Neutrons high-energy

As cosmic rays pass through the upper atmosphere, some of the present is converted to by the capture of high-energy neutrons. The then migrates into... 

Neutron attenuation Emits high-energy neutrons into the soil that collide with hydrogen atoms associated with soil water and counts the number of pulses, which is correlated to moisture content Consists of a probe inserted into access boreholes with aluminum or polyvinyl chloride casing... 

The oxygen analysis by high-energy-neutron activation indicated 0.06 0.06% oxygen. 

In the second type of analysis, high-energy bombardment of soils with neutrons, on the other hand, leads to what is called neutron activation. Reemission of radiation from neutron-activated soil allows for the identification of the elements present. This type of analysis typically requires a source of high-energy neutrons and so requires special equipment [8],... 

Cosmic rays Protons and a particles that enter Earth s atmosphere from outer space. When they collide with atoms or molecules of atmospheric gas, high-energy neutrons can be given off These neutrons can then undergo nuclear reactions with other atmospheric gas atoms and molecules. 

The fast neutron activation (FNA) technology was an outgrowth of attempts to get more information than nitrogen content from neutron interrogation approaches. In FNA, high-energy neutrons, rather than thermahzed neutrons, are used to scan the contents of a container. Gammas from neutrons inelasticaUy scattered on... 

There are not many uses for polonium. Probably the most important is as a source of alpha particles (nuclei of helium atoms) and high-energy neutrons for research and radiation studies. It is also used to calibrate radiation-detection devices. 

Americium does not exist in nature. All of its isotopes are man-made and radioactive. Americium-241 is produced by bombarding plutonium-239 with high-energy neutrons, resulting in the isotope plutonium-240 that again is bombarded with neutrons and results in the formation of plutonium-241, which in turn finally decays into americium-241 by the process of beta decay. Both americium-241 and americium-243 are produced within nuclear reactors. The reaction is as follows Pu + (neutron and X gamma rays) —> " Pu + (neutron and X gamma rays) —> Pu—> Am + beta minus ([ -) followed by " Am—> jNp-237 + Hej (helium nuclei). 

Because such small amounts of berkehum have been produced, not many uses for it have been found. One use is as a source for producing the element californium by bombarding isotopes of berkehum with high-energy neutrons in nuclear reactors. Berkelium is also used in some laboratory research. 

Californium is a transuranic element of the actinide series that is homologous with dysprosium (gjDy), just above it in the rare-earth lanthanide series. Cf-245 was the first isotope of californium that was artificially produced. It has a half-life of just 44 minutes. Isotopes of californium are made by subjecting berkelium to high-energy neutrons within nuclear reactors, as follows + (neutrons and A, gamma rays) — °Bk — °Cf + (3- (beta particle... 

High energy neutron generators are particularly useful in well logging applications. In such applications one important factor is accurate knowledge of the neutron pulses that irradiate the surrounding formation. For example, it is desirable to accurately measure the neutron output, e.g., the number of neutrons emitted by the neutron detector. 

The techniques used to produce a nuclear explosion (i.e., an essentially instantaneous, self-perpetuating nuclear chain reaction) are very complex. A nuclear explosion must utilize a high-energy neutron spectrum (fast neutrons, that is, neutrons with energies > 1 MeV). This results basically from the fact that, for an explosion to take place, the nuclear chain reaction must be very rapid—of the order of microseconds. Each generation in the chain reaction must occur within... 

Studies of the effect of neutron irradiation are divided into three groups slow or thermal neutrons, fission products and reactor neutrons. The slow neutrons are obtained from a radioactive source or high energy neutrons that are produced by deuterium bombardment of a beryllium target in a cyclotron and slowed down passing thru a thick paraffin wax block. The fission products in one case are produced when a desired sample is mixed or coated with uranium oxide and subsequently irradiated with slow neutrons. The capture of neutrons by U23S leads... 

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