An alpha particle is deflected by a magnetic field

Alpha radiation consists of helium-4 nucleus and is readily stopped by a sheet of paper. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. Beta radiation, consisting of electrons, is halted by an aluminium plate. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J Gamma radiation is eventually absorbed as it penetrates a dense material. Lead is good at absorbing gamma radiation, due to its density. Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly

Alpha decay

Alpha particles (named after and denoted by the first letter in the Greek alphabet, α) consist of two protons and two neutrons bound together into a particle identical to a helium nucleus; hence, it can be written as He²⁺ or ⁴₂He²⁺. The Greek alphabet (Ελληνικό αλφάβητο is a set of twenty-four letters that has been used to write the Greek language since the late 9th or early The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical They are a highly ionizing form of particle radiation, and have low penetration. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation Particle radiation is the radiation of Energy by means of fast-moving Subatomic particles. The alpha particle mass is 6. 644656×10^-27 kg, which is equivalent to the energy of 3. 72738 GeV. For other meanings see Giga (disambiguation Giga- (symbol G is a prefix in the SI system of units denoting 109 The charge of an alpha particle is equal to +2e, where e is the magnitude of charge on an electron, e=1. 602176462x10^-19C.

Alpha particles are emitted by radioactive nuclei such as uranium or radium in a process known as alpha decay. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Radium (ˈreɪdiəm is a radioactive Chemical element which has the symbol Ra and Atomic number 88 Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle This sometimes leaves the nucleus in an excited state, with the emission of a gamma ray removing the excess energy. Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός In contrast to beta decay, alpha decay is mediated by the strong nuclear force. In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and In classical physics, alpha particles do not have enough energy to escape the potential of the nucleus. However, the quantum tunnelling effect allows them to escape. In Quantum mechanics, quantum tunnelling is a nanoscopic phenomenon in which a particle violates the principles of Classical mechanics by penetrating a

When an alpha particle is emitted, the atomic mass of an element goes down by roughly 4. The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass 0015 u, due to the loss of 2 neutrons and 2 protons. The unified atomic mass unit ( u) or Dalton ( Da) or sometimes universal mass unit, is an unit of Mass used to express This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. The atomic number of the atom goes down by 2, as a result of the loss of 2 protons; the atom becomes a new element. See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton An example of this is when radium becomes radon gas due to alpha decay. Radon (ˈreɪdɒn is the Chemical element that has the symbol Rn and Atomic number 86

The energy of alpha particles varies, with higher energy alpha particles being emitted from larger nuclei, but most alpha particles have energies of between 3 and 7 MeV. This is a substantial amount of energy for a single particle, but their high mass means alpha particles have a lower speed (with a typical kinetic energy of 5 MeV the speed is 15,000 km/s) than any other common type of radiation (β particles, γ rays, neutrons, etc). Beta particles are high-energy high-speed Electrons or Positrons emitted by certain types of Radioactive nuclei such as Potassium -40 Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions Neutron radiation is a kind of Ionizing radiation which consists of Free neutrons Sources Neutrons may be emitted during either spontaneous Because of their charge and large mass, alpha particles are easily absorbed by materials and can travel only a few centimeters in air. They can be absorbed by tissue paper or the outer layers of human skin (about 40 micrometres, equivalent to a few cells deep) and so are not generally dangerous to life unless the source is ingested or inhaled. A micrometre ( American spelling: micrometer; symbol µm) is one millionth of a Metre, or equivalently one thousandth of a Millimetre Because of this high mass and strong absorption, however, if alpha radiation does enter the body (most often because radioactive material has been inhaled or ingested), it is the most destructive form of ionizing radiation. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation It is the most strongly ionizing, and with large enough doses can cause any or all of the symptoms of radiation poisoning. Radiation poisoning, also called " radiation sickness " or a " creeping dose " is a form of damage to organ tissue due to excessive exposure to It is estimated that chromosome damage from alpha particles is about 100 times greater than that caused by an equivalent amount of other radiation. A chromosome is an organized structure of DNA and Protein that is found in cells. The alpha emitter polonium-210 is suspected of playing a role in lung and bladder cancer related to tobacco smoking. Polonium ( Po) has 33 known isotopes, all of which are radioactive. Lung cancer is a Disease of uncontrolled Cell growth in tissues of the Lung. Bladder cancer refers to any of several types of malignant growths of the Urinary bladder. ^[1]

Most smoke detectors contain a small amount of the alpha emitter americium-241. A smoke detector is a device that detects Smoke and issues an Alarm. Americium (ˌæməˈrɪsiəm is a Synthetic element that has the symbol Am and Atomic number 95 This isotope is extremely dangerous if inhaled or ingested, but the danger is minimal if the source is kept sealed. Many municipalities have established programs to collect and dispose of old smoke detectors, rather than let them go into the general waste stream.

Because alpha particles occur naturally, but can have energy high enough to participate in a nuclear reaction, study of them led to much early knowledge of nuclear physics. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός In Nuclear physics, a nuclear reaction is the process in which two nuclei or nuclear particles collide to produce products different from the initial particles Nuclear physics is the field of Physics that studies the building blocks and interactions of Atomic nuclei. The physicist Ernest Rutherford famously used alpha particles to infer that J. J. Thomson's Plum pudding model of the atom was fundamentally flawed. Ernest Rutherford 1st Baron Rutherford of Nelson, OM, PC, FRS (30 August 1871 – 19 October 1937 was a New Zealand Physicist Sir Joseph John “JJ” Thomson, OM, FRS (18 December 1856 &ndash 30 August 1940 was a British Physicist and Nobel laureate The plum pudding model of the Atom by JJ Thomson, who discovered the Electron in 1897 was proposed in 1904 before the discovery of the atomic nucleus Rutherford's famous gold foil experiment was conducted by his students Hans Geiger and Ernest Marsden. Johannes (Hans Wilhelm Geiger ( September 30, 1882 &ndash September 24, 1945) was a German Physicist. Sir Ernest Marsden ( 19 February 1889 - 15 December 1970) was a English - New Zealand Physicist. A narrow beam of alpha particles was set up, passing through very thin (only a few hundred atoms thick) gold foil. The alpha particles were detected by a zinc sulfide screen, which emits a flash of light upon an alpha particle collision. Zinc sulfide (or zinc sulphide is a Chemical compound with the formula Zn[[Sulfur S]] Rutherford hypothesisized that, assuming the "plum pudding" model of the atom was correct, the positively charged alpha particles would be only slightly deflected, if at all, by the dispersed positive charge predicted. The plum pudding model of the Atom by JJ Thomson, who discovered the Electron in 1897 was proposed in 1904 before the discovery of the atomic nucleus It was found that some of the alpha particles were deflected at much larger angles than expected, with some even bouncing back. Although most of the alpha particles went straight through as expected, Rutherford commented that the few particles that were deflected was akin to shooting a fifteen inch shell at tissue paper only to have it bounce off, again assuming the "plum pudding" theory was correct. It was soon determined that the positive charge of the atom was concentrated in a small area in the center of the atom, hence making the positive charge dense enough to deflect any positively charged alpha particles that happened to come close to what was later termed the nucleus (it was not known at the time that alpha particles were themselves nuclei nor was the existence of protons or neutrons known). Rutherford's experiment subsequently led to the Bohr model (named for Niels Bohr) and later the modern wave-mechanical model of the atom. In Atomic physics, the Bohr model created by Niels Bohr depicts the Atom as a small positively charged nucleus surrounded by Electrons Niels Henrik David Bohr (nels ˈb̥oɐ̯ˀ in Danish 7 October 1885 – 18 November 1962 was a Danish Physicist who made fundamental contributions to understanding

Rutherford's work also improved on previous measurements of the ratio of an alpha particle's mass to charge, allowing him to deduce that alpha particles were helium nuclei. ^[2]

In computer technology, DRAM 'soft errors' were linked to alpha particles in 1978 in Intel's DRAM chips. In Electronics and Computing, an Error is a signal or datum which is wrong The discovery led to strict control of radioactive elements in the packaging of semiconductor materials, and the problem was largely considered 'solved'.

See Also

• beta particle
• cosmic rays
• list of alpha emitting materials
• nuclear physics
• particle physics
• radioactivity
• radioactive isotope
• radioactive decay
• rays:
  • γ (gamma) rays
  • δ (delta) rays
  • ε (epsilon) rays

kingsend

References

• Tipler, Paul; Llewellyn, Ralph (2002). Modern Physics (4th ed. ). W. H. Freeman. ISBN 0-7167-4345-0.