Get best of the week

In the wake of the hot particles. Wilson's Chamber

Hamsters welcome you friends!

Today's post will be devoted to the Wilson condensation chamber with which you can see radiation in the form of tracks of charged particles. The sight is bewitching! In the course we will see how to create such a device, how to start it correctly and find out under what conditions the particles open up the full potential for an outside observer - like you and me.



All the necessary components were ordered from the Chinese province and the work began to boil. Looking ahead, I’ll say that in the following days, without leaving a long binge, I wanted to kill a Chinese man, cut off my finger and sacrifice a ram who scattered pitfalls on the path of personifying radiation tracks. Everything turned out to be not so simple as it seems at first glance. Therefore, I will begin in order.

To assemble the Wilson camera, we need to get two powerful power sources for 5 and 12 volts. In my case, these are server power supplies from mining farms. The label indicates the declared current of 114 Amps. This is clearly in excess, since the real parameters of the current consumption of the installation were 23 Amperes along the 12 volt line and 9 Amperes along the 5 volt line. Ideally, a 500 W computer power supply is suitable here.

The following main elements: this is a cooler on Peltier modules, a high voltage converter for many kilovolts, and a glass viewing chamber through which we have to observe tracks of ionizing radiation.



The cooler can be called the bearing part of this house of cards.It is based on Peltier thermoelectric elements, in which a temperature difference arises on its sides when an electric current flows.

For the installation to work, we need 8 of these elements. Four of them are TEC1-12710 with a declared maximum power consumption of 154 W each, and the same number of elements are TEC1-12706 with a consumed power of 60 W. They will work in sandwich mode. From practice, such an assembly gives a temperature of minus 15 degrees lower than one element separately.



To achieve the highest negative temperatures, the system must be equipped with high-quality water cooling. This is implemented using aluminum radiatorsdesigned specifically for this purpose, a few meters of PVC hose with a diameter of 12 mm, and a brushless submersible pump that can pump 240 liters of water per hour. It is powered by a constant voltage of 12 volts, while consuming 3.6 watts.



Now our task is to connect all the elements together. For this, a metal base was found on which radiators will lie and a metal frame is assembled, which pulls everything together. For these purposes, the aluminum corners and the channel purchased in the nearest hardware store were perfect.

Thermal grease in this case uses gray with the inscription on the can HY-510 .It must be applied in a uniform uniform layer to avoid possible microbubbles. You can use a plastic card for this.



We place thermoelectric converters in the following order. Below are the more powerful TEC1-12710 brands , and above are the TEC1-12706 elements . They are 2 times weaker in power and will also be powered by 5 Volts instead of 12. This is necessary so that the lower element has time to efficiently remove heat from the upper.

Thus, we achieve the greatest efficiency from this assembly.Here is a pyramid of iron and ceramic in the end should work. It is important that all surfaces of Peltier elements are flush, the Chinese are hackneyed with the thickness of aluminum water coolers, which can lead to unnecessary steps in the end. Remember - they are unacceptable!



To increase the surface area on which the viewing chamber will be installed, we cut a square of fiberglass 1 mm thick, it is placed directly on the wires protruding from the modules. No additional supports are provided.

We apply the upper thermal paste as evenly as possible, this is important because now we will glue the black self-adhesive film of the Oracal type on the entire surface , despite the fact that it is quite dense, all the irregularities on it will be clearly visible.

This is the landscape I got from the second attempt. In any case, during cooling, the film is stretched and the surface will look smoother.



If you follow this assembly guide, then as a result, on the surface of the cooler we get a temperature of minus 45 degrees, this will be more than enough for the Wilson chamber to work well. For example, at minus 30 degrees, it does not work at all, and alcohol does not condense well at this temperature. Repeatedly checked.

Put a drop of water on the surface and see what happens to it. The most interesting moment in this observation occurs at the very end, when the crystallization of the droplet reaches the peak. She extends into a sharp cone. With increasing it is clearly visible. Pretty curious effect.

In principle, the assembly is ready, and tracks of charged particles caused by the half-life of various radioactive elements can be observed on its surface. Like two fingers you say! But here the most interesting moments in this whole story open up ...



Briefly go through the places where you can slip and fall.

Peltier elements. They are not as simple as they seem at first glance. This mainly applies to the top modules of TEC1-12706 in this sandwich. So they work outside their operating mode by voltage (5 Volts instead of 12 Volts), their final temperature will differ significantly from each other. I note that all the elements are from one batch, from one plant and from one conveyor.

Here is a simple illustrative example.The pyrometer shows minus 9.5 degrees on the weakest element, and almost 23 degrees on the strongest. The difference is 13 degrees. There were thoughts that this effect is associated with the cooling system, since in the beginning water passes through the first heat exchanger assembly, and then it enters the second. But no, replacing the hoses in places did not lead to anything good.

And how to be now ?! No way. We dress and move forward with new white squares. Lucky that the store is at hand. As a result, four of the eight elements had to be selected to achieve almost the same temperatures on the surfaces. The difference is a couple of degrees.



Viewing camera.Its purpose is multitask: to prevent heat exchange of the cooler with the environment, to prevent the ingress of external air currents, to create a closed space for the circulation of alcohol vapor and to provide unimpeded visual contact with the test sample inside the chamber.

Finding such a plastic container was not easy. The requirement for it is good transparency. Despite all the accuracy and diligence in order to avoid possible scratches, the catch came from where it was least expected. A disposable plastic bag in which the container was located scratched the surface like an emery cloth with each touch of the fingers. Naturally, this is no good, since restoring the surface is already unrealistic.

Plus of such a box is a beautiful view, minus - shooting is possible only in the daytime with proper lighting. During operation, all fingerprints, scratches, unevenness of the walls of the plastic and the other list of minuses will make themselves felt. Observation of decays from above is generally not possible due to cataracts of the lid of the food container.



The way out is to order a semblance of a glass aquarium of the right size. With improvised means we remove all defects, clean, wash, polish and as a result we get a pretty decent camera. The external dimensions of the walls of which are 10 by 10 cm and a height of 12 cm.

On one side of the cube, you can see a centimeter technological cutout in the upper part, it is provided in advance for setting the backlight. It is implemented on seven super-bright white LEDs with a diameter of 3 mm, which are inserted into a plastic base. It is modeled in SolidWorks and printed on a 3D printer.

The visor was not initially provided, but it is necessary so that direct light does not fall into the lens of the camcorder. The overexposed frame against the background of the observed decays is very likely to be inaccessible.



Next, with a diamond crown, you need to drill two holes in the glass on the sides in the upper part of the chamber. This is done using a drill, high speeds and the addition of water. The glass may heat up at the point of friction and crack. Now we need it the least.

On the inside, at the places of the holes, glue the porous sponge. It is a section of the hard abrasive side of a kitchen washcloth. A style for every taste and color. In the future, it will be impregnated with alcohol and serve as a source of the very vapors that will condense at the bottom of the chamber. Through the holes it is convenient to refuel the camera with alcohol during operation.

It would seem that we have completed the main work and now we can start the installation, observing the decay of radioactive sources. Yes, noooh ... no!



For quality monitoring of the tracks you need to perform one important point.Namely, apply high voltage and charge the internal volume of the chamber with positive potential. To do this, a square frame is made inside and contact is brought out through pre-made holes. The frame is made of thin copper wire taken from twisted pair cores.

Here is a simple example of the effect of high voltage on camera performance. She entered the mode and works for a rather long time, but no decays are visible inside. We apply a high voltage, but something is burning inside, and after a couple of seconds the natural radiation background is quite clearly visible. A bunch of small particles fall into the condensation cloud and leave their mark. This effect is similar to a plane flying high in the sky. We do not see the plane, and a cloud of steam behind it can stretch for many kilometers showing the flight path.

As a source of high voltage during the experiments, you can use industrial units BV9-1.5, but it is unlikely that you will find it in free sale.
In the passport to the device there is an electrical circuit diagram, it is built on the basis of a simple push-pull generator with feedback. Let's try to repeat something similar in a more modern version.



On the open spaces of the World Wide Web, circuits of common ZVS generators have been walking for a long time, they are time-tested and do not require any special configuration. You can download the circuit diagram of such a device and Gerber board files here .For assembly, you need only a dozen parts that easily fit in one hand. The most expensive among them are power transistors, in this case it is IRFP250 or IRFP260, it all depends on the input voltage with which you are going to work. Capacitors took brands MKPH 0.33 microfarads, they are used in induction cookers.

A couple of hours of work in the EasyEDA program and at the output we get a compact device with the placement of all elements. Since not everyone knows how to etch printed circuit boards, their production for a nominal amount can be ordered in China .

For assembly, a circuit is not needed, since the mask indicates where and how all the components are located.Before installing transistors on a radiator, it is desirable to lubricate them with thermal grease, but as further practice will show, there will be absolutely no heating during operation. As a result of all the manipulations, we got a powerful, compact, two-stroke ZVS generator. The second name is Push-pull. With it, you can draw long hot arcs from lowercase transformers of domestic TVs.



Before proceeding to the next part, you need to wind the transformer.Marking TVS-110. We remove the primary coil and instead of it we wind with a thick wire 2 windings of 5 turns each with a tap from the middle. With the correct assembly of the high-voltage generator, its operation will look like this. When igniting the arc, the current consumption will be of the order of 2 Amperes at a supply voltage of 12 volts. As the arc increases, the current consumption will increase up to 10 amperes. The arc will be thick and white. You do not need to touch her fingers! By connecting the un9 / 27 multiplier to the output of the line driver, you can get high voltages up to many tens of kilovolts. The output voltage here directly depends on the input. The generator starts from a voltage of 8 volts and above.

For the lazy.In order not to build a vegetable garden, you can use a TDX type strobe from more modern TVs. There is already a voltage multiplier inside. The disadvantage is the output current, in TDKS it is very small.

Now consider the situation that you have all assembled, but the arc at the same time came out thin, blue and in general no. This is a sign of an improperly wound primary winding. It is important to observe the direction of winding in one direction. If wound incorrectly, then this mode of operation even at idle will lead to excessive current consumption. The power reactor, transistors and ferrite will heat up to unimaginable temperatures, more than a hundred degrees. Smoke will most likely go out of the circuit boards, and the insulation of the primary winding wire will turn into cheese from overheating. We figured it out.



After assembling the circuit at the output of the multiplier, we have a high voltage. It must be fed to a frame of copper wire at the top of the Wilson chamber.

What does it affect ?! Since the source of ionizing radiation in the chamber acts continuously, in the near future many ions will form inside the radioactive decay of the source, and the supersaturated alcohol vapor condenses on them creating a fog that interferes with the visual observation of the decays. The positive charge of the high-voltage generator attracts excess ions, improving the picture of the observed process.

It gets an interesting effect when the high-voltage generator is turned on.Inside the chamber, a kind of explosion forms, the nature of which resembles the work of atomic weapons with an epicenter from the center. After that, invisible tracks acquire a thin needle-like character, which is quite easy and simple to observe and study in the future. Thank you for explaining this effect to Zhenya Soloviev and Artem Becquerel.



Everything is ready for launch. In the process, the Peltier elements will be very hot and need to be cooled with high quality. Cold water will help us with this. About 5 liters are cooled in the refrigerator, and everything else is frozen in bottles in the freezer.
Here, beer bottles came in handy for me, double benefit, so to speak)

We place the submersible pump on one side of this ice pool, and on the other there will be a hose through which the water that has taken away heat from the system comes out. Having gone all the way through the ice bottles, it will return back to the pump and the process will be repeated until all the ice has melted in the bottles.



Time to fill the system with noble fluid. Ethanol from the pharmacy was used in the chamber. Many do not recommend using isopropanol, since its vapors react with various plastics, which as a result can lead to various unforeseen situations during operation. I did not check it myself.



So, the moment has come for which we are all gathered here.Turn on the installation. The backlight lights up and the pump starts pumping water through the cooling system. The camera enters the mode within 40 seconds, provided that the water temperature is about five degrees.

Due to the large flow of ionizing radiation, alcohol does not have time to condense on the tracks, which leads to an incomprehensible layer of fog in the central part of the source. The high voltage voltage of the generator does not help to get rid of this effect. At the top we see lonely traces of the strongest particles that could fly farthest. If there is an alpha source in the chamber, then its flow can be reduced with the help of foil and the hole made in it. So the picture looks much more beautiful.



The most amazing thing about this whole process is the observation of the decay of an ordinary natural background.It turns out there are so many that it is difficult to imagine. Dozens of different events are recorded every second in the camera.

Thin, curved tracks are traces of electrons (beta radiation). Thick bold tracks are alpha particles (helium nuclei). As for gamma radiation, they say that the camera is not able to register it.

I just wanted to check it, how something strange happened. One Peltier element has stopped working. The bottom 12 Volt module in the sandwich just took out of order out of the blue. I had to disassemble the installation, understand what the problem was and go to the store for a new element.



Now we need to get radioactive sources. It is desirable that you are not then locked up in places not so remote. Aliekspres will help us with this.

This is an ionization chamber for a smoke detector , it contains americium - 241. Alpha source. Sensitive mica sensor Radioscan 701 with the filter cover removed, shows approximately 7.7 Milliretgen conditionally.

When the temperature reaches below 35-40 degrees, the alcohol becomes supersaturated enough so that tracks of charged particles can be observed in it. In the central part, nothing is now visible, the vapor saturation in this place disappears due to the high intensity of the ionizing radiation source. The whole picture resembles a peacock feather, which gives more than 30,000 thousand decays per centimeter square per minute. I know how much more, since the Radioscan 701 with this measurement goes off the scale.

The physics of the appearance of tracks is due to the fact that an ionizing particle in its path leaves a trace of ions associated with the collision of an alpha particle or electron with the molecules of the gas that is in the chamber. The resulting ions ultimately act as centers of condensation of the supersaturated alcohol. The entire process of track formation is observed at about 3 millimeters above the level of the cooling surface. Everything is simple.



Thorium electrodes for welding WT-20 with a two percent content of radioactive thorium oxide - 232. It is alpha-radioactive with a half-life of only 14.05 billion years. The tracks arising from the decay of thorium are long and beautiful, and in rare cases a particle can fly through the entire chamber. We go further ...



Thorium oxide, as in the case of uranium buttons, is added in the production of glass.The Chinese on aliexpress sell the so-called scalar medallions , which supposedly endow you with some kind of positive energy. The medallion also glows in ultraviolet light and the maximum that is capable of ionizing your cells in the body, causing their premature death. The decay of radioactive thorium in my opinion the most beautiful for visual observation.



Dessert program.X-ray installation on the Soviet kenotron 2Ts2S. Year of release 1965. If you apply a sufficiently high voltage to it, this radio tube can serve as a source of x-ray radiation. At the same time, inside her glass container, one can observe a beautiful blue glow caused by the influence of high voltage. At strong x-ray levels, the glass bottle begins to glow green due to bremsstrahlung. The phenomenon is beautiful, but I recommend watching it only on the screens of your monitors.

Slowly raise the anode voltage on the lamp and at some point the entire bottom of the chamber is covered with small dots caused by low-energy x-rays. The higher the energy of a particle, the less its ionizing ability. At some point, the radiation energy grows and the interaction disappears. Only background tracks are visible, while levels at 40 centimeters from the kenotron reach 5 Millirentgen.

From practice. On the verge of breakdown by high voltage, such a tube gives more than one X-ray at a distance of 30 centimeters. These are the interesting experiments we have obtained. You can see all this and much more on our instagram page. There is always the latest news.



For reference.The shooting of this issue took almost 3 months. The cost of this Wilson camera with all unforeseen expenses cost about 150 bucks. It also includes power supplies and clamp meters with which we measured current. Knowing all the nuances and subtleties in this craft, you can easily assemble such an installation at home and watch with interest the phenomena that are usually not visible to the naked eye. Now you know what radiation looks like and what it is eaten with.

As Japanese wisdom says:
Fast is slow, but without interruption.


Full project video on YouTube
Our Instagram

More articles:


All Articles