Nucleus, energy deposition

Specific Energy—The actual energy per unit mass deposited per unit volume in a small target, such as the cell or cell nucleus, as the result of one or more energy-depositing events. This is a stochastic quantity as opposed to the average value over a large number of instance (i.e., the absorbed dose). 

In summary, microdosimetry is the study and quantification of the spatial and temporal distributions of absorbed energy in irradiated matter [15,17,22,23]. One makes a distinction between regional microdosimetry [the object of which is the study of micro-dosimetric distributions /(z)j and structural microdosimetry (a mathematically more advanced approach, which is concerned with characterizing the spatial distribution of individual energy deposition events, i.e., ionizations and/or excitations). Regional microdosimetry asserts that the effect is entirely determined by the amount of specific energy deposited in the relevant site (typically, a cell nucleus). The two kinds of microdosimetry, regional and structural, were shown to be in fact mathematically equivalent—once the sensitive site is judiciously determined [16]. 

Again the effective reaction is four protons fuse to become one He nucleus. The neutrino from elecffon capture on Be carries away somewhat more energy than the PPI neutrinos, so the local energy deposition from PPII is slightly less than that in PPI. 

In reactions involving complex nuclei, two important quantities related to the Q-value, and also to the incident beam energy, are the excitation energy B (or equivalently U) and the threshold energy Bth- The excitation energy is the excess energy deposited in the product nucleus (O Fig. 3.5). For excitation energies below one Bn, the discretized nature of E is important. 

Rad a unit of radiation dosage corresponding to 10 J of energy deposited per kilogram of tissue (from radiation absorbed dose). (18.7) Radioactive decay (radioactivity) the spontaneous decomposition of a nucleus to form a different nucleus. (2.4 18.1)... 

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