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Investigation of Turkish marbles as shielding materials
Nuclear Instruments and Methods in Physics Research B71 (1992) 201-203 North-Holland
HON B
Beam Interactions with Materials & Atoms
Investigation of Turkish Marbles as shielding materials Hamit Atasoy, Gdkçe Tarcan and Sema Döknien Department of Physics, Çekmece Nuclear Research and Training Center, P.O. Box 1. Airport, Istanbul, Turkey
Received 13 November 1991 and in revised torm 28 January 1992 The natural Turkish marbles, especially Usak Green (UG), Aegean Purple (AP) and Marmara White (MW) were tested as shielding materials using standard gamma sources such as Co-60, Cs-13', and Eu-152 . !'he experiment showed that UG, AP and MW are very effective shields against gamma-rays . The result for this experiment is that the gamma-ray attenuation coefficients of UG. AP and MW are almost equal for the energy range from 0.1 MeV to 1 .4 MeV . Also, the elemental compositions of the natural UG, AP and MW marbles have been determined by fast and thermal neutron activation analysis and fourteen elements including Na, Mg, At, Si CI, K, Ca, V, Ti, Mn, Fe, La, Ba and Sc have been found using the gamma spectroscopic method . The range of element contents of all Turkish marbles are remarkably different, but most of the elements are common such as Ca, Fe, Na, CI, Mg, Si . 1 . Introduction The reduction of radiation leakage into the environment from radiation equipment such as accelerators and reactors can be achieved by judiciously surrounding the eouipment with a shield of radiation attenuating material . The choice of shielding material may significantly affect the resulting radiation leakage detected. More commonly used materials are lead, iron, concrete etc. [1-4] . Very little work has appeared which describes the application of marble for shielding reactors [5] and other radiation-producing devices. The design of a radiation leakage reduction shield for a given application is governed by its attenuation properties, radioactive impurity content, ease of fabrication, economics, laboratory space availability and standardization . In this study, three kinds of natural Turkish marbles (TM) such as U§ak Green (UG), Aegean Purple (AP), Marmara White (MW) originating in the west part of Turkey, have been tested as shielding materials against gamma-rays . The primary purpose of this experiment was to obtain information that would be useful for evaluation of Turkish marbles for predicting the attenuation of gamma-rays by the shielding materials . One of the objectives of this investigation was also to provide an experimental comparison with concrete. In addition, UG, AP, MW were chemically analyzed using the fast and thermal neutron activation techniques and gamma-ray spectroscopy . In a previous paper [6], we reported the elemental composition of the natural Eskisehir Sübrem (ES, a kind of Turkish marble, originating from the Middle of 0168-583X/92/$05 .00 C 1992 - Elsevier
Anatolia), determined using the fast and thermal neutron activation techniques . Also, the gamma shielding ability was tested. 2 . Experimental procedure and results Two types of experiments were employed to test the UG, AP, MW as shielding materials and to determine their elemental compositions . Firstly, we present some studies on the attenuation characteristics of UG, AP and MW. The variations of the total gamma-ray attenuation coefficients with the incident photon energy in the natural marbles have been investigated using the standard gamma sources such as Co-60, Cs-137, Eu-152. We used the classical method to determine approximate values of the shielding thickness necessary for a given attenuation factor for given materials at the different gamma energies . The slabs of TM (density 2.7 g/cm') were of thicknesses varying from 1 .9 to 20.6 cm . Gamma-ray spectra were measured with and without the marble slab placed in very close contact with the source, and the source was located at the center of the marble slab on the detector axis . F( . most samples, ; enough counts were accumulated to make the uncertainty due to counting statistics to be much less than 1% . The total attenuation coefficients u (in cm -1 ) have been obtained by fitting experimental data with the least-squares method and the following equation : I=1(0) exp(-p,t) . Here, 1 and I(0) are the normalized gamma intensities
Science Publishers B .V. All rights reserved
202
H. Atasoy et al. / Turkish Marbles as shielding materials
Table 1 Summary of our experimental results on the total gamma attenuation coefficients Gamma energy E (keV)
Gamma attenuation coefficients k (cm') AP UG MW
244.7 344.3 444.0 661 .7 778 .9 964.0 1112.1 1332.5 1408 .0
0.311(10)`' 0.27405) 0 .26105) 0 .21801) 0 .19400) 0.17501) 0.163(20) 0.13502) 0 .14500)
0 .31704) 0.278(20) 0.25200) 0.22200) 0.19605) 0.178(17) 0.165(21) 0.14(X10) 0.147(20)
0.31302) 0.273(11) 0.249(20) 0.22000) 0.195(15) 0.176(19) 0.163(15) 0.173(18) 0.145(15)
' Errors are shown thus 0.311(10)=0.311±0.010 . with and without the marble slab in place, respectively, and t is the marble slab ILickness in cm . More than 10 marbles with different thicknesses were selected for each energy point. Then the total gamma attenuation coefficients (p,) of the three kinds of Turkish marbles were found as a function of the gamma-ray energies from 0 .2 MeV to 1 .4 MeV. The values of N for UG, AP, MW and ES (in the previous paper [6] as reported) are approximately equal within the errors. Table 1 gives a summary of our experimental results on the total gamma attenuation coefficients l2 (cm - '), for these Turkish marbles . For comparison, this experiment was repeated for ordinary concrete, which is commonly used in laboratories . The results are presented in fig . 1 . Also, it was convenient to present our results as half-value and
F z
w 05 O 11
04 ó U 2
g 03 á z F 02 r Q
ár O r
01 GAMMA ENERGV(keV)
Fig . 1 . Total gamma attenuation coefficients for Turkish marbles and for concrete .
tenth-value layers, namely, the thicknesses of absorber necessary to reduce the intensity of the incident gamma radiation by a factors of 2 and 10, respectively . For comparison, we show in fig . 2 the half-value and tenth-value layers for TM and for concrete. Secondly, the elemental constituent concentrations of UG, AP, MW have been determined by the neutron activation analysis using two different irradiation facilities . A SAMES-T-400 particle accelerator and a 5 MW, TR-2 nuclear research reactor were employed in this experiment for the fast neutron activation analysis (FNÁA) and thermal neutron activation analysis (TNAA), respectively . The elemental concentration of the natural UG, AP and MW marbles have been determined in six replicate runs in the rabbit system of
Table 2 Summary of the experimental results on the elemental concentrations in MW, UG and AP marbles Neutron source
Analysis for
Reaction
Reactor Reactor Reactor Accelerator Reactor Reactor Accelerator Reactor Reactor Reactor Reactor Reactor Accelerator Reactor Reactor
Na Mg AI Si CI K Ca Ca Sc V Ti Mr. Fe Ba La
2'Na(n, y)2° Na 26 Mg(n, y)n Mg 2~AI(n, y) 2"AI 2 "Si(n, p)2"AI "CI(n, y)'"CI `K(n, y)°2 K 44Ca(n, P) °°K a "Ca(n, y)°°Ca °5Sc(n, Y)°6 Sc 2V "V(n,y)s -y)5'Ti 5"Ti(n, y)56Mn 55Mn(n, 56 Fe(n, p)5''Mn "Ba(n, y)" 9Ba " 9 La(n, y )'°°La
Values in mg/e .
Mean concentration (Wg/g) MW UG 29.4± 1 .7 1 .4±0 .5 " 1 .3± 0 .1 1 2.5±0 .5'' 13.9±3 .4 117 .4± 1 .7 46.0±6.6 84 .9± 2 .1 177 .6±9.2 23 .0± 2 .0 1 .8±0.2 '' 538 .0± 10.0 `' 22 .8±5.0 3 .1 ± 1 .1 32 .6±8.8 491 .3+6.8 0.8± 0.8 463 .5±0.8 10.3±0 .7 3.9±3 .1 13.7±3 .4
AP 132 .0± 4 .7 a 180 .3± 10 .1 207 .2± 11 32 .8± 1 .3 5 .8± 1 .1 68 .0± 3 .1 43 .8 ± 7.1 '' 0.3± 0.1 66.5± 1 .2 7.1± 0.2 -
H. Atasoy et al. / Turkish Marbles as shielding materials
203
article [6] and have therefore only briefly mentioned here. The measured elemental compositions of UG, AP, MW are given in table 2 .
20 18
3. Conclusion
16
w z 12 U
10 w m ó 8 ma 6 4
200
400
600
800
1000
1200
1400
GAMMA ENERGY NeV)
Fig. 2. Half-value and tenth-value layer for Turkish marbles and for concrete. the TR-2 reactor with a thermal neutron flux of about 2 .4 x 10 13 n/cm 2 s. Twelve elements (Na, Mg, AI, CI, K, Ca, Sc, V, Ti, Mn, La, Ba) were successfully found in TM via (n, y) reactions using the gamma-ray spectroscopic method. The major elements, Si, Fe, and also Ca were identified using the FNAA technique via the (n, p) reaction with an average flux of about 1 .8 x 10`' n/cm = s at 14 .6 MeV in three replicate runs at the accelerator . After irradiation, samples were analyzed by gamma ray spectrometry with an 82 cm; high-purity germanium (HPGc) detector . More details on the experimental procedure can be found in the previously published
This study was done for three kinds of TM using three gamma sources to show the shielding ability of UG, AP and MW . Experimental values of the gammaray attenuation of TM as a function of photon energy have been obtained from 0 .2 to 1 .4 MeV . Four kinds of Turkish Marbles (TM) (including ES) have been tested as shielding materials against gamma-rays, and it has been shown that their shielding abilities are almost equal within the errors. Therefore, TM has gained new significance as it has been shown to be a better shield than concrete for gamma-rays by about 20%. Also, up to fourteen elements have been detested in UG, AP and MW . The experimental results on the elemental compositions of UG, AP and MW show that the seven elements Na, Mg, Si, CI, K, Mn, Cs are common to all three marbles, but the mean concentrations of these and other elements arc different . Also, UG has four additional elements Sc, Ti, Ba and La not detected in the MW and AP marbles.
References [I1 R . Stephenson, Introduction to Nuclear Engineering, (McGraw-Hill, 1954). [2] D .D. Glower, Experimental reactor analysis and radiation measurements (McGraw-Hill, 1965). [3] D .J . Hughes, Pile neutron research (Addison-Wesley, 1953). [4] J .H . Hubbell, NSRDS-NBS 29 (1969). [51 D. Comar, C. Crouzel, M. Chasteland, R . Riviere, Proc. of the 1968 Int . Conf. on Modern Trends in Activation Analysis, held at the NBS, Maryland Oct. 7-11, 1968 . [6] S . Ddkmen, H. Atasoy, Y. Özbir and G . Tarcan, Nucl . Instr. and Meth. B56/57 (1991) 915 .
HON B
Beam Interactions with Materials & Atoms
Investigation of Turkish Marbles as shielding materials Hamit Atasoy, Gdkçe Tarcan and Sema Döknien Department of Physics, Çekmece Nuclear Research and Training Center, P.O. Box 1. Airport, Istanbul, Turkey
Received 13 November 1991 and in revised torm 28 January 1992 The natural Turkish marbles, especially Usak Green (UG), Aegean Purple (AP) and Marmara White (MW) were tested as shielding materials using standard gamma sources such as Co-60, Cs-13', and Eu-152 . !'he experiment showed that UG, AP and MW are very effective shields against gamma-rays . The result for this experiment is that the gamma-ray attenuation coefficients of UG. AP and MW are almost equal for the energy range from 0.1 MeV to 1 .4 MeV . Also, the elemental compositions of the natural UG, AP and MW marbles have been determined by fast and thermal neutron activation analysis and fourteen elements including Na, Mg, At, Si CI, K, Ca, V, Ti, Mn, Fe, La, Ba and Sc have been found using the gamma spectroscopic method . The range of element contents of all Turkish marbles are remarkably different, but most of the elements are common such as Ca, Fe, Na, CI, Mg, Si . 1 . Introduction The reduction of radiation leakage into the environment from radiation equipment such as accelerators and reactors can be achieved by judiciously surrounding the eouipment with a shield of radiation attenuating material . The choice of shielding material may significantly affect the resulting radiation leakage detected. More commonly used materials are lead, iron, concrete etc. [1-4] . Very little work has appeared which describes the application of marble for shielding reactors [5] and other radiation-producing devices. The design of a radiation leakage reduction shield for a given application is governed by its attenuation properties, radioactive impurity content, ease of fabrication, economics, laboratory space availability and standardization . In this study, three kinds of natural Turkish marbles (TM) such as U§ak Green (UG), Aegean Purple (AP), Marmara White (MW) originating in the west part of Turkey, have been tested as shielding materials against gamma-rays . The primary purpose of this experiment was to obtain information that would be useful for evaluation of Turkish marbles for predicting the attenuation of gamma-rays by the shielding materials . One of the objectives of this investigation was also to provide an experimental comparison with concrete. In addition, UG, AP, MW were chemically analyzed using the fast and thermal neutron activation techniques and gamma-ray spectroscopy . In a previous paper [6], we reported the elemental composition of the natural Eskisehir Sübrem (ES, a kind of Turkish marble, originating from the Middle of 0168-583X/92/$05 .00 C 1992 - Elsevier
Anatolia), determined using the fast and thermal neutron activation techniques . Also, the gamma shielding ability was tested. 2 . Experimental procedure and results Two types of experiments were employed to test the UG, AP, MW as shielding materials and to determine their elemental compositions . Firstly, we present some studies on the attenuation characteristics of UG, AP and MW. The variations of the total gamma-ray attenuation coefficients with the incident photon energy in the natural marbles have been investigated using the standard gamma sources such as Co-60, Cs-137, Eu-152. We used the classical method to determine approximate values of the shielding thickness necessary for a given attenuation factor for given materials at the different gamma energies . The slabs of TM (density 2.7 g/cm') were of thicknesses varying from 1 .9 to 20.6 cm . Gamma-ray spectra were measured with and without the marble slab placed in very close contact with the source, and the source was located at the center of the marble slab on the detector axis . F( . most samples, ; enough counts were accumulated to make the uncertainty due to counting statistics to be much less than 1% . The total attenuation coefficients u (in cm -1 ) have been obtained by fitting experimental data with the least-squares method and the following equation : I=1(0) exp(-p,t) . Here, 1 and I(0) are the normalized gamma intensities
Science Publishers B .V. All rights reserved
202
H. Atasoy et al. / Turkish Marbles as shielding materials
Table 1 Summary of our experimental results on the total gamma attenuation coefficients Gamma energy E (keV)
Gamma attenuation coefficients k (cm') AP UG MW
244.7 344.3 444.0 661 .7 778 .9 964.0 1112.1 1332.5 1408 .0
0.311(10)`' 0.27405) 0 .26105) 0 .21801) 0 .19400) 0.17501) 0.163(20) 0.13502) 0 .14500)
0 .31704) 0.278(20) 0.25200) 0.22200) 0.19605) 0.178(17) 0.165(21) 0.14(X10) 0.147(20)
0.31302) 0.273(11) 0.249(20) 0.22000) 0.195(15) 0.176(19) 0.163(15) 0.173(18) 0.145(15)
' Errors are shown thus 0.311(10)=0.311±0.010 . with and without the marble slab in place, respectively, and t is the marble slab ILickness in cm . More than 10 marbles with different thicknesses were selected for each energy point. Then the total gamma attenuation coefficients (p,) of the three kinds of Turkish marbles were found as a function of the gamma-ray energies from 0 .2 MeV to 1 .4 MeV. The values of N for UG, AP, MW and ES (in the previous paper [6] as reported) are approximately equal within the errors. Table 1 gives a summary of our experimental results on the total gamma attenuation coefficients l2 (cm - '), for these Turkish marbles . For comparison, this experiment was repeated for ordinary concrete, which is commonly used in laboratories . The results are presented in fig . 1 . Also, it was convenient to present our results as half-value and
F z
w 05 O 11
04 ó U 2
g 03 á z F 02 r Q
ár O r
01 GAMMA ENERGV(keV)
Fig . 1 . Total gamma attenuation coefficients for Turkish marbles and for concrete .
tenth-value layers, namely, the thicknesses of absorber necessary to reduce the intensity of the incident gamma radiation by a factors of 2 and 10, respectively . For comparison, we show in fig . 2 the half-value and tenth-value layers for TM and for concrete. Secondly, the elemental constituent concentrations of UG, AP, MW have been determined by the neutron activation analysis using two different irradiation facilities . A SAMES-T-400 particle accelerator and a 5 MW, TR-2 nuclear research reactor were employed in this experiment for the fast neutron activation analysis (FNÁA) and thermal neutron activation analysis (TNAA), respectively . The elemental concentration of the natural UG, AP and MW marbles have been determined in six replicate runs in the rabbit system of
Table 2 Summary of the experimental results on the elemental concentrations in MW, UG and AP marbles Neutron source
Analysis for
Reaction
Reactor Reactor Reactor Accelerator Reactor Reactor Accelerator Reactor Reactor Reactor Reactor Reactor Accelerator Reactor Reactor
Na Mg AI Si CI K Ca Ca Sc V Ti Mr. Fe Ba La
2'Na(n, y)2° Na 26 Mg(n, y)n Mg 2~AI(n, y) 2"AI 2 "Si(n, p)2"AI "CI(n, y)'"CI `K(n, y)°2 K 44Ca(n, P) °°K a "Ca(n, y)°°Ca °5Sc(n, Y)°6 Sc 2V "V(n,y)s -y)5'Ti 5"Ti(n, y)56Mn 55Mn(n, 56 Fe(n, p)5''Mn "Ba(n, y)" 9Ba " 9 La(n, y )'°°La
Values in mg/e .
Mean concentration (Wg/g) MW UG 29.4± 1 .7 1 .4±0 .5 " 1 .3± 0 .1 1 2.5±0 .5'' 13.9±3 .4 117 .4± 1 .7 46.0±6.6 84 .9± 2 .1 177 .6±9.2 23 .0± 2 .0 1 .8±0.2 '' 538 .0± 10.0 `' 22 .8±5.0 3 .1 ± 1 .1 32 .6±8.8 491 .3+6.8 0.8± 0.8 463 .5±0.8 10.3±0 .7 3.9±3 .1 13.7±3 .4
AP 132 .0± 4 .7 a 180 .3± 10 .1 207 .2± 11 32 .8± 1 .3 5 .8± 1 .1 68 .0± 3 .1 43 .8 ± 7.1 '' 0.3± 0.1 66.5± 1 .2 7.1± 0.2 -
H. Atasoy et al. / Turkish Marbles as shielding materials
203
article [6] and have therefore only briefly mentioned here. The measured elemental compositions of UG, AP, MW are given in table 2 .
20 18
3. Conclusion
16
w z 12 U
10 w m ó 8 ma 6 4
200
400
600
800
1000
1200
1400
GAMMA ENERGY NeV)
Fig. 2. Half-value and tenth-value layer for Turkish marbles and for concrete. the TR-2 reactor with a thermal neutron flux of about 2 .4 x 10 13 n/cm 2 s. Twelve elements (Na, Mg, AI, CI, K, Ca, Sc, V, Ti, Mn, La, Ba) were successfully found in TM via (n, y) reactions using the gamma-ray spectroscopic method. The major elements, Si, Fe, and also Ca were identified using the FNAA technique via the (n, p) reaction with an average flux of about 1 .8 x 10`' n/cm = s at 14 .6 MeV in three replicate runs at the accelerator . After irradiation, samples were analyzed by gamma ray spectrometry with an 82 cm; high-purity germanium (HPGc) detector . More details on the experimental procedure can be found in the previously published
This study was done for three kinds of TM using three gamma sources to show the shielding ability of UG, AP and MW . Experimental values of the gammaray attenuation of TM as a function of photon energy have been obtained from 0 .2 to 1 .4 MeV . Four kinds of Turkish Marbles (TM) (including ES) have been tested as shielding materials against gamma-rays, and it has been shown that their shielding abilities are almost equal within the errors. Therefore, TM has gained new significance as it has been shown to be a better shield than concrete for gamma-rays by about 20%. Also, up to fourteen elements have been detested in UG, AP and MW . The experimental results on the elemental compositions of UG, AP and MW show that the seven elements Na, Mg, Si, CI, K, Mn, Cs are common to all three marbles, but the mean concentrations of these and other elements arc different . Also, UG has four additional elements Sc, Ti, Ba and La not detected in the MW and AP marbles.
References [I1 R . Stephenson, Introduction to Nuclear Engineering, (McGraw-Hill, 1954). [2] D .D. Glower, Experimental reactor analysis and radiation measurements (McGraw-Hill, 1965). [3] D .J . Hughes, Pile neutron research (Addison-Wesley, 1953). [4] J .H . Hubbell, NSRDS-NBS 29 (1969). [51 D. Comar, C. Crouzel, M. Chasteland, R . Riviere, Proc. of the 1968 Int . Conf. on Modern Trends in Activation Analysis, held at the NBS, Maryland Oct. 7-11, 1968 . [6] S . Ddkmen, H. Atasoy, Y. Özbir and G . Tarcan, Nucl . Instr. and Meth. B56/57 (1991) 915 .