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NEW ANALYTICAL APPROACH TO CALIBRATE CYLINDRICAL HPGE DETECTOR INCLUDING CORRECTIONS FOR SELF ATTENUATION OF LARGE CYLINDRICAL SOURCES AND ATTENUATION OF ALL DETECTOR HOUSING MATERIALS. M.S. Badawi, M.M. Gouda, A.M. el-Khatib, S.S. Nafee and E.A. el-Mallah Physics Department, Faculty of Science, Alexandria University, 21511 Alexandria, Egypt HPGe semiconductor detectors are very useful for radioactivity measurement and to calculate the absolute activity, the full energy peak efficiency of the detector is needed. In this work, to calibrate the co-axial HPGe semiconductor detector, we introduce a new theoretical approach based on the Direct Statistical method proposed by Selim and Abbas to calculate the full energy peak efficiency for cylindrical detectors. The present method depends on the accurate analytical calculation of the average path length covered by the photon inside the detector active volume and the geometrical solid angle, , to obtain a simple fo rmula for the efficiency. In addition, self attenuation of source matrix (with radius greater than the radius of the detector), the attenuation by the source container and the detector housing materials are also treated by calculating the average path length cross thes e materials. 152Eu aqueous sources covering the energy range from 121 up to 1408 keV were used. Remarkable agreement between the measured and the calculated efficiencies is achieved with discrepancies less than 2%. CALCULATION OF FULL ENERGY PEAK EFFICIENCY OF GAMMA DETECTORS USING AN ANALYT ICAL EFFICIENCY TRANSFER PRINCIPLE M.S. Badawi1), A.M. el-Katib1), M.A. Elzaher2), A.A. Thabet2) and A.A. Sakr3) 1) Physics Department, Faculty of Science, Alexandria University, 21511 Alexandria, Egypt Department of Basic and Applied Science, Faculty of Engineering, Arab Academy for Science, Technology and Maritime Transport, Alexandria, Egypt 3) Physics Department, Faculty of Science, Damanhour University, Egypt

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In this work the full energy peak efficiency of NaI(Tl) -scintillation detector (5.08x5.08 cm2 and 7.62x7.62 cm2) values have been calculated for axial cylindrical sources of different dimensions larger than the coaxial detectors using an analytical approach of effective solid angle calculation and taking into account the source self attenuatio n effect. The detector efficiency for various geometrical conditions is derived from the known efficiency for reference source -detector geometry. The present method shows a great possibility to calibrate the detectors through the determination of the full -energy peak efficiency curve even in the cases when no standard source is available. EFFECT OF X-RAY IRRADIATION ENERGY ON OPTICAL, MECHANICAL AND DIELECTRIC PROPERTIES OF POLYANILINE POLYMETHYLMETHACRYLATE BLEND H.A. Motaweh1), A.A. Sakr1), and T.G. Abdelmalik2) 1) Physics Department, Faculty of Science, Damanhour University, Damanhour, Egypt 2) Physics Deportment faculty of Science, Minia University, Minia. Egypt The effect of x-ray irradiation energy on optical , mechanical and dielectric properties of polyanilie / polymethylmethacrylate blend are investigated at room temperature. The samples are exposed to different radiation doses from 0 to 1000 cGy. The absorption spectra of polyanilie / PMMA blend have been measured with photon energies in the f undamental absorption region at different X-ray doses. The results indicated that a perturbation and degradation feature may take place for X -ray dose below 500 cGy , and cross- linking for higher doses. Young's modulus and dielectric properties of polyanilie/ PMMA samples are carried out at room temperature. The results are explained on the basis of perturbation, degradation and cross -linking of the polyanilie/ polymethylmethacrylate samples. .. , .. , .. , , 5 -50 ­ ­ . . ,


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, ( ). /1/ , /2/ . , . , , . 1. 2. M.A. Piestrup, D.G. Boyers, C.I. Pincus et al., //Phys.Rev. A,1992, 1183. N.N. Nasonov, V.V. Kaplin, S.R. Uglov, M.A. Piestrup, C.K. Gary, //Phys. Rev . E, 2003, 68, 3604.


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, , . , , () () , . , - , . , . , , , , - . , , , , . , , , . .. , , .. , «», , . , , . , . . .. , .. , .. . , «», , () . , , (). , , ­ . , - . , ( ). , . , . DOUGHNUT SCATTERING OF 255 MEV ELECTRONS AT <100> CHANNELING IN SILICON CRYSTAL O.V. Bogdanov
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, Yu.L. Pivovarov1), Y. Takabayashi3), T.A. Tukhfatullin Tomsk Polytechnic University,Tomsk, Russia INFN Laboratori Nazionali di Frascati, Frascati, Italy 3) SAGA Light Source, Tosu, Japan
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The «doughnut scattering» (DS) (scattering of charged relativistic particles by crystal axes in the plane perpendicular to th e axes) was first observed in earlier high-energy channeling experiments (1976­1980) using the proton and meson beams at CERN, see, e.g. in [1]. The properties of both angular and spatial distribution of 255 MeV electrons at <100> channeling in silicon crystal has been investigated experimentally at the linac injector of SAGA [2] light source and by computer simulations. The simulation of trajectories, angular and spatial distributions of electrons on the screen monitor has been performed taking into account ini tial spatial as well as angular beam divergence of electron bea m. Comparison of the experimental and theoretical results shows a good


agreement [3]. Both experimental data and simulations show the brilliant effect of so -called «doughnut scattering that can be used for the diagnostics of the incident beam angular diver gence. 2. 3. 4. REFERENCES Andersen S. K., et al.// Nucl. Instr. and Meth. in Phys. Res. B , 1980, v. 167, p. 1. http://www.saga-ls.jp/ Bogdanov O. V., Pivovarov Yu. L. Takabayashi Y., Tukhfatullin T.A.// RREPS -2011 Proceedings, J. Phys.: Conf. Ser., 2012, (in press). .. , .. 1), .. 1), .. 1) 1) , , 2) , ,
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/1-2/ Si. /3/. , /3/, Si. , /4/. 20 ­ 255 , SAGA - Light Source /5/. 1. 2. 3. 4. 5. Bogdanov O.V., Korotchenko K.B., Pivovarov Yu.L., Tukhfatullin T.A. // Nucl. Instr. And Meth. In Phys. Res. B. , 2008, V266, 3858. Bogdanov O.V., Evdokimov A.A., Korotchenko K.B. et al // Journal of Physics: Conference Series, 2010, Vol. 236, 1. Bogdanov O.V., Fiks E.I., Korotchenko K.B. et al // Journal of Physics: Conference Series, 2010, Vol. 236, 1. Baier V. N., Katkov V. ., Strakhovenko V. M. Electromagnetic Processes at High Energies in Oriented Single Crystals, Singapore, World Scientific Publishing Co, 1998. Takabayashi Y., Kaneyasu ., Iwasaki Y.// Il Nuovo Cimento, 2011, Vol. 34C, 4, 229. ON THE KINETICS AND RADIATION OF PLANAR CHANNELED ELECTRONS IN THICK CRYSTALS O.V. Bogdanov1),2), S.B. Dabagov2),3) INFN laboratori Nazionali di Frascati, Via E. Fermi 40, I-00044 Frascati (RM), Italy 2) Tomsk Polytechnic University, Lenin Ave. 30, Tomsk, 634050 Russia PN Lebedev Physical Institute, Leninsky pr. 53, 119991 Moscow, Russia
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Basic theory of dechanneling processes of relativistic electrons and positrons have been developed Ohtsuki and Kumakhov/1, 2/. In /3/ the evolution of relativistic electron beam in planar channeling has been analyzed. In ours work we have presented a model for the dual -channeling of 855 MeV electrons in a Si (111) crystal, taking into account the effects of dechanneling. The calculations were performed for the initial angular distributions of relativistic electrons in the beam as a function of transverse energy for various angles of incidence with respect to the crystal (111) planes. Within developed model both drift and diffusion coefficients /4/ of the beam density distributions for trapped electron motion in the system of double planes (111) have been evaluated. For 855 MeV electrons channeling in a Si (111) crystal the dechanneling length evaluated from the solution of the Fokker Planck equation equals to 18.8 m. Spectral characteristics of channeling radiation by electrons f moderate energies in thic k crystals have been first obtained taking into account the dynamics of beam scattering at channeling as well as the initial angular distribution of channeled electrons. REFERENCES 1. 2. 3. 4. Kumakhov M.A., and Shirmer G.. Atomic collisions in crystals. Moskva Atomisdat, 1980 (in Russian). Ohtsuki Y.-H.. Charged beam interaction with solids. New York, 1983. Backe H. et al. Nucl. Instr. Meth. in Phys. Res. B 266 (2008) 3835 -3851 Bogdanov O.V., Dabagov S.B. Spectra of Channeling Electron in Thick Si. - Preprint/Instituto Nazionale di Fisica Nucleare; LNF-11/25(IR), 2010. - P. 1-12.


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, /1/. ­ . , . , . , , . , . , . , 10-02-01386-; « », No 224.2012.2 1. .., .., .. .// , 1992, . 55, . 8, . 587 .. .. - , 61108, (), , . , /1/ /2/. - . , , . 1. 2. W. Scandale et al., // Phys. Lett. B, 2011, B701, pp. 180-185. .. // , 2004, 80, . 535-540. : .. , .. , .. , , GEANT 4 . , ( ). . . : 1. , . , . 2. , . , .


.. , .. , .. , .. , .. , .. , , - /1/ /2/. , . , 30 -50 , . (30-50 ) . 1. 2. Freudenberger J., Hell E., Knupher W. // Nucl. Instr. and Meth. in Phys. Res. A., 2001, Vol.466, P.99 .. , .. , .. // .. ., 2008, . 808, .2(38), . 25. .. , .. , .. , .. , .. , , - - /1/. /2,3/ - ~1-5 ~10% , . , l