Author: Dixit, T.S.
Paper Title Page
MOPAB405 Study of Targets to Produce Molybdenum-99 Using 30 MeV Electron Linear Accelerator 1222
 
  • T.S. Dixit, A.P. Deshpande, R. Krishnan, A. Shaikh
    SAMEER, Mumbai, India
 
  Funding: Ministry of Electronics and Information Technology, Government of India (MeitY)
Two approaches to produce 99Mo are studied using GEANT4 are reported in this paper. First, in converter target approach, bremsstrahlung photons are generated in a high Z target. The emitted photons then hit 100Mo secondary target, producing 99Mo through (gamma, n) reaction. Second, in direct target approach, high energy electron beam hits 100Mo target, where both (e, gamma) and (gamma, n) reactions take place simultaneously. A 30 MeV, 5-10 kW beam power electron linac is under development at SAMEER. The acceleration gradient required to achieve 30 MeV energy will be provided by two linacs operated in series configuration and the high average beam power will be achieved by running the system at high duty operation. Main aim of this study is to optimize experimental parameters to maximize specific activity of 99Mo. Since, 100Mo is very expensive material therefore judicious use of the material is very important. Hence, optimization of electron beam energy and target dimensions are studied in detail in both the approaches. It is found that the direct target approach gives higher specific activity compared to the converter target approach.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB405  
About • paper received ※ 19 May 2021       paper accepted ※ 06 June 2021       issue date ※ 14 August 2021  
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TUPAB404 Monte Carlo Studies for Shielding Design for High Energy Linac for Medical Isotope Generation 2469
 
  • N. Upadhyay, S. Chacko
    University of Mumbai, Mumbai, India
  • A.P. Deshpande, T.S. Dixit, P.S. Jadhav, R. Krishnan
    SAMEER, Mumbai, India
 
  The widely used radioactive tracer Technetium-99m (99mTc) is traditionally produced from Uranium via 235U (n, f) 99Mo reactions which depends heavily on nuclear reactors. Design studies for an alternative, cleaner approach for radioisotope generation using a high energy electron linac were initiated at SAMEER to generate 99Mo. The electron beam from a 30 MeV linac with an average current of 350 µA will be bombarded on a convertor target to produce X-rays which will be bombarded on enriched 100Mo target to produce 99Mo via (g, n) reaction. 99mTc will be eluted from 99Mo. The photons and neutrons produced in the process should be shielded appropriately to ensure radiation safety. This paper brings out the use of Monte Carlo techniques for photon and neutron shielding for our application. We used FLUKA to calculate the fluence, angular distribution and dose for photons and neutrons. Then, we introduced various layers of lead followed by HDPE, 5% borated HDPE and 40% boron rubber to ensure that the proposed shielding is sufficient to completely shield the photon as well as neutron radiation and hence is safe for operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB404  
About • paper received ※ 19 May 2021       paper accepted ※ 22 June 2021       issue date ※ 25 August 2021  
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TUPAB405 Design of High Energy Linac for Generation of Isotopes for Medical Applications 2472
 
  • A.P. Deshpande, S.R. Bhat, T.S. Dixit, P.S. Jadhav, A.S. Kottawar, R. Krishnan, M.S. Kumbhare, J. Mishra, C.S. Nainwad, S.R. Name, R. Sandeep Kumar, A. Shaikh, K.A. Thakur, M.M. Vidwans, A. Waingankar
    SAMEER, Mumbai, India
  • A.K. Mishra
    INMAS, New Delhi, India
  • N. Upadhyay
    University of Mumbai, Mumbai, India
 
  Funding: Ministry of Electronics and Information Technology (MeitY), Govt. of India.
After successful implementation of 6 and 15 MeV electron linear accelerator (linac) technology for Cancer Therapy in India, we initiated the development of high energy high current accelerator for the production of radioisotopes for diagnostic applications. The accelerator will be of 30 MeV energy with 350 µA average current provided by a gridded gun. The linac is a side coupled standing wave accelerator operating at 2998 MHz frequency operating at p/2 mode. The choice of p/2 operating mode is particularly suitable for this case where the repetition rate will be around 400 Hz. Klystron with 7 MW peak power and 36 kW average power will be used as the RF source. The modulator will be a solid-state modulator. The control system is FPGA based setup developed in-house at SAMEER. A retractable target with tungsten will be used as a converter to generate X-rays via bremsstrahlung. The x-rays will then interact with enriched 100Mo target to produce 99Mo via (g, n) reaction. Eluted 99mTc will be used for diagnostic applications. The paper lists the challenges and novel schemes developed at SAMEER to make a compact, rugged, and easy to use system keeping in mind local conditions.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB405  
About • paper received ※ 19 May 2021       paper accepted ※ 23 June 2021       issue date ※ 02 September 2021  
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WEPAB208 Energy Sweeping Beam Extraction by the Septum Magnet Assisted with Charge Exchange for a Hadron Therapy 3109
 
  • T.S. Dixit, A. Shaikh
    SAMEER, Mumbai, India
  • T. Adachi, T. Kawakubo, K. Takayama
    KEK, Ibaraki, Japan
 
  An energy sweeping compact rapid cycling hadron therapy based on a fast cycling induction synchrotron has been proposed by KEK and SAMEER as the next generation of hadron therapy machine *. For energy sweep extraction, a C+5 beam is injected, captured and trapped in the barrier bucket. A fraction of the beam is continuously released from the barrier bucket by controlling the timing of barrier pulse generation. Released C+5 ions merge into the coasting beam and moves inwards with ramping of the guiding main magnets. Ions in the coasting beam eventually hit the carbon foil placed inside the beam chamber wall. As a result, C+5 is converted to C+6 and beam orbit is largely changed as it traverses through the downstream bending magnet. This notably facilitates C+6 beam extraction, resulting in a relatively small kick angle of the septum magnet. When the septum is excited in the same way as that of the main magnets, the extracted C+6 beam always places on the center of the irradiation beam line. LISE++ simulations demonstrated the charge exchange efficiency of almost 100 % for expected beam energy. The feasibility of the switching power supply for the septum magnet has been studied.
* PRAB 24, 011601 (2021)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB208  
About • paper received ※ 14 May 2021       paper accepted ※ 22 June 2021       issue date ※ 16 August 2021  
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WEPAB209 Review of Medical Accelerator Development at Sameer, India 3113
 
  • T.S. Dixit, N. Bansode, A.P. Bhagwat, S.T. Chavan, A.P. Deshpande, G. Gaikwad, S. Ghosh, R. Krishnan, C.S. Nainwad, G.D. Panchal, S.N. Pethe, K.A. Thakur, V.B. Ukey, M.M. Vidwans
    SAMEER, Mumbai, India
 
  Funding: Ministry of Electronics and Information Technology (MeitY), Government of India
At the Medical Electronics Division of SAMEER, R&D for the development of a 4 MeV energy electron linac for Cancer therapy was taken up in the late ’80s. An S-band standing wave side coupled structure operating at pi/2 mode was developed for electron acceleration. The linac was integrated with other subsystems in collaboration with CSIO and PGIMER and the first machine was commissioned at PGI, Chandigarh in 1990. Thereafter, a lot of modifications like energy, dose rate, iso-center height etc. were made in the system, and later 4 more machines were commissioned in hospitals for treatment. More than 1,50,000 patients have been treated using SAMEER’s 6 MeV oncology system. Subsequently, development of dual-mode and variable energy electron and photon output machines was undertaken. Two-photon energies of 6 and 15 MV and multiple electron energies starting from 6 to 18 MeV for treatment was offered from the linac. The electron energy variation was done using plunger mechanism in the side coupling cavity. This linac was successfully baked and RF tested for various parameters. This paper describes the experimental parameters achieved for both low and high energy dual-mode linac.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB209  
About • paper received ※ 14 May 2021       paper accepted ※ 07 July 2021       issue date ※ 13 August 2021  
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