On the human radiation exposure as derived from the analysis of natural and man-made radionuclides in soils [Elektronische Ressource] / von Shaban Ramadan Mohamed Harb

On the human radiation exposure as derived
from the analysis of natural and man-made
radionuclides
in soils











Vom Fachbereich
Physik
der Universität
Hannover

zur Erlangung des Grades


Doktor der Naturwissenschaften
Dr. rer. nat.
genehmigte Dissertation

von

(M.Sc. Phys.)
Shaban Ramadan Mohamed Harb


geboren am 10.01.1966
in Qena, Ägypten









2004











































Referent: Prof. Dr. Rolf Michel
Korreferent: PD. Dr. Ingo Leya

Tag der Promotion: 11.02.2004Content I

Content
Content ...........................................................................................................................I
List of Tables..............................................................................................................IV
List of Figures .......................................................................................................... VII
Summary ......................................................................................................................X
Zusammenfassung..................................................................................................... XII
Acknowledgements ..................................................................................................XIII
1 Introduction ........................................................................................................ 1
1.1 Radioactivity in the environment ................................................................................1
1.1.1 Natural Radionuclides in the environment..................................................................1
1.1.1.1 Cosmogenic radionuclides..........................................................................................2
3 Tritium ( H )3
Beryllium-7, 10...................................................................................................3
Carbon-14............................................................................................................3
Krypton................................................................................................................4
1.1.1.2 Terrestrials sources of radiation ..................................................................................5
1.1.1.2.1 Potassium-40...............................................................................................................5
1.1.1.2.2 Rubidium-87................................................................................................................6
1.1.1.2.3 Uranium-238 series..6
238 234 234m 234 Uranium-238 subseries ( U, Th, Pa, U)..............................................7
Radium-2268
218 214 214 214 Radon-222 and its short-lived products ( Po, Pb, Bi, Po) ....................8
210 210 210 Long-lived decay products of Radon-222 ( Pb, Bi, Po).........................10
1.1.1.2.4 Thorium-232 series...................................................................................................10
Thorium-232......................................................................................................11
228 228 228 224 Radium-228 subseries ( Ra, Ac, Th, Ra).........................................
215 212 212 212 208 Randon-220 and its decay products ( Po, Pb, Bi, Po, Tl).................12
1.1.1.2.5 The actinium series....................................................................................................12
1.1.1.2.6 The neptunium series ................................................................................................13
1.1.1.2.7 Decay Relationships Series .......................................................................................13
1.1.2 Man-made Radionuclides in the environment ..........................................................20
1.1.2.1 Strontium-90..............................................................................................................21
1.1.2.2 Iodine-131.................................................................................................................22
1.1.2.3 Cesium-134 and 137..................................................................................................22
1.2 The human radiation exposure ..................................................................................23
1.2.1 External exposure......................................................................................................25
1.2.2 Internal exposures.....................................................................................................27
1.2.2.1 Ingestion....................................................................................................................27
1.2.2.2 Inhalation......28
1.2.3 Mean values and variability of the natural radiation exposure .................................28
2 Experimental 32
2.1 Soil sampling.............................................................................................................32
2.1.1 The trench method32
2.1.2 Template method.......................................................................................................
2.1.3 The bore core method................................................................................................34
2.2 Sample preparation....................................................................................................35
2.3 Experimental methods, measurements and evaluations............................................36
2.3.1 Gamma spectrometry36
2.3.2 HPGe detector...........................................................................................................40
2.3.3 Gamma spectrometry System (HPGe) ......................................................................41
???????????Content II

2.3.4 Energy calibration.....................................................................................................42
2.4 Calibration and efficiency determination of detectors for different measuring
geometries and sample containers............................................................................43
2.4.1 Preparation of reference standard solution (Calibration source QCY48) ...............44
2.4.2 Preparation of standard soil sample procedure ........................................................45
2.4.3 Efficiency calibration................................................................................................45
2.4.4 Analytical efficiency expressions..............................................................................
2.5 Natural Background .................................................................................................58
2.6 Calculation of elemental concentrations ...................................................................60
2.7 Experimental uncertainties........................................................................................62
2.8 Quality assurance including Ringversuch.................................................................67
2.9 Characteristic limits...................................................................................................69
3 Analysis of radionuclides in soils..................................................................... 72
3.1 Concentration of artificial radionuclides in depth profile and surface......................72
3.1.1 137 Cs concentration in depth profile soil samples from Lower Saxony, North
Germany...................................................................................................................73
3.1.1.1 137 Cs deposition densities in soil samples from Lower Saxony, North Germany...79
137 40 -13.1.1.2 Activity concentration of Cs and K [Bq kg ] in surface soil samples from
different sites in Lower Saxony, North Germany. ...................................................81
3.1.2 137 Cs in depth profile soil samples from Lippe, North Rhine-Westphalia, Germany.
..................................................................................................................................83
3.1.2.1 137 Cs deposition densities in soil samples from Lippe, (North Rhine-Westphalia),
Germany.83
137 40 -13.1.2.2 Activity concentration of Cs and K [Bq kg ] in surface soil samples from Lippe
(North Rhine-Westphalia, NRW), Germany..........................................................