Naturally occurring radionuclides can be categorized into two main groups: primordial and cosmogenic, based on their origin. Primordial radionuclides stem from the Earth’s crust, occurring either individually or as part of decay chains. Conversely, cosmogenic radionuclides originate from extraterrestrial sources such as space, the sun, and nuclear reactions involving cosmic radiation and the Earth’s atmosphere. Gamma-ray spectrometry is a widely employed method in Earth sciences for detecting naturally occurring radioactive materials (NORM). Its applications vary from environmental radiation monitoring to mining exploration, with a predominant focus on quantifying the content of uranium (U), thorium (Th), and potassium (K) in rocks and soils. These elements also serve as tracers in non-radioactive processes linked to NORM paragenesis. Furthermore, the heat generated by radioactive decay within rocks plays a pivotal role in deciphering the Earth’s thermal history and interpreting data concerning continental heat flux in geophysical investigations. This paper provides a concise overview of current analytical and measuring techniques, with an emphasis on state-of-the-art mass spectrometric procedures and decay measurements. Earth scientists constantly seek information on the chemical composition of rocks, sediments, minerals, and fluids to comprehend the vast array of geological and geochemical processes. The historical precedence of geochemists in pioneering novel analytical techniques, often preceding their commercial availability, underscores the significance of such advancements. Geochemical analysis has long relied on atomic spectrometric techniques, such as X-ray fluorescence spectrometry (XRFS), renowned for its precision in analyzing solid materials, particularly major and trace elements in geological samples. XRFS proves invaluable in determining the major constituents of silicate and other rock types. This review elucidates the historical development and methodology of these techniques while showcasing their common applications in various geoscience research endeavors. Ultimately, this review aims to furnish readers with a comprehensive understanding of the fundamental concepts and potential applications of XRF, HPGes, and related technologies in geosciences. Lastly, future research directions and challenges confronting these technologies are briefly discussed.

1. Martin JE. Naturally Occurring Radiation and Radioactivity. In: Physics for Radiation Protection. Wiley-VCH Verlag GmbH & Co. KGaA; 2013.

2. Isaksson M. Methods of measuring radioactivity in the environment (No. LUNFD6-NFFR--1017). Lund Univ. (Sweden). Dept. of Nuclear Physics; 1997.

3. Abedin MdJ, Khan R. NORMs distribution in the dust samples from the educational institutions of Megacity Dhaka, Bangladesh: Radiological risk assessment. Journal of Hazardous Materials Advances. 2022; 8: 100155. doi: 10.1016/j.hazadv.2022.100155

4. Abedin MdJ, Khan R. Primordial radionuclides in the dust samples from the educational institutions of central Bangladesh: radiological risk assessment. Heliyon. 2022; 8(11): e11446. doi: 10.1016/j.heliyon.2022.e11446

5. Khandaker MU, Mohd Nasir NL, Asaduzzaman K, et al. Evaluation of radionuclides transfer from soil-to-edible flora and estimation of radiological dose to the Malaysian populace. Chemosphere. 2016; 154: 528-536. doi: 10.1016/j.chemosphere.2016.03.121

6. Khandaker MU, Asaduzzaman K, Sulaiman AFB, et al. Elevated concentrations of naturally occurring radionuclides in heavy mineral-rich beach sands of Langkawi Island, Malaysia. Marine Pollution Bulletin. 2018; 127: 654-663. doi: 10.1016/j.marpolbul.2017.12.055

7. Khan R, Islam HMT, Apon MAS, et al. Environmental geochemistry of higher radioactivity in a transboundary Himalayan River sediment (Brahmaputra, Bangladesh): potential radiation exposure and health risks. Environmental Science and Pollution Research. 2022; 29(38): 57357-57375. doi: 10.1007/s11356-022-19735-5

8. Khan R, Haydar MA, Saha S, et al. (2022). Spatial distribution and radiological risk quantification of natural radioisotopes in the St. Martin’s Island, Bangladesh. In: Soil Health and Environmental Sustainability: Application of geospatial technology. Cham: Springer International Publishing; pp. 369-388.

9. Habib MA, Basuki T, Miyashita S, et al. Distribution of naturally occurring radionuclides in soil around a coal-based power plant and their potential radiological risk assessment. Radiochimica Acta. 2018; 107(3): 243-259. doi: 10.1515/ract-2018-3044

10. Ionizing radiation and health effects. Available online: https://www.who.int/news-room/fact-sheets/detail/ionizing-radiation-and-health-effects (accessed on 3 April 2024).

11. Arogunjo AM, Höllriegl V, Giussani A, et al. Uranium and thorium in soils, mineral sands, water and food samples in a tin mining area in Nigeria with elevated activity. Journal of Environmental Radioactivity. 2009; 100(3): 232-240. doi: 10.1016/j.jenvrad.2008.12.004

12. Abbasi MN, Tufail M, Chaudhry MM. Assessment of heavy elements in suspended dust along the Murree Highway near capital city of Pakistan. World Applied Science Journal. 2013; 21(9): 1266-1275.

13. Kohman TP, Saito N. Radioactivity in Geology and Cosmology. Annual Review of Nuclear Science. 1954; 4(1): 401-462. doi: 10.1146/annurev.ns.04.120154.002153

14. Bastos RO, Appoloni CR, Pinese JPP, et al. Gamma Radiation Dose Rate in Air due to Terrestrial Radionuclides in Southern Brazil: Synthesis by Geological Units and Lithotypes Covered by the Serra do Mar Sul Aero‐Geophysical Project. AIP Conference Proceedings. 2018; 1034(1): 403-406.

15. Bastos RO, Pascholati EM. Environmental gamma radiation in municipalities of Eastern of São Paulo State, Brazil. Terrae. 2005; 2(1-2): 37-45.‏

16. Dickson BL, Scott KM. Interpretation of aerial gamma-ray surveys-adding the geochemical factors. AGSO Journal of Australian Geology and Geophysics. 1997; 17.‏

17. Durrance EM. Radioactivity in geology: principles and applications. United States: N.; 1986.

18. Tarim UA, Gürler O. Source-to-detector distance dependence of efficiency and energy resolution of a 3"x3" NaI (Tl) detector. Avrupa Bilim ve Teknoloji Dergisi. 2018; (13): 103-107.‏ doi: 10.31590/ejosat.443565

19. Sharma RK. Various spectroscopic techniques. Environmental Pollution: Monitoring Modelling and Control. Studium Press; 2017. pp. 181-206.

20. ‏Vargas MJ, Timón AF, Díaz NC, Sánchez DP. Influence of the geometrical characteristics of an HpGe detector on its efficiency. Journal of Radioanalytical and Nuclear Chemistry. 2002; 253.‏

21. Alnour IA, Wagiran H, Ibrahim N, et al. New approach for calibration the efficiency of HpGe detectors. AIP conference proceedings. 2014; 1584(1): 38-44.‏

22. Knoll GF. Radiation detection and measurement. John Wiley & Sons; 2010.

23. Ngaram S, Baffa A, And I, Yunusa M. Determination of natural radionuclide using HPGe detectors. Journal of Environment, Technology & Sustainable Agriculture. 2017; 1: 14-22.

24. Guo Y, Wang Q, Kawazoe Y, et al. A New Silicon Phase with Direct Band Gap and Novel Optoelectronic Properties. Scientific Reports. 2015; 5(1). doi: 10.1038/srep14342

25. Leadbeater T. Lecture Notes on Particle Detectors. Birmingham: Physics and Astronomy. University of Birmingham; 2015.

26. Arif K, Malik AH. Monte Carlo EGS5 simulationsof High Purity Germanium (HPGe) detector. In: Proceedings of the 2015 Power Generation System and Renewable Energy Technologies (PGSRET). pp. 1-3.

27. High Purity Germanium Detectors—HPGe. Available online: https://www.nuclear-power.com/nuclear-engineering/radiation-detection/semiconductor-detectors/high-purity-germanium-detectors-hpge/ (accessed on 3 April 2024).

28. Saegusa J, Kawasaki K, Mihara A, et al. Determination of detection efficiency curves of HPGe detectors on radioactivity measurement of volume samples. Applied Radiation and Isotopes. 2004; 61(6): 1383-1390. doi: 10.1016/j.apradiso.2004.04.004

29. Vargas MJ, Timón AF, Dıaz NC, Sánchez DP. Monte Carlo simulation of the self-absorption corrections for natural samples in gamma-ray spectrometry. Applied Radiation and Isotopes. 2002; 57(6): 893-898.‏

30. Vargas MJ, Dı́az NC, Sánchez DP. Efficiency transfer in the calibration of a coaxial p-type HpGe detector using the Monte Carlo method. Applied Radiation and Isotopes. 2003; 58(6): 707-712.‏

31. Vidmar T, Korun M, Likar A, Martinčič R. A semi-empirical model of the efficiency curve for extended sources in gamma-ray spectrometry. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2001; 470(3): 533-547.‏

32. Al-Masri MS, Aba A, Al-Hamwi A, et al. Preparation of in-house reference soil sample containing high levels of naturally occurring radioactive materials from the oil industry. Applied Radiation and Isotopes. 2004; 61(6): 1397-1402. doi: 10.1016/j.apradiso.2004.04.007

33. Melquiades FL, Appoloni CR. Self-absorption correction for gamma spectrometry of powdered milk samples using Marinelli beaker. Applied Radiation and Isotopes. 2001; 55(5): 697-700.‏

34. San Miguel EG, Pérez-Moreno JP, Bolı́var JP, et al. 210Pb determination by gamma spectrometry in voluminal samples (cylindrical geometry). Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2002; 493(1-2): 111-120.‏

35. Abbas MI, Selim YS. Calculation of relative full-energy peak efficiencies of well-type detectors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2002; 480(2-3): 651-657.‏

36. Harb S, Salahel Din K, Abbady A. Study of efficiency calibrations of HPGe detectors for radioactivity measurements of environmental samples. In: Proceedings of the 3rd Environmental Physics Conference; 19-23 February 2008; Aswan, Egypt.‏

37. Akkurt I, Gunoglu K, Arda SS. Detection Efficiency of NaI(Tl) Detector in 511–1332 keV Energy Range. Science and Technology of Nuclear Installations. 2014; 2014: 1-5. doi: 10.1155/2014/186798

38. El-Gamal H, Negm H, Hasabelnaby M. Detection efficiency of NaI (Tl) detector based on the fabricated calibration of HPGe detector. Journal of Radiation Research and Applied Sciences. 2019; 12(1): 360-366.‏ doi: 10.1080/16878507.2019.1672313

39. Rathore V, Senis L, Andersson Sundén E, et al. Geometrical optimisation of a segmented HPGe detector for spectroscopic gamma emission tomography—A simulation study. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2021; 998: 165164. doi: 10.1016/j.nima.2021.165164

40. Ahmadi S, Ashrafi S, Yazdansetad F, et al. A computational modelling of low-energy gamma ray detection efficiency of a cylindrical NaI(Tl) detector. Radiation Physics and Chemistry. 2021; 188: 109581. doi: 10.1016/j.radphyschem.2021.109581

41. Tsoulfanidis N. Nuclear Fission Reactors. Nuclear Technology. 1983; 63(1): 187-187. doi: 10.13182/nt83-a33318 ‏

42. Böhlen TT, Cerutti F, Chin MPW, et al. The FLUKA Code: Developments and Challenges for High Energy and Medical Applications. Nuclear Data Sheets. 2014; 120: 211-214. doi: 10.1016/j.nds.2014.07.049

43. Ferrari A, Sala PR, Fasso A, Ranft J. FLUKA: A Multi-particle Transport Code. Stanford Linear Accelerator Center, Stanford University; 2005.

44. Tekin HO. MCNP-X Monte Carlo Code Application for Mass Attenuation Coefficients of Concrete at Different Energies by Modeling 3 × 3 Inch NaI(Tl) Detector and Comparison with XCOM and Monte Carlo Data. Science and Technology of Nuclear Installations. 2016; 2016: 1-7. doi: 10.1155/2016/6547318

45. Akkurt İ, Tekin HO, Mesbahi A. Calculation of Detection Efficiency for the Gamma Detector using MCNPX. Acta Physica Polonica A. 2015; 128(2B): B-332-B-335. doi: 10.12693/aphyspola.128.b-332

46. Salgado CM, Brandão LEB, Schirru R, et al. Validation of a NaI(Tl) detector’s model developed with MCNP-X code. Progress in Nuclear Energy. 2012; 59: 19-25. doi: 10.1016/j.pnucene.2012.03.006

47. Mouhti I, Elanique A, Messous MY, et al. Validation of a NaI(Tl) and LaBr3(Ce) detector’s models via measurements and Monte Carlo simulations. Journal of Radiation Research and Applied Sciences. 2018; 11(4): 335-339. doi: 10.1016/j.jrras.2018.06.003

48. Akkurt İ, Waheed F, Akyildirim H, et al. Performance of NaI(Tl) detector for gamma-ray spectroscopy. Indian Journal of Physics. 2021; 96(10): 2941-2947. doi: 10.1007/s12648-021-02210-1

49. Tekin HO, ALMisned G, Issa SAM, et al. Calculation of NaI(Tl) detector efficiency using 226Ra, 232Th, and 40K radioisotopes: Three-phase Monte Carlo simulation study. Open Chemistry. 2022; 20(1): 541-549. doi: 10.1515/chem-2022-0169

50. Hendriks PHGM, Limburg J, De Meijer RJ. Full-spectrum analysis of natural γ-ray spectra. Journal of Environmental Radioactivity. 2001; 53(3): 365-380.‏

51. Løvborg L, Christiansen EM, Bøtter-Jensen L, Kirkegaard, P. Pad facility for the calibration of gamma-ray measurements on rocks (No. RISO-R—454). Risoe National Lab.; 1981.

52. Agency IE. The radiological accident in San Salvador: A Report. International Atomic Energy Agency; 1990.

53. Biere PE, Aina JO, Olaoye MO, et al. Calibration of a 5 × 5 NaI(Tl) for Prompt In-Situ Gamma-ray Spectrometry System. Materials and Geoenvironment. 2021; 68(1): 1-5. doi: 10.2478/rmzmag-2021-0001

54. Boson J. Improving accuracy of in situ gamma-ray spectrometry [PhD thesis]. Radiation Physics Umeå University; 2008.‏

55. Beck HL, Gogolak C, DeCampo J. In situ Ge (Li) and NaI (T1) gamma-ray spectrometry (No. HASL-258). United States Atomic Energy Commision, New York, NY (United States). Health and Safety Lab.‏; 1972.

56. Kallmann H. Scintillation Counting with Solutions. Physical Review. 1950; 78(5): 621-622. doi: 10.1103/physrev.78.621.2

57. Reynolds GT, Harrison FB, Salvini G. Liquid Scintillation Counters. Physical Review. 1950; 78(4): 488-488. doi: 10.1103/physrev.78.488‏

58. Pochwalski K, Radoszewski T. Disintegration rate determination by liquid scintillation counting using the triple to double coincidence ratio (TDCR) method. Institute of Nuclear Research, Warsaw, INR; 1848.

59. Malonda AG, Garcia-Toraño E. Evaluation of counting efficiency in liquid scintillation counting of pure β-ray emitters. The International Journal of Applied Radiation and Isotopes. 1982; 33(4): 249-253.

60. Introduction Liquid Scintillation—mn/safe/nukwik. Available online: https://wiki.uio.no/mn/safe/nukwik/index.php/Introduction_Liquid_Scintillation (accessed on 3 April 2024).

61. Broda R, Cassette P, Kossert K. Radionuclide metrology using liquid scintillation counting. Metrologia. 2007; 44(4): S36-S52. doi: 10.1088/0026-1394/44/4/s06

62. Peng CT, Li U. Analysis of solvent components in commercial liquid scintillation cocktails. LSC. 1992; 92: 157.

63. Hung NQ, Chuong HD, Vuong LQ, et al. Intercomparison NaI(Tl) and HPGe spectrometry to studies of natural radioactivity on geological samples. Journal of Environmental Radioactivity. 2016; 164: 197-201. doi: 10.1016/j.jenvrad.2016.07.035

64. Osprey® Universal Digital MCA Tube Base for Scintillation Spectrometry. Available online: https://www.mirion.com/products/technologies/spectroscopy-scientific-analysis/gamma-spectroscopy/detector-electronics/osprey-universal-digital-mca-tube-base-for-scintillation-spectrometry (accessed on 3 April 2024).

65. Lépy MC. Presentation of the COLEGRAM software. Note Technique LHNB/04/26. 2004. Available online: http://www.lnhb.fr/pdf/NT_04-26_Colegram.pdf (accessed on 12 January 2024).

66. IAEA. certification of IAEA gamma spectrometry reference materials, RGU-1, RGTh-1 and RGK-1, Report-IAEA/RL/148. International Atomic Energy Agency; 1987.

67. Gilmore G. Practical gamma-ray spectroscopy. John Wiley & Sons; 2008.

68. ‏Lépy MC, Ferreux L, Hamon C, Plagnard J. ACORES yield curve adjustment software. Technical note LNHB. Available online: http://www.lnhb.fr/en/

69. GUM: Guide to the Expression of Uncertainty in Measurement—Evaluation of measurement data. Available online: https://www.bipm.org/documents/20126/2071204/JCGM_100_2008_E.pdf/cb0ef43f-baa5-11cf-3f85-4dcd86f77bd6 (accessed on 12 January 2024).

70. Shakhashiro A, Mabit L. Results of an IAEA inter-comparison exercise to assess 137Cs and total 210Pb analytical performance in soil. Applied Radiation and Isotopes. 2009; 67(1): 139-146. doi: 10.1016/j.apradiso.2008.07.014

71. Adetunji A, Olorunfemi AO, Abe O, et al. Anomalous concentrations of radionuclides in the groundwater of Ede area, southwestern Nigeria: a direct impact of geology. Environmental Earth Sciences. 2018; 77(17). doi: 10.1007/s12665-018-7799-2

72. Lydie RM, Nemba RM. Quantitative determination of 226Ra and 228Ra in reservoir and tap water in Yaoundé area, Cameroon. Glob. J. envir. Res. 2008; 2(3): 110-113.‏

73. Jibiri NN, Mbawanku AO, Oridata AA, Ujiagbedion C. Natural radionuclide concentration levels in soil and water around cement factory. Ewekoro, Ogun state. Nigeria Journal of physics. 1999; 11: 12-16.‏

74. Ajayi IR, Ajayi OS, Fusuyi AS. The natural radioactivity of surface soils in Ijero-Ekiti, Nigeria. Nig. J. Phys. 1995; 7: 101-103.‏

75. Farai IP, Sanni AO. Year-long variability of Rn-222 in a groundwater system in Nigeria. Journal of African Earth Sciences (and the Middle East). 1992; 15(3-4): 399-403.

76. Ahmed NK. Natural Radioactivity of Ground and Drinking Water in Some Areas of Upper Egypt. Turkish Journal of Engineering & Environmental Sciences. 2004; 28(6).‏

77. Nasirian M, Bahari I, Abdullah P. Assessment of natural radioactivity in water and sediment from Amang (tin tailing) processing ponds. Malays J Anal Sci. 2008; 12(1): 150-159.‏

78. Lydie RM, Nemba RM. The annual effective dose due to natural radionuclides in the reservoir and tap water in Yaoundé area, Cameroon. The South Pacific Journal of Natural and Applied Sciences. 2009; 27(1): 61. doi: 10.1071/sp09011

79. Ajayi OS, Adesida G. Radioactivity in some sachet drinking water samples produced in Nigeria. Iran. J. Radiat. Res. 2009; 7(3): 151-158.

80. Nwankwo LI. Study of natural radioactivity of groundwater in Sango-Ilorin, Nigeria. Journal of Physical Science and Application 2012; 2(8): 289.‏

81. Rahman SAA. Measurement of 226Ra in river water using liquid scintillation counting technique. Journal of Nuclear and Related Technologies. 2010; 7(02): 12-23.‏

82. de Oliveira J, Mazzilli BP, de Oliveira Sampa MH, Bambalas E. Natural radionuclides in drinking water supplies of Sao Paulo State, Brazil and consequent population doses. Journal of Environmental Radioactivity. 2001; 53(1): 99-109.‏

83. Borai EH, Lasheen YF, El-Sofany EA, et al. Separation and subsequent determination of low radioactivity levels of radium by extraction scintillation. Journal of Hazardous Materials. 2008; 156(1-3): 123-128. doi: 10.1016/j.jhazmat.2007.12.004

84. Kim YJ, Kim CK, Lee JI. Simultaneous determination of 226Ra and 210Pb in groundwater and soil samples by using the liquid scintillation counter-suspension gel method. Applied Radiation and Isotopes. 2001; 54(2): 275-281.

85. Lasheen YF, Seliman AF, Abdel-Rassoul AA. Simultaneous measurement of 226Ra and 228Ra in natural water by liquid scintillation counting. Journal of Environmental Radioactivity. 2007; 95(2-3): 86-97. doi: 10.1016/j.jenvrad.2007.02.002

86. Kozłowska B, Walencik A, Dorda J, et al. Uranium, radium and 40K isotopes in bottled mineral waters from Outer Carpathians, Poland. Radiation Measurements. 2007; 42(8): 1380-1386. doi: 10.1016/j.radmeas.2007.03.004

87. May D, Schultz MK. Sources and Health Impacts of Chronic Exposure to Naturally Occurring Radioactive Material of Geologic Origins. Practical Applications of Medical Geology. 2021; 403-428.‏

88. NCRP. Ionizing radiation exposure of the population of the United States. NCRP; 2006.

89. Marsh JW, Bailey MR. A review of lung-to-blood absorption rates for radon progeny. Radiation Protection Dosimetry. 2013; 157(4): 499-514. doi: 10.1093/rpd/nct179‏

90. Taylor D, Bligh P, Duggan M. The absorption of calcium, strontium, barium and radium from the gastrointestinal tract of the rat. Biochemical Journal. 1962; 83(1): 25-29. doi: 10.1042/bj0830025

91. Lubin JH, Boice JD, Edling C, et al. Lung Cancer in Radon-Exposed Miners and Estimation of Risk from Indoor Exposure. JNCI Journal of the National Cancer Institute. 1995; 87(11): 817-827. doi: 10.1093/jnci/87.11.817

92. Field RW, Steck DJ, Smith BJ, et al. Residential Radon Gas Exposure and Lung Cancer: The Iowa Radon Lung Cancer Study. American Journal of Epidemiology. 2000; 151(11): 1091-1102. doi: 10.1093/oxfordjournals.aje.a010153