Alpha particle Aluminum

Alpha carbon atoms, 348 Alpha decay, 417, 443 Alpha particle, 417 scattering, 245 Aluminum boiling point, 365 compounds, 102 heat of vaporization, 365 hydration energy, 368 hydroxide, 371 ionization energies, 269, 374 metallic solid, 365 occurrence, 373 properties, 101 preparation, 238. 373 reducing agent, 367 Alums, 403 Americium... 

But none of the experiments succeeded. Rutherford and Chadwick came close. They probably produced neutrons when they performed an experiment in which they bombarded aluminum with alpha particles. However, they saw nothing. In those days, neutral particles were hard to detect. Protons and electrons, which were electrically charged, could be manipulated with magnetic and electric fields. Neutrons couldn t. 

Since the Joliot-Curies believed that a similar capture of the alpha-particle, with formation of an isotope of phosphorus, had occurred during the bombardment of the aluminum, they treated a piece of irradiated aluminum with hydrochloric acid. The liberated hydrogen carried with it the new activity, probably in the form of phosphine, leaving the aluminum residue inactive. The nuclear reaction which took place during the bombardment was therefore as follows ... 

Beta particles are normally faster than alpha particles and not as easy to stop. For this reason, they are able to penetrate light materials such as paper and clothing. They can penetrate fairly deeply into skin, where they have the potential for harming or killing cells. They are not able to penetrate deeply into denser materials, however, such as aluminum. Beta particles, once stopped, become part of the material they are in, like any other electron. 

Alpha particles are the least-penetrating form of radiation and can be stopped by a sheet of paper. Beta particles readily pass through paper but not through a sheet of aluminum. Gamma rays penetrate several centimeters into solid lead. 

ALPHA PARTICLE. A helium nucleus emitted spontaneously from radioactive elements both natural and, man-made. Its energy is in tire range of 4-8 MeV and is dissipated in a very short path. i.e.. in a few centimeters of air or less than 0.005 mm of aluminum. It has the same mass (4) and positive charge (2) as Ihe helium nucleus. Accelerated in a cyclotron alpha-parlicles can be used to bombard the nuclei uf oilier elements. 

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... 

Another example of the use of alpha particles to induce a nuclear reaction is the conversion of aluminum to radioactive phosphorus ... 

The metals of most concern are the heavy metals, especially cadmium, lead, and mercury. Although it is a metalloid with characteristics of both metals and nonmetals, arsenic is commonly classified as a heavy metal for a discussion of its toxicity. Though not particularly toxic, zinc is abundant and may reach toxic levels in some cases. For example, zinc accumulates in sewage sludge and crop productivity has been lowered on land fertilized with sludge because of zinc accumulation. Copper may be toxic to plants. Aluminum, a natural constituent of soil, may be leached from soil by polluted acidic rainwater and reach levels that are toxic to plants. Other metals that may be of concern because of their toxicides include chromium, cobalt, iron, nickel, and vanadium. Radium, a radioactive alpha particle-emitting metal, can be very toxic at even very low levels in water or food. 

Rutherford and his assistant Hans Geiger directed a well-defined beam of alpha particles at thin foils of aluminum and gold. 

Nitrogen-14 was bombarded by alpha particles (helium nuclei), producing oxygen-17 and protons (hydrogen nuclei). In 1934, Irene Johot-Curie (1897- 1956), the daughter of Marie Curie, produced an isotope of phosphorus by bombarding aluminum-27 with alpha particles from polonium ... 

Alluvial systems Alpha particle Alternative energy sources Alternative medicine Altruism Aluminum Aluminum hydroxide Alzheimer disease Amaranth family (Amaranthaceae) Amaryllis family (Amaryllidaceae) American Standard Code for Information Interchange Ames test Amicable numbers Amides Amino acid Ammonia Amm onification Amnesia Amniocentesis Amoeba Amphetamines Amphibians Amplifier Amputation Anabolism Anaerobic Analemma Analgesia... 

Beta radiation which consists of electrons. They are more penetrating than alpha particles and can pass through 1-2 centimetres of water. In general, a sheet of aluminum a few millimetres thick will stop beta radiation. 

The large amount of energy released in charged-particle bombardment tends to exclude this method where thermally labile organic or biological materials are employed as targets. However, Odeblad (54) was able to determine sodium in urine and other elements in biological materials by means of the weak source of alpha particles (160 millicuries) derived from the decay of Po . A similar source of alpha particles has been used to determine aluminum by the reaction AP (a,n)P —half-life 2.5 min (66). 

Write a balanced nuclear equation for the induced transmutation of aluminum-27 into phosphorus-30 by alpha particle bombardment. A neutron is emitted from the aluminum atom in the reaction. 

You are given all of the particles involved in an induced transmutation reaction, from which you must write the balanced nuclear equation. Because the alpha particle bombards the aluminum atom, they are reactants and must appear on the reactant side of the reaction arrow. Obtain the atomic number of aluminum and phosphorus from the periodic table. Write out the nuclear reaction, being sure to include the alpha particle (reactant) and the neutron (product). 

The penetrating abilities of the particles and rays are proportional to their energies. Beta particles and positrons are about 100 times more penetrating than the heavier and slower-moving alpha particles. They can be stopped by a g-inch-thick (0.3 cm) aluminum... 

USE Source of neutrons when bombarded with alpha particles according to the equation jBe + JHe J C + jn This yields about 30 neutrons per million alpha particles. Also as neutron reflector and neutron moderator in nuclear reactors. In beryllium copper and beryllium aluminum alloys (by direct reduction of beryllium oxide with carbon in the presence of Cu nr Al). In radio tube parts. In aerospace structures. In inertial guidance systems. 

Example 4.8 What is the range of a 10-MeV alpha particle in aluminum ... 

For other materials, Eq. 4.15 should be used after the range in aluminum is determined from Eqs. 4.18 and 4.19. A very comprehensive paper dealing with proton stopping power, as well as range, for many materials is that of Janni." The range of protons and deuterons can be calculated from the range of an alpha particle of the same speed using the formula... 

Calculate the stopping power in aluminum for a 6-MeV alpha particle. 

J Calculate the energy loss of a 6-MeV alpha particle going through an aluminum foil with thickness equal to one-fourth of the range of the alpha (remember dE/dx is not constant as the particle slows down). 

In contrast to alpha emission, beta emission is characterized by production of particles with a continuous spectrum of energies ranging from nearly zero to some maximum that is characteristic of each decay process. The jS particle is not nearly as effective as the alpha particle in producing ion pairs in matte r because of its small mass (about /7(XK) that of an alpha particle), At the same time, its penetrating power is substantially greater than that of the alpha particle. Beta-particle energies are frequently related to the thickness of an absorber, ordinarily aluminum, required to stop the particle. 

Eigure 2.3 is a graph of the range calculated by the continuous-slowing-down approximation (CSDA) of an alpha particle, in both air and aluminum. The data that generated the graph (ICRU 1993) indicate that a 5-MeV alpha particle has a... 

---