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Cosmic thesaurus

Bremsstrahlung​

Radiation produced when electrical charges are slowed down. When quick electrons interact with matter, part of their energy is converted into electromagnetic radiation in the form of bremsstrahlung (braking radiation). The fraction of energy converted into "bremsstrahlung" increases with the electron energy and is greater the greater the atomic number of the material that makes up the absorbing medium. [Source: Radiation Detection and Measurement, Glenn F. Knoll - issue 3rd3^{rd}]

Calorimeter​

A calorimeter measures the energy that a particle loses as it passes through its volume. Generally, the calorimeter is designed to completely stop or “absorb” most particles from a collision, forcing them to deposit all their energy within the detector, thus measuring their total energy. Calorimeters have to perform two different tasks at the same time – stopping particles and measuring energy loss – so they usually consist of layers of different materials: a “passive” or “absorbent” high-density material (e.g. lead) interspersed with an “active” medium such as plastic scintillators or liquid argon.

Electromagnetic calorimeters measure the energy of electrons and photons as they interact with electrically charged matter particles. Hadronic calorimeters sample the energy of hadrons (quark-containing particles such as protons and neutrons) as they interact with atomic nuclei. Calorimeters can stop most known particles except muons and neutrinos. Adapted from Science at CERN: How a detector works

Scintillator​

Material that emits light scintillations when struck by a charged particle or high-energy photon. There are a variety of scintillator materials (organic, inorganic, gaseous), and your choice depends on the intended application.

A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier (SiPM). PMTs absorb the light emitted by the scintillator and re-emit it in the form of electrons through the photoelectric effect. The subsequent multiplication of these electrons (sometimes called photoelectrons) results in an electrical pulse that can be analyzed providing significant information about the particle that originally reached the scintillator. Sources: Wikipedia, Radiation Detection and Measurement, Glenn F. Knoll - 3rd3^{rd} edition

Coincidence​

We use the term coincidence when several events occur within a small temporal or spatial distance. The invention of the coincidence circuit, awarded with the Nobel Prize in Physics, was the basis of many important discoveries. In experiments with particles and astroparticles, the coincidence method helps to minimize errors or filter out special events. To achieve this, a causal relationship must be known between the simultaneous occurrence of signals and the physical phenomenon to be observed.

For example, for our Cosmic experiment if we have the detectors connected in coincidence, an output signal will only be generated when each detector registers an input signal within a small previously defined time interval. The basic assumption is that the cosmic ray muons to be observed have enough energy to penetrate several detectors and each produces a signal. Since these muons move at nearly the speed of light, input signals occur in very short time intervals to the detectors. Moreover, many low-energy phenomena can trigger a signal in one detector but not in several. However, such events occur randomly, without any time connection. Consequently, the output signal from coincidentally connected detectors is much more likely to come from a muon than any other phenomenon.

Decay​

It is the spontaneous process by which an unstable subatomic particle transforms into several other particles. The particles created in this process (final state) must each be less massive than the original, although the total invariant mass of the system must be conserved. A particle is unstable if there is at least one allowed final state into which it can decay. Unstable particles often have multiple ways of decaying, each with its associated probability. Decays are mediated by one or more fundamental forces. Particles in the final state may be unstable and subject to further decay.

The π\pi meson (or pion) composed of an anti-quark quark is a good example of an unstable particle. Charged pions π+\pi^{+} and π−\pi^{-} transform after an average lifetime of 2.6×10−82.6\times10^{-8}s). Charged pions decay into muons (μ\mu) and muon neutrinos (νμ\nu{\mu}) and neutral pions decay into photon pairs. Source: Particle Data Group

Furthermore, radioactive decay is the process in which an unstable atomic nucleus is transformed into a lighter nucleus accompanied by the emission of particles or radiation. Source: Wikipedia

Trace detector​

In particle physics, tracking is the process of reconstructing the trajectory (or track) of electrically charged particles in a track detector. Particles that penetrate the volume of the trace detector leave a record of their passage through interaction with the material of the detector components. The presence of a magnetic field in the entire detector, or part of it, allows the momentum of the electrically charged particle to be obtained directly from the local curvature of the reconstructed trajectory.

In the LHC's trace detectors, particle trajectories are not directly visible but are recorded as tiny electrical signals that particles fire as they pass through the detector. Then, an algorithm reconstructs the recorded trajectory patterns. The muon, for example, barely interacts with matter - it can travel through meters of dense material before being stopped. For this reason, muon chambers—specialized tracking devices for detecting muons—often make up the outermost layer of a detector (like the LHC's ATLAS). Adapted from: Science at CERN: How a detector works

Stratosphere​

The stratosphere is characterized by air movements in a horizontal direction. Its base is located between 7 and 17 km from the surface and its top is approximately 50 km above sea level, being the second layer of the atmosphere – between the troposphere and the mesosphere. The temperature increases with height (from −50to10∘-50 to 10^{\circ}C). It has a small concentration of water vapor and a constant temperature close to the border region, called stratopause. Many jet planes fly in the stratosphere because it is very stable. It is in this layer that the diffusion of sunlight begins (which creates the blue sky). Source: Wikipedia.

eV (electron volt)​

Unit of energy measurement equivalent to 1.60217733(49)×10−191.602 177 33 (49)\times 10^{-19} joules. By definition, an electron volt is the amount of kinetic energy gained by a single electron when accelerated by an electrical potential difference of one volt (1 V), in a vacuum. Source: Wikipedia

Photon​

Carrying particle of the electromagnetic interaction force (see guide "The Standard Model of particle physics").

Ion​

An ion is an atom with one or more electrons removed (positive ion) or added (negative ion).

ionization​

The process by which an atom or molecule loses or gains electrons to form ions.

Isotope​

Slightly different versions of the same element, differing only in the number of neutrons in the atomic nucleus – the number of protons is the same.

Relativistic​

Concerning relativity or phenomena that occur at speeds close to the speed of light in a vacuum.