view
CMS detector, frontal view. The detectors have a layered structure - each layer registers its own changes in the environment

There are also four different detectors on the big ring that collect the data. Accordingly, when the beams are already circulating around the ring, collimators (huge magnets) are turned on, which deflect the beams and make them collide - the collision itself occurs in the center of one of the detectors. When protons collide, new particles are born, which we register. This is the essence of the experiment. Such launches and collisions occur around the clock all year round - not so that the collider was launched once, something was knocked over, and that's it.

Each detector has a control room: the detector itself is in the mine, and the control room is on the surface, where about twenty people sit around the clock, and each is responsible for some kind of detector subsystem - you collect different information from parts of the system and can then get the big picture. In addition to the people who sit on the subsystems, there are also people responsible for collecting data, monitoring the detector as a whole, there is a shift supervisor, a person who is in charge of the magnet - they all sit in the same room and observe the work.

Another detector - ALICE

It so happened historically that our laboratory is engaged in the physics of heavy ions: this is when not beams of protons are sent into the ring, but beams of lead ions or gold ions. The peculiarity is that when the nuclei collide, the environment in which the collision occurs becomes denser. They began to collide ions, because there were theoretical predictions that it would be possible to observe a new state of matter - quark-gluon plasma - in which the Universe was located a few microseconds after the Big Bang. This is a superdense medium, and matter in this state has the properties of both a solid and a gas, liquid and plasma. The idea of ​​the experiment is to compare what happens when you collide protons and when you collide ions. When you collide lead, the medium is so dense that some particles cannot fly out and fly through this medium - they are extinguished in it. The fact that such a state really exists was confirmed at the end of 2010.

About business trips: I come once in the summer and once in the winter, for two months. It takes me half a minute to get from the hostel to work. There is such an inner world, where there are many people, and it is quite different from the ordinary world. There the line is blurred between what you seem to be working and relaxing. It is an endless process that cannot be stopped. In total, about thirty thousand people live there, you feel like a small cog in a huge machine. It is difficult to invent or discover something on your own when you are involved in such a giant apparatus.

View from a hostel room at CERN

About the CERN device: By its structure, CERN is an international collaboration, in which 150 institutes from 37 countries participate, and there are few of their own staff. Most of the people who work there are not CERN employees, they hold some kind of positions in the institutes participating in the collaboration, as in my case. And in the state of Cernov there are only the coolest, super-honored Nobel laureates on a life contract, who have already come up with everything they could, in this life and live in a house at the foot of the mountain, drive from there in retro cars. All in all, aging rock stars from physics.

About specialization: Every physicist is far from universal. They are divided into different categories: if globally, then experimenters and theoreticians, and between them - those who are engaged in analysis. In turn, experimenters are divided into those who are engaged in the physics of the detector, and those who are involved in the physics of the accelerator. That is, those who accelerate particles and who register them are two different areas, and accelerators are highly valued, because there are fewer of them in the world - we do not prepare them in Moscow, only in Novosibirsk. Physicists who are engaged in the detector know little about the accelerator, they practically do not intersect with the accelerators, these are two separate castes. Some start, others catch.

About shifters: When you sit on shift - there is morning, day and night, each for eight hours - there are a lot of monitors, and you have to keep a lot of information in your head at once. Plus, everything is so cleverly arranged that before you become a replacement, you have to go through the training - three shifts, when you sit with a full-fledged replacement, then, when you have learned, they already give you apprentices. It happened so that I taught adult uncles who know physics much better than me. The peculiarity of this work is that you do not do much alone, so it develops the ability to contact. When there is correspondence between Russians (and there are a lot of them there), we get a semi-English-semi-Russian language, because for many words there are no Russian analogues. Shifter is a changer in English. We do not call each other changers, we call each other shifters. Also, no one there says "Higgs boson", everyone just says "Higgs".

One of the concerts at the Hardronic Fest

About entertainment: There are insanely many people at CERN, and they are all addicted to something - there are clubs of interest - from weightlifting and choral singing to chess and frisbee. There is a music club - three rehearsal rooms - and about fifteen groups that organize the Hardronic Festival in the summer - it lasts two days with a huge big stage. Groups consisting entirely of researchers perform there. Unusual little - mostly some cover bands, but still. There I play a little - when I go, I always take my guitar with me. The rehearsal room has all the recording equipment - I play to the metronome, I write the drums, then I mix it.

About access to information: On business trips, I was there eight times - more than a year in total. But it makes no difference to me where to work - here or there, because you even connect to CERN servers from a distance. There are gigabit networks that connect institutions around the world. Part of the data is stored on hard drives, but most of it is stored on cassettes controlled by a special robot. You write just one command while sitting in Moscow - the robot at CERN goes to the required section, takes out your cassette, inserts it, reads it, transfers it to the hard disk, and you receive the data.

The Higgs boson is the particle believed to be responsible for the mass in matter. All particles are in the field that creates the Higgs boson. Being in this field, they have mass. There is the so-called Standard Model - this is the model of the world that we all go through from school. In it, all interactions are divided into four types: strong, weak, electromagnetic and gravitational. Each interaction has a carrier - for example, an electron has an electromagnetic one. So, all carrier particles have long been discovered and recorded, except for the Higgs boson. The fact that it exists tells us that this model is consistent and we seem to understand quite well what is happening in the Universe. In any case, the Standard Model is just a model, in physics we are always talking about models. Any model is correct only up to some decimal place, the most accurate model does not exist.

The search and study of the Higgs boson at the Large Hadron Collider is carried out by two detectors - CMS and ATLAS. For the last two years, they have not opened the Higgs, but methodically closed the areas where it cannot be. And there was a very small window where he could be. Last year, a large rally of all participants in the collaboration was assembled, where it was announced that in 2012 they would be able to find out for sure whether the Higgs boson actually exists or not.

Side view of the ATLAS detector. Its frontal view can be seen on the very first image in this material.

About the burnout process: When the accelerator was just launched, it was a hot time, because something was constantly breaking. We called it “burnout process” - that is, when the detector just started working, everything that was unreliable had to break down, so that later the work would return to a normal pace. Gradually, the detector dies: some parts - due to the fact that there is a lot of radiation there, immediately upon collision and all these materials wear out - lose their properties. At the end of this year, there will be a big shutdown of the collider for a year or even two years for an upgrade, they will dig into the detectors, and change some magnets in the accelerator itself in order to reach the originally declared power.

About what's next: All this work on the design of the collider began in the late 1980s, my father managed to take part in all this - somewhere before the year 1994. After that, there was a conflict between the Russians and the Americans, and he left. In Russia, a lot of children are being trained, who will then go to work at CERN, in our country there are many accelerators, and a lot of experience has already been accumulated. And then 400 students a year finish their studies at CERN in the summer. That is, generations change, and experiments continue.