Bubble chamber: the principle of action, device, circuit. Advantages and disadvantages of the bubble chamber

In the middle of the 20th century, a bubble chamber was invented - a device that was actively used to observe microparticles. For the most part, it was used by physicists who observed the microcosm. Even today, despite the colossal development of technology and the availability of various electronic sensors, schoolchildren are shown photographs of particles made with the help of bubbles.

About how the camera came about

As already noted above, in the middle of the 20th century, this invention appeared. And all because the scientist-physicists did not manage to investigate the charged particles with the available detectors. By that time, everyone already knew what a proton, neutron, electron and positron were. In 1950 the solution of this question was taken up by D. Glazer. The scientist tried to use both chemical and physical reactions, electrical and liquid, as well as solid conversions. But he decided to dwell on the liquid phenomenon, and to be more precise, on the principle of overheating of the working mixture. The basic requirements that Donald put forward to his invention is the high speed of operation, which allows to capture a particle in a photo at the right time. Of course, the bubble chamber and the cloud chamber are somewhat similar. But there are a number of differences, which we, in fact, will talk further.

Bubble chamber: the principle of action

Diethyl ether was used as the working fluid , which had the advantage of a low price. In addition, it could easily be obtained in pure form. The essence was to heat this liquid to the boiling point (1400 degrees Celsius), and then cool to room temperature. At this time, radioactive material, for example cobalt, is brought up, then with an interval of about 60 seconds, the working fluid boils. Once a minute, one could capture the movement of particles on a photograph.

To illustrate everything, Glazer used two cameras made of refractory glass and filled with diethyl ether. Heating was carried out in an oil bath, and the pressure could be lowered by means of a handle. At this time, the camera was launched. On average, the frame rate was about 3000 per second. This made it possible to capture the motion of particles in the vessels. Later the bubble chamber Was a little automated, but the principle of action remained the same. Most often used a Geiger counter, which allowed to track the appearance of radiation.

Bubble camera: device

Now let's talk a little about what the present invention is. In most cases, it is a vessel that has several small windows. The chambers were filled with a special liquid and placed in a magnetic field. Always used pressure above atmospheric. Sometimes a cryostat was used, which was necessary to cool the working fluid (RJ) boiling at low temperatures. Just before the release of radioactive elements from the accelerator, the pressure in the chambers was relieved and an overheated liquid was obtained. All that has a charge, on its way leaves bubbles with boiling liquid. Only a fraction of a microsecond is sufficient to carry out the reaction. In a moment, the bubbles became an order of magnitude larger. For lighting, the lamp and three cameras were switched on, with the help of which the stereo image was obtained.

The final stage of the experiment

At the final stage, a complex analysis of the trajectory and character of the motion of charged radioactive particles was carried out. There are cases when photos were taken for processing for several days, but they were processed for months. When a spiral was obtained, this indicated the passage of an electron. The so-called forks spoke of the presence of neutral particles. In most cases, based on the data obtained 3-photos, carefully measured the trajectory of the elements. If you could restore the picture completely, you could create a spatial picture. At first scientists were engaged in this, but such a study could take years. The situation changed with the advent of computers, which greatly accelerated the process.

On the advantages of using cameras of this type

As noted above, the device is a bit like Wilson's invention by the principle of action. But there are a number of undeniable advantages. The most weighty advantage can be considered the speed of operation, which with a high probability allows you to fix a noticeable phenomenon on the photograph.

Another plus is that fluid is a fluid that has a high density. This greatly increases the chance that an expected event will occur in a given environment. What is the advantage of a bubble chamber, is that its cycle of operation takes quite a bit of time. This parameter is simply a necessary condition for using the device in accelerators of different types. The superheated liquid can be obtained quickly enough, for this it is only necessary to reduce the pressure in the system. Here, in principle, all the main advantages of this device.

A little about the shortcomings

As was noted at the very beginning of this article, at the present time there is simply a huge number of different electronic sensors that allow you to find the necessary objects with high accuracy, select the necessary elements at a high speed, and determine their spatial picture. It is in insufficient controllability that the main shortcomings of the bubble chamber are concluded. As a rule, most of the results obtained do not represent any scientific interest, but it may take quite some time to throw away the unnecessary in a photograph. Another disadvantage is that the device is simply impossible to start immediately, in particular, this is due to the inertia of the working fluid and other physical parameters. In principle, we have figured out the shortcomings, let's go further.

About the technical side

A little more than 100 copies of bubble chambers were registered during the time of using this method of detecting charged particles. During this time, a variety of liquids were used, such as helium, hydrogen, freon, xenon, propane and others. The same applies to temperatures that began with ultralow ones and ended with rooms for xenon. "Gargamel" - the last bubble chamber, the scheme of which is not fundamentally different from the others. But in its chambers was filled about 18 tons of freon. This device allowed to make a great discovery for those times - the interaction between neutral points. The largest specimen had a diameter of 4.5 meters. The device was designed to work with hydrogen. But the whole problem was that new accelerators were invented, which produced bundles of radioactive particles at a tremendous speed, so no bubble chambers could cope.

A few important points

It is worth paying attention to the fact that at present, these cameras are no longer being used. Almost everyone wrote them off, but as it turned out, it was a premature decision. In 2002, with the help of bubbles, new particles called pentaquarts were discovered. But again, this is the result of not studies of the same year, but an elementary check of photographs obtained many years ago. This suggests that you can find something that is worth of what has been done in the past.

Moreover, the computational power of modern technology is so great that it takes very little time to process each picture. In principle, the efficiency of this type of track detector is currently quite low, so it is not advisable to use them, however, once obtained experimental data can be useful today.

Conclusion

Well, that's all that can be said about what a bubble chamber is. The scheme of the device is quite simple, like all ingenious. It is worth saying a few words that the effectiveness of such devices largely depends on their size. The larger the camera, the higher the chance to find something useful. Nevertheless, with an increase in dimensions, the price of materials and working fluid increases, which in large amounts has an impressive cost. Now you know what a bubble chamber is, the principle of which is based on overheating of the liquid. This effect has been investigated along and across, therefore nowadays electronic sensors are considered more relevant, which benefit in all respects.