Fission Fragment Interactions

A highly positive charged fission fragment interacts with the detector gas and causes ionizations. 

X-rays, often used in radiation chemistry, differ from y-rays only operationally namely, X-rays are produced in machines, whereas y-rays originate in nuclear transitions. In their interaction with matter, they behave similarly—that is, as a photon of appropriate energy. Other radiations used in radiation-chemical studies include protons, deuterons, various accelerated stripped nuclei, fission fragments, and radioactive radiations (a, /, or y). 

Fission chambers use neutron-induced fission to detect neutrons. The chamber is usually similar in construction to that of an ionization chamber, except that the coating material is highly enriched U235. The neutrons interact with the U235, causing fission. One of the two fission fragments enters the chamber, while the other fission fragment embeds itself in the chamber wall. 

It gives reasonable fission barriers, fission isomer energies, and fission isomer lifetimes [KUM86]. Agreement with the fission lifetimes is also quite reasonable (see Fig. 7). This did require the introduction of two additional parameters (the strength and the A A -dependence) for the nuclear part of the fragment-fragment interaction. 

Absorptive reactions are (n, a), (n, p), in,y), or (n, fission). In the case of an (n, y) reaction, the neutron may be detected through the interactions of the gamma emitted at the time of the capture, or it may be detected through the radiation emitted by the radioisotope produced after the neutron is captured. The radioisotope may emit /3 or or y or a combination of them. By counting the activity of the isotope, information is obtained about the neutron flux that produced it. This is called the activation method. If the reaction is fission, two fission fragments are emitted being heavy charged particles, these are detected easily. 

Example Problem Consider the case of 240-MeV 32S interacting with 181Ta, which fissions. What would be the laboratory correlation angle between the fragments if the full linear momentum of the projectile was transferred to the fissioning system ... 

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