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Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics , which studies the atom as a whole, including its electrons .
For an axially symmetric shape with the axis of symmetry being the z axis, the Hamiltonian is = + (+) ( ). Here m is the mass of the nucleon, N is the total number of harmonic oscillator quanta in the spherical basis, is the orbital angular momentum operator, is its square (with eigenvalues (+)), = (/) (+) is the average value of over the N shell, and s is the intrinsic spin.
The nuclear shell model is partly analogous to the atomic shell model, which describes the arrangement of electrons in an atom, in that a filled shell results in better stability. When adding nucleons ( protons and neutrons ) to a nucleus, there are certain points where the binding energy of the next nucleon is significantly less than the last one.
If the nucleus is assumed to be spherically symmetric, an approximate relationship between nuclear radius and mass number arises above A=40 from the formula R=R o A 1/3 with R o = 1.2 ± 0.2 fm. [6] R is the predicted spherical nuclear radius, A is the mass number, and R o is a constant determined by experimental data.
The first nuclear explosive devices provided the basic building blocks of future weapons. Pictured is the Gadget device being prepared for the Trinity nuclear test. Nuclear weapons design are physical, chemical, and engineering arrangements that cause the physics package [1] of a nuclear weapon to detonate. There are three existing basic design ...
The decay scheme of a radioactive substance is a graphical presentation of all the transitions occurring in a decay, and of their relationships. Examples are shown below. It is useful to think of the decay scheme as placed in a coordinate system, where the vertical axis is energy, increasing from bottom to top, and the horizontal axis is the proton number, increasing from left to right.
The liquid drop model is one of the first models of nuclear structure, proposed by Carl Friedrich von Weizsäcker in 1935. [5] It describes the nucleus as a semiclassical fluid made up of neutrons and protons, with an internal repulsive electrostatic force proportional to the number of protons.
The nuclear force is a close-range force (it is strongly attractive at a distance of 1.0 fm and becomes extremely small beyond a distance of 2.5 fm), and virtually no effect of this force is observed outside the nucleus. The nuclear force also pulls neutrons together, or neutrons and protons. [11]