HANAA* Humans Applying Neutron Activation Analysis Hassan Amany Noura Ahmed Ali

Transcription

1 HANAA* Humans Applying Neutron Activation Analysis Hassan Amany Noura Ahmed Ali Neutron & Gamma ray Spectrometry Ahmed Mohamed Hassan, Assistant Lecturer, Physics Department, Faculty of Science, Mansoura University, Measurements of gamma-ray activity of environmental samples from Egypt Amany Hamdy Abdullah, Radioactive Isotopes Production Facility, Egyptian Atomic Energy Authority ETRR-2, Optimizing the shielding of TANGRA NaI(Tl) array Noura Hassan, Assistant Lecturer in physics, Faculty of Engineering, Egyptian Russian University, Feasibility study of humidity of furnace coke by neutrons Ahmed Abd Elfatah Elhoushy, Nuclear Engineer, Alexandria University, Faculty of Engineering, Nuclear & Radiation Engineering Department, Prompt Gamma Neutron Activation Analysis in Mining Yasser Farrag Ali, Biophysics Laboratory, Physics Dept., Faculty of science, Al-Azhar University, Shielding of BGO probe from 239 Pu-Be neutron-gamma radiation Material Analysis Using Characteristic Gamma Rays from Neutron Induced Nuclear Reactions * HANAA means: Happiness, Bliss, Felicity, Joy, Peace,.

2 Measurements of gamma-ray activity of environmental samples from Egypt By Mr/ Ahmed Hassan Assistant lecturer, Mansoura university, Egypt Supervision: Dr. Ivan Ruskov, Senior scientist, FLNP Mr. Constantin Hramko, engineer, FLNP

3 Outline Aim of the work. Experimental work. Sample Preparation and HpGe setup. Results and discussion. Conclusions. References.

4 The Problem Contamination process due to production operation of certain components that contain hazard materials around fertilizer factories area. Study of activity concentration of natural radionuclides such as 226 Ra, 232 Th and 40 K around this area in plant samples to evaluate the potential health hazards on general public.

5 Experimental work (samples locations and preparation) Plant sample Washing Drying Powder Polyethylene Container 4W Counting

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7 Results and discussion This figure shows the variation of activity concentrations of 226 Ra and 232 Th at different positions. This figure shows the variation of activity concentrations of 40 K at different positions.

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9 Conclusions The obtained results illustrate the following observation, the study area is still in the zones of normal radiation level except position P1L which are higher than the permissible maximum values for indoor and outdoor exposures. It was recommend to avoid this area for public health.

10 References

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13 Assessment the shielding property of iron for BGO scintillation detector from 239 Pu-Be neutron source

14 Shielding of scintillation detectors from direct penetration of neutrons from the source. Especially, when there is willing to study the interaction of fast neutron with medium and heavy nuclei detect secondary nuclear radiation (neutrons and gamma quanta)

15 Elastic scattering Inelastic scattering Neutron capture Compound nucleus

16 Neutron Source Spontaneous fission of heavy nuclides Isotopic neutron source Based on (γ,n) and (α,n) reaction in beryllium 239 PuBe

17 BGO (Ø76 x 65 mm)

18 Data acquisition system (DAQ): MCA ADCM and its software main panel LINUX operation system ADCM digitizing of the analog signals and store the time-amplitude of each of them in list-mode (one-by-one) (.DAT) C++ ROMANA and TOFANA analyze the listmode.dat files and create.root files containing the histograms (Energy- and Timedistributions) of the recorded events. ROOT scripts for calculation of channel-energy calibration curves and determine the efficiency of gamma-ray detectors. ADCM16-LTC, 16-channel/ 14-bit/100MHz, ADC-boards from AFI Electronics.

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22 Iron of thickness at least 30 cm compared to lead allows one to achieve the highest suppression factors at for the count rate. Based on these results, It is recommended to use iron instead of lead, because it has many advantages: Cheap. Has less mass than lead.

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24 Optimizing the shielding of TANGRA NaI(Tl) array By Amany Hamdy Abdullah Supervisor Dr. Ivan Ruskov, senior FLNP

25 TANGRA (TAgged Neutrons & Gamma RAys) TANGRA-project has been recently started in Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR) in Dubna to study some important for fundamental and applied nuclear physics reactions (n,n), (n,n'γ), (n,2n), (n,f), (n,gf), induced by 14.1 MeV neutrons.

26 Main components:

27 In the frame of TANGRA-project some experimental work was done in order to choose the optimum type and thickness of a shielding to protect NaI(Tl) scintillation gamma-ray detectors from the ING-27 direct 14.1 MeV neutrons.

28 Data acquisition system (DAQ) LINUX operation system ADCM digitizing of the analog signals and store the time-amplitude of each of them in list-mode (one-byone) (.DAT) MCA ADCM and its software main panel C++ ROMANA and TOFANA analyze the listmode.dat files and create.root files containing the histograms (Energy- and Time-distributions) of the recorded events. ROOT scripts for calculation of channel-energy calibration curves and determine the efficiency of gamma-ray detectors.

29 The objective of this study was to investigate the shielding effectiveness of different combination of layers from lead (Pb), iron (Fe), polyethylene (PE) and/or borated polyethylene (BPE)

30 Experimental setup The shields, composed from layers of different materials, was positioned between the neutron generator ING-27 and the investigated hexagonal NaI(Tl) scintillation probe as shown below.

31 Number of events N o and N d was determined from the corresponding gamma-ray pulse-height spectra (number of events per amplitude channel) as a function of the light output (LO) of the NaI(Tl) scintillator in MeVee units (equivalent to 1 MeV electron light output).

32 Number of events (x10 3 ) Experimental results Fe, d 0 cm 10 cm 20 cm 30 cm 40 cm 50 cm Amplitude (MeVee) Fig. 4. Amplitude distributions of events recorded by NaI(Tl) probe located behind 10, 20, 30, 40 and 50 cm thick Fe shields, compare with that of the bare probe, in the NaI(Tl) scintillator light output interval of LO = MeVee.

33 Number of events cm Fe 50 cm Pb Amplitude (MeVee) Fig. 5. Amplitude distributions of events recorded by NaI(Tl) probe behind 50 cm thick Fe and Pb shields in the interval of LO = MeVee. The lowest light output limit was LO = 0.2 MeVee.

34 Number of events Fe(40cm)+BPE(10cm) Fe(30cm)+BPE(10cm)+Pb(10cm) Fe(20cm)+BPE(10cm)+Pb(20cm) Fe(10cm)+BPE(10cm)+Pb(30cm) Amplitude (MeVee) Fig. 6. Amplitude spectra of events recorded by NaI(Tl) probe behind 50 cm thick.

35 From Fig.6 one can conclude that a) In the presents of BPE it is important to have additional heavy metal shield before NaI(Tl) to suppress gamma-rays from the interaction of the moderated (by Fe) neutrons with the BPE-nuclei and b) In the case of triple-layer shields, the complementary thicknesses of Fe and Pb shown the same level of suppression in the range of experimental data uncertainties.

36 Discussion and conclusions A shield with both Fe and BPE could be more effective than just Fe or BPE alone, because the advantages of both Fe and BPE are utilized. Iron (Fe) is effective in slowing down high-energy neutrons (e.g., 14-MeV source neutrons) and attenuating gammas, while hydrogen of BPE is effective in slowing down fast neutrons (till a few MeV), and 10 B has a high absorption cross section for thermal neutrons and a low production yield of gammas. So, a shield made of 30cm Fe followed by a 20 cm BPE-layer can meet the goal. According to the experimental results obtained in this methodological work, three layer shields made of Fe(30cm)+BPE(10cm)+Pb(10cm) or Fe(20cm)+BPE(10cm)+Pb(20cm) provided the highest suppression factors on the hexagonal NaI(Tl) gamma-ray detector load.

37 Thank you for your attention

38 By Noura Hassan Ibrahim Physics Demonstrator, ERU By Under Supervision Assistant Lecturer, Prof. Faculty Dr. Samir of Engineering, Yousha El-Khamessy Egyptian Russian University Professor of Nuclear Physics, Physics Dep., ASU Under supervision Dr. Hesham Ibrahim Shahbunder Assistant Professor of Nuclear Engineering, Physics Dep., ASU Senior Frank Dr. Ashraf Laboratory Hamed of Neutron Physics, JINR Assistant Professor 2012

39 OUTLINE 39 Introduction Neutron and Gamma-ray Spectrometry. Literature review. Aim of the work. Methodology. Experimental set-up. Results & Conclusion.

40 40 Introduction

41 41 Neutron and Gamma-ray Spectrometry Gamma-ray spectrometry is an analytical method that allows the identification and quantification of gamma emitting isotopes in a variety of matrices.

42 Literature Review 42 A. El Abd; A method for moisture measurement in porous media based on epithermal neutron scattering; Applied Radiation and Isotopes; P. Peter; In-Situ element analysis from gamma-ray and neutron spectra using a pulsed neutron source; University of Groningen; A. Anaqvi; Moisture measurements of wood and sugar samples using neutron transmission technique; Nuclear instruments and methods in physics research; R. Ziemer; Effects of neutron source type on soil moisture measurement; USDA-Cal. I. Goldeberg, et. al.; measurement of moisture content and density of soil masses using radioactive methods; LUNAR

43 43 Literature Review

44 44 Aim of the Present Work Study the possibility of determining the humidity of furnace coke using 239 Pu-Be source

45 45 Methodology The proposed method for determining the humidity of a test sample by the analysis of spectra of prompt gamma rays that emitted from the test sample after irradiated by fast neutron. The humidity of test sample can be determined from the characteristic gamma lines of Hydrogen and Oxygen.

46 Interaction of neutron with water 46 Neutron capture Fast neutron Inelastic scattering 1 H( KeV) 16 O(6129 KeV) Fig. 1: Interaction of Neutron with Nucleus

47 Experimental Setup Pu-Be source (A=5*10 6 n/s) BGO scintillation detector Combined shielding bricks (Fe + Bi). A computerized 16-channel read out system.

48 Experimental Setup 48 LINUX operation system ADCM digitizing of the analog signals and store the time-amplitude of each of them in list-mode (one-byone) (.DAT) C++ ROMANA and TOFANA analyze the list-mode.dat files and create.root files containing the histograms (Energy- and Time-distributions) of the recorded events. ROOT scripts for calculation of channel-energy calibration curves and determine the efficiency of gamma-ray detectors. Data acquisition system (DAQ): MCA ADCM and its software main panel

49 49 Results and Discussion A 2 kg coke sample, containing a variable amount of water (from 2% up to 80%), was irradiated with 239 Pu-Be neutrons every time for 10 hours

50 50 Results

51 51 Results

52 52 Results

53 53 Conclusion These measurements show that it is possible to determine the amount of water, added into the coke sample, analyzing the characteristic gamma-ray spectra.

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55 Prompt-gamma neutron activation analysis in mining By Ahmed Abd El fatah Elhoushy Nuclear Engineer,Faculity Of Engineering, Alexandria University Supervisor Dr / Ivan Ruskov Senior Scientist, Frank Laboratory Of Neutron Physics

56 Outline Introduction Experimental work Results and discussion Conclusions

57 Introduction What is Neutron Activation Analysis (NAA)? NAA is a method for qualitative and quantitative determination of elements based on the measurement of characteristic radiation from radionuclides formed by neutron irradiation of the material. According to type of emitted γ-ray measured If the Prompt γ-ray is the measured radiation Prompt γ -ray neutron activation analysis (PGNAA) The measurements take place during irradiation. If Delayed γ-ray is the measured radiation. Delayed γ -ray neutron activation analysis (DGNAA) The measurements take place after a certain decay period.

58 Aim of the work An experiment for deterimining the elemental composition of material by (PGNAA) using 239 Pu-Be neutron source. used reaction is Inelastic scattering (n, n γ)

59 Experimental work An experiment setup for deterimining the elemental composition of material by (PGNAA) We use a 239 Pu-Be as source of continous neutron flux with energy around 4.2 Mev To register gamma rays coming from interaction of neutrons with nuclei we use HPGe detector. To protect the detectors from direct radiation of neutron source we use shielding of Pb/Bi of nearly 30 cm total length

60 Experimental work Three types of ore samples for analysis 1. Concentrate sample with high concentration of P2O5-38,95% 2. Tail sample with low concentration of P2O5 0,9% 3. X sample (mixture) with concentration of P2O5 between the value of first and second Table 1. Content of different controlled elements in phosphate ore Controlled element P 2 O 5 Al 2 O 3 CaO SiO 2 Fe 2 O 3 K 2 O H 2 O TiO 2 Na 2 O concentrate, mass % Tails, mass %

61 Experimental work Back ground radiation curve was recorded without sample inside. 60 Co : and KeV 137 Cs : KeV Important step in work with any gammaspectroscopy instrument is to have well done channelenergy calibration. In our case the calibration was performed by two methods: 1. by standard point sources ( 60 Co & 137 Cs) 2. by irradiation of metal samples. The channel-energy calibration curve

62 Results and discussion in the figure below is shown the comparison between gamma-spectra from three irradiated samples (concentrate black, tails red, X mixture purple) and background blue ) Part of gamma-ray energy spectrum ( ) MeV

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64 In Figure 2 is shown the comparison between the measurements made with different types of detectors: HPGe (with high resolution) BGO (with high efficiency) Although BGO has a higher efficiency of gamma-ray detection, it has a moderate energy resolution. For example: if we compare Figure 1 with Figure 2 especially the interval between 2.20 and 2.25 MeV,. in case of HPGe we can see that there are three lines from different sources ( 27 Al, background and 31 P). In case of BGO (Figure 2, green and dark-blue lines) these gammalines, either from concentrate or from tails samples, can not be divided. Figure 1. Part of gamma-ray energy spectrum ( MeV). Figure 2 Comparison of the energy resolutions of HPGe and BGO detectors.

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66 γ-line energy, kev Some of the Identified Isotopes gamma-lines in the acquired spectra. Attachment (Concentrate /Tails) Isotope Table energy, kev 751 Concentrate SE 31 P 1266, Concentrate 44 Ca 761, Mixture 27 Al 56 Fe 843,76 846, Tails 48 Ti 983, Tails 27 Al 1014, Concentrate 44 Ca 1157, Mixture, 56 Fe 1238,27 Tails 1266 Concentrate 31 P 1266, Mixture 56 Fe 39 K 1360, , Tails 23 Na 1635, Mixture, 56 Fe 1810,76 Tails 2151 Concentrate 31 P 2148, Tails 27 Al 2212,01 γ-line energy, kev Attachment (Concentrate /Tails) Isotope Table energy, kev 2237 Concentrate 31 P 2233, Mixture, Tails 56 Fe 23 Na 2523 Mixture 56 Fe 39 K 2239, , , , , , Tails 28 Si 27 Al 48 Ti 39 K 2838, , , , Concentrate 31 P 3134, Concentrate SE 40 Ca 3736, Concentrate 40 Ca 48 Ti 3736, , Mixture, Tails 48 Ti 7585,00

67 Conclusions An experimental setup for determining the elemental composition of materials by prompt gamma-ray neutron activation analysis (PGNAA) was commissioned and tested. The acquired spectra was processed and decoded successful.

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69 Thank you for your attention