Radioaktivnost v pitnih vodah Slovenije

magistrsko delo

Klara Poiškruh (Author), Matej Lipoglavšek (Mentor), Jasmina Kožar Logar (Co-mentor)

Abstract

Cilj magistrske naloge je prikaz izračuna ocene indikativne doze iz rezultatov presejalne metode za ugotavljanje skupnih specifičnih aktivnosti sevalcev žarkov α in β. Motivacija je predvsem v enostavnosti in hitrosti te metode v primerjavi z metodama visokoločljivostne spektrometrije γ in radiokemičnimi analizami. Prednost metode ugotavljanja skupnih specifičnih aktivnosti sevalcev žarkov α in β je tudi zaznava vseh sevalcev žarkov α in β, slabost pa, da o dejanskih koncentracijah aktivnosti posameznih radionuklidov nimamo podatkov. Dobro umerjeni in kalibrirani tekočinskoscintilacijski števci so predpogoj za ugotavljanje skupne specifične aktivnosti sevalcev žarkov α in β. Del naloge je zato tudi prikaz priprave merjencev z znanimi skupnimi specifičnimi aktivnostmi sevalcev žarkov α in β in različnimi radionuklidi za kalibracijo tekočinskoscintilacijskih števcev Quantulus in izračun diskriminacijskih vrednosti PSA. Kalibraciji sledijo vzorčenje, priprava merjencev vodovodnih vod in izračun skupnih specifičnih aktivnosti sevalcev žarkov α in β. Vzorčevalna mesta vodovodov so bila razporejena po širšem območju Slovenije, skupno 20 lokacij. Izračunali smo tudi skupne specifične aktivnosti sevalcev žarkov α in β iz koncentracij aktivnosti posameznih radionuklidov, ki so bili iz istih vzorcev poročani z metodo visokoločljivostne spektrometrije γ in z radiokemičnimi analizami. Izkazalo se je, da se meritve med seboj dobro ujemajo. Za približno oceno indikativne doze torej lahko uporabimo podatke skupnih specifičnih aktivnosti sevalcev žarkov α in β, če uporabimo dozne faktorje za skupne specifične sevalce žarkov α ali β, določene v tem delu. Za natančejši izračun pa potrebujemo podatke o koncentracijah aktivnosti posameznih radionuklidov visokoločljivostne spektrometrije γ in radiokemičnih analiz.

Keywords

radioaktivnost;pitna voda;sevalci alfa in beta;uran;torij;kalij;tekočinskoscintilacijska spektrometrija;visokoločljivostna spektrometrija gama;radiokemične analize;efektivna doza;indikativna doza;

Data

Language:	Slovenian
Year of publishing:	2021
Typology:	2.09 - Master's Thesis
Organization:	UL FMF - Faculty of Mathematics and Physics
Publisher:	[K. Poiškruh]
UDC:	539.16
COBISS:	67094019
Views:	396
Downloads:	66
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Radioactivity in drinking water in Slovenia
Secondary abstract:	The aim of the master's thesis is to present the calculation of the estimated dose from the results of the screening method for determining the gross activities of α and β-ray emitters. The motivation is mainly in the simplicity and speed of this method compared to high-resolution γ-ray spectrometry methods and radiochemical analyzes. The advantage of the method of determining the gross activities of α and β-ray emitters is also the detection of all α and β-ray emitters, and the disadvantage is that we do not have data on the actual activity concentrations of individual radionuclides. Well calibrated liquid scintillation counters are a must for determining the gross activity of α and β-ray emitters. Therefore, part of the task is to present the preparation of samples with known activities of α and β-ray emitters and different radionuclides for calibration of Quantulus liquid scintillation counters and calculation of PSA values. Calibration is followed by sampling, preparation of tap water for measurements and calculation of gross activities of α and β-ray emitters. Sampling points of water supply systems were distributed over a wide area of Slovenia, a total of 20 locations. The total specific activities of α and β-ray emitters were also calculated from the activity concentrations of individual radionuclides, which were reported from the same samples by the methods of high - resolution γ-ray spectrometry and radiochemical analyzes. The measurements turned out to match well with each other. Data on the total specific activities of α and β-ray emitters can therefore be used to approximate the indicative dose, using the dose factors for the total specific α or β-ray emitters shown in this work. For a more accurate calculation, we need data on the activity concentrations of individual radionuclides in high-resolution γ-ray spectrometry and radiochemical analyzes.
Secondary keywords:	radioactivity;drinking water;alpha and beta emitters;uranium;thorium;potassium;liquid-scintillation spectrometry;gamma-ray spectrometry;radiochemical analyses;effective dose;indicative dose;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Thesis comment:	Univ. v Ljubljani, Fak. za matematiko in fiziko, Oddelek za fiziko
Pages:	74 str.
ID:	13018508