(or TANK)- currently the largest and most powerful particle accelerator in the world. This colossus was launched in 2008, but for a long time it worked at reduced capacity. Let's figure out what it is and why we need a large hadron collider.
History, myths and facts
The idea of creating a collider was announced in 1984. And the project for the construction of the collider itself was approved and adopted already in 1995. The development belongs to the European Center for Nuclear Research (CERN). In general, the launch of the collider attracted a lot of attention not only from scientists, but also from ordinary people from all over the world. They talked about all sorts of fears and horrors associated with the launch of the collider.
However, someone even now, quite possibly, is waiting for an apocalypse associated with the work of the LHC and is cracking at the thought of what will happen if the Large Hadron Collider explodes. Although, first of all, everyone was afraid of a black hole, which, at first being microscopic, would grow and safely absorb first the collider itself, and then Switzerland and the rest of the world. The annihilation catastrophe also caused great panic. A group of scientists even filed a lawsuit in an attempt to stop construction. The statement said that the antimatter clumps that can be produced in the collider will begin to annihilate with matter, starting a chain reaction and the entire Universe will be destroyed. As the famous character from Back to the Future said:
The entire Universe, of course, is in the worst case scenario. At best, only our galaxy. Dr. Emet Brown.
Now let's try to understand why it is hadronic? The fact is that it works with hadrons, or rather accelerates, accelerates and collides hadrons.
Hadrons– a class of elementary particles subject to strong interactions. Hadrons are made of quarks.
Hadrons are divided into baryons and mesons. To make it easier, let's say that almost all the matter known to us consists of baryons. Let's simplify even further and say that baryons are nucleons (protons and neutrons that make up the atomic nucleus).
How the Large Hadron Collider works
The scale is very impressive. The collider is a circular tunnel located underground at a depth of one hundred meters. The Large Hadron Collider is 26,659 meters long. Protons, accelerated to speeds close to the speed of light, fly in an underground circle across the territory of France and Switzerland. To be precise, the depth of the tunnel ranges from 50 to 175 meters. Superconducting magnets are used to focus and contain beams of flying protons; their total length is about 22 kilometers, and they operate at a temperature of -271 degrees Celsius.
The collider includes 4 giant detectors: ATLAS, CMS, ALICE and LHCb. In addition to the main large detectors, there are also auxiliary ones. Detectors are designed to record the results of particle collisions. That is, after two protons collide at near-light speeds, no one knows what to expect. To “see” what happened, where it bounced and how far it flew, there are detectors stuffed with all kinds of sensors.
Results of the Large Hadron Collider.
Why do you need a collider? Well, certainly not to destroy the Earth. It would seem, what is the point of colliding particles? The fact is that there are a lot of unanswered questions in modern physics, and studying the world with the help of accelerated particles can literally open up a new layer of reality, understand the structure of the world, and maybe even answer the main question of “the meaning of life, the Universe and in general” .
What discoveries have already been made at the LHC? The most famous thing is the discovery Higgs boson(we will devote a separate article to him). In addition, they were open 5 new particles, the first data on collisions at record energies were obtained, the absence of asymmetry of protons and antiprotons is shown, unusual proton correlations discovered. The list goes on for a long time. But the microscopic black holes that terrified housewives could not be detected.
And this despite the fact that the collider has not yet been accelerated to its maximum power. Currently the maximum energy of the Large Hadron Collider is 13 TeV(tera electron-Volt). However, after appropriate preparation, the protons are planned to be accelerated to 14 TeV. For comparison, in the accelerators-precursors of the LHC, the maximum obtained energies did not exceed 1 TeV. This is how the American Tevatron accelerator from Illinois could accelerate particles. The energy achieved in the collider is far from the highest in the world. Thus, the energy of cosmic rays detected on Earth exceeds the energy of a particle accelerated in a collider by a billion times! So, the danger of the Large Hadron Collider is minimal. It is likely that after all the answers are obtained using the LHC, humanity will have to build another more powerful collider.
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The Large Hadron Collider (LHC) is a typical (albeit super-powerful) colliding particle accelerator designed to accelerate protons and heavy ions (lead ions) and study the products of their collisions. The LHC is a microscope with the help of which physicists will unravel what and how matter is made of, obtaining information about its structure at a new, even more microscopic level.
Many were looking forward to what would happen after its launch, but nothing actually happened - our world is very boring for something really interesting and grandiose to happen. Here is civilization and its crown of creation is man, it’s just that a certain coalition of civilization and people has turned out, having rallied together for the past century, we are polluting the earth in geometric progression, and wantonly destroying everything that has been accumulating for millions of years. We'll talk about this in another post, so here it is HADRON COLLIDER.
Contrary to the numerous and varied expectations of peoples and the media, everything passed quietly and peacefully. Oh, how everything was exaggerated, for example, the newspapers repeated from issue to issue: “LHC = the end of the world!”, “The path to disaster or discovery?”, “Annihilation Catastrophe”, they almost predicted the end of the world and a giant black hole, in which will suck in the whole earth. Apparently these theories were put forward by envious physicists who at school failed to obtain a certificate of completion with the number 5 in this subject.
For example, there was a philosopher Democritus, who in his ancient Greece (by the way, modern schoolchildren write this in one word, because they perceive it as a non-existent strange country, like the USSR, Czechoslovakia, Austria-Hungary, Saxony, Courland, etc. - “Ancient Greece”) he expressed a certain theory that matter consists of indivisible particles - atoms, but scientists found evidence of this only after approximately 2350 years. An atom (indivisible) can also be divided, this was discovered 50 years later, on electrons and kernels, and core– for protons and neutrons. But they, as it turned out, are not the smallest particles and, in turn, consist of quarks. Today, physicists believe that quarks- the limit of the division of matter and nothing less exists. There are six known types of quarks: up, strange, charm, beauty, true, down - and they are connected using gluons.
The word "collider" comes from the English collide - to collide. In a collider, two particle launches fly towards each other and when they collide, the energies of the beams are added. Whereas in conventional accelerators, which have been built and operating for several decades (their first models of relatively moderate size and power appeared before the Second World War in the 30s), the beam hits a stationary target and the energy of such a collision is much less.
The collider is called “hadron” because it is designed to accelerate hadrons. Hadrons- this is a family of elementary particles, which include protons and neutrons; they make up the nuclei of all atoms, as well as various mesons. An important property of hadrons is that they are not truly elementary particles, but consist of quarks “glued together” by gluons.
The collider became large because of its size - it is the largest physical experimental installation ever existing in the world, only the main ring of the accelerator stretches more than 26 km.
It is assumed that the speed of protons accelerated by the LHC will be 0.9999999998 of the speed of light, and the number of particle collisions occurring in the accelerator every second will reach 800 million. The total energy of colliding protons will be 14 TeV (14 teraelectrovolts, and lead nuclei - 5.5 GeV for each pair of colliding nucleons. Nucleons(from Latin nucleus - nucleus) - a common name for protons and neutrons.
There are different opinions about the technology for creating accelerators today: some claim that it has reached its logical limit, others that there is no limit to perfection - and various reviews provide reviews of designs whose size is 1000 times smaller, and whose performance is higher than the LHC' A. In electronics or computer technology, miniaturization is constantly taking place with a simultaneous increase in performance.
Large Hardon Collider, LHC - a typical (albeit extremely) accelerator of charged particles in the beams, designed to disperse the protons and heavy ions (lead ions) and study the products of their collisions. BAC is this microscope, in which physics will unravel, what and how to make the matter of getting information about its device in a new, even more microscopic level.
Many waited eagerly, but what comes after his run, but nothing in principle and has not happened - our world is missing much that has happened is something really interesting and ambitious. Here it is a civilization and its crown of creation man, just got a sort of coalition of civilization and the people, unity, together for over a century, in a geometric progression zagazhivaem land, and beschinno destroying anything that accumulated millions of years. On this we will talk in another message, and so - that he Hadron Collider.
Despite the many and varied expectations of peoples and the media all went quietly and peacefully. Oh, how it was all bloated, like the newspaper firm by number of rooms: “BAC = the end of the world!”, “The road to discovery or disaster?”, “Annihilation catastrophe”, almost the end of the world and things are a gigantic black hole in zasoset that all the land. Perhaps these theories put forward envious of physics, in which the school did not receive a certificate of completion from the figure 5, on the subject.
Here, for example, was a philosopher Democritus, who in ancient Greece (and, incidentally, today's students write it in one word, as seen this strange non-existent, like the USSR, Czechoslovakia, Austria-Hungary, Saxony, Kurland, etc . - “Drevnyayagretsiya”), he had some theory that matter consists of indivisible particles - atoms, but the proof of this, scientists have found only after about 2350 years. Atom (indivisible) - can also be divided, it is found even after 50 years on the electrons and nuclei and the nucleus - protons and neutrons at. But they, as it turned out, not the smallest particles and, in turn, are composed of quarks. To date, physicists believe that quarks — the limit of division of matter and anything less does not exist. We know of six types of quarks: the ceiling, strange, charmed, charming, genuine, bottom — and they are connected via gluons.
The word “Collider” comes from the English collide – face. In the collider, two particles start flying towards each other and with the collision energy beams added. While in conventional accelerators, which are under construction and work for several decades (the first of their models on moderate size and power, appeared before the Second World War in the 30s), puchek strikes on fixed targets and the energy of the collision is much smaller.
"Hadronic" collider named because it is designed to disperse the hadrons. Hadrons - is a family of elementary particles, which include protons and neutrons, composed of the nucleus of all atoms, as well as a variety of mesons. An important feature of hadrons is that they are not truly elementary particles, and are composed of quarks, “glued” gluon.
The big collider has been because of its size — is the largest physical experimental setup ever in the world, only the main accelerator ring stretches for more than 26 km.
It is assumed that the velocity of dispersed tank will 0.9999999998 protons to the speed of light, and the number of collisions of particles originating in the accelerator every second, to 800 million total energy of colliding protons will be 14 TeV (14 teraelektro-volt, and the nuclei of lead - 5.5 GeV for each pair of colliding nucleons. nucleons (from Lat. nucleus - nucleus) - the generic name for the protons and neutrons.
There are different views on the creation of accelerator technology to date: some say that it came to its logical side, others that there is no limit to perfection — and the various surveys provided an overview of structures, which are 1000 times smaller, but higher productivity BUCK 'Yes. In the electronics or computer technology is constantly miniaturization, while the growth of efficiency.
The history of the creation of the accelerator, which we know today as the Large Hadron Collider, dates back to 2007. Initially, the chronology of accelerators began with the cyclotron. The device was a small device that easily fit on the table. Then the history of accelerators began to develop rapidly. The synchrophasotron and synchrotron appeared.
In history, perhaps the most interesting period was the period from 1956 to 1957. In those days, Soviet science, in particular physics, did not lag behind its foreign brothers. Using years of experience, a Soviet physicist named Vladimir Veksler made a breakthrough in science. He created the most powerful synchrophasotron at that time. Its operating power was 10 gigaelectronvolts (10 billion electronvolts). After this discovery, serious samples of accelerators were created: the large electron-positron collider, the Swiss accelerator, in Germany, the USA. They all had one common goal - the study of the fundamental particles of quarks.
The Large Hadron Collider was created primarily thanks to the efforts of an Italian physicist. His name is Carlo Rubbia, Nobel Prize laureate. During his career, Rubbia worked as a director at the European Organization for Nuclear Research. It was decided to build and launch a hadron collider on the site of the research center.
Where is the hadron collider?
The collider is located on the border between Switzerland and France. Its circumference is 27 kilometers, which is why it is called large. The accelerator ring goes deep from 50 to 175 meters. The collider has 1232 magnets. They are superconducting, which means that the maximum field for acceleration can be generated from them, since there is practically no energy consumption in such magnets. The total weight of each magnet is 3.5 tons with a length of 14.3 meters.
Like any physical object, the Large Hadron Collider generates heat. Therefore, it must be constantly cooled. To achieve this, the temperature is maintained at 1.7 K using 12 million liters of liquid nitrogen. In addition, 700 thousand liters are used for cooling, and most importantly, a pressure is used that is ten times lower than normal atmospheric pressure.
A temperature of 1.7 K on the Celsius scale is -271 degrees. This temperature is almost close to what is called the minimum possible limit that a physical body can have.
The inside of the tunnel is no less interesting. There are niobium-titanium cables with superconducting capabilities. Their length is 7600 kilometers. The total weight of the cables is 1200 tons. The inside of the cable is a weave of 6,300 wires with a total distance of 1.5 billion kilometers. This length is equal to 10 astronomical units. For example, equals 10 such units.
If we talk about its geographical location, we can say that the rings of the collider lie between the cities of Saint-Genis and Forney-Voltaire, located on the French side, as well as Meyrin and Vessourat - on the Swiss side. A small ring called PS runs along the diameter of the border.
The meaning of existence
In order to answer the question “what is a hadron collider for,” you need to turn to scientists. Many scientists say that this is the greatest invention in the entire history of science, and that without it, science as we know it today simply has no meaning. The existence and launch of the Large Hadron Collider is interesting because when particles collide in the hadron collider, an explosion occurs. All the smallest particles scatter in different directions. New particles are formed that can explain the existence and meaning of many things.
The first thing scientists tried to find in these crashed particles was a theoretically predicted elementary particle by physicist Peter Higgs, called This amazing particle is a carrier of information, it is believed. It is also commonly called the “particle of God.” Its discovery would bring scientists closer to understanding the universe. It should be noted that in 2012, on July 4, the hadron collider (its launch was partially successful) helped discover a similar particle. Today, scientists are trying to study it in more detail.
How long...
Of course, the question immediately arises: why have scientists been studying these particles for so long? If you have a device, you can run it and take more and more data each time. The fact is that operating a hadron collider is an expensive proposition. One launch costs a lot of money. For example, annual energy consumption is 800 million kWh. This amount of energy is consumed by a city with a population of about 100 thousand people, by average standards. And that doesn't include maintenance costs. Another reason is that at the hadron collider, the explosion that occurs when protons collide is associated with receiving a large amount of data: computers read so much information that it takes a lot of time to process. Even though the power of computers that receive information is great even by today's standards.
The next reason is no less well-known. Scientists working with the collider in this direction are confident that the visible spectrum of the entire universe is only 4%. It is assumed that the remaining ones are dark matter and dark energy. They are trying to prove experimentally that this theory is correct.
Hadron Collider: for or against
The put forward theory of dark matter has cast doubt on the safety of the hadron collider. The question arose: “Hadron collider: for or against?” He worried many scientists. All the great minds of the world are divided into two categories. “Opponents” put forward an interesting theory that if such matter exists, then it must have a particle opposite to it. And when particles collide in the accelerator, a dark part appears. There was a risk that the dark part and the part we see would collide. Then this could lead to the death of the entire universe. However, after the first launch of the hadron collider, this theory was partially broken.
Next in importance comes the explosion of the universe, or rather, the birth. It is believed that during a collision it is possible to observe how the universe behaved in the first seconds of its existence. The way it looked after the Big Bang originated. It is believed that the process of particle collisions is very similar to that which occurred at the very beginning of the universe.
Another equally fantastic idea that scientists are testing is exotic models. It seems incredible, but there is a theory that suggests that there are other dimensions and universes with people similar to us. And oddly enough, the accelerator can help here too.
Simply put, the purpose of the accelerator is to understand what the universe is, how it was created, and to prove or disprove all existing theories about particles and related phenomena. Of course, this will take years, but with each launch new discoveries emerge that revolutionize the world of science.
Facts about the accelerator
Everyone knows that an accelerator accelerates particles to 99% of the speed of light, but not many people know that the percentage is 99.9999991% of the speed of light. This amazing figure makes sense thanks to the perfect design and powerful acceleration magnets. There are also some lesser known facts to note.
The approximately 100 million data streams coming from each of the two main detectors could fill more than 100,000 CD-ROMs in a matter of seconds. In just one month, the number of disks would reach such a height that if they were stacked, they would be enough to reach the Moon. Therefore, it was decided to collect not all the data that comes from the detectors, but only those that will be allowed to be used by the data collection system, which in fact acts as a filter for the received data. It was decided to record only 100 events that occurred at the moment of the explosion. These events will be recorded in the archive of the Large Hadron Collider computer center, which is located in the European Laboratory for Particle Physics, which is also the location of the accelerator. What will be recorded will not be those events that were recorded, but those that are of greatest interest to the scientific community.
Post-processing
Once recorded, hundreds of kilobytes of data will be processed. For this purpose, more than two thousand computers located at CERN are used. The task of these computers is to process primary data and form a database from it that will be convenient for further analysis. Next, the generated data flow will be sent to the GRID computer network. This Internet network unites thousands of computers located in different institutes around the world and connects more than a hundred large centers located on three continents. All such centers are connected to CERN using fiber optics for maximum data transfer speeds.
Speaking about facts, we must also mention the physical indicators of the structure. The accelerator tunnel is deviated by 1.4% from the horizontal plane. This was done primarily in order to place most of the accelerator tunnel in a monolithic rock. Thus, the placement depth on opposite sides is different. If we count from the side of the lake, which is located near Geneva, then the depth will be 50 meters. The opposite part has a depth of 175 meters.
The interesting thing is that the lunar phases affect the accelerator. It would seem how such a distant object can influence at such a distance. However, it has been observed that during the full moon, when the tide occurs, the land in the Geneva area rises by as much as 25 centimeters. This affects the length of the collider. The length thereby increases by 1 millimeter, and the beam energy also changes by 0.02%. Since the beam energy must be controlled down to 0.002%, researchers must take this phenomenon into account.
It is also interesting that the collider tunnel has the shape of an octagon, and not a circle, as many imagine. Corners are created by short sections. They contain installed detectors, as well as a system that controls the beam of accelerating particles.
Structure
The Hadron Collider, whose launch involves a lot of parts and a lot of excitement among scientists, is an amazing device. The entire accelerator consists of two rings. The small ring is called the Proton Synchrotron or, to use its abbreviations, PS. The Big Ring is the Super Proton Synchrotron, or SPS. Together, the two rings allow the parts to accelerate to 99.9% of the speed of light. At the same time, the collider also increases the energy of protons, increasing their total energy by 16 times. It also allows particles to collide with each other approximately 30 million times/s. within 10 hours. From the 4 main detectors, at least 100 terabytes of digital data per second are obtained. Obtaining data is determined by individual factors. For example, they can detect elementary particles that have a negative electrical charge and also have half spin. Since these particles are unstable, their direct detection is impossible; it is only possible to detect their energy, which will be emitted at a certain angle to the beam axis. This stage is called the first launch level. This stage is monitored by more than 100 special data processing boards, which have built-in implementation logic. This part of the work is characterized by the fact that during the period of data acquisition, more than 100 thousand blocks of data are selected per second. This data will then be used for analysis, which occurs using a higher level mechanism.
Systems at the next level, on the contrary, receive information from all detector threads. The detector software runs on a network. There it will use a large number of computers to process subsequent blocks of data, the average time between blocks is 10 microseconds. Programs will have to create particle marks corresponding to the original points. The result will be a generated set of data consisting of impulse, energy, trajectory and others that arose during one event.
Accelerator parts
The entire accelerator can be divided into 5 main parts:
1) Electron-positron collider accelerator. The part consists of about 7 thousand magnets with superconducting properties. With their help, the beam is directed through a circular tunnel. They also concentrate the beam into one stream, the width of which is reduced to the width of one hair.
2) Compact muon solenoid. This is a general purpose detector. Such a detector is used to search for new phenomena and, for example, to search for Higgs particles.
3) LHCb detector. The significance of this device is to search for quarks and their opposite particles - antiquarks.
4) Toroidal installation ATLAS. This detector is designed to detect muons.
5) Alice. This detector captures lead ion collisions and proton-proton collisions.
Problems when launching the Hadron Collider
Despite the fact that the presence of high technology eliminates the possibility of errors, in practice everything is different. During the assembly of the accelerator, delays and failures occurred. It must be said that this situation was not unexpected. The device contains so many nuances and requires such precision that scientists expected similar results. For example, one of the problems that scientists faced during the launch was the failure of the magnet that focused the proton beams immediately before their collision. This serious accident was caused by the destruction of part of the fastening due to the loss of superconductivity by the magnet.
This problem occurred in 2007. Because of this, the launch of the collider was postponed several times, and only in June the launch took place; almost a year later, the collider was launched.
The latest launch of the collider was successful, collecting many terabytes of data.
The Hadron Collider, which was launched on April 5, 2015, is operating successfully. Over the course of a month, the beams will be driven around the ring, gradually increasing their power. There is no purpose for the study as such. The beam collision energy will be increased. The value will be raised from 7 TeV to 13 TeV. Such an increase will allow us to see new possibilities in particle collisions.
In 2013 and 2014 serious technical inspections of tunnels, accelerators, detectors and other equipment took place. The result was 18 bipolar magnets with superconducting function. It should be noted that their total number is 1232 pieces. However, the remaining magnets did not go unnoticed. In the rest, the cooling protection systems were replaced and improved ones were installed. The magnetic cooling system has also been improved. This allows them to remain at low temperatures with maximum power.
If everything goes well, the next launch of the accelerator will take place only in three years. After this period, planned work is planned to improve and technically inspect the collider.
It should be noted that repairs cost a pretty penny, not taking into account the cost. The Hadron Collider, as of 2010, has a price tag of 7.5 billion euros. This figure puts the entire project in first place on the list of the most expensive projects in the history of science.
The phrase “Large Hadron Collider” has become so deeply entrenched in the media that an overwhelming number of people know about this installation, including those whose activities are in no way connected with the physics of elementary particles, or 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, costing tens of billions of dollars, with which several thousand scientists from all over the world work. A significant contribution to the popularity of the collider was made by the so-called “God particle” or 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-kilometer 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, and the workers approached the tunneling 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 energy of 209 GeV. After this, its dismantling began. Over the eleven years of its operation, LEP has brought a number of discoveries to physics, including the discovery of W and Z bosons and their further research. Based on the results of these studies, it was concluded that the mechanisms of electromagnetic and weak interactions are similar, as a result of which theoretical work began on combining these interactions into the electroweak.
In 2001, construction of the Large Hadron Collider began on the site of the electron-positron accelerator. Construction of the new accelerator was completed at the end of 2007. It was located at the LEP site - 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, construction and operation of the facility is led by the European Organization for Nuclear Research - CERN.
CERN
It is worth mentioning briefly about the CERN organization (Conseil Européenne pour la Recherche Nucléaire). This organization acts as the world's largest laboratory in the field of high energy physics. Includes three thousand permanent employees, and several thousand more researchers and scientists from 80 countries take part in CERN projects.
At the moment, there are 22 countries participating in the project: Belgium, Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Sweden, Switzerland, Great Britain - 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 the work of the organization in one way or another, 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 public interest. Let's look at these questions further.
Collider - translated from English means “one who collides.” The purpose of such a setup is to collide particles. In the case of the hadron collider, the particles are played by hadrons - particles participating in strong interactions. These are protons.
Getting protons
The long journey of protons originates in the duoplasmatron - the first stage of the accelerator, which receives hydrogen in the form of gas. A duoplasmatron is a discharge chamber where an electrical discharge is conducted through a gas. So hydrogen, consisting of only one electron and one proton, loses its electron. In this way, plasma is formed - a substance consisting of charged particles - protons. Of course, it is difficult to obtain pure proton plasma, so the resulting plasma, which also includes a cloud of molecular ions and electrons, is filtered to isolate the proton cloud. Under the influence of magnets, proton plasma is knocked into a beam.
Preliminary acceleration of particles
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 created inside the accelerator is graded in such a way that particles between the hollow cylinders always experience an accelerating force in the direction of the next electrode. Without delving entirely into the proton acceleration mechanism at this stage, we only note that at the output from LINAC 2, physicists receive a beam of protons with an energy of 50 MeV, which already reaches 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 the collider also accelerates lead ions, which will make it possible to study quark-gluon plasma. They are accelerated in the LINAC 3 ring, similar to LINAC 2. In the future, experiments with argon and xenon are also planned.
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 they create has a high intensity, and a particle passing through it receives acceleration as a result of the field potential difference. So, after just 1.2 seconds, the particles are accelerated in the 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 is 628 meters in diameter and is equipped with 27 magnets that direct the particle beam in a circular orbit. Here the particle protons reach 26 GeV.
The penultimate ring for accelerating protons is the Super Proton Synchrotron (SPS), the circumference of which reaches 7 kilometers. Equipped with 1317 magnets, the SPS accelerates particles to an energy of 450 GeV. After about 20 minutes, the proton beam enters the main ring - the Large Hadron Collider (LHC).
Acceleration and collision of particles in the LHC
Transitions between accelerator rings occur through electromagnetic fields created by powerful magnets. The collider's main ring consists of two parallel lines in which particles move in a circular 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 them weighing up to 27 tons. To avoid overheating of the magnets, a helium-4 circuit is used, through which approximately 96 tons of the substance 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, in a second, a beam of protons passes through the large ring of the collider 11,000 times. Before the particles collide, they will circulate around the ring for 5 to 24 hours.
Particle collisions occur at four points in the main LHC ring, where 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 the search for the Higgs boson to the particles that may make up dark matter. Although it has the same scientific goals as the CMS experiment, ATLAS uses different technical solutions and a different magnetic system design.
Beams of particles from the LHC collide at the center of the ATLAS detector, creating oncoming debris in the form of new particles that fly out from the collision point in all directions. Six different detection subsystems, arranged in layers around the point of impact, record the path, momentum and energy of the particles, allowing them to be individually identified. A huge system of magnets bends the paths of charged particles so that their impulses can be measured.
The interactions in the ATLAS detector create a huge flow of data. 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 calculation systems are then used to analyze the recorded collision events.
The detector is 46 meters high and 25 meters wide, while its mass is 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 site of CERN, near the village of Meyrin in Switzerland. The installation consists of 4 main components:
- The inner detector has a cylindrical shape, the inner ring is located just a few centimeters from the axis of the passing particle beam, and the outer ring has a diameter of 2.1 meters and a length of 6.2 meters. It consists of three different sensor systems immersed in a magnetic field. An internal detector measures the direction, momentum and charge of the electrically charged particles produced in each proton-proton collision. The main elements of the internal detector are: a Pixel Detector, a Semi-Conductor Tracker (SCT) and a Transition radiation tracker (TRT).
- Calorimeters measure the energy that a particle loses as it passes through a detector. It absorbs particles arising during a collision, thereby recording their energy. Calorimeters consist of layers of high-density “absorbing” material—lead—alternating with layers of “active medium”—liquid argon. Electromagnetic calorimeters measure the energy of electrons and photons as they interact with matter. Hadron calorimeters measure the energy of hadrons when they interact with atomic nuclei. Calorimeters can stop most known particles except muons and neutrinos.
LAr (Liquid Argon Calorimeter) - ATLAS calorimeter
- The Muon Spectrometer consists of 4,000 individual muon chambers using four different technologies to identify muons and measure their momentum. Muons typically pass through an internal detector and calorimeter, requiring a muon spectrometer.
- ATLAS's magnetic system bends particles around different layers of detector systems, making it easier to track particle tracks.
The ATLAS experiment (February 2012) involves more than 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 a broad physics program, ranging from studying the standard model (including the Higgs boson) to searching for particles that may make up dark matter. Although it has the same scientific goals as the ATLAS experiment, CMS uses different technical solutions and a different magnetic system design.
The CMS detector is built around a huge solenoid magnet. It is a cylindrical coil of superconducting cable that generates a 4 Tesla field, approximately 100,000 times the Earth's magnetic field. The field is limited 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 and serves to bend the trajectory of charged particles emitted from the point of impact. Trajectory distortion makes it possible to distinguish between positively and negatively charged particles (since they bend in opposite directions), as well as to 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 located 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; combining these points of collision of the particle with different layers allows us to further determine its trajectory.
- Calorimeters - electronic and hadronic, see ATLAS calorimeters.
- Sub-detectors - allow you to detect muons. They are represented by 1,400 muon chambers, which are located in layers outside the coil, alternating with metal plates of the “yoke”.
The CMS experiment is one of the largest international scientific studies in history, involving 4,300 people: particle physicists, engineers and technicians, students and support staff from 182 institutions, 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 designed 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 today's universe is made of atoms. Each atom contains a nucleus of protons and neutrons (except hydrogen, which has no neutrons), surrounded by a cloud of electrons. Protons and neutrons, in turn, are made 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 constituent particles such as protons and neutrons. This is called confinement.
Collisions in the LHC create temperatures more than 100,000 times hotter than at the center of the Sun. The collider enables collisions between lead ions, recreating conditions similar to those that occurred immediately after the Big Bang. Under these extreme conditions, protons and neutrons “melt,” freeing the quarks from their bonds with gluons. This is quark-gluon plasma.
The ALICE experiment uses the ALICE detector, which weighs 10,000 tons, is 26 m long, 16 m high and 16 m wide. The device consists of three main sets of components: tracking devices, calorimeters and particle identifier 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 includes more than 1,000 scientists from more than 100 physics institutes in 30 countries.
LHCb (Large Hadron Collider beauty experiment)
The experiment examines the small differences between matter and antimatter by studying a type of particle called a beauty quark or b quark.
Instead of surrounding the entire collision point with a closed detector, like ATLAS and CMS, the LHCb experiment uses a series of subdetectors to detect predominantly forward particles—those that were pointed forward by a collision in one direction. The first sub-detector is installed close to the collision point, and the others are installed one after the other at a distance of 20 meters.
The LHC creates a large abundance of different types of quarks before they quickly decay into other forms. To catch b quarks, complex moving tracking detectors were developed for LHCb, located close to the movement of the particle beam through the collider.
The 5,600-ton LHCb detector consists of a direct spectrometer and flat-plate detectors. It is 21 meters long, 10 meters high and 13 meters wide, and is located 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 particles thrown forward after the collision of particle beams. They simulate cosmic rays, which scientists are studying as part of the 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 produce such particle cascades will help physicists interpret and calibrate large-scale cosmic ray experiments that can span thousands of kilometers.
LHCf consists of two detectors that are located along the LHC, 140 meters away on either side of the ATLAS impact point. Each of the two detectors weighs just 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 on the collider. Its mission is to study protons themselves, by precisely measuring protons produced in low-angle collisions. This region is known as the "forward" direction and is not accessible to other LHC experiments. TOTEM detectors extend almost half a kilometer around the CMS interaction point. TOTEM has almost 3,000 kg of equipment, including four nuclear telescopes, as well as 26 Roman pot detectors. The latter type allows detectors to be positioned as close as possible to the particle beam. The TOTEM experiment includes approximately 100 scientists from 16 institutes in 8 countries (August 2014).
Why is the Large Hadron Collider needed?
The largest international scientific installation explores a wide range of physical 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 has already been discovered (in 2012), very little is known about its nature and further research could bring greater clarity to the mechanism of its operation.
- Study of quark-gluon plasma. When lead nuclei collide at high speeds, . is formed in the collider. Her research can bring results useful both for nuclear physics (improving the theory of strong interactions) and astrophysics (studying the Universe in its first moments of existence).
- Search for supersymmetry. This research aims to disprove or prove “supersymmetry,” the theory that every elementary particle has a heavier partner called a “superparticle.”
- Study 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 better level, which in turn will open up opportunities for the creation of new technologies.
Practical benefits of the Large Hadron Collider and fundamental 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 quark-gluon plasma as something significant. The connection of such studies with the life of an ordinary person is not obvious. Let's look at a short example with nuclear energy:
In 1896, French physicist Antoine Henri Becquerel discovered the phenomenon of radioactivity. For a long time it was believed that humanity would not switch 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 application. Experts managed to rethink their attitude to the energy contained in the nucleus of an atom in 1939, when German scientists Lise 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 series of fundamental research did applied science come into play, which, on the basis of these discoveries, invented a device for producing nuclear energy - an atomic reactor. The scale of the discovery can be assessed 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%.
All new technologies are based on certain fundamental knowledge. Here are a couple more brief examples:
- In 1895, Wilhelm Conrad Roentgen noticed that when exposed to X-rays, a photographic plate darkens. Today, radiography is one of the most used examinations in medicine, allowing one to study the condition of internal organs and detect infections and swellings.
- In 1915, Albert Einstein proposed his own. Today, this theory is taken into account when operating GPS satellites, which determine the location of an object with an accuracy of a couple of meters. GPS is used in cellular communications, cartography, transport monitoring, but primarily in navigation. The error of a satellite that does not take into account general relativity would grow by 10 kilometers per day from the moment of launch! And if a pedestrian can use his mind and a paper map, then airline pilots will find themselves in a difficult situation, since it is impossible to navigate by clouds.
If today a practical application for the discoveries made at the LHC has not yet been found, this does not mean that scientists are “tinkering at the collider in vain.” As you know, a reasonable person always intends to obtain the maximum practical application from existing 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 has already been demonstrated above, the connection between fundamental discoveries and the technologies that use them may sometimes not be at all obvious.
Finally, let us note the so-called indirect discoveries, which are not set as the initial goals of the study. They occur quite often, since making a fundamental discovery usually requires the introduction and use of new technologies. Thus, the development of optics received an impetus from fundamental space research, based on observations by astronomers through a telescope. In the case of CERN, this is how a ubiquitous technology emerged - the Internet, a project proposed by Tim Berners-Lee in 1989 to facilitate the search for CERN organization data.
It is the search for ways to combine two fundamental theories - GTR (about gravitational theory) and the Standard Model (the standard model that combines three fundamental physical interactions - electromagnetic, strong and weak). Finding a solution before the creation of the LHC was hampered by difficulties in creating the theory of quantum gravity.
The construction of this hypothesis involves the combination of two physical theories - quantum mechanics and general relativity.
To do this, several popular and modern approaches were used - string theory, brane theory, supergravity theory, and also the theory of quantum gravity. Before the construction of the collider, the main problem in carrying out the necessary experiments was the lack of energy, which cannot be achieved with other modern charged particle accelerators.
The Geneva LHC gave scientists the opportunity to conduct previously impossible experiments. It is believed that in the near future many physical theories will be confirmed or refuted with the help of the apparatus. One of the most problematic is supersymmetry or string theory, which has long divided physics into two camps - the “stringers” and their rivals.
Other fundamental experiments carried out as part of the LHC work
The research of scientists in the field of studying top- , which are the heaviest quarks and the heaviest (173.1 ± 1.3 GeV/c²) of all currently known elementary particles, is also interesting.
Because of this property, even before the creation of the LHC, scientists could only observe quarks at the Tevatron accelerator, since other devices simply did not have sufficient power and energy. In turn, the theory of quarks is an important element of the acclaimed Higgs boson hypothesis.
Scientists carry out all scientific research on the creation and study of the properties of quarks in the top-quark-antiquark steam room at the LHC.
An important goal of the Geneva project is also the process of studying the mechanism of electroweak symmetry, which is also associated with the experimental proof of the existence of the Higgs boson. To define the problem even more precisely, the subject of study is not so much the boson itself, but the mechanism for breaking the symmetry of the electroweak interaction predicted by Peter Higgs.
The LHC is also conducting experiments to search for supersymmetry - and the desired result will be both proof of the theory that any elementary particle is always accompanied by a heavier partner, and its refutation.