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Flashcards in Nuclear And Particle Physics ! Deck (26)
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The proton number and nucleon number.

Proton number is the number of protons inside the nucleus of particular atom. Aka atomic number.
Nucleon number is the number of nucleons (protons and neutrons) inside the nucleus of s particular atom. Aka mass number.
Atoms of the same element which contain the same number of protons but can have varying numbers of neutrons are called isotopes.


The strong nuclear force

Acts between nucleons and holds the nucleus together against the electrostatic repulsion of the protons.


Fundamental particles

Are particles that cannot be broken down into smaller components



Are particles consisting of a combination of quarks to give a net zero or whole number charge. Neutrons and protons are hadrons.



Are fundamental particles; electrons and neutrinos are leptons.



Are components of hadrons, and have a fractional electric charge. To date, believed to be fundamental particles. Different types of quarks: up, down and strange.



A fundamental particle (lepton) with almost no mass and zero charge. Each neutrino has an antimatter partner, called an antineutrino.


The weak nuclear force

Is felt by both quarks and leptons. It can change quarks from one type to another or leptons from one type to another and is responsible for beta decay.



Is a particle of antimatter that has the same rest mass (mass at zero speed) but, if changed, the equal and opposite charge to its corresponding particle. For example, the positron (e+) anti of electron.


An alpha-particle

Is a particle comprising two protons and two neutrons ejected from the nucleus during radioactive decay. It is identical to a helium nucleus and is emitted due to its unusually high stability as a particle.


A Beta-particle

Is a high-speed electron emitted from the nucleus during beta decay. It is produced when a neutron changes into a proton.



Is a form of electromagnetic wave with wavelengths between 10^-16 and 10^-9 m. Emitted from the nucleus during gamma decay.


Beta-minus decay. Also mention the quark transformation and charge!

A neutron in the nucleus breaks down into a proton under the influence of the weak nuclear force, and a beta-minus particle and an electron antineutron are emitted. A beta- minus particle is an electron.
0 0 _
d —> u + e + v
-1 0
-1/3 —> (2/3 + -1 +0) = -1/3


Beta-plus decay. Also mention the quark transformation and charge!

A proton in the nucleus breaks down into a neutron under the influence of the weak nuclear force, and a beta-plus particle and an electron neutrino are emitted. A beta-plus particle is a positron.
0 0
U —> d + e + v
+1 0
2/3 —> (-1/3 +1 +0) = 2/3


Activity, A

Is the number of nuclear decays (the number of gamma rays emitted) per unit time. Measured in becquerel (Bq)


The decay constant, lander

Is the probability that an individual nucleus will decay per unit time. Given by lander=A/N, (s^-1).


Half-life, t1/2

Is defined as the mean time taken for the activity, A of a source, or number of undecayed nuclei present, to halve.


Carbon dating

Is the technique used to determine the age of organic matter from the relative proportions of the carbon-12 and carbon-14 isotopes that it contains, using the half-life of carbon-14.



Is the process in which a particle and its antiparticle interact and their combined mass is converted to energy via E = mc^2.


Pair production

I the process of creating a particle-antiparticle pair from a high-energy photon.


Mass defect

Is the difference in mass between the mass between the mass of a nucleus and the total mass of its separate nucleons.


The binding energy of a nucleus

Is the minimum energy required to separate the nucleus (protons and neutrons) into its constituent parts.


Induced nuclear fission

Occurs when a nucleus absorbs slow-moving neutrons and the resulting unstable nucleus undergoes a fission reaction to split into smaller number of neutrons, releasing energy.


Chain reaction

Is the sequence of nuclear reactions produced when an induced nuclear fission reaction triggers more than one further fission reaction.


Control rod

Is a rod that can be lowered into the core of a nuclear reactor, absorb neutrons and slowdown the chain reaction. Control rods are usually made of boron.



Is a substance used in a nuclear reactor which slows down neutrons so that they have a greater chance of being absorbed by the fissile nuclear fuel. The moderator is usually made of graphite.