A fast method to measure the thickness of removed layer from etching of SSNTD based on EDXRF

Ways to Measure Metals: From ICP-MS to XRF

PURPOSE OF REVIEW

This review explores the use of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and X-ray Fluorescence (XRF) for quantifying metals and metalloids in biological matrices such as hair, nails, blood, bone, and tissue. It provides a comprehensive overview of these methodologies, detailing their technological limitations, application scopes, and practical considerations for selection in both laboratory and field settings. By examining traditional and novel aspects of each method, this review aims to guide researchers and clinical practitioners in choosing the most suitable analytical tool based on their specific needs for sensitivity, precision, speed, and sample preparation.

RECENT FINDINGS

Recent studies highlight enhanced capabilities of both ICP-MS and XRF technologies, making them more adaptable to various analytical needs. ICP-MS is renowned for its unmatched sensitivity and precision in detecting ultra-trace metals and metalloids in complex biological samples, such as lead in plasma or seawater. XRF advancements include lower detection limits and reduced sample preparation time, enabling rapid, non-destructive analyses, ideal for quick field assessments. Portable XRF analyzers have revolutionized on-the-spot testing, providing robust data without traditional wet-lab constraints. Moreover, hybrid techniques combining ICP-MS and XRF features are emerging, offering rapid and precise metal analysis for environmental monitoring, clinical diagnostics, and epidemiological studies. Matching analytical methods to specific research demands is critical. ICP-MS is the gold standard for detailed quantitative analysis in laboratories, while XRF excels in non-destructive, immediate field applications. Selection should consider sample complexity, sensitivity, speed, and cost-efficiency. Integrating ICP-MS and XRF offers a versatile approach to metals analysis, transforming practices in environmental science and healthcare diagnostics. As these technologies evolve, they are promising to expand capabilities in detecting and understanding the roles of metals and metalloids in health and the environment.

Simple and low cost alternative method for detecting photoneutrons produced in some radiotherapy treatments using SSNTDs

A simple and low cost alternative which is able to identify thermal and fast neutrons in a clinical environment of radiotherapy is presented. CR-39 and LR-115 Solid State Nuclear Track Detectors (SSNTDs) were used, estimating their viability. In order to register alpha tracks due to thermal neutrons, natural boric acid tablets were placed in close contact to the detector, whereas in order to detect epithermal neutrons, some were additionally covered in a thin cadmium layer. Different configurations were assembled, changing the position of the converter with respect to the detector and the incident neutron fluence, which was evaluated in different positions of a radiotherapy table. The contribution due to environmental ²²²Rn and its daughters to the track density registered by the detector during the measurements was found to be negligible. It is concluded that the designed experimental set up constitutes a trustworthy and affordable method to carry out neutron measurements with the recommended configurations provided for the CR-39 detector, and not with LR-115.

Characterization of alpha-particle tracks in cellulose nitrate LR-115 detectors at various incident energies and angles

Cellulose nitrate LR-115 detectors were irradiated with alpha particles in the energy range from 1 to 5 MeV at incident angles from 20° to 90°, using an (241)Am source. After etching in a 2.5 N NaOH solution kept at 60 °C for various periods, the diameters of the major and minor axes of the track openings, track growing rate, track etch rate, etching ratio, and track length were found as a function of energies and incident angles. The measured track parameters were compared to calculated values, and the etching ratio was formulated as a Durrani-Green's function of the incident energy and angle.

Derivation of V function for LR 115 SSNTD from its sensitivity to 220Rn in a diffusion chamber

The sensitivity of the LR 115 detector inside a diffusion chamber to (220)Rn gas concentration is dependent on the removed active layer thickness during chemical etching. This dependence is related to the V function for the LR 115 detector (where V is the ratio between the track etch velocity V(t) and the bulk etch velocity V(b)) and the geometry of the diffusion chamber. The present paper presents the experimentally determined relationship between the sensitivity of the LR 115 detector inside a Karlsruhe diffusion chamber (determined from the number of etched tracks completely penetrating the active cellulose nitrate layer) and the removed active layer thickness. These data were used to derive the V function for the LR 115 detector, which took the functional form of the Durrani-Green's function, i.e., V=1+((a1e-)(a2R+a3e(-a)4R))(1(-e)(-a5R)), with the best-fitted constants as a(1)=14.50, a(2)=0.50, a(3)=3.9 and a(4)=0.066.

Theoretical basis for long-term measurements of equilibrium factors using LR 115 detectors

In this paper, we propose a method to determine the equilibrium factor using a bare LR 115 detector. The partial sensitivities rhoi of the LR 115 detector to 222Rn and its alpha-emitting short-lived progeny, 218Po and 214Po, were investigated. We first determined the distributions of lengths of major and minor axes of the perforated alpha tracks in the LR 115 detector produced by 222Rn, 218Po and 214Po through Monte Carlo simulations. The track parameters were calculated using a track development model with a published V function, by assuming a removed active layer of 6.54 microm. The distributions determined for different alpha emitters were found to completely overlap with one another. This implied equality of partial sensitivities for radon and its progeny, which was also confirmed through analytical considerations. Equality of partial sensitivities makes possible convenient measurements of the proxy equilibrium factor Fp, which is defined in the present work as (F1+F3) and is equal to the ratio between the sum of concentrations of the two alpha emitting radon progeny (218Po+214Po) to the concentration of radon gas (222Rn). In particular, we have found Fp = (rho/rhoitC0)-1, where rho (track/m2) is the total track density on the detector, rhoi = 0.288 x 10(-2) m, t is the exposure time and C0 (Bq/m3) is the concentration of 222Rn. If C0 is known (e.g. from a separate measurement), we can obtain Fp. The proxy equilibrium factor Fp is also found to be well correlated with the equilibrium factor between radon gas and its progeny through the Jacobi room model. This leads to a novel method for long-term determination of the equilibrium factor.