Alpha particle oxide

The use of this direct oxide reduction process is replacing fluoride reduction as it eliminates neutron exposure to operating personnel (alpha particles from plutonium decay have sufficient energy to eject neutrons from fluorine by the a,n reaction) and eliminates reduction residues which require subsequent recovery. 

Examples of tunneling in physical phenomena occur in the spontaneous emission of an alpha particle by a nucleus, oxidation-reduction reactions, electrode reactions, and the umbrella inversion of the ammonia molecule. For these cases, the potential is not as simple as the one used here, but must be selected to approximate as closely as possible the actual potential. However, the basic qualitative results of the treatment here serve to explain the general concept of tunneling. 

Sample preparation is rather involved. A sample of urine or fecal matter is obtained and treated with calcium phosphate to precipitate the plutonium from solution. This mixture is then centrifuged, and the solids that separate are dissolved in 8 M nitric acid and heated to convert the plutonium to the +4 oxidation state. This nitric acid solution is passed through an anion exchange column, and the plutonium is eluted from the column with a hydrochloric-hydroiodic acid solution. The solution is evaporated to dryness, and the sample is redissolved in a sodium sulfate solution and electroplated onto a stainless steel planchette. The alpha particles emitted from this electroplated material are measured by the alpha spectroscopy system, and the quantity of radioactive plutonium ingested is calculated. Approximately 2000 samples per year are prepared for alpha spectroscopy analysis. The work is performed in a clean room environment like that described in Workplace Scene 1.2. 

The Mars Pathfinder rover carried an Alpha Proton X-ray Spectrometer (APXS), and the two Mars Exploration Rovers (MER - Spirit and Opportunity) carried Alpha Particle X-ray Spectrometers (also called APXS, but in this case more precise versions of the Pathfinder instrument, though without the ability to monitor protons for light element analyses). These instruments contained radioactive curium sources (Fig. 13.16) whose decay produced a-particles, which irradiated target rocks and soils. The resulting characteristic X-rays provided measurements of major and minor element abundances. The MER rovers also carried Mossbauer spectrometers, which yielded information on iron oxidation state. 

In experiments the concentration of curium must tic kept low in order to avoid Ihe Formation of a reducing medium due to (lie neiion of the i4 Cin alpha particles on H 0. At a concentration of lO-5 molar in curium, and under conditions where aniericium(lll) is oxidized lo ameiiciuintVI) in the same solution, the curium is not oxidized above the till) stale with ammonium peroxydisullate. 

The ionization potential of nitric oxide is nine volts, and the ratio of molecules reacting to ion-pairs produced by an energy input of 8.6 calories is 1.6. In Table I it is seen that for a given input of cathode rays the reaction is 2.3 times as great for nitric oxide as for oxygen. The very low yield with carbon dioxide is in perfect agreement with Lind s results with alpha particles.13 Apparently the C02 ions recombine without chemical rearrangement. 

Iodine is obtained by oxidizing iodides from seawater or brines using Cl2, concentrated H2S04, Fe3+, or other oxidizing agents. Astatine is produced naturally by the radioactive decay of uranium or thorium. Production of At is also accomplished by bombarding Bi with alpha particles,... 

The deposition of polonium on metal wires gives rise to a useful a-source. Tips of metal wires having a length 10 mm and a diameter of 0.2 mm were utilized. They were made of Al, Ni, Pd, Pt or An. Each was immersed in 100 pi of a solution containing °Po (300 Bqml ) for 15 h at 27°. Alpha particle emission was measured using a liquid scintillation system. There was an observed diminution in the a-pulse spectra for all of the wires except Al. This was attributed to the mutual diffusion between the wire metal and °Po. The °Po deposited on the Al wire had a tendency to be eluted with the liquid scintillator. This was attributed to physical absorption on the porous metal oxide layer on the Al wire and °Po. The °Po deposited by the Al wire had a tendency to be eluted with the liquid scintillator. It was possible to prepare a °Po -Al wire as a useful a-source by heating at 120° for 30 minutes. 

Miller, A.C., Stewart, M., Brooks, K., Shi, L., Page, N. (2002a). Depleted uranium-catalyzed oxidative DNA damage absence of significant alpha particle decay. J. Inorg. Biochem. 91 ... 

The alpha aluminum oxide was purchased from Alpha Products, Thiokol/Ventron Division. The aluminum oxide h d a particle size of 40 microns, a surface area of 160 m /g, and consisted of 90% AI2O2 and 9% H2O, according to the manufacturer. The aluminum oxide was dried in 50 g batches under a vacuum for two days before use. 

SIMS analysis of electrodeposited Th alpha-particle sources gives rise to higher signals for the ThO and ThO/ than for Th. This leads to difficulties in quantitation as the oxide to atomic ion ratios will be sensitive to local oxygen concentrations. Isobaric... 

One of the simplest and cheapest safety devices found in homes and other buildings is a battery-operated smoke detector. And americium is an important part of it. A small piece of americium oxide made with the americium-241 isotope is sealed inside the smoke detector. The americium-241 gives off alpha particles. The alpha particles strike air molecules, causing them to break apart. The pieces formed in this process—ions—are electrically charged. 

The alkali metals are not found free in nature, because they are so easily oxidized. They are most economically produced by electrolysis of their molten salts. Sodium (2.6% abundance by mass) and potassium (2.4% abundance) are very common in the earth s crust. The other lA metals are quite rare. Francium consists only of short-lived radioactive isotopes formed by alpha-particle emission from actinium (Section 26-4). Both potassium and cesium also have natural radioisotopes. Potassium-40 is important in the potassium-argon radioactive decay method of dating ancient objects (Section 26-12). The properties of the alkali metals vary regularly as the group is descended (Table 23-1). 

In the Bell System for bipolar, metal oxide semiconductor (MOS) and hybrid integrated circuitry (HIC), RTV silicone elastomer has proven to be one of the most effective encapsulants for mechanical, moisture and alpha particle protection of the IC devices. This RTV material is also one of a few commercial polymer materials that meet most of the Bell System encapsulant specifications. However, the RTV material occasionally experiences some material variations and creates production problems in IC devices shop coating. ... 

Another complication in plutonium solution is the gradual, spontaneous reduction of Pu(VI) to Pu(IV), and Pu(IV) to Pu(III), caused by ionization products of alpha particles emitted in radioactive decay [SI]. The rate of alpha reduction is slow, however. For example, the observed rate of reduction of Pu(VI) in 0.5 M HCl at 25°C is 0.0035 g-equiv/day per mole of plutonium, which corresponds to a half-life of 199 days for reduction of Pu(VI) to Pu(TV). From these rates and the known alpha-decay rate and decay energies of plutoniiun, it is estimated that approximately 80 eV of dissipated alpha energy in this solution brings about the addition of one electron in reducing plutonium ions. After several hundred days the plutonium reaches an average oxidation state intermediate between Pu(III) and Pu(IV). 

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. 

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