Study of Ef Fec Tive Atomic Num Bers and Elec Tron Den Si Ties, Kerma of Al Co Hols, Phan Tom and Human Or Gans, and Tis Sues Sub Sti Tutes

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V. P. Singh, et al.: Study of Ef fec tive Atomic Num bers and Electron Densi ties, ... Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145 137

STUDY OF EF FEC TIVE ATOMIC NUM BERS AND ELEC TRON DEN SI TIES, KERMA OF AL CO HOLS, PHAN TOM AND HUMAN OR GANS, AND TIS SUES SUB STI TUTES

Vishwanath P. S I N G H * and Nagappa M. BADIGER

De part ment of Phys ics, Karnatak Uni ver sity, Dharwad, Karnatak, India

Sci en tific pa per DOI: 10.2298/NTRP1302137S

Ef fec tive atomic num bers (ZPIeff) and elec tron den si ties of eighteen al co hols such as wood alco - hol, CH3OH; grain al co hol, C2H5OH; rubbing alco hol, C3H7OH; butanol, C4H9OH; amyl alco hol, C5H11OH; cetyl alco hol, C16H33OH; eth yl ene gly col, C2H4(OH)2; glyc erin, C3H5(OH)3; PVA, C2H4O; erythritol, C4H6(OH)4; xylitol, C5H7(OH)5; sorbitol, C6H8(OH)6; volemitol, C7H9(OH)7; allyl al co hol, C3H5OH; geraniol, C10H17OH; propargyl alco hol, C3H3OH; inositol, C6H6(OH)6, and men thol, C10H19OH have been cal cu lated in the pho ton en ergy re gion of 1 keV-100 GeV. The es ti mated val ues have been com pared with ex per i- men tal val ues wher ever pos si ble. The com par i son of ZPIeff of the alco hols with water phan tom and PMMA phan tom indi cate that the ethyl ene gly col, glyc erin, and PVA are sub sti tute for PMMA phantom and PVA is sub sti tute of wa ter phan tom. ZPIeff of alco hols have also been compared with hu man or gans and tis sues. Eth yl ene gly col, glyc erin and PVA, allyl al co hol, and wood alco hols are found tis sue sub sti tutes for most of hu man or gans. Kerma which is the prod - uct of the en ergy fluence and mass en ergy-ab sorp tion co ef fi cient, have been cal cu lated in the en - ergy re gion from 1 keV to 20 MeV for the al co hols. The results show the kerma is more or less in de pend ent of en ergy above 100 keV. Key words: al co hol, phan tom, ef fec tive atomic num ber, hu man tis sue, gamma, kerma

INTRODUCTION tic, rubber, glass boro sili cate, A-5 tissue equiva lent mate ri als such as wax, plastic or solid water are avail - Gamma in ter ac tion with matter is thrust area in able for dosimetric anal ysis. Some alco hols have been ra di a tion mea sure ment, nu clear phys ics, ra di a tion re cently used for dosimetric ap pli ca tions [4]. phys ics, med i cal phys ics, ra di a tion do sim e try, ra di a- Mass at ten u a tion co ef fi cients (µ/r), ef fec tive tion pro tec tion, ra di a tion bi ol ogy, nu clear tech nol ogy, atomic number (Zeff) and ef fec tive elec tron den si ties clin i cal ap pli ca tions as well as in med i cal di ag nos tics (Neff) are the dosimetric in ter est pa ram e ters for the [1] and space re search [2]. Gamma ra di a tion is mea- pho ton in ter ac tion. The mass at ten u a tion co ef fi cient is sured by ra di a tion de tec tors of var i ous me di ums such a measure of pho ton in ter ac tion with matter; it is used as solid, liquid, and gaseous. The radi a tion dose ab - to de rive the mo lec u lar, atomic cross-sec tion, ef fec tive sorbed by human body is measured by dosim e ters of atomic number and effec tive electronic density. Any equiv a lent atomic num ber. Do sim e ters of such type param e ter of the above can be used for photon inter ac - are se lected for dose measure ment such as LiF per- tion study. The photon inter acts with medium by sonal do sim e ters and ra di a tion mon i tors. Quality as- photo-ab sorp tion, Compton scat ter ing and pair-pro- sur ance of the do sim e ters is car ried out by cali bra tion duction process which depends on the photon energy of the dosim e ters on human body equiva lent phantom. and constit u ent atomic number of the ele ments. The Wa ter and poly-methyl-metha-crylate (PMMA) are photo-ab sorption and pair-produc tion are the com- the ver sa tile ma te ri als suit able for stan dard phan toms plete photon removal process whereas Compton inter - used for ra dio ther apy and ra di a tion do sim e try due to action slows down photon energy and then is removed clos est hu man body tissue equiva lent [3]. Other vari - by photo-ab sorp tion in ter ac tion. ous tissue equiva lent mate ri als such as Perspex, plas- The the o ret i cal val ues for mass at ten u a tion co ef - ficients and cross-sec tions of about 100 dif ferent ele - ments, compounds, and mixtures have been complied @ * Cor re spond ing au thor; e-mail: kudphyvps rediffmail.com by Berger and Hubbell [5] and given in the form of Perma nent ad dress: Health Phys ics Sec tion, Kaiga Atomic Power Staton-3&4, NPCIL, Karwar, 581400, Karnatak, India XCOM software at ener gies 1 keV to 100 GeV which V. P. Singh, et al.: Study of Effective Atomic Numbers and Electron Densi ties, ... 138 Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145 has been transformed to WinXcom software at win- phan tom, PMMA phantom, human organs and tissues dow platform for easy export in excel form [6, 7]. is graphi cally shown for the inter ested photon energy Mass at ten u a tion co ef fi cients, ef fec tive atomic num- re gions. bers and elec tron den si ties of com pos ite ma te ri als are pho ton en ergy de pend ent. The mass at ten u a tion co ef - fi cients of mate rial at var ious en er gies are used for es - COMPUTATIONAL METHOD ti ma tion of ef fec tive atomic number by ra tio ef fec tive atomic cross-sec tion to effec tive electronic cross-sec - Direct method tion. A simi lar pro gram XmuDat also cal cu lates mass at ten u a tion co ef fi cient, mass en ergy trans fer, mass at- Com pu ta tions of the ef fec tive atomic num ber ten u a tion co ef fi cients for el e ments, com pounds, and and electron densities of the alco hols for total gamma mixtures in the energy range from 1 to 50 MeV photon pho ton in ter action have been carried out by practi cal en ergy range for the medi cal phys ics in ter est [8]. for mula [25]. The mass at ten u a tion co ef fi cients of the Sev eral re search ers have stud ied pho ton in ter ac - ele ments in our study have been obtained from tion pa ram e ters like the Zeff and Neff for vari ous com - WinXcom com puter program [5, 6]. The atomic num - posite mate ri als at photon energy from 1 keV to 1 GeV ber and atomic mass of el ements have been taken from [9], to tal mass at ten u a tion co ef fi cients, ef fec tive atomic atomic weight of el e ments [26]. The effec tive atomic and electron num bers for PbO, bar ite, cole man ite, tin - num ber, ZPIeff cal, and ulex ite at 80.1, 302.9, 356.0, 661.7, and 1250.0 keV photon ener gies [10], effec tive atomic number of æ mö ç ÷ the com pos ite ma te ri als such as bakelite, nylon, teflon Sif i A i ç ÷ è r øi etc. in the photon energy region 280-1115 keV by mea- ZPleff = (1) sur ing the in co her ent scat ter ing cross-sec tion [11], spin Ai æ mö Sif i ç ÷ ice com pounds and con crete shield ing ma te ri als [12, Z j è r øi 13]. The most use ful pho ton in ter ac tion pa ram e ter, Zeff and Neff, are available for few solu tions [14], where fi is the molar fraction in the mixture/com pound, µ thermoluminescent do sim e ters [15], or ganic com - – the lin ear at ten u a tion co ef fi cient, r – the density, µ/r – pounds [16], gases and gaseous mixture [17], amino ac- the mass at ten u a tion co ef fi cient, A – the atomic weight, Z ids [18], fatty acids and carbo hy drates [19], photon in- – the atomic num ber, and the ratio A/Z, be tween the ter ac tion pa ram e ters of com mon sol vents [20], and atomic mass and the atomic num ber is approx i mately mass at ten u a tion co ef fi cients of eth a nol have been ex - con stant. The mass at ten u a tion co ef fi cients of in di vid ual per i men tally in ves ti gated in pho ton en ergy 0.123-1.33 el e ments are ob tained from WinXcom program for pho- MeV [21]. ton energy 1 keV to 100 GeV. In the pres ent work, we have se lected dosimetric The ef fec tive electron den sity is given by Neff = inter est of eigh teen alco hols con tain ing H, C, and O el- = NAZ/A which is gen er alized as ements such as wood alco hol, rubbing alco hol, n ZPleff ZPleff butanol, amyl alco hol, cetyl al co hol, eth yl ene gly col, N eff = NA = N A (2) glyc erin, poly vi nyl al co hol (PVA), erythritol, xylitol, åin i A i th sorbitol, volemitol, allyl al co hol, geraniol, propargyl where ni is the number of atoms of the i. con stit u ent al co hol, inositol, men thol, poly vi nyl al co hol, and el e ment, n – the to tal num ber of at oms in the mole cule, com puted Zeff and Neff for to tal pho ton in ter ac tion in and – the av er age atomic mass of the alco hols. photon energy range 1 keV to 100 GeV. The PVA is pres ently used as a ra di a tion shield ing for ra di a tion protec tion, hard drives from data corrup tion, amino Kerma of alcohols relative to air acid from ox ida tive dam age in space flight [22]. The ef fec tive atomic num ber and elec tron den si ties have Ki netic en ergy re leased per unit mass (kerma) is been com pared with avail able pos si ble ex per i men tal defined as the ini tial ki netic energy of all sec ond ary values at few photon ener gies [23, 24]. The ef fective charged par ticles lib er ated per unit mass at a point of atomic number of alco hols have been compared with inter est by uncharged radi a tion [27, 28]. It is appli ca - wa ter phan tom, PMMA phantom, human organs, and ble to in di rect ion iz ing ra di a tion such as pho tons and tis sues to ex plore pos si bil i ties for tis sue sub sti tutes. neutrons and has the unit, J/kg = Gy, as the absorbed Kerma of al co hol rel a tive to air (Ka) also have been dose. Kerma is di rectly related to photon fluence and computed for photon energy region 1 keV to 20 MeV. like li hood of in ter act ing me dium. Com puted pho ton in ter ac tion pa ram e ters for al co hols Kerma de rived as let y [Jm–2] is energy fluence are found very use ful for phan tom and tissue substi tute of mono-ener getic photon passing through A area, A for dosimetric in ter est, shield ing ef fec tive ness, ex po- of an absorber. The photon energy transferred from sure and energy ab sorption build-up factors. In addi - uncharged ioniz ing gamma radi a tion to charge parti cle tion, the phantom equiva lence compared with water in a volume over a short distance dx behind the area is V. P. Singh, et al.: Study of Ef fec tive Atomic Num bers and Electron Densi ties, ... Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145 139 then (y µen) A dx where µen is mass energy-ab sorp tion RESULTS AND DISCUSSION coef fi cient. Since the mass in the volume with density r is rA dx, the kerma is Ef fec tive atomic num bers, ZPIeff of the alco hols are given in tab. 1 along with ef fective atomic num ber ymen Adx æ men ö based on XmuDat. In tab. 1 we have shown the ratio of K = =yç ÷ (3) rAdx è r ø ZPIeff of al cohol to water and PMMA phantom for min- There fore, the kerma is the product of the en ergy imum and maxi mum values to un derstand the close - fluence and mass en ergy-ab sorp tion co ef fi cient. ness of alco hols with phantoms at those ener gies. Kerma of the al co hols rela tive to air can be de rived as Com par i son of ZPIeff with exper i ment is given in tab. 2. The vari a tion of ZPIeff with the photon energy for alco - æ men ö hols is shown in figs. 1 and 2. The varia tion of Neff with ç ÷ photon energy for alco hols is shown in fig. 3. Figure 4 K alcohol è r øalcohol K a = = (4) gives vari a tion of kerma values for alco hols rela tive K air æ men ö to air, K in the photon energy region from1 keV to ç ÷ a è r øair 20 MeV. Figures 5 and 6 give the percent age de via tion of Z of al co hols rel a tive to PMMA phantoms, water Now the com pu ta tion of kerma is cal cu la tion of PIeff phantom for energy re gion 1 keV to 100 GeV, human mass en ergy-ab sorp tion co ef fi cient, µ /r of alcohol en or gans and tissues in the photon energy re gion from and air by the follow ing rela tion 1 keV to 20 MeV. men æ men ö = åwi ç ÷ (5) r i è r ø i Effective atomic number where wi and (men/r)i are the weight fraction and the mass en ergy-ab sorp tion co ef fi cient of the i th con stit u - The vari a tion of Z with gamma photon en- ent el ement present in the al co hol. For any chemi cal PIeff ergy is shown in fig. 1. From the figure it is clear that com pound, wi is given by the ZPIeff of the alco hols varies with energy. In the en- ni Ai wi = (6) ergy range of 1 keV to 100 GeV, the varia tion of ZPIeff Si ni Ai with energy is mainly dom inated by dif ferent photon

The values of (men/r)i have been taken from the in ter ac tion pro cesses namely pho to elec tric ab sorp - com pi la tion of Hubbell and Selt zer [29]. tion, Compton scatter ing and pair produc tion. The

Table 1. Effective atomic numbers of the alcohols (Z ) ()Z PIeff alcohol PIeff alcohol Formula/| ZPIeff Description (Zeff)XmuDat (Z ) ()Z Monomer PIeff water PIeff PMMA Min Max Min Max Min Max

Wood alcohol CH3OH 6.80 3.0007 7.3884 0.90 0.93 0.83 1.06

Grain alcohol C2H5OH 6.47 2.8895 7.0652 0.87 0.89 0.80 1.01

Rubbing alcohol C3H7OH – 2.8339 6.8619 0.85 0.86 0.79 0.99

Butanol C4H9OH 6.15 2.8006 6.7222 0.84 0.84 0.78 0.97

Amyl alcohol C5H11OH – 2.7784 6.6204 0.83 0.83 0.77 0.95

Cetyl alcohol C16H33OH – 2.7064 6.2308 0.81 0.78 0.75 0.89

Ethylene glycol C2H4(OH)2 – 3.4008 7.3943 1.02 0.93 0.94 1.06

Glycerin C3H5(OH)3 6.95 3.5723 7.3962 1.07 0.93 0.99 1.06

PVA C2H4O 6.62 3.4293 7.0739 1.03 0.89 0.95 1.02

Erythritol C4H6(OH)4 – 3.6675 7.3972 1.10 0.93 1.02 1.06

Xylitol C5H7(OH)5 – 3.7281 7.3978 1.12 0.93 1.04 1.06

Sorbitol C6H8(OH)6 – 3.7701 7.3982 1.13 0.93 1.05 1.06

Volemitol C7H9(OH)7 – 3.8008 7.3985 1.14 0.93 1.06 1.06

Allyl alcohol C3H5OH – 3.2006 6.8687 0.96 0.86 0.89 0.99

Geraniol C10H17OH – 2.9660 6.3629 0.89 0.80 0.82 0.91

Propargyl alcohol C3H3OH – 3.7507 6.8755 1.12 0.86 1.04 0.99

Inositol C6H6(OH)6 – 4.0008 7.4002 1.20 0.93 1.11 1.06

Menthol C10H19OH – 2.8392 6.3602 0.85 0.80 0.79 0.91

Water H2O 7.51 3.3343 7.9818 1.00 1.00 0.93 1.15

PMMA C5H8O2 6.56 3.6007 6.9646 0.90 0.93 1.00 1.00 V. P. Singh, et al.: Study of Effective Atomic Numbers and Electron Densi ties, ... 140 Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145 vari a tion in ZPIeff is large below 100 keV where photo - electric process is domi nant and the varia tion is almost con stant be tween 0.3-3 MeV where the Compton scat- tering process is domi nant and further above 100 MeV almost constant which is due to the pair produc tion pro cess. There fore, the ZPIeff value varies from 6.33 to 7.34 at 1 keV, varies from 2.7 to 4.0 at 1 MeV and varies from 2.92 to 4.33 at 10 GeV. It is needless to say that the higher values in the low energy region is due to pho to elec tric ab sorp tion pro cess, the in ter me di ate values in the medium energy re gion due to the Compton scatter ing and higher val ues in the high energy re gion is due to pair produc tion process. All varia tions can be clearly ex plained by the Z depend ence of total atomic 4-5 cross-sec tions, thus ZPIeff as Z for photo elec tric ab- sorption, Z for Compton scatter ing and Z2 for pair pro- duction. It follows from the above that the photo elec - tric absorp tion cross-section gives higher weight to the high Z ele ments than the other processes and is propor - tional to Z4-5 which clearly explains the maxi mum values of ZPIeff in the low energy re gion. In con trast, the Compton scat ter ing cross-sec tion is pro por tional to Z, giving less weight to the high Z ele ments than photo - elec tric ab sorp tion and pair pro duc tion pro cesses. Hence, the given alco hols have the low values of ZPIeff in this en ergy re gion. These results are in good agree- Figure 2. Effec tive atomic numbers for ment with the ex peri men tal results as ex plained in next non-co her ent of al co hols, wa ter, and PMMA phan tom sec tion. From figs. 1 and 2, it is clearly seen that ZPIeff of the water phantom is higher than all the alco hols in photo ab sorp tion re gion whereas com pa ra ble in shows that ZPIeff of wood alco hol is identi cal in the Compton and pair produc tion regions. Also fig. 1(a) photon energy 1 keV to 100 GeV.

Fig ure 1. Ef fec tive atomic num bers of al co hols, Fig ure 3. Ef fec tive elec tron den si ties of al co hols, wa ter, wa ter, and PMMA phan tom and PMMA phan tom V. P. Singh, et al.: Study of Ef fec tive Atomic Num bers and Electron Densi ties, ... Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145 141

Effective electron densities

The Neff of the alco hols con tain ing low atomic number ele ments H, C, and O is shown in fig. 3. The 22 ZPIeff of the alco hols are found in the range of 1.5×10 to 2.7×1023 electron/cm 3 with mini mum for C16H33OH. It is to be noted that the Neff value is min i- mum for al co hol con tain ing the max i mum car bon and hy dro gen at oms. The Neff val ues fol lows vari a tion of ZPIeff val ues with low est val ues in Compton scat ter ing region and high values in photo-absorp tion and pair pro duc tion re gion.

Fig ure 4. En ergy de pend ency of kerma rel a tive to air Comparison with experiments of al co hols

Ex per i men tal data of ef fec tive atomic num ber of duc tion. Ka val ues of all the se lected alco hols are in the pos si ble al co hols have been com pared. The ex per i men- range of 0.57 to 0.98 in the photon energy range from 1 tal values along with our calcu lated val ues are given in keV to 80 keV. The Ka values of water are found of tab. 2. From the table we notice a good agreement be - 1.02 to 1.18 in photon energy region of 1 keV to 80

Table 2. Comparison of effective atomic numbers with literature values Photon energy [keV] Alcohol Literature* 54 59.54 81 123 356 511 662 1173 1274 1333 a 3.83 – 2.99 2.96 2.92 3.11 3.00 2.92 2.90 2.99 Wood alcohol c 3.21 3.17 3.08 3.03 3.00 3.02 3.00 2.99 2.99 3.00 a 3.00 – 3.02 2.8 2.7 2.91 3.85 2.85 2.85 – Grain alcohol c 3.06 3.03 2.95 2.91 2.89 2.91 2.89 2.89 2.89 2.89 b 2.92 ± 0.09 – – – – – – – – – Butanol c 2.94 2.92 2.85 2.82 2.80 2.82 2.80 2.80 2.80 2.80 a 3.46 – 3.48 3.56 3.44 3.69 3.63 3.55 3.57 3.54 Glycerin b 3.81 ± 0.12 – – – – – – – – – c 3.80 3.76 3.66 3.60 3.57 3.59 3.57 3.57 3.57 3.58 *(a) A. H. El-Kateb and A. S. Ab dul-Hamid, 1991; (b) B. S. Sidhu et al, 2012; (c) present com pu tational work

tween cal cu lated and ex per i men tal val ues of ef fec tive keV. Above 100 keV the Ka val ues are in the range of 1 atomic numbers. From the compar i son we notice that to 1.14. We have found that the Ka values are higher low en ergy pho tons have un der gone the pho to elec tric for poly-al co hols com pared with mono-al co hol and ab sorp tion, me dium en ergy pho tons pho to elec tric and wa ter be cause the 16O weight frac tions are larger. The Compton scatter ing and high energy photons the pair Ka values of all the alco hols vary from 0.40 to 1.07 be- produc tion process. To the best of our knowledge, there low 100 keV where photo absorp tion is domi nat ing in- are no ex peri men tal data in the liter a ture for photon en- ter action process. In medium and high photon energy, er gies above 1333 keV where in only pair produc tion Ka values are found to be more or less same. pro cess is the ma jor in ter ac tion pro cess.

Kerma of alcohols Water and PMMA phantom substitute

The vari a tion of kerma rel a tive to air (Ka) of the Phan toms for cal i bra tion of the per sonal do sim e- alco hols for photon energy 1 keV to 20 MeV is shown ters are ISO, PMMA, and water phantoms, used as hu- in fig. 4. It is to be noted that the Ka val ues of wa ter are man tis sue sub sti tutes. It is found that the ZPIeff of the higher than alco hols in the en tire photon energy re gion alco hols are in range of the water and PMMA phan- 1 keV to 20 MeV. We have found that the Ka val ues are toms except slight varia tion for water phantom in equal to 1 at photon energy of ~80 keV. Ka vari a tion photo-ab sorp tion re gion. Per cent age de vi a tion with pho ton en ergy rep re sents vari a tion of ef fec tive (DZPIeff = Computed ZPIeff – Phantom ZPIeff)100/phan- atomic num bers in par tial pho ton in ter ac tion pro cess; tom ZPIeff) of the alco hols rela tive to phan tom is shown photo absorp tion, Compton scatter ing, and pair pro- in fig. 5(a, b). The DZPIeff for PMMA phantom for pho- V. P. Singh, et al.: Study of Effective Atomic Numbers and Electron Densi ties, ... 142 Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145

of the DZPIeff (%) of the al cohols as shown in fig. 6(a-h). Per cent age de vi a tions (DZPIeff = computed ZPIeff – hu man or gans and tissue ZPIeff) 100/human or gans and tissue ZPIeff) of the alco hols are found within range of –40% to + 30% for photon energy re gion of 1 keV to 20 MeV. Figure 6(a-f) show that glycerin, PVA and eth yl - ene gly col are nearest skellton muscle, soft tissue, lung tissue, blood, and brain substi tute in photon energy re - gion, 0.1 to 10 MeV whereas glycerin is only possi ble substi tute in energy above 10 MeV. Figure 6(d) shows that PVA and allyl al cohol are adi pose tissue substi tute in photon energy of 1 keV to 0.01 MeV whereas allyl alco hol and wood alco hols are near est ad i pose tis sue equiv a lent in pho ton en ergy of 0.1 MeV to 20 MeV. Figure 6(g) shows that in low photon energy of 1 keV to 0.01 MeV, wood al cohol, inositol, volemitol, xylitol, glycerin, eth yl ene glycol, PVA, and erythritol are breast tissue substi tute whereas eth ylene gly col and PVA are breast substi tute in remain ing energy region. Figure 6(h) shows that glycer ine is eye lens substitute in photon energy of 0.1 to 20 MeV. Simi larly it was found that glyc erin may be sub - sti tute for ovary, testis, and soft tissue (4-com part - ment) in photon energy region of 0.1 to 20 MeV.

Fig ure 5. DZPIeff [%] of alco hols rel ative PMMA and wa - ter phantoms CONCLUSIONS ton energy range 1 keV to 100 GeV are found of The pres ent com pu ta tion of ZPIeff and Neff are –24.88% to +11.50% whereas –36.45% to +19.98% based on atomic pho ton-in ter ac tion cross-sec tions. In for water phantom. It is to be noted that the DZ vari- PIeff the pres ent ap prox i ma tion, ZPIeff and Neff are in de - ation is very large in photon energy 0.008 to 0.03 MeV pendent of any chemi cal bonding effects of the alco - sim i lar to pho to elec tric ab sorp tion. We found that hols. A much larger and higher-dimen sional data base DZPIeff value for the ethyl ene glycol, glycerin and PVA would be re quired to ac com mo date mo lec u lar and rel a tive to PMMA phantom are near to zero in photon other matrix envi ron ments of the target atom [1]. Care- energy from 10 keV to 10 MeV there fore these al co - ful ex peri ments would be required to study any possi - hols are substi tute of PMMA phantom. In energy ble chem i cal bond ing en vi ron ment on pho ton-in ter ac- range 100 MeV to 100 GeV, propargyl alco hol is most tion cross-sections and effec tive atomic numbers of suit able sub sti tute for PMMA phantom. The suitable the alco hols. By our study, we conclude that: substi tute for the water phantom is found erythritol al- · the ef fective atomic num ber and the corre spond - cohol in the photon energy re gion, of 100 keV to 15 ing ef fec tive elec tron den sity of eigh teen al co hols MeV. Figure 5(b) shows that PVA is wa ter phantom have been calcu lated in photon energy region substi tute in energy region of 100 keV to 100 GeV. from 1 keV to 100 GeV, · three en ergy re gions are ap prox i mately E < 0.01 MeV, 0.05 MeV < E < 5 MeV, and E > 200 MeV, Human organ and tissues substitute the main photon-in ter action processes in these regions are pho to elec tric ab sorp tion, in co her ent Human organs and tissues substi tutes have been Compton scatter ing and pair produc tion, respec - com piled by White [30]. The ZPIeff of al cohols have tively, been compared with wa ter and PMMA phantoms in · the maxi mum values of ef fective atomic num ber the ear lier sec tion. Sim i larly we have in ves ti gated for and electron den sities for to tal and non-coher ent human organs and tissue such as skele ton muscle, soft scatter ing are found in the low-energy range of tissue, lung tissue, ad ipose tissue, blood, brain, breast pho to elec tric ab sorp tion re gion, tissue, eye lens, ovary, testis, and soft tissue 4-com - · the mini mum values of ef fective atomic num ber part ment [2] by cal cu lat ing the per cent age de vi a tion and elec tron den si ties are found at in ter me di ate V. P. Singh, et al.: Study of Ef fec tive Atomic Num bers and Electron Densi ties, ... Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145 143

Figure 6. DZPleff [%] of alco hols rel a tive to hu man or gans and tissues V. P. Singh, et al.: Study of Effective Atomic Numbers and Electron Densi ties, ... 144 Nuclear Technol ogy & Ra dia tion Pro tection: Year 2013, Vol. 28, No. 2, pp. 137-145

en er gies, typ i cally 0.05 MeV < E < 5 MeV, where [8] Nowotny, R., XMuDat: Pho ton At ten u a tion Data on Compton scat ter ing is dom i nant, PC, IAEA-NDS-195, Inter na tional Atomic En ergy Agency, Vi enna, Aus tria, 1998 · the single values of the ef fective atomic num ber [9] Han, I., Demir, L., Detemination of Mass At ten u a tion and the electron den sity provided by the pro gram Co ef fi cient, Ef fec tive Atomic and Elec tron Num bers XMuDat are found be tween mini mum and maxi - for Cr, Fe, and Ni Al loys at Dif fer ent En er gies, Nucl. mum valves calcu lated, Instrum. Meth ods Phys. Res. B., 267 (2009), pp. 3-8 [10] Un, A., Sahin, Y., De ter mi na tion of Mass At ten u a tion · the poly-alco hols are having large kerma values Co ef fi cients, Ef fec tive Atomic and Elec tron Num- com pared with mono-al cohol in photo absorp tion bers, Mean Free Paths and Kermas for PbO, Barite re gion, and Some Bo ron Ores, Nu clear Instru. and Meth ods · kerma cal cu la tion and equiv a lence anal y sis of al- in Phys. Res. Sec tion B: Beam Inter. with Ma ter. and At oms, 269 (2001), 13, pp. 1506-1511 cohols with wa ter phantom, PMMA phantom, hu- [11] Prasanna, K. S., Manjunathguru, V., Umesh, T. K., 210 man or gans and tissues have thrown light for Effec tive Atomic Numbers of Some H-, C-, O- Based phan tom and tis sue sub sti tutes use ful in ra di a tion Com pos ite Ma te ri als De rived from Dif fer en tial In co- phys ics, dosimetric in ter est, med i cal ap pli ca tions her ent Scat ter ing Cross-Sec tion PRAMANA-J, Phys- and ra dio di ag no sis, and ics, 74 (2010), 4, pp. 555-562 [12] Singh, V. P., Badiger, N. M., Com pre hen sive Study of · ethyl ene glycol, glycerin and PVA, allyl al cohol and En ergy Ab sorp tion and Ex po sure bueld-up Factor for wood al cohols are very useful alco hols for tissue Concrete Shield ing in Pho ton En ergy Range 0.015-15 sub sti tute in ra di a tion phys ics and radiobiology. MeV upto 40 mfp Pen e tra tion Depth: De pend ency of Den sity, Chem i cal El e ment, Pho ton En ergy, Int. J. Nu clear En ergy Sci ence and Tech nol ogy, 7 (2012), 1, pp. 75-99 ACKNOWLEDGEMENT [13] Singh, V. P., Badiger, N. M., Pho ton In ter ac tion Pa - ram e ters of Some Spin Ice Compounds, Int. J. Nu- Authors would like to thank Prof. L. Gerward, clear En ergy Sci ence and Tech nol ogy, 7 (2012), pp. De part ment of Phys ics, Tech ni cal Uni ver sity of Den - 57-74 mark, for provid ing the WinCom program. [14] Kulwant, S., et al., In ter ac tion of Pho tons with Some So lu tions, Amer i can Nu clear So ci ety, 61 (2001), 3-6, pp. 537-540 [15] Shivalinge, G., et al., Pho ton Mass At ten u a tion Co ef fi - AUTHOR CONTRIBUTIONS cients, Effec tive Atomic Numbers and Electron Densi - ties of Thermoluminescent Dosimetric Com pounds, The idea for study of new dosimetric mate rial Pramana Jour nal of Phys ics, 63 (2004), 3, pp. 529-541 was put forward by V. P. Singh, theo ret ical cal cula - [16] El-Kateb, A. H., Ab dul-Hamid, A. S., Pho ton At ten - tions were done by V. P. Singh, and analy sis and dis- u a tion Co ef fi cient Study of Some Or ganic Ma te ri als Con tain ing Hy dro gen, Car bon and Ox y gen, Appl. cussion was carried out by V. P. Singh and N. M. Radia. Isot., 42 (1991), 3, pp. 303-307 Badiger. The manuscript was writ ten and figures were [17] Singh, V. P., Badiger, N. M., Ef fec tive Atomic Num - prepared by V. P. Singh. bers, Elec tron Den si ties and Tis sue Equiv a lence of Some Gases and Mix tures for Do sim e try of Ra di a tion De tec tors, Nucl Technol Radiat, 27 (2012), 2, pp. REFERENCES 117-124 [18] Shivalinge, G., Krishnaveni, S., Ramakrishna, G., Studies on Ef fective Atomic Numbers and Electron [1] Hubbell, J. H., Review of Photon Inter ac tion Den sities in Amino Ac ids and Sugars in the En ergy Cross-Sec tion Data in the Med i cal and Bi o log i cal Range 30-1333 keV, Nu clear In stru ments and Meth - Con text, Phys. Med. Biol., 44 (1999), R1-22 ods in Phys ics Re search. 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Hy dro gen, Car bon, and Ox y gen, Appl. Rad. Isot., 42 [28] Attix, F. H., In tro duc tion to Ra dio log i cal Phys ics and (1991), pp. 303-307 Ra di a tion Do sim e try (John Wiley and Sons, New [24] Baltej, S. S., et al, Study of Mass At ten u a tion Co ef fi - York, USA), 1986 cients, Effec tive Atomic Numbers and Electron Densi - [29] Hubbell, J. H., Seltzer, S. M., Tables of X-Ray Mass ties for Some Low Z Com pounds of Dosim e try In ter est At ten u a tion Co ef fi cients and Mass En ergy Ab sorp tion at 59.54 keV In ci dent Pho ton En ergy, An nals of Nu - Coef fi cients from 1 keV to 20 MeV for ele ments Z = 1 clear En ergy, 42 (2012), pp. 153-157 to 92 and 48 Ad di tional Sub stances of Dosimetric In- [25] Manohara, S. R., et al, On the Effec tive Atomic Num - ter est NISTIR-5632, Gaithersburg, Md., National In - ber and Elec tron Den sity: A Com pre hen sive Set of For - sti tute of Stan dards and Tech nol ogy, 1995 mu las for all Types of Ma te ri als and En er gies Above 1 [30] White, D. R., Tis sue Sub sti tute in Ex per i men tal Ra di a- keV, Nuclear In struments and Meth ods in Phys ics Re - tion Physics, Med. Phys., 5 (1978), 6, pp. 467-479 search B, 266 (2008), pp. 3906-3912 [26] Wieser, M. E., Berglund, M., Atomic Weight of Ele - ments 2007, (IUPAC Tech ni cal Re port) Pure Appl. Chem., 81 (2009), 11, pp. 2131-2150 [27] ***, ICRU 1980 Ra di a tion Quan ti ties and Units Re - port 33 of the In ter na tional Com mis sion on Ra di a tion Received on Octo ber 30, 2012 Units and Mea sure ments (Bethesda, Md., ICRU) Accepted on Janu ary 23, 2013

Vi{vanat P. SING, Nagapa M. BADIGER

STUDIJA O EFEKTIVNIM ATOMSKIM BROJEVIMA I GUSTINAMA ELEKTRONA, KERMI U ALKOHOLIMA, FANTOMU, QUDSKIM ORGANIMA I TKIVNIM EKVIVALENTIMA

Za osamnaest vrsta alkohola, kao {to su metanol CH3OH, etanol C2H5OH, izopropil alkohol C3H7OH, butanol C4H9OH, amil alkohol C5H11OH, cetil alkohol C16H33OH, etilen glikol C2H4(OH)2, glicerin C3H5(OH)3, polivinil akohol C2H4O, eritritol C4H6(OH)4, ksilitol C5H7(OH)5, sorbitol C6H8(OH)6, volemitol C7H9(OH)7, alil alkohol C3H5OH, geraniol C10H17OH, propargil alkohol C3H3OH, inozitol C6H6(OH)6 i mentol C10H19OH, izra~unati su efektivni atomski broj ZPIeff i gustina elektrona u opsegu energija fotona od 1 keV do 1 GeV. Izvr{eno je upore|ivawe procewenih i eksperimentalnih vrednosti, gde god je bilo mogu}e. Z PMMA Pore|ewe PIeff alkohola sa vodenim fantomom i fantomom od pleksiglasa , pokazuje da su etilen glikol, glicerin i polivinil alkohol zamena za pleksiglas PMMA fantome, dok se polivinil alkohol mo`e koristiti i kao zamena za vodeni fantom. Izvr{eno je i pore|ewe sa qudskim organima i tkivima. Za etilen glikol, glicerin, polivinil alkohol, alil alkohol i metanol utvr|eno je da se mogu koristiti kao zamena za qudsko tkivo za ve}inu organa. Kerma, koja je proizvod fluensa energije i masenog koeficijenta apsorpcije, izra~unata je u opsegu energija od 1 keV do 20 MeV za razmatrane alkohole. Rezultati pokazuju da je kerma iznad 100 keV mawe-vi{e nezavisna od energije.

Kqu~ne re~i: alkohol, fantom, efektivni atomski broj, qudsko tkivo, gama zra~ewe, kerma