Have you ever noticed that your clock at home shows different times? And how to understand which of all the options is correct? We will learn the answers to all these questions by thoroughly studying the principle of operation of atomic clocks.

Atomic clock: description and principle of operation

Let's first understand what the mechanism of an atomic clock is. An atomic clock is a device that measures time, but it uses its own vibrations as the periodicity of the process, and everything happens at the atomic and molecular level. Hence the accuracy.

It is safe to say that atomic clocks are the most accurate! It is thanks to them that the Internet and GPS navigation function in the world, we know the exact location of the planets in the solar system. The error of this device is so minimal that we can confidently say that they are world-class! Thanks to atomic clocks, the entire world synchronization takes place, it is known where certain changes are located.

Who invented, who created, and also who came up with this miracle watch?

Back in the early forties of the twentieth century, it was known about the atomic beam of magnetic resonance. At first, its application did not concern watches in any way - it was only a theory. But already in 1945, Isidor Rabi proposed to create a device, the concept of which was that they work on the basis of the above described technique. But they were arranged in such a way that they showed inaccurate results. And already in 1949, the National Bureau of Standards informed the whole world about the creation of the first atomic clock, which was based on molecular compounds of ammonia, and already in 1952, technologies were mastered to create a prototype based on cesium atoms.

Hearing about the atoms of ammonia and cesium, the question arises, but are these wonderful clocks radioactive? The answer is unequivocal - no! They do not have atomic decay.

Nowadays, there are many materials from which atomic clocks are made. For example, it is silicon, quartz, aluminum and even silver.

How does the device work?

Let's take a look at how nuclear-powered clocks look and work. To do this, we offer a description of their work:

For the correct functioning of this particular clock, not a pendulum is needed, nor a quartz oscillator. They use signals that arise due to the quantum transition of one electron between two energy levels of an atom. As a result, we are able to observe an electromagnetic wave. In other words, we get frequent fluctuations and an ultra-high level of system stability. Every year, due to new discoveries, processes are modernized. Not so long ago, the specialists of The National Institute fStandardsand Technology (NIST) became champions, setting an absolute world record. They were able to bring the accuracy of the atomic clock (based on strontium) to the very minimum deviation, namely: for 15 billion years, one second runs. Yes, yes, it didn’t seem to you that this is the age that is now being assigned to our Universe. This is a huge discovery! After all, it was strontium that played the most important role in this record. The moving atoms of strontium in its spatial lattice, which scientists created using a laser, acted as an analogue of the “ticking”. As always in science, in theory everything seems enchanting and already improved, but the instability of such a system may turn out to be less joyful in practice. It is because of its instability that the cesium-based device gained worldwide popularity.

Now consider what such a device consists of. The main details here are:

• quantum discriminator;
• quartz generator;
• electronics.

A quartz oscillator is a kind of self-oscillator, but to produce a resonant element, it uses piezoelectric modes of a quartz crystal.

Having a quantum discriminator and a quartz oscillator, under the influence of their frequency, they are compared, and when a difference is detected, the feedback circuit requires the crystal oscillator to adjust to the required value and increase stability and accuracy. As a result, at the output we see the exact value on the dial, which means the exact time.

Early models were quite large, but in October 2013, BathysHawaii made a splash with the release of miniature atomic wristwatches. At first, everyone took this statement as a joke, but it soon turned out that it was really true, and they function on the basis of the atomic source Cesium 133 The safety of the device is ensured by the fact that the radioactive element is contained in the form of a gas in a special capsule.A photo of this device has scattered around the world.

Many in the topic of atomic clocks are interested in the issue of a power source. The battery is a lithium-ion battery. But alas, it is not yet known how long such a battery will last.

BathysHawaii watches were truly the first atomic wristwatches. Previously, cases of release of a relatively portable device were already known, but, unfortunately, it did not have an atomic power source, but only synchronized with real overall clocks via wireless radio. It is also worth mentioning the cost of such a gadget. The pleasure was estimated at 12 thousand US dollars. It was clear that with such a price, watches would not gain wide popularity, but the company did not strive for this, because they released them in a very limited batch.

We know of several types of atomic clocks. There are no significant differences in their design and principles, but there are still some differences. So, the main ones are in the means of finding changes and their elements. The following types of watches can be distinguished:

1. Hydrogen. Their essence lies in the fact that hydrogen atoms are supported at the right level of energy, but the walls are made of a special material. Based on this, we conclude that it is hydrogen atoms that very quickly lose their energy state.
2. cesium. The basis for them are cesium beams. It is worth noting that these watches are the most accurate.
3. Rubidium. They are the simplest and very compact.

As mentioned earlier, atomic clocks are a very expensive gadget. Thus, the pocket watch Hoptroff No. 10 is a bright representative of a new generation of toys. The price of such a stylish and very accurate accessory is 78 thousand dollars. Only 12 copies were released. The mechanism of this device uses a high-frequency oscillatory system, which is also equipped with a GPS signal.

The company did not stop there and it is in its tenth version of the watch that it wants to apply the method of placing the movement in a gold case, which will be printed on a popular 3D printer. It has not yet been calculated exactly how much gold will be used for this version of the case, but the estimated retail price of this masterpiece is already known - it amounted to about 50 thousand pounds sterling. And this is not the final price, although it takes into account all the volumes of research, as well as the novelty and uniqueness of the gadget itself.

Historical facts about the use of watches

How, when talking about atomic clocks, not to mention the most interesting facts that are associated with them and time in general:

1. Did you know that the oldest sundial was found in ancient Egypt?
2. The error of atomic clocks is minimal - it is only 1 second for 6 million years.
3. Everyone knows that there are 60 seconds in a minute. But few people delved into how many milliseconds are in one second? And they are not many and not few - a thousand!
4. Every tourist who was able to visit London was sure to want to see Big Ben with their own eyes. But unfortunately, not many people know that Big Ben is not a tower at all, but the name of a huge bell that weighs 13 tons and rings inside the tower.
5. Have you ever wondered why the hands of our clocks go exactly from left to right, or how we used to say “clockwise”? This fact is directly related to how the shadow moves on the sundial.
6. The very first wristwatch was invented in the recent 1812. They were made by the founder of Breguet for the Queen of Naples.
7. Before the First World War, wrist watches were considered only a women's accessory, but soon, due to their convenience, they were also chosen by the male part of the population.

In the 21st century, satellite navigation is developing at a rapid pace. You can determine the position of any objects that are somehow connected with satellites, whether it be a mobile phone, a car or a spacecraft. But none of this could have been achieved without atomic clocks.
Also, these watches are used in various telecommunications, for example, in mobile communications. This is the most accurate watch that has ever been, is and will be. Without them, the Internet would not be synchronized, we would not know the distance to other planets and stars, etc.
In hours, 9,192,631,770 periods of electromagnetic radiation are taken per second, which occurred during the transition between two energy levels of the cesium-133 atom. Such clocks are called cesium clocks. But this is only one of three types of atomic clocks. There are also hydrogen and rubidium clocks. However, cesium clocks are used most often, so we will not dwell on other types.

How a cesium atomic clock works

The laser heats the atoms of the cesium isotope and at this time, the built-in resonator registers all the transitions of the atoms. And, as mentioned earlier, after reaching 9,192,631,770 transitions, one second is counted.

A laser built into the watch case heats the atoms of the cesium isotope. At this time, the resonator registers the number of transitions of atoms to a new energy level. When a certain frequency is reached, namely 9,192,631,770 transitions (Hz), then a second is counted, based on the international SI system.

Use in satellite navigation

The process of determining the exact location of an object using a satellite is very difficult. Several satellites are involved in this, namely more than 4 per receiver (for example, a GPS navigator in a car).

Each satellite has a high-precision atomic clock, a satellite radio transmitter and a digital code generator. The radio transmitter sends a digital code and information about the satellite to Earth, namely orbit parameters, model, etc.

The clock determines how long it takes for this code to reach the receiver. Thus, knowing the speed of propagation of radio waves, the distance to the receiver on Earth is calculated. But one satellite is not enough for this. Modern GPS receivers can receive signals from 12 satellites simultaneously, which allows you to determine the location of an object with an accuracy of up to 4 meters. By the way, it is worth noting that GPS navigators do not require a subscription fee.

High-precision atomic clocks that make an error of one second in 300 million years. This clock, which replaced an old model that had a one-second error in a hundred million years, now sets the standard for American civil time. Lenta.ru decided to recall the history of the creation of atomic clocks.

First atom

In order to create a clock, it is enough to use any periodic process. And the history of the emergence of time measuring instruments is partly the history of the emergence of either new energy sources or new oscillatory systems used in watches. The simplest clock is probably the sun clock, requiring only the sun and an object to cast a shadow to operate. The disadvantages of this method of determining the time are obvious. Water and hourglasses are no better either: they are suitable only for measuring relatively short periods of time.

The oldest mechanical clock was found in 1901 near the island of Antikythera on a sunken ship in the Aegean Sea. They contain about 30 bronze gears in a wooden case measuring 33 by 18 by 10 centimeters and date back to around 100 BC.

For almost two thousand years, mechanical watches have been the most accurate and reliable. The appearance in 1657 of the classic work of Christian Huygens "Pendulum Clock" ("Horologium oscillatorium, sive de motu pendulorum an horologia aptato demonstrationes geometrica") with a description of a time reference device with a pendulum as an oscillating system, was probably the apogee in the history of the development of mechanical devices of this type.

However, astronomers and navigators still used the starry sky and maps to determine their location and exact time. The first electric clock was invented in 1814 by Francis Ronalds. However, the first such instrument was inaccurate due to its sensitivity to temperature changes.

The further history of watches is connected with the use of different oscillatory systems in devices. Introduced in 1927 by employees of Bell Labs, quartz watches used the piezoelectric properties of a quartz crystal: when an electric current is applied to it, the crystal begins to shrink. Modern quartz chronometers can achieve an accuracy of up to 0.3 seconds per month. However, since quartz is subject to aging, over time the watch becomes less accurate.

With the development of atomic physics, scientists proposed using particles of matter as oscillatory systems. This is how the first atomic clock appeared. The idea of ​​using atomic vibrations of hydrogen to measure time was suggested back in 1879 by the English physicist Lord Kelvin, but this became possible only by the middle of the 20th century.

Reproduction of a painting by Hubert von Herkomer (1907)

In the 1930s, the American physicist and discoverer of nuclear magnetic resonance, Isidore Rabi, began working on cesium-133 atomic clocks, but the outbreak of war prevented him. Already after the war, in 1949, the first molecular clock using ammonia molecules was created at the US National Committee of Standards with the participation of Harold Lyonson. But the first such instruments for measuring time were not as accurate as modern atomic clocks.

The relatively low accuracy was due to the fact that due to the interaction of ammonia molecules with each other and with the walls of the container in which this substance was located, the energy of the molecules changed and their spectral lines broadened. This effect is very similar to the friction in a mechanical watch.

Later, in 1955, Louis Esssen of the UK's National Physical Laboratory introduced the first caesium-133 atomic clock. This clock accumulated an error of one second in a million years. The device was named NBS-1 and began to be considered a cesium frequency standard.

The circuit diagram of an atomic clock consists of a crystal oscillator controlled by a feedback discriminator. The oscillator uses the piezoelectric properties of quartz, while the discriminator uses the energy vibrations of atoms, so that the vibrations of quartz are tracked by signals from transitions from different energy levels in atoms or molecules. Between the generator and the discriminator there is a compensator tuned to the frequency of atomic vibrations and comparing it with the vibration frequency of the crystal.

The atoms used in the clock must provide stable vibrations. Each frequency of electromagnetic radiation has its own atoms: calcium, strontium, rubidium, cesium, hydrogen. Or even molecules of ammonia and iodine.

time standard

With the advent of atomic time measuring instruments, it became possible to use them as a universal standard for determining the second. Since 1884, Greenwich time, considered the world standard, has given way to the standard of atomic clocks. In 1967, by decision of the 12th General Conference of Weights and Measures, one second was defined as the duration of 9192631770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom. This definition of a second does not depend on astronomical parameters and can be reproduced anywhere on the planet. Cesium-133, used in the standard atomic clock, is the only stable isotope of cesium with 100% abundance on Earth.

Atomic clocks are also used in the satellite navigation system; they are necessary to determine the exact time and coordinates of the satellite. Thus, each satellite of the GPS system has four sets of such clocks: two rubidium and two cesium, which provide a signal transmission accuracy of 50 nanoseconds. The Russian satellites of the GLONASS system also have cesium and rubidium atomic time measuring devices, and the satellites of the unfolding European geopositioning system Galileo are equipped with hydrogen and rubidium ones.

The accuracy of hydrogen clocks is the highest. It is 0.45 nanoseconds in 12 hours. Apparently, the use of such accurate clocks by Galileo will bring this navigation system to the fore in 2015, when its 18 satellites will be in orbit.

Compact atomic clock

Hewlett-Packard was the first company to develop a compact atomic clock. In 1964, she created the HP 5060A cesium instrument, the size of a large suitcase. The company continued to develop this direction, but since 2005 it has sold its atomic clock division to Symmetricom.

In 2011, Draper Laboratories and Sandia National Laboratories developed and Symmetricom released the first Quantum miniature atomic clock. At the time of release, they cost about 15 thousand dollars, were enclosed in a sealed case measuring 40 by 35 by 11 millimeters and weighed 35 grams. The power consumption of the watch was less than 120 milliwatts. Initially, they were developed by order of the Pentagon and were intended to serve navigation systems that function independently of GPS systems, for example, deep under water or land.

Already at the end of 2013, the American company Bathys Hawaii introduced the first "wrist" atomic clock. They use the SA.45s chip manufactured by Symmetricom as the main component. Inside the chip is a capsule with cesium-133. The design of the watch also includes photocells and a low-power laser. The latter provides heating of gaseous cesium, as a result of which its atoms begin to move from one energy level to another. The measurement of time is just made by fixing such a transition. The cost of the new device is about 12 thousand dollars.

Trends towards miniaturization, autonomy and accuracy will lead to the fact that in the near future there will be new devices using atomic clocks in all areas of human life, from space research on orbiting satellites and stations to domestic applications in indoor and wrist systems.

Often we hear the phrase that atomic clocks always show the exact time. But from their name it is difficult to understand why atomic clocks are the most accurate or how they work.

The fact that the name contains the word "atomic" does not mean at all that the watch is a danger to life, even if thoughts of an atomic bomb or a nuclear power plant immediately come to mind. In this case, we are just talking about the principle of the clock. If in an ordinary mechanical clock gears make oscillatory movements and their movements are counted, then in atomic clocks oscillations of electrons inside atoms are counted. To better understand the principle of operation, let's recall the physics of elementary particles.

All substances in our world are made up of atoms. Atoms are made up of protons, neutrons and electrons. Protons and neutrons combine with each other to form a nucleus, which is also called a nucleon. Electrons move around the nucleus, which can be at different energy levels. The most interesting thing is that when absorbing or giving off energy, an electron can move from its energy level to a higher or lower one. An electron can receive energy from electromagnetic radiation by absorbing or emitting electromagnetic radiation of a certain frequency at each transition.

Most often there are watches in which atoms of the element Cesium -133 are used to change. If in 1 second the pendulum conventional watches makes 1 oscillatory motion, then the electrons in atomic clocks based on Cesium-133, when moving from one energy level to another, they emit electromagnetic radiation with a frequency of 9192631770 Hz. It turns out that one second is divided into exactly this number of intervals, if it is calculated in atomic clocks. This value was officially adopted by the international community in 1967. Imagine a huge dial, where there are not 60, but 9192631770 divisions, which are only 1 second. It is not surprising that atomic clocks are so accurate and have a number of advantages: atoms do not age, do not wear out, and the oscillation frequency will always be the same for one chemical element, which makes it possible to simultaneously compare, for example, the readings of atomic clocks far in space and on Earth, not afraid of mistakes.

Thanks to atomic clocks, mankind in practice was able to test the correctness of the theory of relativity and make sure that, than on Earth. Atomic clocks are installed on many satellites and spacecraft, they are used for telecommunications needs, for mobile communications, they compare the exact time on the entire planet. Without exaggeration, it was thanks to the invention of the atomic clock that humanity was able to enter the era of high technology.

How do atomic clocks work?

Cesium-133 is heated by evaporating cesium atoms, which are passed through a magnetic field, where atoms with the desired energy states are selected.

Then the selected atoms pass through a magnetic field with a frequency close to 9192631770 Hz, which creates a quartz oscillator. Under the influence of the field, the cesium atoms again change their energy states, and fall on the detector, which fixes when the largest number of incoming atoms will have the “correct” energy state. The maximum number of atoms with a changed energy state indicates that the frequency of the microwave field is chosen correctly, and then its value is fed into an electronic device - a frequency divider, which, reducing the frequency by an integer number of times, gets the number 1, which is the reference second.

Thus, the cesium atoms are used to check the correct frequency of the magnetic field produced by the crystal oscillator, helping to keep it constant.

It is interesting: although the atomic clocks that exist today are unprecedentedly accurate and can run without errors for millions of years, physicists are not going to stop there. Using atoms of various chemical elements, they are constantly working to improve the accuracy of atomic clocks. Of the latest inventions - atomic clocks on strontium, which are three times more accurate than their cesium counterpart. It would take them 15 billion years to be just a second behind – a time longer than the age of our universe…

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Atomic clock January 27th, 2016

Switzerland, or even Japan, will not be the birthplace of the world's first pocket watch with a built-in atomic time standard. The idea of ​​their creation originated in the heart of the UK from the London-based brand Hoptroff

Atomic, or as they are also called "quantum clocks", is a device that measures time using natural vibrations associated with processes occurring at the level of atoms or molecules. Richard Hoptroff decided that it was time for modern gentlemen who are interested in high-tech devices to change their pocket mechanical watches for something more extravagant and extraordinary, and also in line with modern urban trends.

So, the public was shown an elegant pocket atomic watch Hoptroff No. 10, which can surprise the modern generation, tempted by an abundance of gadgets, not only with its retro style and fantastic accuracy, but also with its service life. According to the developers, having this watch with you, you will be able to remain the most punctual person for at least 5 billion years.

What else can you find out about them interesting ...

Photo 2.

For all those who have never been interested in such watches, it is worth briefly describing the principle of their operation. Inside the "atomic device" there is nothing that resembles a classic mechanical watch. In Hoptroff no. 10 there are no mechanical parts as such. Instead, atomic pocket watches are equipped with a sealed chamber filled with a radioactive gaseous substance, the temperature of which is controlled by a special furnace. The exact timing is as follows: lasers excite the atoms of a chemical element, which is a kind of “filler” of the clock, and the resonator captures and measures each atomic transition. Today, the basic element of such devices is cesium. If we recall the SI system of units, then in it the value of a second is connected with the number of periods of electromagnetic radiation during the transition of cesium-133 atoms from one energy level to another.

Photo 3.

If in smartphones the processor chip is considered the heart of the device, then in Hoptroff No. 10 this role is taken by the module-generator of the reference time. It is supplied by Symmetricom, and the chip itself was originally focused on use in the military industry - in unmanned aerial vehicles.

The CSAC atomic clock is equipped with a temperature-controlled thermostat containing a cesium vapor chamber. Under the influence of a laser on cesium-133 atoms, their transition from one energy state to another begins, for which a microwave resonator is used to measure it. Since 1967, the International System of Units (SI) has defined one second as 9,192,631,770 periods of electromagnetic radiation arising from the transition between two hyperfine levels of the ground state of the cesium-133 atom. Based on this, it is difficult to imagine a more technically accurate watch based on cesium. In time, with recent advances in timekeeping, new optical clocks based on an aluminum ion pulsing at ultraviolet frequency (100,000 times the microwave frequencies of cesium clocks) will be hundreds of times more accurate than atomic timepieces. To put it simply, Hoptroff's new No.10 pocket watch has an accuracy of 0.0015 seconds per year, 2.4 million times better than COSC standards.

Photo 4.

The functional side of the device is also on the verge of fantasy. With it, you can find out: time, date, day of the week, year, latitude and longitude in different values, pressure, humidity, sidereal hours and minutes, tide forecast and many other indicators. The watch comes in gold, and it is planned to use 3D printing to create its precious metal case.

Richard Hoptrof sincerely believes that this particular production option for his offspring is the most preferable. To slightly change the design component of the design, it will not be necessary to rebuild the production line at all, but to use the functional flexibility of the 3D printing device for this. True, it is worth noting that the shown prototype watch was made in the classical way.

Photo 5.

Time is very precious these days, and the pocket watch Hoptroff No. 10 is a direct confirmation of this. According to preliminary information, the first batch of nuclear devices will be 12 units, and as for the cost, the price for 1 copy will be $78,000.

Photo 6.

According to Richard Hoptroff, Managing Director of the brand, Hoptroff's London residence played a key role in the idea. “In our quartz movements, we use a high-precision oscillatory system with a GPS signal. But in the center of London it is not so easy to catch this very signal. Once, during a trip to the Greenwich Observatory, I saw a Hewlett Packard atomic clock there and decided to purchase something similar for myself via the Internet. And I couldn't. Instead, I came across information about a Symmetricon chip, and after three days of thinking, I realized that it would be perfect for a pocket watch.”

The chip in question is the SA.45s cesium atomic clock (CSAC), a first generation of miniature atomic clocks for GPS receivers, backpack radios and drones. Despite its modest dimensions (40 mm x 34.75 mm), it is unlikely to fit in a wrist watch. Therefore, Hoptroff decided to equip a rather solid pocket model (82 mm in diameter) with them.

In addition to being the most accurate watch in the world, Hoptroff No 10 (the brand's tenth movement) also claims to be the first gold case made using 3D printing technology. Hoptroff is not yet sure how much gold will be needed to make the case (work on the first prototype was completed when the issue went to press), but suggests that its cost will be "a minimum of several thousand pounds." And with all the R&D required to develop the product (think of the tide function for harmonic constants for 3,000 different ports), you'd expect the final retail price to be in the region of £50,000.

Gold case of model No. 10 at the exit from the 3D printer and in finished form

Buyers automatically become members of an exclusive club and will be required to sign a written commitment not to use the atomic clock chip as a weapon. “This is one of the terms of our contract with the supplier,” explains Mr. Hoptroff, “because the atomic chip was originally used in missile guidance systems.” Not much for being able to get a watch with impeccable accuracy.

The lucky owners of the No.10 by Hoptroff will have much more than just a high-precision watch at their disposal. The model also doubles as a pocket navigation device, allowing longitude to be determined to within one nautical mile, even after many years at sea, using a simple sextant. The model will receive two dials, but the design of one of them is still kept secret. The other is a whirlwind of counters displaying as many as 28 complications: from all possible chronometric functions and calendar indicators to a compass, thermometer, hygrometer (a device for measuring humidity levels), barometer, latitude and longitude counters and an indicator of high / low tide. And this is not to mention the vital indicators of the state of the atomic thermostat.

Hoptroff plans to launch a number of new products, including an electronic version of George Daniels' legendary complicated Space Traveler watch. They are currently being worked on to integrate Bluetooth technology into the watch to store the wearer's personal information and allow automatic adjustment of complications such as the moon phase display.

The first copies of No.10 will appear next year, but for now the company is looking for suitable partners among retailers. “We could certainly try to sell it online, but this is a premium model, so you still need to hold it in your hands to appreciate it. This means that we will still have to use the services of retailers, and we are ready to start negotiations,” concludes Mr. Hoptroff.

And even The original article is on the website InfoGlaz.rf Link to the article from which this copy is made -