Alpha particles are groups of two protons and two neutrons i. e. helium nuclei. Alpha particles create shorter and thicker tracks in a cloud chamber. Rays of alpha particles are called alpha radiation. It is the least penetrating kind of radiation; it can be stopped by a sheet of paper or even a few metres of air.
Natural sources of alpha radiation are, for example, uranium, radium or radon. Radon-222 isotope is known for its potential to cumulate in buildings, since it is often naturally released from Earth’s crust. An example of an artificial source of alpha radiation is the americium-241 nuclide of the element americium, which does not exist naturally.
Various thin, twisted or straight cloud tracks are formed by electrons. Length and shape of an electron track, depends on the energy of the incoming electron. High energy electrons form straight lines, electrons with lower energy easily change their direction when colliding with molecules of isopropyl alcohol. Electrons displayed in a cloud chamber have their origin in both radioactive transformations that happened on earth, and in secondary cosmic radiation. A ray of electrons is called beta minus radiation. Beta radiation is more intense than alpha radiation; it can be effectively blocked by about 1 mm thick slab of lead.
Positron is the first discovered particle of antimatter; it is the antiparticle of an electron. Its track is identical to the electron one. Tracks of these particles can be distinguished only when the cloud chamber is placed into a magnetic field. This causes the tracks of electrons and positrons to bend in the opposite directions due to opposite charge. After all, this is how the positron was observed by Carl Anderson in 1932, who received a Nobel Prize in physics for this discovery. Observed positrons originate from the cosmic radiation or from the natural radioactive decay on Earth. Rays of emitted positrons are called beta plus radiation.
An example of a natural source of beta plus radiation is potassium-40, which happens to be contained in significant amounts in bananas. Consumption of one banana represents a dose equivalent to about 1 % of an average daily dose of natural radiation. We can encounter positrons in medicine as well, specifically in Positron Emission Tomography (PET). It is a diagnostic method, which can visualise only desired tissue. This method is based on introduction of radiopharmaceuticals, into the body of a patient. These radiopharmaceuticals are sources of beta plus radiation, i. e., emitters of positrons. Escaping positrons annihilate with electrons in atoms of human body while creating photons. Consequently, the detector registers these photons and calculates the position of annihilation. It is also possible to identificate annihilation of positron and electron in a cloud chamber from the characteristic appearance of their tracks.
Thick tracks that often extend over the whole area of a cloud chamber belong to protons, particles that make atomic nuclei. These protons originate in cosmic radiation. Proton tracks can vary in length from the whole width of the chamber all the way to a dot – depending on the angle at which the proton enters the cloud chamber. Protons are also used in medicine, specifically in radiotherapy. In proton therapy accelerated protons are used to irradiate ill tissue; specifically tumours and carcinomas. Proton therapy is an example of a real life application of, originally, a research device. Protons are accelerated using a particle accelerator called cyclotron.
Muons are created by interaction of cosmic rays with the atmosphere and penetrate all the way to the Earth’s surface, where we can observe them e. g. in a cloud chamber. We can observe muons in spite of their short lifetime due to time dilation, one of the effects described by the special theory of relativity. Muons move towards ground at a speed close to the speed of light and thus can arrive before they decay.
Thus, if you see a cloud track in a cloud chamber similar to electron, but completely straight due to large speed, it may very well be a muon!
Cosmic radiation are rays of particles coming at high speed from space and hitting the Earth’s atmosphere. There, a creation of secondary cosmic radiation occurs during interaction with molecules of air. We can clearly distinguish cosmic radiation in a cloud chamber, because air showers take form of several cloud tracks oriented in the same direction and arriving at the same time. Particles of cosmic radiation originate mainly in the Sun but also in the interstellar or even intergalactic space.
During a fly-by of a relatively heavy particle with high energy, it is possible to observe tracks of delta ray radiation. These tracks are electrons which are ripped from molecules of isopropyl alcohol by heavy particles like protons. In the cloud chamber, we can then see a straight track of a proton surrounded by thin tracks of electrons. These escaping electrons are called the delta ray electrons.
Gamma radiation is not directly visible in a cloud chamber because it is an electromagnetic wave radiation and not a ray of charged particles. However, it is possible to compensate for this partially. By bringing a source of gamma radiation close to the glass of a cloud chamber, electrons are ripped from glass molecules and shot inside the chamber. Consequently, we can observe these electrons in the cloud chamber.
V-shaped tracks are created by two alpha particles, which were emitted within a very small region of space. When radon-220 is present in the cloud chamber, we can see its decay to polonium-216 followed by an almost immediate decay to lead-212. These two decays can be detected as V-shaped tracks of two alpha particles originating from the same point. Radon-220 can be injected into the observation area using the interactive Radon module button.
Nuclear half-life is a time interval needed for a half of the particles to decay. In a cloud chamber we can demonstrate this phenomenon using radon-220 and its characteristic V-shaped tracks. After injecting radon-220 into the observation area of the chamber, we observe the maximum frequency of V-shaped tracks. Radon-220 has half-life of one minute. Therefore, after this interval, we observe a half of the initial V-shaped track frequency. If we wait another minute, another half-life interval, we measure a quarter (a half of a half) of the initial frequency. Radon-220 can be injected into the observation area using the interactive Radon module button.
Thorium series is one of the four basic decay chains in nature. These chains are known series of decays of common radioactive elements, their transformations to new elements and the radiation they emit.
In a cloud chamber we can observe a part of the thorium series after injection of radon-220. Radon-220 decays to polonium-216 that almost immediately decays to lead-212. Since both of these transformations produce alpha particles, thick, V-shaped tracks are observed. Radon-220 can be injected into the observation area using the interactive Radon module button.
Apart from the background radiation, ionising radiation can also be observed by placing an artificial radiation source into the observation area of the cloud chamber. An example of an artificial source of alpha particles (alpha radiation) is americium-241. Upon insertion of a sample, we can observe outgoing tracks of alpha particles. An artificial source of alpha radiation (americium-241) can be robotically inserted into the observation area using the interactive Radionuclide module.
Apart from the background radiation, ionising radiation can also be observed by placing an artificial radiation source in the observation area of the cloud chamber. An example of a source of electrons (beta radiation) is strontium-90. Upon insertion of a sample, we can observe numerous long thin tracks of electrons resembling a radial fan. An artificial source of electrons (e. g. strontium-90) can be robotically inserted into the observation area using the interactive Radionuclide module.
Pions are particles consisting of a pair of elementary particles – quarks “u” and “d”. They always contain one quark and one anti-quark. In a cloud chamber we can observe tracks only of the charged pions. Tracks of pions are very similar to electron tracks and thus are very difficult to distinguish from each other. It is possible only by inspection of the propagation of their tracks. Pions originate in the secondary cosmic radiation that is created in the upper part of atmosphere by interaction of the primary cosmic radiation with molecules of air.
Kaons are particles consisting of a pair of elementary particles – one quark “s” and one of the quarks “u” and “d”. They always contain one quark and one anti-quark. In a cloud chamber, we can distinguish kaons from other particles only by observing their decay into pions. Kaons were discovered in cloud chamber photographs in 1947 during cosmic-ray air shower research. They originate in the secondary cosmic radiation that is created in the upper part of atmosphere by interaction of the primary cosmic radiation with molecules of air.
In a cloud chamber it is possible to observe a decay by weak interaction of muons into electrons. This decay is clearly visible in the track propagation. A thicker muon track suddenly sharply breaks and becomes thinner – a muon has decayed and a thinner track of an electron is observed. The rest of resulting particles – muon neutrino and electron antineutrino – is not charged and thus cannot be observed in a cloud chamber.
Annihilation occurs when a particle meets its antiparticle. The best-known example is annihilation of an electron and a positron, which creates two gamma photons. In a cloud chamber we observe this phenomenon as two thin tracks which end at the same point. Gamma photons are not observable in a cloud chamber since they do not carry any electrical charge. It is also possible to encounter this phenomenon in the opposite order i. e. a gamma photon decomposes creating an electron-positron pair.
The first ultra-high energy particle, which had energy comparable with a kinetic energy of a flying football balloon, was observed in 1991. This particle must have come from space, but its exact origin has not been explained yet. The Oh-My-God particle resembles a high-speed proton in its properties. Theoretically it is possible to observe such particle in a cloud chamber, but only a few such particles have been recorded to date.
Nuledo Cloud Chambers are manufactured with the highest precision and care for maximum satisfaction of our customers. However, our duty does not end in the manufacturing hall.
A professional team of the Nuledo company will deliver your Nuledo Cloud Chamber directly to the exhibition place, install it and train the demonstrators in its operation. All functions of the Nuledo Cloud Chamber will be demonstrated.
The price of shipping and installation depends on the final location and is not included in the price of the device. Contact us for a price offer.