Effects of etching time on alpha tracks in solid state nuclear track detectors

Abstract

Solid State Nuclear Track Detectors (SSNTDs) are used extensively for monitoring alpha particle radiation, neutron flux and cosmic ray radiation. Radon gas inhalation is regarded as being a significant contributory factor to lung cancer deaths in the UK each year. Gas concentrations are often monitored using CR39 based SSNTDs as the natural decay of radon results in alpha particles which form tracks in these detectors. Such tracks are normally etched for about 4 hours to enable microscopic analysis. This study examined the effect of etching time on the appearance of alpha tracks in SSNTDs by collecting 2D and 3D image datasets using laser confocal imaging techniques. Etching times of 2 to 4 hours were compared and marked differences were noted in resultant track area. The median equivalent diameters of tracks were 20.2, 30.2 and 38.9 µm for etching at 2, 3 and 4 hours respectively. Our results indicate that modern microscope imaging can detect and image the smaller size tracks seen for example at 3 hours etching time. Shorter etching times may give rise to fewer coalescing tracks although there is a balance to consider as smaller track sizes may be more difficult to image. Thus etching for periods of less than 4 hours clearly merits further investigation as this approach has the potential to improve accuracy in assessing the number of tracks.

3D imaging of volcanic ash using the confocal microscope; a comparison of natural fragments and experimentally vesiculated volcanic glass

“…The unmodified particles in the strew slides and the thick section material were imaged on an Olympus LEXT 4100 (Olympus Corporation, Japan) 3D measurement scanning laser confocal microscope in a similar manner to that described by Wertheim et al (2009Wertheim et al ( , 2010 and Gillmore et al (2017). 30 bubbles were imaged in fine mode setting using the LEXT microscope's x50 or x100 lenses.…”

Performance of radon monitors in a purpose-built radon chamber

“…CR-39 etched track detectors are composed of a diffusion container and a 100 mm 2 plastic polymer placed inside, with an effective surface of 51.69 mm 2 . Alpha particles from radon and its progeny decay strike the plastic leaving tracks that can be counted after etching in a NaOH solution (Ali et al 2009, Gillmore et al 2017. The track density on the plastic (obtained using a microscope with image analysis software) can be related to radon exposure and radon concentration by using a conversion factor, given by the manufacturer and verified by LaRUC.…”

Parameters Affecting Bulk Etch Rate VBfor CR-39 Detector

“…These parameters are the bulk etches rate VB and the track etches rate VT. [10]. The CR-39 detector is extensively practiced in space radiation experiments [11].…”

“…Energy, direction, and charge of an incident particle may be facilely researched by measuring the trajectory profile at rightly chosen terms of temperature T of the etchant solution, etchant time and its concentration N. These parameters might affect the etching eliminating processes without irradiated detector material and detecting of the tracks [11]. The VB can be measured by various methods like track diameter method of the fission fragment, weight difference before and after etching, and laser interferometer during the chemical etching [12].…”