The track structure of the signal measured by the semiconductor pixel detector Timepix3 was modelled in the Monte Carlo MCNP® code. A detailed model at the pixel-level (256 × 256 pixels, 55 × 55 µm² pixel size) was developed and used to generate and store clusters of adjacent hit pixels observed in the measured data because of particle energy deposition path, charge sharing, and drift processes. An analytical model of charge sharing effect and the detector energy resolution was applied to the simulated data. The method will help the user sort the measured clusters and distinguish radiation components of mixed fields by determining the response of Timepix3 detector to particular particle types, energies, and incidence angles that cannot be measured separately.

For spectroradiometers, the characterisation of their wavelength scale and spectral bandwidth underpins the quality of measured data substantially. This characterisation can be performed using metrology-grade tuneable monochromatic sources, which are currently available only in a few laboratories worldwide. Yet in numerous applications, only the in-field calibration is a feasible solution. We have designed and developed a tuneable and portable radiation source (TuPS) in the wavelength range from 300 to 350 nm for the in-field characterisation of Dobson spectrometers' wavelength scale and slit function, with standard uncertainties better than 0.02 nm in wavelength and with the bandwidth of emitted radiation smaller than 0.13 nm full width at half maximum (FWHM). The TuPS is designed such that only minor modifications of its optical system extend/shift its spectral range towards visible and near-infrared spectral regions and thus expand its application for characterisation of any spectroradiometers in the relevant spectral region of interest.

This work presents new calculations of conversion coefficients (CCs) from total air kerma to dose-equivalent quantities H’(0.07), H’(3), H*(10), H _p(0.07), H _p(3), and H _p(10) for area and personal dosimetry for mono-energetic photons in the energy range from 2 keV to 50 MeV, assuming secondary charged particle equilibrium. Calculations using the Monte Carlo N-Particle® (MCNP) code were performed for a large number of photon energies with the aim of preventing errors resulting from possible improper interpolation between currently available sparsely spaced CC values, when an average CC value over a photon fluence spectrum needs to be determined. The CC values were compared with the values published in the ISO 4037-3:2019 standard. A very close agreement was achieved for the majority of CCs. Larger discrepancies were found for some CCs, often for low photon energies or large angles of radiation incidence, which were taken from older publications or when CC values were interpolated or extrapolated. Furthermore, some differences were found in the MeV energy range, which are significant for dosimeter calibrations, e.g. the presented values of CC to H*(10) for the main photon energies of ¹³⁷Cs and ⁶⁰Co radionuclides are both lower by 2.8%. Finally, it was found that the values of CCs to H _p(0.07; E, α)_slab given in ISO 4037-3:2019 were not taken correctly from the source publication. In conclusion, the CC values given in ISO 4037-3:2019 should be updated in view of the results obtained.

The Czech national standard of low gas flow is based on the dynamic gravimetry principle, defining the flow rate as the mass loss of gas from a pressure bottle which is continuously weighed. This weighing is performed in ambient atmosphere, which brings two problems. First, the buoyancy corrections are the main and unavoidable source of uncertainty. Second, condensation of the water vapor on the pressure bottle can occur, due to its cooling below dew point at higher flow rates. A weighing carried out in a hermetically closed atmosphere suppresses the problematic buoyancy effects. A weighing in a vacuum does the same, and also eliminates any danger of water condensation. The paper describes the hermetic and vacuum mode modifications together with the relevant uncertainty analyses.

For spectroradiometers the characterisation of their wavelength scale and spectral bandwidth underpins substantially the quality of measured data. This characterisation can be performed using metrology-grade tuneable monochromatic sources, which are currently available only in a few laboratories world-wide. Yet in numerous applications only the in-field calibration is a feasible solution. We have designed and developed a Tuneable and Portable radiation Source (TuPS) in the wavelength range from 300 nm to 350 nm for the in-field characterization of Dobson and Brewer spectrometers wavelength scale and slit-function with uncertainties better than 0.02 nm in wavelength and with the bandwidth of emitted radiation smaller than 0.1 nm FWHM. The TuPS is designed such that only minor modifications of its optical system extends/shifts its spectral range towards visible and near-infrared spectral regions and thus expand its application for characterisation of any spectroradiometers in the relevant spectral region of interest.

This study focuses on detecting addictive substances in the human body using modern instrumental methods, specifically the Dräger DrugTest 5000 (DDT 5000) device. Addictive substances are classified by legal status, chemical structure, and patterns of use. The study evaluates various biological matrices for drug detection, identifying oral fluid as the most suitable option due to its non-invasiveness and appropriate detection window. The core objective is to experimentally verify the detection limits of selected substances using the DDT 5000 and compare the findings with the manufacturer’s specifications. Results indicate that most detection limits are below or consistent with those declared by the manufacturer, except for heroin. A notable finding concerns tetrahydrocannabinol (THC), where extremely low and potentially unreliable detection limits were observed, suggesting the need for further verification. In conclusion, the DDT 5000 demonstrates high sensitivity, specificity, and accuracy, making it a reliable tool for rapid detection of most abused substances.