We review the theory of the electromagnetic interactions between rapidly moving charged particles and the matter through which they pass. The emphasis will be on very massive electric ($\ensuremath{-}100\ensuremath{\le}{Z}_{1}100$) and magnetic ($|g|=137e \mathrm{and} \frac{137e}{2}$) particles moving with relativistic velocities ($\ensuremath{\beta}g0.2$, $\ensuremath{\gamma}l100$). Consideration will be given to both the stopping power of the projectile and to the response of the absorbing medium to the excitation caused by the projectile.

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Theoretical and experimental aspects of the energy loss of relativistic heavily ionizing particles

This paper reviews some aspects of solid-state nuclear track detectors (SSNTDs) and their applications in the radon and other research fields. Several geometrical models for the track growth given in the literature are described and compared. It is found that different models give close results for the dimensions of track openings. One of the main parameters that govern track formation is the bulk etch rate Vb. Dependences of Vb on different parameters such as the preparation procedures, etching conditions, irradiation before etching, etc. are examined. A review of existing methods for determination of the bulk etch rate and track etch rate Vt is also given. Examples of Vt functions for some detectors are presented. Some unsolved questions related to Vt and some contradictory experimental results published in the literature are also summarized in the paper. Applications of SSNTDs for radon and progeny measurements are discussed. New designs of diffusion chambers that have appeared in the last few years are portrayed. A review of analytical and Monte Carlo methods for the calculation of the calibration factors in radon measurements is presented. Particular attention has been given to methods of long-term passive measurements of radon progeny with SSNTDs. These measurements are rather difficult and there is not yet a widely accepted solution. One possible solution based on the LR 115 SSNTD is outlined here. Methods for retrospective radon measurements are also described. Various applications of SSNTDs in other fields of physics and other sciences are briefly reviewed at the end of the paper. # 2004 Elsevier B.V. All rights reserved.

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Formation and growth of tracks in nuclear track materials

Latent nuclear tracks are damaged zones, created along the paths of rapidly moving ions in solids. They are stored indefinitely in many insulators and can be used to initiate a phase separation process by one of several procedures that remove, collect, or transform material along the latent track. The resulting two-step technique is based on separate inscription and development stages, similar to the lithographic techniques using visible light, uv, x rays, or electrons. In contrast to these other techniques, however, it is applicable even to mechanically very stable, chemically inert, radiation-resistant dielectric materials. The most common development procedure is track etching, which acts as a chemical "amplifier" that dissolves the damaged zone of the latent track preferentially, creating etch pits or channels that can be extremely fine. Etched track diameters start around 10 nm and increase linearly with the etching time. The most outstanding feature of the technique is that one single particle is sufficient to create a developable damage. This unique combination of recording and revealing properties makes possible a single-particle structuring tool with a very wide array of applications. With the advent of high-energy, heavy-ion accelerators, with ion ranges between micrometers and centimeters, large-scale application of the technique to the imprinting of structure onto solids has become possible. At present, most frequently random track arrays are employed to induce global property changes of the solid volume or surface. In the future, scanning ion microbeam technology will make possible local generation of oriented track structures with high precision. This "ultimate" microtool should provide the versatility of a computer-controlled mechanical lathe. This review describes the processes involved in track generation. It outlines applications that are on the verge of being commercialized at present and considers future possibilities.

Production and use of nuclear tracks: imprinting structure on solids

High-resolution spectrometry of charged particles from inertial-confinement-fusion (ICF) experiments has become an important method of studying plasma conditions in laser-compressed capsules. In experiments at the 60-beam OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)], utilizing capsules with D2, D3He, DT, or DTH fuel in a shell of plastic, glass, or D2 ice, we now routinely make spectral measurements of primary fusion products (p, D, T, 3He, α), secondary fusion products (p), “knock-on” particles (p, D, T) elastically scattered by primary neutrons, and ions from the shell. Use is made of several types of spectrometers that rely on detection and identification of particles with CR-39 nuclear track detectors in conjunction with magnets and/or special ranging filters. CR-39 is especially useful because of its insensitivity to electromagnetic noise and its ability to distinguish the types and energies of individual particles, as illustrated here by detailed calibrations of its response to 0.1–13.8 MeV protons from a Van de Graaff accelerator and to p, D, T, and α from ICF experiments at OMEGA. A description of the spectrometers is accompanied by illustrations of their operating principles using data from OMEGA. Sample results and discussions illustrate the relationship of secondary-proton and knock-on spectra to capsule fuel and shell areal densities and radial compression ratios; the relationship of different primary fusion products to each other and to ion temperatures; the relationship of deviations from spherical symmetry in particle yields and energies to capsule structure; the acceleration of fusion products and the spectra of ions from the shell due to external fields; and other important physical characteristics of the laser-compressed capsules.

Spectrometry of charged particles from inertial-confinement-fusion plasmas

Clustered DNA damage sites, in which two or more lesions are formed within a few helical turns of the DNA after passage of a single radiation track, are signatures of DNA modifications induced by ionizing radiation in mammalian cells. Mutant hamster cells (xrs-5), deficient in non-homologous end joining (NHEJ), were irradiated at 37 degrees C to determine whether any additional double-strand breaks (DSBs) are formed during processing of gamma-radiation-induced DNA clustered damage sites. A class of non-DSB clustered DNA damage, corresponding to approximately 30% of the initial yield of DSBs, is converted into DSBs reflecting an artefact of preparation of genomic DNA for pulsed field gel electrophoresis. These clusters are removed within 4 min in both NHEJ-deficient and wild-type CHO cells. In xrs-5 cells, a proportion of non-DSB clustered DNA damage, representing approximately 10% of the total yield of non-DSB clustered DNA damage sites, are also converted into DSBs within approximately 30 min post-gamma but not post-alpha irradiation through cellular processing at 37 degrees C. That the majority of radiation-induced non-DSB clustered DNA damage sites are resistant to conversion into DSBs may be biologically significant at environmental levels of radiation exposure, as a non-DSB clustered damage site rather than a DSB, which only constitutes a minor proportion, is more likely to be induced in irradiated cells.

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Processing of clustered DNA damage generates additional double‐strand breaks in mammalian cells post‐irradiation

https://escholarship.org/content/qt6ks81489/qt6ks81489.pdf?t=p21nen

E.K. Shirk

Papers

A nuclear-track-recording polymer of unique sensitivity and resolution