Alpha particles bombardment with

Fukaxawa, C.A. 47, 12483e (1953). Alpha particle bombardment with radon effects the conversion of kitol to vitamin A Embree, Shantz, foe. cit. U.S. pats. 2,414,458... 

Emilio Gino Segre (1905-1989 Nobel Prize for physics 1959), together with Dale Raymond Corson ( 1914) and Kenneth Ross Mackenzie ( 1912) obtained the element in tiny amounts by bombardment of bismuth with alpha particles. Halogen with no stable isotope. 

The production of artificially produced radioactive elements dales back to the early work of Rutherford in 1919 when it was found that alpha particles reacted with nitrogen atoms to yield protons and oxygen atoms. Curie and Joliot found (1933) that when boron, magnesium, or aluminum were bombarded with alpha particles from polonium, the elements would emit neutrons, protons, and positrons. They also found that upon cessation... 

Thermal neutrons in the reactor are efficient in producing ( , y) neutron capture reactions e.g. Fe (n, y) f< Fe. The products of these reactions will have an excess of neutrons and generally decay by (/ ", y) emission. The major disadvantage is that the radioactive atoms will always be diluted with many -non-radioactive atoms and chemical separation is not possible, (n, y) reactions are however usefully exploited in neutron activation analysis (p. 471). With fast neutrons, proton, deuteron or alpha particle bombardment a change in atomic number accompanies the.reaction and chemical separation of the carrier free radiotracer becomes possible,... 

The isotope Cm-"- is an alpha-particle emitter, with haU-life about 5 months. Another isotope of (urium has also been made. It is Cm-" made by bombarding plutonium, with high-speed helium ions ... 

In 1934, Irene Curie JoUot, daughter of Marie and Pierre Curie, and her husband, FredericJoliot, bombarded aluminum (Al) with alpha particles and observed neutrons and a positron. The Joliots discovered that when the flow of alpha particles striking the Al was stopped, the neutron emissions stopped, but the positron emissions continned. They reasoned that the alpha particles reacted with aluminum nuclei to produce phosphorus-30 nuclei, which then decayed to produce positrons. 

X-rays can be emitted from a sample by bombarding it with electrons, alpha particles, or with other X-rays. When electrons or alpha particles are used as the excitation source, the process is called X-ray emission or particle-induced X-ray emission (PIXE). This is the basis of X-ray microanalysis using an electron microprobe (Chapter 14) or an SEM. An alpha particle X-ray spectrometer (APXS) is currently on the Mars Curiosity rover collecting data on Martian rock composition. 

Astatine can be produced by bombarding bismuth with energetic alpha particles to obtain the relatively long-lived 209-211At, which can be distilled from the target by heating in air. 

Ernest O. Lawrence, inventor of the cyclotron) This member of the 5f transition elements (actinide series) was discovered in March 1961 by A. Ghiorso, T. Sikkeland, A.E. Larsh, and R.M. Latimer. A 3-Mg californium target, consisting of a mixture of isotopes of mass number 249, 250, 251, and 252, was bombarded with either lOB or IIB. The electrically charged transmutation nuclei recoiled with an atmosphere of helium and were collected on a thin copper conveyor tape which was then moved to place collected atoms in front of a series of solid-state detectors. The isotope of element 103 produced in this way decayed by emitting an 8.6 MeV alpha particle with a half-life of 8 s. 

The first radioactive isotopes to be made in the laboratory were prepared in 1934 by Irene Curie and her husband, Frederic Joliot They achieved this by bombarding certain stable isotopes with high-energy alpha particles. One reaction was... 

When bismuth-209 is bombarded with nickel-64, one neutron and a new isotope, X, is formed. The isotope then goes through a series of alpha particle emissions. 

The experiment conducted by Rutherford and his co-workers involved bombarding gold foil with alpha particles, which are doubly charged helium atoms. The apparatus used in their experiment is shown in Figure 14-9. The alpha particles are produced by the radioactive decay of radium, and a narrow beam of these particles emerges from a deep hole in a block of lead. The beam of particles is directed at a thin metal foil, approximately 10,000 atoms thick. The alpha particles are delected by the light they produce when they collide with scintilltaion screens, which are zinc sulfide-covered plates much like the front of the picture tube in a television set. The screen... 

Glenn Theodore Seaborg (1912-1999), together with Stanley Gerald Thompson (1912-1967) and Albert Ghiorso ( 1915). The bombardment of americium-241 with alpha particles led to element 97 with atomic mass number 243. The enrichment involved chemical methods, as the properties of the element were assumed to be analogous to those of the lanthanides. 

Name named after California, where Cf was first produced at the University of Berkeley by bombardment of Curium with alpha particles. 

It is known that 10B collects in brain tumors to a greater extent than in normal tissue. Research has been conducted on the use of the isotope 10B for treating brain tumors. Bombardment of the tumor with slow neutrons leads to the production of alpha particles (4He2+) and lithium nuclei that have enough energy to destroy the abnormal tissue. 

D—This was determined by bombarding gold foil with alpha particles. 

Astatine - the atomic number is 85 and the chemical symbol is At. The name derives from the Greek astatos for unstable since it is an unstable element. It was first thought to have been discovered in nature in 1931 and was named alabamine. When it was determined that there are no stable nuclides of this element in nature, that claim was discarded. It was later shown that astatine had been synthesized by the physicists Dale R. Corson, K. R. Mackenzie and Emilio Segre at the University of California lab in Berkeley, California in 1940 who bombarded bismuth with alpha particles, in the reaction Bi ( He, 2n ) "At. Independently, a claim about finding some x-ray lines of astatine was the basis for claiming discovery of an element helvetium, which was made in Bern, Switzerland. However, the very short half-life precluded any chemical separation and identification. The longest half-life associated with this unstable element is 8.1 hour °At. 

In 1932 James Chadwick (1891—1974) bombarded beryllium with alpha particles (helium nuclei) that produced free neutrons. Since then, this nuclear process has made beryhium a reliable neutron emitter for laboratory nuclear research. Beryhium is not only an excellent moderator to slow down high-speed neutrons in nuclear reactors, but it also can act as a... 

There is no natural curium on Earth. All of its isotopes are man-made and artificially produced through nuclear reactions with other elements. The curium isotope Cm-242 was first produced by bombarding plutonium-239 with helium nuclei (alpha particles), which contributed neutrons that changed Pu to g Cm. 

The pure metal of berkelium does not exist in nature and has never been directly artificially produced, although the first isotope of berkelium produced was berkelium-243. It was artificially formed by bombarding americium-241 with the nuclei of helium (alpha particles), as follows " Am+lalpha particle = 2 protons + 2 neutron)—> Bk. (Note Two protons as well as two neutrons are found in the nucleus of helium, and thus the two protons changed the atomic number of americium [ jAm] to berkelium [j Bk].) Today a different process is used to produce berkelium in small amounts, as follows Cm+(5n = neutrons X = gamma rays) —> (becomes) —> Bk + P- = (beta-minus decay). 

In addition, some atoms of Unq-258 were produced by the same reaction, and Unq-261 was produced by bombarding isotopes of curium-248 with oxygen-18, as follows gCm-248 + gO-18 —> jj, Unq-261 + 5 alpha particles. 

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