Track of charged particles

VIII. Tracks of Charged Particles and Their Structure... 

Thus, part of the energy transferred to a molecular medium by a charged particle is certainly delocalized. And though later this energy is localized on one of the molecules, this localization is stochastic, and thus the coordinates of the points of ionization and excitation cannot be determined more precisely than to within the magnitude of bpl or Ax we have presented previously. This circumstance is important, first of all, when one simulates tracks of charged particles using the Monte Carlo method, where the track is presented as a set of points where the interaction took place.302 303 Even if the plasmon states are not formed in the system, the... 

VIII. TRACKS OF CHARGED PARTICLES AND THEIR STRUCTURE... 

Price PB, Walker RM (1963) Fossil tracks of charged particles in mica and the age of minerals. J Geophys Res 68 4847-4862... 

Structure of Charged Particle Tracks in Condensed Media... 

INTERACTION OF CHARGED PARTICLES WITH MOLECULAR MEDIUM AND TRACK EFFECTS IN RADIATION CHEMISTRY... 

When we study the effect of charged particles on a substance, we often need to estimate the probabilities of excitation or ionization as functions of the distance from the axis of the track (i.e., of the impact parameter b). This is done using the quasi-classical approach, within which we assume that the charged particle moves along a definite trajectory. In the... 

The passage of a charged particle through a medium results in the formation of disturbance areas along the particle s trajectory that contain excited molecules, positive ions, and knocked out electrons and atoms. These disturbances areas make up the track of the particle (see Section VIII). An important role in the process of formation of the track and in the following radiation-chemical transformations is played by the degree of delocalization of the initially absorbed energy. 

Considering the track structures as spherical or cylindrical formations and using the methods of diffusion kinetics, it proved to be possible to explain many experimental facts concerning the radiolysis of water solutions, in particular, the dependence of yields on LET.361 It is owing to this that the LET was considered to be a universal qualitative characteristic of radiation, and the concentration of active particles was considered to be in direct dependence on the LET with no regard for the type of charged particle. 

The radiation effect produced by heavy ions can be simulated with electrons if the ions have high velocities. It is in this case that the spatial distribution of active particles in the track is close to the one in tracks of fast electrons. At small velocities of heavy ions the tracks of delta electrons overlap each other to a considerable extent, which results in the concentration of charged particles in a microvolume of the ion s track being very high. With development of powerful pulsed electron accelerators it became possible to create high concentrations of active particles in a medium. According to Ref. 372, with such accelerators one is able to reproduce and study the processes occurring in tracks of heavy ions. 

The underwater Cerenkov technique allows the tracking of charged relativistic particles. In water (whose refractive index for blue light is, n 1.35) Cerenkov photons are emitted along particle track at i), 42°. The time sequence of photons hits on PMTs is correlated by the causality relation (see figure 5) ... 

The claim by G A that only one of these traditions developed techniques to imitate real-world conditions is quite misleading. Both traditions used the cloud chamber to manufacture an artificial environment that approximates known phenomena. For the Cavendish physicists, the cloud chamber became one of the defining instruments of particle physics, precisely because the laboratory phenomena were modeled on the movement of the charged particles. The knotty clouds blended into the tracks of alpha particles and the threadlike" clouds simulate beta-particle trajectories (Galison Assmus, 1989, p. 268). Of course, G A are correct that these physicists aspired to dissect nature into its fundamental components, reflecting the long tradition of the corpuscular conception of matter. 

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