Nuclear Track Etch Detectors Research Articles

Application of Ag+-doped phosphate glasses as nuclear track etch detectors

The Ag+-doped phosphate glass which is commonly employed as the radiophotoluminscence (RPL) dosimeter has been applied as a nuclear track etch detector. The glass is etchable in the NaOH solutions and forms clear nuclear etch pit. The etching performances and track parameters vary as a function of the concentration of NaOH solution. The most sensitive normality was confirmed to be 7 N. The track response is controllable with NaOH concentration at the range of Z∗/β ≥ 80 (Z∗: effective charge, β: velocity). The charge spectroscopic resolution for Xe (Z∗/β = 107) was found to be 0.23 cu (charge unit), which would allow to identify individual nuclear charge of ultra heavy nuclei around Actinides in the cosmic rays. The Ag+-doped phosphate glass would be a promising detector for high Z spectroscopy for cosmic ray and nuclear physics fields and has the potential to operate not only RPL dosimeter but also nuclear track etch detector.

Comparative study of seismic surveillance on radon in active and non-active tectonic zone of West Bengal, India

Study of radon behaviour in soil or groundwater provides important information in case of seismic activity within the earth’s crust. In a previous work, we have tried to correlate the occurrence of radon concentration anomalies in soil with incidents of earthquakes within the distance of 1000 km from the experimental site. The experiment was performed at Kolkata, West Bengal, India (22.53°N, 88.4°E) which is not located in an active fault zone. In extension of our study we have performed simultaneous measurement of radon in an active fault zone at Jalpaiguri (26.53°N, 88.76°E), West Bengal, India as well as in Kolkata – a non-active fault zone. The variation of radon concentration in soil gas was measured by SSNTDs [Solid State Nuclear Track-etch Detector(s)]. Interesting features of an anomalous fluctuation in radon concentration in both the seismic as well as non-seismic zones prior to any particular earthquake is reported.

The study of radon levels and absorbed dose in the staff and visitors of Alisadr Cave

CR-39 passive integrating Solid State Nuclear Track etch Detectors (SSNTDs) were used to measure atmospheric radon concentrations in the Alisadr show cave in Hamedan province, Iran. This was done in order to assess the risk from natural environmental radiation to tourists and cave guides. The study was carried out in 12 locations in the winter and spring periods. The mean radon concentration during the winter period was 1504.6 Bq m−3 and the highest value was 2280.4 Bq m−3 during spring. The average absorbed dose for visitors and guides was estimated as 0.02 mSv per visit, and 4.32 mSv per season, respectively. The annual average absorbed dose is rather more significant for staff, being in the order of 16.50 mSv.

Elevated radon concentrations in a Pleistocenic cave operating as a show cave

Radon measurements were carried out, using solid-state nuclear track-etch detectors (SSNTDs) with type CA 80-15 cellulose nitrate films, in a Pleistocenic cave at Petralona, in Halkidiki, northern Greece, 55 km distant from the city of Thessaloniki. Radon levels as high as 88 kBq m −3 (2.38 nCi l −1) recorded inside the cave is equivalent to 11.90 WL in terms of occupational exposure to radon and its decay products. Absorbed dose rates were measured using TL dosimeters, type TLD-200 (CaF 2-Dy), in a continuous monitoring program (integrated measurements). Dose rate levels as high as 110 nGy h −1 were recorded inside the cave.

Radon Concentrations and Dose Assessment in a Tunnel under Construction in Costa Rica

A preliminary study of radon concentration in the air was carried out in a tunnel under construction over three different sampling periods from June 2001 to August 2002. The concentration was measured with LR-115 Type II nuclear track etch detectors and E-PERM detectors. The average radon concentrations for each sampling period were : 1082 Bq m-3, 1550 Bq m-3 and 414 Bq m-3. Possible formation of convection cells inside the tunnel can explain the variation of radon concentration. A dose assessment calculation was carried out to estimate the effective doses of the construction workers. The maximum effective dose was estimated at 13.5 msv y-1 for an eight-hour shift.

Nuclear track-formation models and the response of BP-1 detectors

The mechanism of nuclear track formation in solids is poorly understood, despite decades of experience with nuclear track-etch detectors. One of the roadblocks has been the lack of precision tests of track-formation models. Here we exploit the unparalleled resolution of a glass nuclear track-etch detector, BP-1, to test track-formation models. By the use of calibration beams, we have corrected all signals for fluctuations in detector response, eliminating a possible source of systematic error. Within this dataset we compared signals due to the same particle charge over a large range of Lorentz factor. We show from a variety of lines of evidence that the response of BP-1 is not a simple function of total energy loss nor of other quantities derived from total energy loss such as restricted energy loss. A generic feature of a large class of models is a significant relativistic rise, which we do not observe. We show that an empirical hybrid model fits the response of BP-1 detectors over a wide range of charge and energy.

Radon concentrations and absorbed dose measurements in a Pleistocenic cave

Radon concentration measurements were carried out using solid-state nuclear track-etch detectors (SSNTDs) type CA 80-15 cellulose nitrate films, in a Pleistocenic cave at Petralona, in Halkidiki, Northern Greece, at 55 km from the city of Thessaloniki. Radon levels as high as 88 kBq.m-3 (2.38 nCi.l-1) have been recorded inside the cave equivalent to 11.90 WL in terms of occupational exposure to radon and its decay products. Absorbed dose rates were performed using TL dosimeters, type TLD-200 (CaF2-Dy) in a continuous monitoring program (integrated measurements). Dose rate levels as high as 110 nGy.h-1 were recorded inside the cave. In interpreting the high levels of radiation doses, radioactivity measurements regarding the naturally occurring 238U, 232Th and 40K radionuclides were carried out in various speleothems found at different sites in the cave.

The MACRO detector at Gran Sasso

MACRO was an experiment that ran in the Laboratori Nazionali del Gran Sasso from 1988 to 2000. Its principal goal was to observe magnetic monopoles or set significantly lower experimental flux limits than had been previously available in the velocity range from about β=10 −4 to unity. In addition it made a variety of other observations. Examples are: setting flux limits on other so far unobserved particles such as nuclearites and lightly ionizing particles, searching for WIMP annihilations in the Earth and the Sun and for neutrino bursts from stellar collapses in or near our Galaxy, and making measurements relevant to high energy muon and neutrino astronomy and of the flux of up-going muons as a function of nadir angle showing evidence for neutrino oscillations. The apparatus consisted of three principal types of detectors: liquid scintillator counters, limited streamer tubes, and nuclear track etch detectors. In addition, over part of its area it contained a transition radiation detector. The general design philosophy emphasized redundancy and complementarity. This paper describes the technical aspects of the complete MACRO detector, its operational performance, and the techniques used to calibrate it and verify its proper operation. It supplements a previously published paper which described the first portion of the detector that was built and operated.

Study of radon concentrations in oil refinery premises and citydwellings

Radon and its progeny concentrations were measured in several dwellings at anoil refinery premises and these concentrations were compared with those foundin dwellings in Mathura and Agra cities. Radon progeny concentrations weremeasured using LR-115 type II nuclear track etch detectors. The radonconcentrations were estimated by using a value of 0.42 for the equilibriumfactor. The geometric means (GM) of radon concentrations in the refinerydwellings, Mathura city and Agra city dwellings were 97, 91 and 75 Bq m-3with geometric standard deviations of 1.7, 1.8 and 1.8 respectively. Theaverage lifetime risk of lung cancer for an adjusted annual average chronicradon exposure of 69 Bq m-3 (7.8 mWL; WL = working level)with an occupancy factor of 0.7 comes out to be 5.4×10-3.

Radon Mapping of Soils in St. Elizabeth, Jamaica

Soil gas measurements of radon were made in St. Elizabeth, Jamaica using nuclear track etch detectors. The results were compared to gamma-ray spectroscopy measurements made in the laboratory on soil samples collected at the radon measurement sites. An assessment of the degree of disequilibrium of uranium and thorium was also made by comparison with neutron activation analysis, delayed neutron counting and equivalent uranium and thorium measurements. The results to date for equivalent uranium and radon show a strong correlation and indicate the possibility of soil radon mapping in Jamaica using gamma-ray spectroscopy. Three anomalous sites have been identified.

Measurement of the Isotopic Composition of Manganese, Iron, and Nickel in the Galactic Cosmic Rays

view Abstract Citations (16) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Measurement of the Isotopic Composition of Manganese, Iron, and Nickel in the Galactic Cosmic Rays Westphal, A. J. ; Afanasyev, V. G. ; Price, P. B. ; Solarz, M. ; Akimov, V. V. ; Rodin, V. G. ; Shvets, N. I. Abstract Using the small collector of the Trek experiment, a nuclear track-etch detector deployed on board the Russian space station Mir, we have made a measurement of the isotopic composition of manganese, iron, and nickel in the Galactic cosmic rays (GCR) at energies between 150 and 400 A MeV. We find that the isotopic composition of iron and nickel in the GCR source is consistent with solar system values; in particular, [60Ni]/[58Ni] is 0.78+-0.280.29 times the solar value, in contradiction to two previous results. The measurements were made in 1991-1992, during a maximum in solar activity and unusually strong solar modulation; we estimate that the analyzed GCR ions had kinetic energies between 550 and 1200 A MeV outside of the heliosphere. Based on our upper limit for the abundance of 56Ni, we place a lower limit of ∼24 days on the time between nucleosynthesis and acceleration of GCR material; the lack of significant enhancements in 54Fe or 60Ni excludes the possibility of major contributions of neutron- rich supernova zones to the GCR source. We do not find a strong depletion of 54Mn, indicating that this isotope does not completely decay during propagation. We also place upper limits on the abundances of 54Fe, 57Fe, 58Fe, 62Ni, and 64Ni. Our limit on the abundance of 58Fe is nearly a factor of 3 lower than previously reported upper limits. Publication: The Astrophysical Journal Pub Date: September 1996 DOI: 10.1086/177725 Bibcode: 1996ApJ...468..679W Keywords: ISM: COSMIC RAYS; NUCLEAR REACTIONS; NUCLEOSYNTHESIS; ABUNDANCES; ISM: ABUNDANCES full text sources ADS |

Dosimetry of neutrons and high energy particles with nuclear track detectors

ICRP 60 Recommendations increase requirements on the lower detection limit of individual neutron dosimeters by a factor estimated up to about five. Besides, aicrew members should be taken as an occupationally exposed persons, the fields on the board of an aircraft contain, as in the case of high energy accelerator environment, not negligible part of high energy particles. There is the question, to what extent existing nuclear track etch detectors can fulfill new requirements arising. Previous and recently published results concerning the neutron and high energy particle dosimetry are presented, reviewed and analyzed. Results of some intercomparison programs are also included.

Environmental scanning electron microscope imaging examples related to particle analysis.

This work provides examples of some of the imaging capabilities of environmental scanning electron microscopy applied to easily charged samples relevant to particle analysis. Environmental SEM (also referred to as high pressure or low vacuum SEM) can address uncoated samples that are known to be difficult to image. Most of these specimens are difficult to image by conventional SEM even when coated with a conductive layer. Another area where environmental SEM is particularly applicable is for specimens not compatible with high vacuum, such as volatile specimens. Samples from which images were obtained that otherwise may not have been possible by conventional methods included fly ash particles on an oiled plastic membrane impactor substrate, a one micrometer diameter fiber mounted on the end of a wire, uranium oxide particles embedded in oil-bearing cellulose nitrate, teflon and polycarbonate filter materials with collected air particulate matter, polystyrene latex spheres on cellulosic filter paper, polystyrene latex spheres "loosely" sitting on a glass slide, and subsurface tracks in an etched nuclear track-etch detector. Surface charging problems experienced in high vacuum SEMs are virtually eliminated in the low vacuum SEM, extending imaging capabilities to samples previously difficult to use or incompatible with conventional methods.

Lignite and tin ores exploration in southern part of Thailand by using nuclear track-etch detectors

Both lignite and tin mines in Southern of Thailand are associated with uranium ore. In lignite exploration, Bangpudum Lignite Mine at Krabi Province was chosen for this studied because we know the exact location and deposition of coal seam by using other geophysical technique and also confirm by borehole. The size 1x2 cm2 of cellulose nitrate CN-85 films were used, each film was stuck at the inner bottom of a softdrink cup. Each cup was put up side down at the bottom of a borehole about 75 cm depth from the earth surface and laid about 10 m apart. All the cups were put in the hole along the line in order to cover about 280 metre in the cross sectional direction long of the known coal seam. After one month, all the film detectors were collected and etched with 6.25N NaOH at 60°C about 25 minutes long in order to enlarge the latent alpha registration tracks. These alpha particles were emitted from radon gas (Rn-222) which was generated from uranium associated with lignite ore. The registration track density per area of each CN-85 film was studied by optical microscope at 400x magnifications. We found that the track densities of the films have high correlation with the depth of the known coal seam while high and low track densities will correspond to the shallow and deep coal seam respectively. Also, track density was significantly higher than background. A similar manner of experiment was designed for tin ore exploration at Ronpibul district, Nakorn Si Thammarat province. The result is in progress and will present at the conference.

Passive one-element track etch dosemeter for simultaneous measurement of radon, thoron and decay products in air

For environmental and individual monitoring a passive small-size individual dosemeter has been recently developed which makes use of tracksize distribution technique to separate and identify different α-energy groups. The dosemeter of the size 4 cm diam. and 2 cm height consists of a hemispherical cup of electrically conductive material which can be used either as an open chamber ar as a diffusion chamber for the measurement of radon only. Makrofol E covered with a conductive foil is used as nuclear track etch detector. The paper describes the mathematical dosemeter model, the evaluation technique for separating α-energy groups and discusses results from pilot studies in houses and mines, where the dosemeter has been integrated in the miners helmets.

Measurement of radon and thoron present in the environment using nuclear track etch detector technique

Abstract The use of solid state nuclear tract detectors (SSNTD) is one of the most convenient techniques to assess the average radiation levels of alpha activities in the environment. This technique has been used to assess the radon and thoron concentrations in some high background areas of South India and underground non-uranium mines in Bihar State. Exposed SSNTD films are chemically etched in an alkali solution and the alpha tracks are evaluated under an optical microscope. The detailed procedure for this study and the calibration of the etched films for conversion of alpha track density to radon and thoron concentrations in pCi l-1 are given in this paper. It was found that 1.9 tracks cm-2 day-1 and 6.2 tracks cm-2 day-1 were produced by exposing the LR-115 foils to 1 pCi l-1 of thoron and radon respectively.

THE FEASIBILITY OF HEAVY CHARGED‐PARTICLE MICROSCOPY*

The idea of applying accelerated heavy ions to microscopy was developed and proposed about ten years ago. The advancement of heavy-ion accelerator technology has promoted development of a new imaging system for diagnostic radiology. The plastic nuclear track-etch detector technique has recently been used for microradiography with low-energy heavy ions, and images of various biological specimens, including living plant cells, have been obtained. A simple and straightforward theoretical analysis indicates that a resolution of a few hundred angstroms may be reached in imaging a living cell with heavy particles of 10-..mu..m range. At present, however, such a high resolution is not expected, since the radiation damages to the specimen can be very severe at high doses. With certain improvement the present heavy-ion microradiography technique, nevertheless, can be used for gaining information on the density of organelles in a living cell and for obtaining a three-dimensional image of a living cell. A preliminary study on contrast mechanisms suggests that the heavy-ion microscope may give an equal or better contrast than the electron microscope. Other possible means of getting information with heavy-ion microscopes should be explored also. An energy or range analysis of heavy particles that passed through the biological specimen withmore » a proper detector, for example can provide additional information of interest.« less