Nuclear Physics

The familiar alpha particle scattering by thin gold foil experiment has given evidence for the existence of hard nucleus at the central region of the atom. The relevent interpretation was given by Rutherford.

O-15 is the nuclear symbol for oxygen-15, which has 8 protons and 7 neutrons. It is a radioactive isotope of oxygen often used in medical imaging studies.

The matter that is "consumed" is converted into energy, according the the equation E=mc2.

The original matter mostly becomes the final matter, though a small amount is converted into heat. The amount converted into heat is small enough however, that the larger subatomic particles are all accounted for.

We could take as an example a fusion reaction in which a deuterium atom and a tritium atom are fused into helium. Deuterium and tritium are both isotopes of hydrogen, 2H and 3H respectively. The 2H nucleus consists of one proton and one neutron. The 3H nucleus consists of one proton and two neutrons. Each atom also has one electron. The total before fusion is two protons, two electrons, and three neutrons.

After the fusion takes place, the product is one helium atom, of the isotope 4He, plus one free neutron. The 4He atom has two protons and two neutrons, plus two electrons. Thus, the total of particles after fusion is two protons, two electrons, and three neutrons. In this case, however, the helium atom and the neutron are both very, very hot.

So the number of protons, neutrons, and electrons is the same after the reaction as it was before.

The equation on converting between energy and mass is E=mc2, as you know. The amount of energy released in the fusion example above is the difference between the mc2 before the reaction and the mc2 after the reaction. While this difference in mass is so small that it is not reflected in the counts of large subatomic particles, it is nonetheless there.

The masses, in Atomic Mass units, of the atoms and the neutron are:

at the beginning

2H - 2.014102

3H - 3.016049

which add to 5.030151

at the end

n - 1.008665

4He - 4.002602

which add to 5.011267

so the difference between the masses before and after the reaction is 0.018884 atomic mass units, which represents the amount of mass converted into energy in the reaction.

Gamma rays were not really "invented" by any one person. They are a form of electromagnetic radiation that exists naturally in the universe. Their discovery is credited to French scientist Paul Ulrich Villard in 1900.

When an atom releases both an alpha and a beta particle, it transforms into a different element with a lower atomic number. This process is known as double beta decay. The atom undergoes nuclear transmutation to achieve a more stable configuration.

Americium is a manufactured element that is not found in nature. The radioactive metal was created at the University of Chicago Metallurgical Lab (now the Argonne National Laboratory) in 1944 by American (hence, the name) scientists Glenn Seaborg, Ralph James, Leon Morgan and Albert Ghiorso, through a process of bombarding plutonium with high energy electrons until it changes form several times, then using beta decay to achieve the final result.

Americium is used in smoke detectors, and is also a source of gamma rays, but has few other practical applications.

Americium

Atomic No: 95
Atomic Weight: 243

Periodic Table: 7
Classification: Metal
Group: Actinide

Half-Life: 432.2 years

Decays into neptunium-239 by alpha decay.


Answer

Americium was first obtained by Glenn T. Seaborg, Leon O. Morgan, Ralph A. James and Albert Ghiorso in 1944 (University of Chicago) as a result of some nuclear reactions: Pu 239----(n,gamma)---Pu 240-----(n,gamma)--- Pu 241---- beta rays---- Am 241

Glenn T. Seaborg in 1944 with his team at the university of California at Berkley.

If we are dating a substance on unknown age, no, this is because, we are assuming we know how much substance was initially present, also we assume there has been no contamination, lastly we assume the decay rate has always been the same.

In a reactor, or atomic bomb, uranium 235 (for example) will not always split into the same kinds of atoms; rather, different kinds of waste products can be produced. Some of them will decay faster, some slower. The real problem is with products that have a half-life of a few decades or centuries. If a product (like uranium itself) has a half-life of billions of years, the radiation it gives off will not be very significant. If on the other hand a product has a half-life of days - well, the radiation will be very strong, but after a few weeks not much is left. However, part of the nuclear waste can remain for decades or centuries, and still give off a significant amount of radiation. No specific timeframe can be given - if (say) a certain isotope has a half-life of 50 years, that means that after 50 years, half of the substance will be left; after another 50 years, a quarter of the original substance, etc. It will not suddenly disappear at a certain moment; but after several times the half-life, the amount left will be insignificant. On the other hand, the by-products of this decay can again be other radioactive isotopes.

Through acceleration.

Gravity and acceleration are equivalent: they're each associated with a force that's proportional to the mass of the object. Amusement parks take advantage of this in "virtual reality" theaters: they simulate acceleration with gravity, by rocking the seats backward or forward to simulate speeding up or slowing down. Artificial gravity in space is the converse: simulating gravity with acceleration.

Acceleration can be linear or centripetal.

Continuous linear acceleration requires continuous energy input. The kinetic energy is proportional to the velocity squared. It's prohibitively expensive and doesn't allow you to stay any place for very long -- including near-earth orbit.

Centripetal acceleration is acceleration toward a center point -- it changes the direction of motion but not the tangential speed. Everything that rotates experiences "artificial gravity." That's why curves in roads -- especially high-speed race tracks -- have to be banked. For an object spinning in space without friction, it takes energy to start and stop the rotation, but it doesn't take any energy to sustain a constant rotation. Conservation of momentum keeps the object spinning. Constant centripetal acceleration (through rotation) is much more sustainable than constant linear acceleration, and it also allows the spinning thing to remain in orbit around the Earth or Sun or other planet.

You can find an artificial-gravity calculator on-line at: http://www.artificial-gravity.com/sw/SpinCalc/

You can find more information at: http://www.artificial-gravity.com/

Alpha and beta particles are the same in that changes in unstable atomic nuclei can release alpha particles or can beta particles (depending on the isotope involved), and both are forms of particulate radiation.

An isotope with a short half life is not necessarily more dangerous than one with a longer half life. For example, we can compare 99mTc, with a half life of about 6 hours, with 228Rn, with a half life of about 6 years.

99mTc decays, emitting a low energy gamma ray, to produce 99Tc. This is also radioactive, and emits low energy beta particles, but its half life is about 211,000 years, and its product is not radioactive. 99mTc is a synthetic isotope used for a variety of medical diagnostic purposes.

228Rn is the radon gas many people have in their basements. Since it is a gas, it can decay in a person's lungs, producing a chain of 9 radioactive isotopes, each decaying to produce the next in turn, and each of elements normally found as solids, so they probably remain in the lungs. The longest lived of these isotopes has a half life of less than two years, and the second longest lived has a half life of less than four days. So if radon decays in a person's lungs, the remainder of the decay chain will probably happen in that person's lungs during that person's lifetime.

Clearly 99mTc, with a half life of 6 hours, is much less dangerous than 228Rn, with a half life of 6 years.

Alpha particles have the least penetrating power compared to gamma rays and beta particles. This is because alpha particles are heavier and more positively charged, which makes them easily absorbed by materials, including skin.

ADM300's are rugged and reliable and designed for use in harsh environments. With built-in GM detectors, a standard ADM300 will detect measure, and digitally display both dose and dose rate levels of gamma radiation from 10 μR/hr to 10,000 R/hr (0.1 μSv/hr to 100 Sv/hr) and beta radiation from 10 μR/hr to 5 R/hr (0.1 μSv/hr to 0.05 Sv/hr).

Gamma rays are a form of electromagnetic radiation, and therefore travel at the speed of light.

This would require an extremely massive gravitational field, i.e. an extremely massive object, on the scale of stars.

The same goes for beta particles; electrons and positrons, who already travel at nearly the speed of light due to their low mass.

Alpha particles, however, due have some mass, and therefore travel at only 5% the speed of light, still fast enough to escape the Earth, but not fast enough to be affected by larger planets, perhaps.

Yes, electrons have a mass, as everything has mass. However, an electron's mass is so small that it is considered to be 0.

The mass and size of an alpha particle compare with the masa and size of beta particle in the sense that the alpha particle is significantly larger in both size and mass that the beta and gamma particles. This is why it is called the alpha particle.

A beta particle is an electron, this has a mass much less than a proton or neutron and so was can use zero in most situations.

However in some calculations for mass defect of whole atoms and Q-value calculations in nuclear decays it can become important, in these calculations.

An electron has a mass of 511 keV/(c^2), and an AMU is 931 MeV/(c^2).

So, dividing the electron mass by the AMU mass, we get the mass of the beta in AMU:

511/931000 = 0.00055 AMU.

Applications of plutonium:

• explosive in nuclear weapons

• nuclear fuel in nuclear power reactors

• the isotope 238Pu is used as energy source in spacecrafts or other applications (radioisotope thermoelectric generators)

• neutron generator, as Pu-Be source

The charge to mass ratio of an electron is approximately -1.76 x 10^11 coulombs per kilogram. This means that electrons have a very small mass compared to their charge. This value was first measured by J.J. Thomson in his experiments with cathode rays.

No, radioactive decay is not a chemical reaction. Radioactive decay is a type of change in the nucleus of an atom that results from instability in that nucleus. And that is a nuclear reaction rather than a chemical one.

The binding energy (Strong Atomic Force) released is much greater when fusion occurs than when fission occurs. As an example, that is why fission bombs typically have yields around 100 to 500 kilotons of equivalent TNT, while fusion bombs typically have yields in the 25 to 50 megaton range. The problem is that fusion requires a lot of energy to initiate - in fact, most fusion bombs use a fission bomb to set them off.