2011 Particle Accelerator Conference - List of Authors (Dhole, S.D.)

Paper	Title	Page
THP009	Collimator Design of 15 MeV Linear Accelerator Based Thermal Neutron Source for Radiography	2154
	B.J. Patil, V.N. Bhoraskar, S.D. Dhole University of Pune, Pune, India S.T. Chavan, R. Krishnan, S.N. Pethe SAMEER, Mumbai, India A.J. Patil DANA, Pune, India
	Neutron Radiography is a powerful non-destructive testing technique used for the analysis of objects which are widely used in security, medical, nuclear and industrial applications. Optimization of the thermal neutron radiography facility has been carried out using 15 MeV LINAC based neutron source. In this case, a neutron collimator has been designed along with g-n target, moderator, reflector and shielding. The g-n target has been optimized based on their photonuclear threshold. The moderating properties have been studied for few light elements to optimize best suitable moderator for radiography system. The major part of the design was to optimize the collimator for neutron beam which decides quality of the image given. To get best values of collimator parameters such as collimation ratio, gamma content, neuron flux, cadmium ratio, beam uniformity, etc. a FLUKA simulation was carried out. The collimator has been optimized with cadmium lining square cone to capture the scattered thermal neutrons and the collimation ratio to L/D=18. The neutron flux of the optimized facility obtained at the object plane is 1.0·10⁺⁵ n/(cm²-sec¹) and neutron to gamma ratio is 1.0·10⁺⁵ n/(cm²-mR¹).

THP010	Optimization of Dual Scattering Foil for 6 to 20 MeV Electron Beam Radiotherapy	2157
	B.J. Patil, V.N. Bhoraskar, S.D. Dhole University of Pune, Pune, India S.T. Chavan, R. Krishnan, S.N. Pethe SAMEER, Mumbai, India
	From last 50 years, electron beam therapy has an important radiation therapy modality. The electron beam from the LINAC is of size ~ 2 mm, whereas the size required for actual treatment is usually larger than 2 X 2 cm² up to 30 X 30 cm² at the isocenter. In the present work, it is proposed to use dual scattering foil system for production of clinical electron beam. The foils for 6 to 20 MeV electrons were optimized using the Monte Carlo based FLUKA code. The material composition, thickness of primary foil, Gaussian width and thickness of secondary foil were optimized such that it should meet the design parameters such as Dose at iso-center, beam uniformity, admixture of bremsstrahlung, etc. A pencil beam of electrons passing through primary foil converted into Gaussian shape and falling at the centroid of secondary foil which experienced maximum scattering, whereas falling at the edge experienced the minimum scattering. This results into flat profile of electron at isocenter. In conclusion, the primary scattering foil has been optimized with high Z element (Ta) having uniform thickness, whereas the secondary foil has been optimized with low Z element (Al) having Gaussian shape.

THP020	Effects of 6 MeV Electron Irradiation on ZnO Nanoparticles Synthesized by Microwave Method	2166
	K.B. Sapnar, V.N. Bhoraskar, S.D. Dhole University of Pune, Pune, India K.M. Garadkar, L..A. Ghule Shivaji University, Nanomaterials Reasearch Laboratory, Kolhapur, India
	The sizes of zinc-oxide (ZnO) nanoparticles were synthesized by microwave method and were tailored by electron irradiation method. The ZnO nanoparticles having size of ~46 nm synthesised by microwave method were exposed to different fluences of 6 MeV electrons over the range from 1x10¹⁵ to 2.5x10¹⁵ e^- /cm². The electron irradiated ZnO nanoparticles were characterized by XRD, SEM, UV techniques. The XRD results show that the particle size reduced continuously from 46 nm to 15 nm with the increase in electron fluence and SEM images also confirms the formation of nanoparticles of minimum size of around 14 nm. The band gap of the ZnO nanoparticle also increased from 3.29 to 3.42 eV as the size reduced. The result shows the ZnO particles are broken in to smaller size under electron irradiation and increase in the band gap indicates the formation of defects in ZnO. The electron irradiation method is found to be an efficient method in tailoring the size of ZnO nano particles. The nanosized ZnO particles can suit for the applications such as photovoltaics, photocells and antimicrobial activity.

Paper

Title

Page

Collimator Design of 15 MeV Linear Accelerator Based Thermal Neutron Source for Radiography

2154

B.J. Patil, V.N. Bhoraskar, S.D. Dhole
University of Pune, Pune, India
S.T. Chavan, R. Krishnan, S.N. Pethe
SAMEER, Mumbai, India
A.J. Patil
DANA, Pune, India

Neutron Radiography is a powerful non-destructive testing technique used for the analysis of objects which are widely used in security, medical, nuclear and industrial applications. Optimization of the thermal neutron radiography facility has been carried out using 15 MeV LINAC based neutron source. In this case, a neutron collimator has been designed along with g-n target, moderator, reflector and shielding. The g-n target has been optimized based on their photonuclear threshold. The moderating properties have been studied for few light elements to optimize best suitable moderator for radiography system. The major part of the design was to optimize the collimator for neutron beam which decides quality of the image given. To get best values of collimator parameters such as collimation ratio, gamma content, neuron flux, cadmium ratio, beam uniformity, etc. a FLUKA simulation was carried out. The collimator has been optimized with cadmium lining square cone to capture the scattered thermal neutrons and the collimation ratio to L/D=18. The neutron flux of the optimized facility obtained at the object plane is 1.0·10⁺⁵ n/(cm²-sec¹) and neutron to gamma ratio is 1.0·10⁺⁵ n/(cm²-mR¹).

THP010

Optimization of Dual Scattering Foil for 6 to 20 MeV Electron Beam Radiotherapy

2157

B.J. Patil, V.N. Bhoraskar, S.D. Dhole
University of Pune, Pune, India
S.T. Chavan, R. Krishnan, S.N. Pethe
SAMEER, Mumbai, India

From last 50 years, electron beam therapy has an important radiation therapy modality. The electron beam from the LINAC is of size ~ 2 mm, whereas the size required for actual treatment is usually larger than 2 X 2 cm² up to 30 X 30 cm² at the isocenter. In the present work, it is proposed to use dual scattering foil system for production of clinical electron beam. The foils for 6 to 20 MeV electrons were optimized using the Monte Carlo based FLUKA code. The material composition, thickness of primary foil, Gaussian width and thickness of secondary foil were optimized such that it should meet the design parameters such as Dose at iso-center, beam uniformity, admixture of bremsstrahlung, etc. A pencil beam of electrons passing through primary foil converted into Gaussian shape and falling at the centroid of secondary foil which experienced maximum scattering, whereas falling at the edge experienced the minimum scattering. This results into flat profile of electron at isocenter. In conclusion, the primary scattering foil has been optimized with high Z element (Ta) having uniform thickness, whereas the secondary foil has been optimized with low Z element (Al) having Gaussian shape.

THP020

Effects of 6 MeV Electron Irradiation on ZnO Nanoparticles Synthesized by Microwave Method

2166

K.B. Sapnar, V.N. Bhoraskar, S.D. Dhole
University of Pune, Pune, India
K.M. Garadkar, L..A. Ghule
Shivaji University, Nanomaterials Reasearch Laboratory, Kolhapur, India

The sizes of zinc-oxide (ZnO) nanoparticles were synthesized by microwave method and were tailored by electron irradiation method. The ZnO nanoparticles having size of ~46 nm synthesised by microwave method were exposed to different fluences of 6 MeV electrons over the range from 1x10¹⁵ to 2.5x10¹⁵ e^- /cm². The electron irradiated ZnO nanoparticles were characterized by XRD, SEM, UV techniques. The XRD results show that the particle size reduced continuously from 46 nm to 15 nm with the increase in electron fluence and SEM images also confirms the formation of nanoparticles of minimum size of around 14 nm. The band gap of the ZnO nanoparticle also increased from 3.29 to 3.42 eV as the size reduced. The result shows the ZnO particles are broken in to smaller size under electron irradiation and increase in the band gap indicates the formation of defects in ZnO. The electron irradiation method is found to be an efficient method in tailoring the size of ZnO nano particles. The nanosized ZnO particles can suit for the applications such as photovoltaics, photocells and antimicrobial activity.