| Paper | Title | Page |
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| TUPMA115 | Simulations of Non-uniform High Density Electronegative Plasma for Optimization of H- ions and their Extraction | 265 |
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| Numerical simulations of radio frequency multi-cusp volume type H- ion source have been performed under non-uniform electronegative plasma equilibrium conditions in order to understand the physics of formation of various ion species (H+, H-, e- etc.) and for optimization of H- ion formation and extraction. Coupled momentum balance equations along with continuity equations were solved in a cylindrical geometry to obtain the density profile of various ion species. The relevant cross-section data available in the literature as a function of temperature has been used in the computation. The hydrodynamic model of plasma in equilibrium with background neutral gas has been used. Low degree of ionization ( ~1%) has been assumed. The collision less sheath formation, penetration of electric and magnetic field and power requirement to sustain the plasma has been worked out numerically. An effort has been made to give a self-consistent numerical scheme for the solution of inductively coupled plasma (ICP) in equilibrium, and the results obtained have been presented | ||
| WEPMA065 | Experience of Beam Diagnostic Systems in Commissioning Stage of Indus-2 | 413 |
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| Indus-2 is a 2.5 GeV synchrotron radiation source under commissioning at this center. Beam injection trials in the storage ring began in August 2005. Beam diagnostics systems played an important role during commissioning of the storage ring. Beam diagnostic systems installed in the machine include beam profile monitor, orbit measurement system, wall current monitor, DCCT, striplines, tune measurement system and sighting beam line. This paper describes the diagnostic systems, experience of operation of these systems during commissioning, results obtained and the present status. During the initial stages of beam injection and circulation in INDUS-2 wall current monitors, beam profile monitors and sighting beam line proved to be of utmost help. In the current stage of near routine beam operation, the main focus has shifted to the measurement of beam parameters with the objective of improving beam current and lifetime. A study of beam orbit measurement was recently taken up. The beam orbit was measured before and after generating an orbit perturbation. A study of betatron tune measurements has been initiated. | ||
| THC2MA02 | Experiences with the Manufacturing, Testing and Quality Control of Large Number of Superconducting Magnets | 567 |
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| Raja Ramanna Centre for Advanced Technology has successfully completed the supply of nearly 2000 nos. Superconducting Corrector (SC) Magnets for the LHC project at CERN. Initial prototypes were developed at RRCAT in collaboration with CERN and large scale production was done in industry. These corrector magnets require precision components, accurate assembly procedure, elaborate testing and stringent quality control required for repeatable performance. A number of sub technologies were developed for these magnets at RRCAT and successfully transferred to Industry. These include precision coil winding, joining SC wire to get low contact resistance, measuring it at 4.2 K. Ultrasonic welding machine and automatic coil winding machines were developed. Cryogenic testing procedures and test facility were established at RRCAT. SC switches and current leads were designed and fabricated. Cryogenic testing at 4.2 K and magnetic measurement at 300 K for all the 2000 magnets were done at RRCAT. Special tooling and inspection gauges for in process inspection were made. In this paper we describe the experience gained during technology development, prototyping and technology transfer to industry. | ||
| THPMA013 | Effect of Eddy Current in Magnetic Lamination on Pulsed Septum Magnet Response | 643 |
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Indus-2 Pulsed septum magnets have been developed using 0.1 mm thick Ni-Fe laminations, which were electrically insulated from each other. These laminations were annealed in Hydrogen furnace & then oxidized in a Air controlled furnace. A process has been optimized to get 10-micron oxidization thickness on both sides of lamination. A pulse test set up has been built to characterize the laminations at high magnetization rates (‘~ 1 T/us). Electromagnetic simulation of the main field in the gap & field free region ' leakage/stray field for Septum magnets were performed using Flux 2D. A stray field (~1G-m) was stringent so as not to distort circulating beam. Magnetic screen has been optimized to minimize the stray fields. A pulsed thin & thick septum magnets were excited using 50 ms half sine wave, the field homogeneity in the order of 100 PPM & Integrated stray field 0.7 G-m has been obtained. This paper focus on Eddy current effect in lamination on pulse magnetic response, attenuation, phase shift & resonance in lamination due to pulse frequency. Modeling of magnetic circuit, shielding of septum & pulse response of NiFe lamination at high magnetic amplitudes(1.2T ) is also presented.
R. K. Mishra, P. Pareek, M. M.Pandey, V. Gaud, S. Senthil kumar |
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| THPMA032 | Active Filter for Harmonic Mitigation for Magnet Power Supplies of INDUS-II | 671 |
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| Power supplies used for powering of magnets in INDUS-I and INDUS-II uses different type of power converters including SMPS and thyristorised power converters. Though considerations are given to keep the harmonic loading on a.c. mains low while designing these power supplies and selecting a suitable power converter for the required power, still they give a significant amount of harmonic loading on a.c. mains. In all the high power d.c. power supplies, wide variation in operating point leads to a considerable amount of reactive power generation and harmonic loading on ac mains. In this work a study has been performed to know the variation of reactive power with time on some of the d.c. power supplies of INDUS-II. Various options to improve the power factor has been studied and their advantages & limitations for accelerator magnet power supplies has been highlighted. A combined system of a shunt passive and small rated series active filter has been proposed. The compensation principle is described and filtering characteristics are discussed in detail. A scale down prototype of proposed series active filter has been developed in lab and experimental results produced. | ||
| THPMA036 | Utilizing Multiplier Stack's Reflected Parasitic Capacitance to Achieve ZVS Operation of Resonant Inverter for 750 keV DC Accelerator | 677 |
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| This paper presents the analysis and design of a 40 KHZ high order LCLC resonant inverter that utilizes the reflected capacitance of the symmetrical Cockroft Walton mulitiplier stack as its tank circuit component. The inverter is being used for energizing the 750 keV dc accelerator at RRCAT, Indore. The reflected capacitance which is intended to be used as the tank component consists of winding capacitances of the HV transformer and reflected capacitance of the multiplier stack. This capacitance along with a compensating inductor is used to achieve the ZVS operation of the inverter. The reflected capacitance at the primary of the HV Transformer with HV generator connected at its secondry, was found to be 4.1 μF. When transferred to the secondry of the transformer , the effective capacitance was 0.177 nF. The compensating inductance required then was 93 mH to keep the resonating frequency very close to switching frequency of 40 KHZ. This selection kept the no load circulating current demand at the inverter end to the minimum possible. The inverter is presently being used to energise the Accelerator. | ||
| THPMA039 | 300 kV/ 6 kW Power Supply System for Self-shielded Low Energy DC Accelerator at RRCAT Indore | 679 |
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| A compact, low energy, self-shielded dc accelerator for industrial applications requiring beam energy in the range of 100 to 300 keV is under development at RRCAT, Indore. The power supply and control system for this accelerator is discussed here in this paper. The high voltage source is a series fed cascade generator driven by a 30 kHz sine wave inverter. Two asymmetrical cascade generators are run in parallel to enhance the current capacity of the generator. A 15-0-15 kV, 30 kHz ferrite core transformer interfaces the cascade generators with IGBT based H-bridge inverter. A buck chopper controls the dc bus voltage of the inverter so as to control the terminal voltage of the high voltage generator. A low power high frequency inverter generates the filament power supply floating at terminal voltage of the accelerator through a capacitive isolation column. Control of the filament power supply is achieved by sensing the accelerator beam current and controlling the low power inverter in a closed loop. A PC based control system designed with Lab-view 7.0 software and ADUC812 Micro-converter cards monitors and displays the various parameters of the power supply and accelerator. | ||
| THPMA046 | Study and Comparison of Reactive Power Compensation Schemes for Air-Core Transformer in ELV-type DC Accelerators | 688 |
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| The ELV-type electron accelerators are widely used in industrial and research applications. The scheme for generating high voltage in these machines is based on air-core transformer, which has large leakage inductance and small magnetizing inductance. To minimize the reactive power loading on the inverter feeding the primary winding, suitable compensation scheme must be employed. Conventional compensation scheme using shunt capacitor and a series inductor however can minimize the reactive power only at one particular loading condition. Also the compensating inductor becomes heavy and bulky. In this paper, the results of studies done to investigate suitability of various compensation networks are presented. Following desirable features are looked for: (1) Near-unity power factor operation under all loading conditions. (2) Nearly load independent output voltage. (3) Minimum additional reactive components. (4) Elimination of compensating inductor. Characteristics of compensation networks are studied and compared using simulation software PSpice wherein with the proposed method, normalized results suitable for comparison are directly obtained. | ||
| THPMA085 | Mechanical Coupling between the LHC Cryogenic Distribution Line and the Short Straight Section housing the Superconducting Quadrupole. Theoretical Analysis and Experimental Validation | 758 |
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| 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. | ||
| THPMA088 | Bremsstrahlung Converter For High Power EB Radiation Processing Facility | 767 |
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| 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. | ||
| THPMA096 | Installation and Integration of Indus-2 | 782 |
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| The Synchrotron Radiation Sources consist of a large number of components of varying nature. Some components are light but highly delicate whereas some are big and heavy. However all components need a careful handling during their installation. Unit-cell mock-up assembly and virtual simulation of the installation process using software tools contributed significantly in visualizing various handling schemes, checking interferences and defining the assembly sequence. We have recently completed the installation and integration of 2.5 GeV Synchrotron Radiation Source, Indus-2, by adopting a set procedure of installation and pre-defined sequence. This paper presents, an overview of procedures, sequence of assembly, equipments and toolings used for material handling and safety precautions taken during the whole task of installation and assembly. | ||
| THPMA129 | High Power Industrial Electron Accelerator | 824 |
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| 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. | ||
| THPMA131 | Indian Participation in LHC, SPL and CTF-3 Projects at CERN, Switzerland | 829 |
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| After signing a Protocol on 29 March 1996 to the 1991 cooperation agreement with CERN, Switzerland, India is participating in the construction of CERN’s most challenging and ambitious particle accelerator the “Large Hadron Collider” (LHC). The contributions span from hardware, software, and skilled manpower support for evaluation of some of the LHC sub-systems and presently to the support in commissioning of various subsystems of LHC. With major achievements on Indian part during the course of time CERN has now invited India to jointly participate further to build CERN’s Advanced Accelerator Projects like Super conducting Proton LINAC, SPL and Compact Linear Collider Test Facility, CTF-3. The present paper describes the achievements to date and high lights the ongoing and future collaboration activities. |