CR-39 Solid-state Track Detectors Research Articles

Calibration of CR-39 solid state track detectors with monoenergetic protons from 0.3 MeV to 2.5 MeV

The2H(d,p)3H reaction is one of the most crucial reactions in the Big Bang nucleosynthesis (BBN). It is of particular interest to investigate this kind of reactions in plasma environments, generated by high intensity lasers, which are similar to real astrophysical conditions. We have experimentally investigated the2H(d,p)3H reaction using laser-driven counter-streaming collisionless plasmas at the Shenguang-II laser facility. CR-39 track detectors are widely employed as the main diagnostics in such experiments and laser-driven ion acceleration. In this work, we performed calibration of CR-39 track detectors with monoenergetic protons from the tandem accelerator, and then presented their track diameters for proton energies ranging from 300 keV to 2.5 MeV and for etching times between 4 and 28 hours. In addition, we recommended the optimal etching time at the typical etching conditions, which will be very useful for the following massive data analysis from the CR-39 detectors.

Geometrical parameters of tracks registered by collimated alpha particles on CR-39 detector

The latent tracks formed on CR-39 solid state track detector on exposure of alpha radiations emanating from a collimated 241Am source were developed by a chemical etching method. Alpha track images were captured by an optical microscope and were processed by using Image Pro-Plus (6.0) software. GEANT4 simulations were carried out to obtain the angular and energy distribution profiles of the alpha particles. Apart from fluence, geometric parameters like aspect ratio (the ratio of the major to minor axis) and the depth profiles of etched tracks were measured experimentally and correlated with simulated angular and energy profile of incident radiations. Reasonable agreement was observed in the fluence and depth profile information obtained from experiments and simulations.

Generation of fast protons in moderate-intensity laser–plasma interaction from rear sheath

Forward fast protons are generated by the moderate-intensity laser–foil interaction. Protons with maximum energy 190 keV are measured by using magnetic spectrometer and CR-39 solid state track detectors along the direction normal to the rear surface. The experimental results are also modeled by the particle-in-cell method, investigating the time-varying electron temperature and the rear sheath field. The temporal and spatial structure of the sheath electrical field, revealed in the simulation, suggests that these protons are accelerated by target normal sheath acceleration (TNSA) mechanism.

Ultra-high resolution radiography using CR-39 solid state track detectors and atomic force microscopy

We have developed an ultra-high resolution charged particle radiography technique using CR-39 solid state track detectors and an atomic force microscope (AFM). Very small etch pits about 80 nm in diameter were measured with the AFM. We planned to apply this technique to high resolution autoradiography. Such practical applications often require accurate positioning between the sample mounted on a CR-39 detector and particle tracks recorded in the CR-39 in order to determine the radiation dose distribution inside the sample. As a fiducial marker for the positioning, aluminum patterns were deposited on the CR-39 surface using a photolithography technique. The aluminum patterns were dissolved through a typical etching process for CR-39 detectors and pattern-shaped steps were left on the surface. Using these patterns should ensure accurate positioning between the sample and the etch pits in autoradiography. This method provides a new technique for radiation imaging of biological samples at a subcellular scale.

Disturbing effects in spent fuel assay using CR-39 detectors

Neutron emission of spent reactor fuel assemblies was studied with CR-39 solid state track detectors in a nuclear plant. To reduce the effect of disturbing events, a shape selection method was used. For typical exposures the γ-dose fell in the interval of 0.5–3 kGy. The sensitivity decrease was found to be 23±5%kGy γ-dose The overall effect of neighbouring assemblies was within the statistical uncertainty (5%), i.e negligible.

The simultaneous imagining of boronated tissue sections and the location of fissionable actinide particles in CR-39 solid state track detector, utilising a neutron-induced autoradiographic technique

Reports on a new neutron-induced autoradiographic technique in which soluble boron is incorporated into fixed tissue sections to produce good resolution images of the tissue in an overlaid pre-etched CR-39 plate, while still preserving the original section for staining and histological examination. The tissue images are formed from tracks produced by the 10B(n, alpha ) reaction. This technique was developed from earlier work by the authors (Morris and Batchelor, 1987). The procedure is to be used for the simultaneous imaging of lung tissue and the location within it of fissionable actinide particles, such as uranium dioxide. Also discussed is the suitability of the technique to estimate the relative amounts of soluble boron present in tumour and nontumour systems needed for 10B neutron capture therapy studies.

The location of boron-containing dust in the lung, utilising neutron-induced autoradiography techniques with a CR-39 solid state track detector

The authors report two new developments in the use of CR-39 to measure boron-containing particles in the lung. In one of these, the relative amount of particulate boron located within a lung tissue section can be estimated by counting the number of tracks produced by the 10B (n, alpha ) reaction. In the other, a lung section, and the location of boron-containing particles within it, can be imaged onto a plate of CR-39. Also discussed, as an incidental finding, is a separate technique to image a lung tissue section onto a pre-etched CR-39 plate while still preserving the original section for staining and histological examination. The ultimate aim is to measure the relative mass and spatial distribution of tourmaline aggregates in post mortem lungs from Cornish tin miners, using a CR-39 homopolymer solid state track detector and neutron-induced autoradiography, with subsequent image analysis on a Quantimet 720.

プラスチック固体飛跡検出器ＣＲ３９を用いた高速中性子ラジオグラフィ

プラスチック固体飛跡検出器ＣＲ３９を用いた高速中性子ラジオグラフィ