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Bapna, S. C.

Paper Title Page
THPMA085 Mechanical Coupling between the LHC Cryogenic Distribution Line and the Short Straight Section housing the Superconducting Quadrupole. Theoretical Analysis and Experimental Validation 758
 
  • S. Dutta, S. C. Bapna, J. Dwivedi, S. Kotaiah, A. Kumar, R. S. Sandha, H. C. Soni
    RRCAT, Indore (M. P.)
  • C. Garion, A. Poncet, B. Skoczen
    CERN, Geneva
 
  The cryogenic module of the Short Straight Section (SSS) of Large Hadron Collider (LHC) is supplied with liquid & gaseous Helium through a jumper connection, which links the valve distribution box of the Cryogenic Distribution Line (QRL) & the SSS. The internal as well as external features of the jumper construction allow for sufficient flexibility to reduce the reaction forces responsible for elastic deformations when the SSS is moved for alignment. The SSS is composed of a cold mass and an external vacuum vessel equipped with fiducials for allowing the precise alignment of the machine when the cryostat is finally closed. A deformation of the structure from reaction forces induced by relative displacements of the SSS and the QRL, if unpredictable, would result in a dangerous misalignment of the quadrupole magnetic axis. A unified FE model, validated by a 40 meter long dedicated test setup at CERN, was generated at RRCAT to study the elastic behaviour of the SSS under the conditions of alignment. Transfer functions linking the action on the SSS external alignment jacks and the position of the cold mass are now available that will be used to properly align the machine in operation.  
THPMA087 Prototype Beam Dump For 10 kW LINAC 764
 
  • R. S. Sandha, S. C. Bapna, J. Dwivedi, V. C. Petwal, H. C. Soni
    RRCAT, Indore (M. P.)
 
  A 10 MeV, 10 kW electron LINAC has been developed at RRCAT, Indore for developing applications in the area of radiation processing of agricultural products and medical sterilization. This paper presents the functional requirements, design and manufacturing aspects of beam dump for this LINAC. Activation, conversion of electron energy into primary bremmstralung and radiation damage are important parameters for material selection of the beam dump. Other important parameters considered are mechanical strength, thermal conductivity, corrosion in ozone environment and manufacturability. Calculations of heat deposition due to electrons & photons, thermal design, hydraulic, structural and engineering design were done. FEM based analysis was performed for calculating temperature rise, deformation and stresses. The maximum temperature is estimated to be about 320 K. A prototype beam dump has been manufactured and installed and it is being tested under actual operating conditions.  
THPMA088 Bremsstrahlung Converter For High Power EB Radiation Processing Facility 767
 
  • V. C. Petwal, S. C. Bapna, S. Kotaiah, R. S. Sandha
    RRCAT, Indore (M. P.)
  • K. V. Subbaiah
    Safety Research Institute, Indira Gandhi Center for Atomic Research, Tamilnadu
 
  A radiation processing facility based on 10 kW Linac is being set up at RRCAT for irradiation of food products and sterilization of medical items. The facility is planned to operate in electron (10 MeV) and X-ray (5 & 7.5 MeV)mode. The required X-rays will be generated by bombarding an optimised target with 5 or 7.5 MeV electron beam. Monte Carlo simulation with MCNP has been performed to optimise the design of the targets for maximizing the X-ray output. The composite target is made of Ta, water & SS. Characteristics of the emerging X-ray field e.g. photon energy spectrum, angular distribution, radial dose and depth dose distribution in unit density material have been simulated & compared for 5 & 7.5 MeV. Our simulation results show that for optimised design, the fraction of the energy transmitted at 5 & 7.5 MeV is 9.3% & 14.2 % respectively, which is useful for radiation processing. The most probable energy of the photons is 0.3 MeV for both 5 and 7.5 MeV electrons and the average energy is 0.84 MeV & 1.24 MeV respectively. Large fraction of electron beam power is dissipated as heat in the targets. Necessary data has been generated to carry out thermal design.  
THPMA129 High Power Industrial Electron Accelerator 824
 
  • S. C. Bapna, R. Banwari, M. Borage, A. Kasliwal, S. Kotaiah, A. Kumar, P. Kumar, R. Promod, S. R. Tiwari, S. V. Venkateswaran
    RRCAT, Indore (M. P.)
 
  Development of 2.5MeV/ 100kW air-core transformer type electron Accelerator is in progress at RRCAT in collaboration with BINP, Russia. Energy of the accelerator is variable from 1 to 2.5 MeV with maximum beam current, power and beam scanning width of 50mA, 100kW and 1.5m respectively. High voltage generator, accelerating tube and injector control unit are housed inside the tank filled with pressurized SF6. A 430Hz, 150kW input power source to high voltage generator is based on a high-frequency switching (25kHz) dual half-bridge inverter and modular in construction with 6 modules (each 30kW) operating in parallel. In case one module fails, remaining modules will continue to feed power without de-rating. In this scheme, transformer leakage and magnetizing inductances will be compensated with high voltage capacitors eliminating the need of bulky inductors. The beam is scanned in two mutually perpendicular directions using scanning magnets. The control system uses microcontroller ADuC 812 based cards. Each subsystem will have one such card and a single RS485 multidrop communication link with the PC. The accelerator will be useful for various industrial applications.