Dose rate measurement

Nearly all decommissioning and dismantling (D&D) projects are steered by the characterisation of the plant being dismantled. This radiological characterisation is a complex process that is updated and modified during the course of the D&D. One of the tools for carrying out this characterisation is the performance of in-situ measurements.

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A recent inter-comparison (Murray et al., 2015) has helped to highlight variability in the measurement of dose rate between luminescence laboratories. Part of this variability probably reflects the difficulties of homogenising and dissolving samples so that the < 500 mg used in e.g. ICP-MS and NAA is representative.

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This dispersion highlights the danger of relying on individual calibrations, and is clearly undesirable. Here we continue our investigation into providing reliable calibration materials for trapped electron dating. A comparison of the apparent quartz β source dose rates shows that there is no significant dependence on the geological source of the quartz.

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The beta-particle emission from a sediment or rock sample can be measured very precisely using beta-counting instruments. The observed count rate is largely a function of the radionuclide concentration in the sample, so has the potential to provide a precise estimate of the natural radiation dose rate.

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Previous work has been unable to establish a relationship between K concentration and De in single-grains of feldspar. Here we use four well-bleached sediments with low external dose rate (typically ≤1.5 Gy ka−1 ) to investigate this relationship.

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It is desirable to be able to establish the relationship between the spatial distribution of luminescence and chemical composition/mineralogy. This is especially true in complex, heterogeneous samples such as solid coarse-grained rock slices and separated feldspar grains, where the internal dose rate is very dependent on the effective size of luminescent regions of the sample.

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One of the objectives of the EMPIR project 16ENV04 “Preparedness” is the harmonization of methodologies for the measurement of doses with passive dosimetry systems for environmental radiation monitoring in the aftermath of a nuclear or radiological event. In such cases, measurements are often performed at low radiation dose rates, close to the detection limit of the passive systems.

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In the aftermath of a nuclear or radiological accident, an extended mapping of reliable dose rate values is of key importance for any governmental decision and countermeasures. Presently, numerous dosimetry network stations, operated by the national governments of the member states in Europe, provide such dose rate data on an hourly basis.

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The decision thresholds that indicate the presence of artificial radioactivity are calculated for the count rates in the low energy region of the spectra, the man-made count rates and the ambient dose equivalent rates from the background flights performed at altitudes ranging between 10 m and 60 m.

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Beta Dose Rate heterogeneity is a recognized source of uncertainty when applying luminescence dating to heterogeneous samples, such as coarse crystalline rocks and clast-rich sediments. Simulations have shown that a combination of a heterogeneous distribution of minerals and radioactive elements can lead to complex dose distributions, overdispersion and potentially to bias in equivalent dose determinations.

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Gamma-ray spectrometry is a well-established technique which enables to perform qualitative and quantitative analyses of gamma-ray emitting radionuclides. In trapped charge dating, portable spectrometers can be used to acquire spectra in the field, allowing for the assessment of radionuclide concentrations and hence the determination of dose rates at the exact location where samples are collected for dating.

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Low concentrations of morphine are required for safe dosing for intrathecal injections. Sometimes, manual dilution of morphine is performed to achieve these low concentrations, but risks dilution errors and bacterial contamination. The primary goal was to compare the concentrations of morphine and bupivacaine between four groups of syringes. The secondary goal was to investigate the difference in contamination rate between these groups.

6p vizhangzhidong 29-12-2021 13 0   Download

This paper presents a complete process in designing and manufacturing a marine buoy integrated with a radiation sensor. The radiation detector can measure both dose rate and radiological spectrum. The ORMS also combines multimodal data transmission and various programmed software for data processing, signal transmission, and system control. Therefore, the proposed configuration system has potential application in terms of performance and maintenance.

8p vicolinzheng 14-12-2021 24 0   Download

Rapeseed is one of the most important oilseeds crop in Assam, which plays a major role in enhancement the income of marginal and small farmers of Darrang district. One of the major constraints of low productivity of rapeseed farming is using of local varieties. However, delayed sowing & use of higher seed rate resulting into dense plant population, uneven plant population, uncontrolled weeds, ignorance about recommended doses of fertilizers and lack of plant protection measures were the predominant identified causes of low productivity of oilseeds in the district.

4p trinhthamhodang9 16-12-2020 10 1   Download

KGdF4 polycrystalline doped with the different concentration of Sm3+ ions were synthesized by hydrothermal technique. Thermoluminescence (TL) glow curves of samples were measured in the range from 50 oC to 400 oC after irradiating beta, neutron and X-ray radiations. The response of TL intensity to impurity concentration and neutron dose were studied in detail. The TL kinetic parameters such as activation energy (E) and frequency factor (s) were estimated by using the method of heating rate variation.

6p trinhthamhodang9 10-12-2020 14 1   Download

The administration of ketones to induce a mild ketosis is of interest for the alleviation of symptoms associated with various neurological disorders. This study aimed to understand the pharmacokinetics (PK) of D-β-hydroxybutyrate (BHB) and quantify the sources of variability following a dose of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (ketone monoester). Healthy volunteers (n = 37) were given a single drink of the ketone monoester, following which, 833 blood BHB concentrations were measured. Two formulations and five dose levels of ketone monoester were used.

11p caothientrangnguyen 09-05-2020 14 1   Download

Hepcidin (H25) is a hormone peptide synthesized by the liver that binds to ferroportin and blocks iron export. In this study, H25 was inhibited by administration of single and multiple doses of an anti-H25 monoclonal antibody Ab 12B9m in cynomolgus monkeys. The objective of this analysis was to develop a pharmacodynamic model describing the role of H25 in regulating iron homeostasis and the impact of hepcidin inhibition by Ab 12B9m. Total serum H25 and Ab 12B9m were determined in each animal. Corresponding measurements of serum iron and hemoglobin (Hb) were obtained.

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Chickpea (Cicer arietinum L.) is commonly known as gram which is one of the important pulse crops of the State. Front line demonstrations were conducted at 100 farmer's field in 40 hectares of 11 villages. To demonstrate production potential and economic benefits of improved technologies comprised viz., improve varieties (JAKI 9218 and JG 14) with seed rate of 75 kg/ha, line sowing with spacing of 30 cm (R-R) and 10 cm (P-P), seed treatment with bavistin 2 g/kg seed, balance dose of fertilizer, weed management and plant protection measures.

5p chauchaungayxua3 07-02-2020 9 0   Download

Harmful cyanobacterial blooms have become a global threat to human health and aquatic biota around the world. While the ecotoxicity of cyanobacterial toxins such as microcystins (MCs) has been studied extensively, the toxicity of non-toxin producing cyanobacteria has not been evaluated to the same extent. In this study, five strains of Microcystis wesenbergii were isolated from the Tri An reservoir and cultured under laboratory conditions. Microscopic observation was used for morphological identification. The MCs concentration was measured by highperformance liquid chromatography (HPLC).

6p chauchaungayxua2 07-01-2020 36 1   Download

Nitrogen is the major nutrient element required for the plant growth and development. In rice, development of varieties with improved nitrogen use efficiency will reduce the nitrogen fertilizer application. This study was investigating the genotypic differences in photosynthetic nitrogen use efficiency, nitrogen use efficiency, yield and yield related traits of 12 different rice genotypes under two different nitrogen levels viz., T1 and T2. Different physiological and agronomical characters were measured in selected 12 genotypes, growing in field.

10p quenchua2 15-12-2019 12 0   Download