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power-supply

 
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TUPMA026 A Prototype of the SSRF Power Supply Control System controls, storage-ring, booster, linac 139
 
  • J. G. Ding, L. R. Shen, H. Zhao, H. J. Zhu
    SINAP, Shanghai
  The Shanghai Synchrotron Radiation Facility (SSRF) is a third generation, 3.5GeV synchrotron light source currently being constructed at the Shanghai Institute of Applied Physics (SINAP) in Shanghai, China. There will be approximately 700 magnet power supplies (PS) in the storage ring, booster, linac and transport lines. According to the requirement of control precision, reliability and stability of the magnet power supplies, we decided to use the PSI-designed PS control system for PS control. Each magnet PS has a local digital controller for a digital regulation loop and a 5MHz optical point-to-point link to the VME level. The low-level EPICS interface is identical for all magnet power supplies. Industry Pack (IP) modules with standard carrier cards are used as VME interface with eight links per VME card. The VME-based front-end consists of a PowerPC7455 SBC board, IP carriers and IP I/O modules. A prototype of the PS control system has been setup and tested at SINAP. Control and monitoring of the prototype has been implemented with EPICS toolkit. This paper describes the progress and software development of the prototype, and discusses our near future plan.  
 
TUPMA064 ILC Activity at JINR and Siting in Dubna Region linear-collider, collider, electron, luminosity 202
 
  • G. V. Trubnikov, Yu. N. Denisov, I. N. Meshkov, G. Shirkov, A. N. Sissakian
    JINR, Dubna, Moscow Region
  JINR actively participates in ILC project. JINR physicists are planning to take part in several fields of activity in ILC: works on photo injector prototype, participation in design and construction of cryomodules, laser metrology, etc. Moreover Joint Institute is full-member pretender for possible hosting of ILC in the region near Dubna. International intergovernmental status of JINR, comfortable location of site, well developed infrastructure, geological, climate and relief conditions may become powerful advantages of Dubna siting among other proposals of ILC location. All above mentioned topics are discussed in the presented report.  
 
TUPMA111 Present Status of J-PARC MR Synchrotron extraction, septum, synchrotron, injection 259
 
  • T. Koseki, H. Kobayashi, H. Matsumoto, M. Yoshioka
    KEK, Ibaraki
  The Japan Proton Accelerator Research Complex (J-PARC) is a joint project of High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Agency (JAEA). The J-PARC accelerator complex is composed of a 400 MeV proton linac, a 3 GeV Rapid-Cycling Synchrotron (RCS), and a 50 GeV Proton Synchrotron (MR). Installation of the MR which has two extraction sections, fast extraction for the Neutrino Facility and slow extraction for the Hadron Facility, is now underway. Test of injection and extraction components such as septum magnets and kicker magnets is progressed as well. Beam commissioning scenario is now being prepared. Maintenance scenario of activated components is also crucial in a high power proton accelerator. Beam commissioning will start in May 2008.  
 
WEPMA002 A Large Area Scanning Magnet For Homogeneous Irradiation of Targets controls, impedance, dipole, ion 339
 
  • A. Mandal, R. Kumar, G. Rodrigues, S. K. Suman
    IUAC, New Delhi
  The scanner is an important tool for accelerator based material science research. For high energy (~100 MeV) ion beam scanner has to be magnetic one. Major problem faced with magnetic scanner is its high inductance which causes large impedance to the a.c. power supply used to energise the magnet. We have designed a magnetic scanner keeping attention to minimise its inductance. The scanner is composed of two independent H-type dipole magnets which are fed by saw tooth pulses. It can scan over an area of 25 mm x 25mm at a distance of 1 metre. The power supplies for this scanner have also been designed. These are bipolar, wideband, high speed amplifirs that can reproduce complex waveform without any distotion. The ratings are 60V, 50A operating at 50Hz for x-scanner and 5V,70A at 0.2Hz for y-scanner. Design and performance of the scanner magnet and power supplies will be presented.  
 
WEPMA073 Control System based on PCs and PLCs for the L-band Linac at Osaka University controls, linac, electron, klystron 425
 
  • R. Kato, G. Isoyama, S. Kashiwagi, S. Suemine, T. Yamamoto
    ISIR, Osaka
  The L-band electron linac at the Institute of Scientific and Industrial Research (ISIR), Osaka University, has been remodeled for higher stability and reproducibility of operation. A computer control system has been newly introduced for the linac not only to realize precise reproducibility of operation but also to make routine operation possible by even an unskilled operator. The new control system is based on personal computers (PCs) and programmable logic controllers (PLCs). The PCs and the PLCs are connected with networks using two different communication protocols. As the network connecting the PLCs, we have chosen FL-net, which is an open PLC network for factory automation. On the other hand, the PCs communicate each other with Ethernet. In order to transfer control information between these two networks with different protocols, one of the PCs is equipped with both FL-net and Ethernet and works as a gateway server. The PC converts data in the common memory in FL-net to the form accessible to the other PCs and vice versa. In this paper, we present details of the control system and operational experiences.  
 
WEPMA080 Control System for the Bending MPS at PLS Linac controls, linac, monitoring, klystron 437
 
  • J. H. Kim, J. Choi, K. M. Ha, J. Y. Huang, H.-S. Kang, J. M. Kim, S.-C. Kim, I. S. Ko
    PAL, Pohang, Kyungbuk
  The former control system of the bending MPS (Magnet Power Supply) has a three-layered architecture. It was developed by in-house members in early 1993. It is upgraded based on EPICS as the protocol for the full upgrade of the PLS control system. We have replaced the former VME 68K CPU boards with OS-9 to new Power CPU boards operated by VxWorks as IOC in the linac klystron gallery. The upgraded bending MPS control system consists of a MVME5100 EPICS IOC core in the lower level control. It is implemented with the MEDM tool of EPICS to provide friendly Graphical User Interfaces. This paper describes the VME IOC and OPI and embedded local controller in MPS cabinet used for the bending MPS control in the PLS linac

Pohang Accelerator Laboratory, Pohang, 790-784, KoreaThis works supported by the Ministry of Science and Technology, Korea.

 
 
WEPMA085 Implementation and Experience of Energy Ramping for Indus-2 controls, dipole, quadrupole, sextupole 443
 
  • R. K. Agrawal, A. Chauhan, P. Fatnani, R. Husain, K. Saifee, M. Seema, Y. M. Sheth, G. Singh
    RRCAT, Indore (M. P.)
  Beam energy ramping in Synchrotron Radiation Sources (SRS) requires synchronous increase in power supply currents attached to various magnets. This paper describes the implementation at various layers of control system architecture, experience of ramping beam energy from injection energy to 2 GeV. The total Ramping system hardware and software for both Magnet power supplies and RF cavity voltage are described with problems faced during the energy ramping. The implemented ramping system provides a tracking uncertainty less than 10μsec in time.  
 
WEPMA086 First Experiences with Central Web Based Fault Information System controls, radiation, synchrotron, synchrotron-radiation 446
 
  • B. S. Srivastava, P. Fatnani
    RRCAT, Indore (M. P.)
  Indus Control System operating the Indus-1 and Indus-2 Synchrotron Radiation Sources facilities at RRCAT, Indore is a widely distributed system. It employs, for Indus-1 8 VME Controllers, 300 interface modules, 7 Operator Computers and for Indus-2 approximately 100 Layer-3 VME stations, 10 Layer-2 Supervisory Controllers, 11 Operator Computers and 6 Server Machines. The whole control system is being operated in shifts to provide synchrotron radiation from Indus-1 to users as well as carrying out commissioning experiments of Indus-2. To keep it up and running the faults encountered during its operation are rectified at site and complete observations and rectifications of the faults are recorded electronically by the shift crewmembers in a central web based fault information system. This System is based on three tiers software architecture and has been developed using Java Servlets, HTML, JavaScript and SQL Database. Using relational database, facilities have been provided by the system for logging, e-mailing, acknowledging, exploring and analyzing the faults of various sub systems. This paper briefly describes experience implementations and functionalities provided by the system.  
 
WEPMA090 Status of the Superconducting Insertion Devices Control System at TLS controls, insertion, insertion-device, cryogenics 455
 
  • K. H. Hu, J. Chen, K. T. Hsu, S. Y. Hsu, C. H. Kuo, D. Lee
    NSRRC, Hsinchu
  Superconducting insertion devices installed at Taiwan Light Source to service fast growth X-ray users’ community. Control system is implemented to support the operation of all these superconducting insertion devices. Control system coordinates the operation of the main power supply and the trimming power supply to charge/discharge the magnet and provide essential interlock protection for the coils and vacuum ducts. Quench detection and various cryogenic interlock are designed to protect the system. Friendly user interface and control applications are developed to support routine operation. Diagnostic the trip of superconducting insertion devices related to machine operation is also addressed. Design consideration and details of the implementation will be summary in this report.  
 
WEPMA099 A New, PXI Bus Based, Pattern Memory System for the Siam Photon Source. synchrotron, booster, controls, photon 461
 
  • G. G. Hoyes
    NSRC, Nakhon Ratchasima
  A new pattern memory system has been built from PXI bus modules to ramp the booster synchrotron magnet and RF power supplies, replacing an old and proprietary Toshiba system. The new system is compact, rugged, easy to program using LabVIEW, easy to repair and low cost.  
 
WEPMA105 High Power Test of C-band Accelerating System for Japanese XFEL Project klystron, linac, vacuum, collider 470
 
  • K. Shirasawa, T. Inagaki, H. Kitamura, T. Shintake
    RIKEN Spring-8 Harima, Hyogo
  • H. Baba, H. Matsumoto
    KEK, Ibaraki
  • S. Miura
    MHI, Hiroshima
  ?The C-band (5712 MHz) choke-mode type accelerating structure will be used for SCSS: SPring-8 Compact SASE Source project. Since the C-band accelerator generates higher accelerating gradient than traditional S-band accelerator, it makes the machine size compact and the cost low. In order to confirm the performance of the C-band accelerating system for the 8 GeV XFEL machine, the system including the same accelerating structure and RF system have been installed in the SCSS prototype accelerator. The first SASE amplification was observed at 49 nm on June 2006. In the prototype machine, four 1.8 m long C-band accelerating structures are used to accelerate electron up to 250 MeV. The C-band accelerator?unit has one 50 MW klystron and pulse compressor, where two types of pulse compressors: SKIP and SLED were adapted. After 300-hour RF conditioning, accelerating gradient up to 32 MV/m was achieved and we confirmed there is no serious problem. Now we continue the RF conditioning to get higher accelerating gradient and find the practical limit. In this paper, we would like to report on the RF conditioning and the achieved performance of the C-band accelerator.  
 
WEPMA110 Development of 100 kW RF Amplifier for Superconducting Cyclotron at VECC impedance, cyclotron, higher-order-mode, controls 476
 
  • S. S. Som, M. B. Banerjee, D. S.B. Bhattacharyay, S. B. Biswas, P. G. Gangopadhyay, A. Mandal, S. K. Manna, A. K. Mukherjee, S. P. Pal, J. S.P. Prasad, P. R. Raj, M. S. Saha, S. Saha, S. Seth, K. V. krishnaiah
    DAE/VECC, Calcutta
  High power rf amplifiers (3 nos.) have been developed at our centre for feeding power to three nos. of coaxial rf cavities of the k500 Superconducting Cyclotron. Each of this amplifier can supply output power of 100 kW (max.) at 50 Ω impedance within the frequency range of 9 MHz to 27 MHz. The amplifier, based on Eimac 4CW 150,000E water-cooled tetrode, is tuned by moving the sliding short of the coaxial cavity within the said frequency range. An inductive coupling loop is inserted along one side of the coaxial cavity through the sliding short and is matching the output impedance of 50 ohm. The four identical Bridge-T network in the grid of the final amplifier are driven with equal power levels of up to 150 watts. The amplifier is operated in Class-AB mode with power gain of 22 dB. A PC-based stepper motor controlled sliding short movement system have been done. The frequency response of the input circuit of the amplifier has been measured using Vector Network Analyzer and the result is very satisfactory.  
 
WEPMA119 Control Characteristics of the PEFP RF System controls, klystron, proton, site 485
 
  • H.-J. Kwon, Y.-S. Cho, I.-S. Hong, H. S. Kim, K. T. Seol, Y.-G. Song
    KAERI, Daejon
  A 20 MeV proton accelerator has been developed and tested at Proton Engineering Frontier Project (PEFP) as a front-end part of the 100 MeV accelerator. The initial test results showed that more stable rf operation was necessary to investigate the machine characteristics more deeply. A LLRF control system using commercially available digital board was newly developed and tested for this purpose. The goals of the rf control for 20 MeV accelerator are to achieve errors within 1 % in amplitude and 1 degree in phase against external perturbations such as the change of resonant frequency, fluctuation of klystron power supply voltage and also beam loading. In addition, the PEFP 20 MeV DTL has unique characteristics that single klystron drives four tanks simultaneously. In this paper, the initial test results of the rf system with digital controller are presented and its control characteristics are discussed.  
 
WEPMA142 Commissioning and Operational Experience with INDUS-2 RF Systems injection, controls, klystron, vacuum 517
 
  • M. Lad, M. K. Badapanda, A. Bohrey, P. R. Hannurkar, A. Jain, M. K. Jain, N. Kumar, M. Prasad, V. Rajput, D. Sharma, N. Tiwari, R. K. Tyagi, R. K.DEO. deo
    RRCAT, Indore (M. P.)
  2.5 GeV, 300mA Synchrotron Radiation Source Indus-2 is under commissioning phase at RRCAT, Indore. The beam injection in Indus 2 from Booster Synchrotron started in July 2005,since then RF system is in operation. RF system compensates the SR losses experienced by the circulating electrons in the bending magnets and insertion devices. In addition to compensate Synchrotron losses, RF system will have to supply power for boosting energy from 600 MeV to 2.5 GeV. Indus-2 RF system employs four numbers of ELETTRA make elliptical cavities to generate 1500 kV accelerating RF voltage at 505.812 MHz. Each RF cavity is powered by 64 kW RF amplifier. With around 650 KeV of SR losses the system is designed to provide cavity gap voltage such that sufficiently high quantum and Touschek lifetime is achieved. Initially conditioning of all four RF cavities was performed. Then system was handed over for operation and with beam trials optimization of different parameters of RF system is being done. The paper describes test results of Indus-2 RF system & commissioning and operational experience of Indus-2 RF system.  
 
WEPMA145 Development of A 35 Kw Power Amplifier At 350 Mhz For RFQ Accelerator Based Neutron Generator controls, rfq, cathode, simulation 526
 
  • M. M. Pande, V. K. Handu, N. R. Patel, V. Rao, A. Soni
    BARC, Mumbai
  • K. R. Shinde
    New Affiliation Request Pending, -TBS-
  A Radio Frequency Quadrupole (RFQ) based 14 MeV Neutron generator is being developed at BARC, as a part of its ADSS program. It is estimated that RF power of about 70 KW is required in RFQ to accelerate 1mA deuterium beam up to 400 KeV. Hence two RF systems, feeding power of about 35 KW at each of the two ports of the accelerator, are being developed. Each RF system employs a 100 W solid state driver, 1500 W intermediate power amplifier (IPA) using EIMAC 8938, and a high power amplifier (HPA) using TH571B. Solid state driver has been tested to 100 W. The IPA has been tested to 100 W in grounded grid configuration and with half wavelength strip line output circuit. The HPA cavity with tube is installed and being analyzed at low power. The 6 1/8 inch, 50 Ω coaxial transmission line has been simulated in Microwave Studio for analyzing RF parameters. The anode power supply (12KV/10 Amp) of HPA has been tested and installed. A spark gap based crowbar circuit for anode is under construction. For HPA the thyristor based safeguard circuit for screen grid, a ramping filament control circuit (0 to 8 Volts in 5 minutes) and an overall control-interlock system has also been developed.  
 
THZMA03 Construction of Shanghai Synchrotron Radiation Facility storage-ring, linac, controls, vacuum 593
 
  • Z. Zhao, H. Ding, H. Xu
    SINAP, Shanghai
  The Synchrotron Radiation Facility (SSRF), a third generation light source based on a 3.5GeV storage ring, is under construction at Zhang-Jiang Hi-Tech Park in Shanghai. The SSRF groundbreaking was made in December 2004 and the construction of the SSRF main and auxiliary buildings was completed in November 2006. The construction and installation of the SSRF accelerator components are under going with the target schedule of starting storage ring commissioning in April 2008 and the user operation in April 2009. This paper reports the construction progress of the Shanghai Synchrotron Radiation Facility.  
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THPMA004 RF Amplifiers and Structures for ISAC/TRIUMF linac, controls, rfq, RF-structure 631
 
  • A. K. Mitra, Z. T. Ang, I. V. Bylinskii, K. Fong, R. E. Laxdal, J. Lu, R. L. Poirier, V. Zviagintsev
    TRIUMF, Vancouver
  The ISAC-I accelerator is comprised of two room temperature linacs; a 35MHz RFQ and a 106MHz separated function drift tube linac producing an accelerating voltage up to 4.5MV and 8.1MV respectively. In addition a pre-buncher, chopper and several re-bunchers are used in the accelerator chain to manipulate the longitudinal phase space. A heavy ion superconducting linac is being installed at ISAC/TRIUMF to increase the energy of ISAC-I from 1.5 MeV/u to 6.5 MeV/u for ISAC-II. A first stage, now in commissioning, consists of twenty medium beta cavities driven by twenty, 106MHz, tube amplifiers. In the second stage of ISAC-II, 20 high beta quarter wave superconducting cavities will be installed operating at 141 MHz. A transfer line connecting ISAC-I and ISAC-II has a room temperature buncher cavity at 35 MHz. This report will summarize rf amplifiers employed in ISAC facility and discuss the choice of amplifiers for the second stage of ISAC-II. Some of the re-furbishing and improvements that are done to ISA-I rf system will also be discussed.  
 
THPMA008 Field Measurement Results of the Quadrupole Magnets for ATF2 quadrupole, sextupole, extraction, coupling 637
 
  • M. Masuzawa, Y. Suetsugu, R. Sugahara
    KEK, Ibaraki
  ATF2 will be built at KEK as a test facility for the final focus system for the ILC. The specifications for the final focus system require transverse focusing of the electron beam to be nearly 40 nm. The quadrupole magnets for the ATF2 beam line have been designed and manufactured. The diameter of the magnet bore is 32 mm and the length is 180 mm. The magnets have to meet strict specifications for the multipole components, especially the sextupole components, in order to achieve the required small beam size. Precision measurement is required not only for the multipole components but also for the magnetic center and median plane. Field measurement results of these small bore magnets will be reported.  
 
THPMA017 Mathematical Model for Fast and Slow Dumping of K-500 Superconducting Cyclotron Magnet dumping, cyclotron, monitoring, vacuum 655
 
  • A. De, S. Saha, S. K. Thakur
    DAE/VECC, Calcutta
  A superconducting cyclotron (K-500) is under construction at Variable Energy Cyclotron Centre. Two superconducting coils ' named 'Alpha' and 'Beta' ' generates the main magnetic field of the cyclotron. Subsequent to the in-house fabrication of the two coils, it was assembled into the cryostat and the magnet assembly completed. Immediately after the cool down, the superconducting coils were energized. Two dump resistors ' slow and fast ' serve to dissipate the energy stored in the coils externally depending upon the situation. Various sets of data were collected during these dumping conditions and based on these an approximate mathematical model was constructed to simulate the dumping characteristics. This model took into account the lead drops, the cable and the joint resistances along with the dump resistor values and the self and mutual inductances (that varied with current) of the coil.  
 
THPMA023 Construction of SSRF Magnet Power Supply System controls, booster, storage-ring, linac 664
 
  • T. J. Shen, H. G. Chen, C. L. Guo, Z. M. Hu, D. M. Li, R. Li, H. Liu, S. L. Lu, X. Wang, W. F. Wu, R. N. Xu, S. M. Zhu
    SINAP, Shanghai
  The Shanghai Synchrotron Radiation Facility (SSRF) is a third-generation synchrotron radiation light source under construction. In SSRF, there are 520 sets of magnet power supplies for the storage ring and 163 sets for injector. All of the power supplies are in PWM switched mode with IGBT. A high precision stable output power supply for 40 dipoles rated at 840A/800V with the stability of ±2·10-5/8hrs will be used for storage ring. 200 sets of chopper type power supply will be used for exciting main winding of quadrupoles respectively. In booster ring, two sets of dynamic power supply for dipoles and two sets for quadrupoles will run at the biased 2Hz sinusoidal wave. All above power supplies will work with digital power supply controllers designed by PSI. All power supplies are being manufactured at professional power supply companies in China.  
 
THPMA024 Implementation of High Precision Magnet Power Supply using the DSP controls, feedback 666
 
  • K.-H. Park, J. Choi, C. W. Chung, S.-H. Jeong, D. E. Kim
    PAL, Pohang, Kyungbuk
  • B.-K. Kang
    POSTECH, Pohang, Kyungbuk
  This paper presents the precision magnet power supply for the Pohang Light Source using the digitally controlled PWM method. The required current to energize the some magnets was 600 A with the high precision of ~10ppm at least to accomplish a high stable beam operation. This power supply has been implemented using a digital signal processor, TMS320F28 series from Texas Instruments, with high speed external 16-bit ADCs. The designed digital controller includes both a current feedback loop and a DC link voltage feed-forward loop, which was applied by the PI control scheme. To reduce the output current ripple, the damped L-C filter was fabricated at both the DC link and load sides. Various experimental results such as stability, bandwidth and harmonic analysis, as well as simulation are given to verify the characteristics of the DSP based magnet power supply.  
 
THPMA028 Regulation Scheme for Precision Magnet Power Supply feedback, controls, antiproton, monitoring 669
 
  • S. Bandyopadhyay, M. Das
    DAE/VECC, Calcutta
  Accelerators require extremely precise high-current magnet power supplies to drive their magneto-optic devices for proper beam dynamics. The dc precision of the power supply, which generally defines the absolute tolerance of its current, can be split up into three distinct parts — ripple, short-term and long-term stability. To ensure that the output current is within an error-band of 10ppm or less, a three-loop regulation topology has been developed and implemented in a high current magnet power supply (750A/12V) that uses transistor bank as the series pass element.  
 
THPMA032 Active Filter for Harmonic Mitigation for Magnet Power Supplies of INDUS-II impedance, controls, resonance, feedback 671
 
  • Y. P. Singh, S. Kotaiah, A. C. Thakurta
    RRCAT, Indore (M. P.)
  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.  
 
THPMA033 Digital Power Supply Development at the PLS controls, simulation, booster, feedback 674
 
  • K. M. Ha, J. H. Kim
    PAL, Pohang, Kyungbuk
  Digital power supply controller using the Digital Signal Processor (DSP) and Field Programmable Gate Array (FPGA) has been developed over the year at the Pohang Light Source (PLS). Recently, full digital power supply controller has been completed and tested. A new digital controller is designed as 3U euro-standard size and provides overall performance of the power supplies stability better than 5 ppm short-term stability (< 1 min) and 25 ppm long-term stability (< 12 hours). The digital controller made use of the digital PID current controller with one-pole digital filter and feed-forward voltage ripple compensation control algorithms. By implementation of the digital controller, it is capable of high step resolution (150 ps) Digital Pulse Width Modulation (DPWM) for FET or IGBT switch drivers and high resolution (18-bit, 400 kSPS) analog to digital converter (ADC) for current and voltage signal measurements. In this paper the hardware and software structure of the developed digital controller and experimental results of digital power supply are described.

Pohang Accelerator Laboratory, Pohang, 790-784, Korea* This works supported by the Ministry of Science and Technology, Korea.

 
 
THPMA039 300 kV/ 6 kW Power Supply System for Self-shielded Low Energy DC Accelerator at RRCAT Indore controls, electron, damping, cathode 679
 
  • R. Banwari, A. Kasliwal, S. Kotaiah, A. Kumar, T. G. Pandit, P. R. Peteti, A. Upadhyay
    RRCAT, Indore (M. P.)
  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.  
 
THPMA045 Analysis and Design of Parallel Resonant Network Power Supply for a Rapid Cycling Synchrotron synchrotron, proton, quadrupole, target 685
 
  • S. R. Tiwari, M. Borage, K. Swarna
    RRCAT, Indore (M. P.)
  Rapid Cycling Synchrotron (RCS) requires dc biased sinusoidal excitation for electromagnets. Power supplies based on resonant schemes are best suited for such applications, as only the losses of the resonant network are drawn from the mains and the magnets are energized by resonating its inductance with external energy storage elements. In this paper study of various options for powering the magnets and its excitation source is carried out. Optimization of network elements for parallel resonant network with respect to the operating and investment cost is carried out. Tolerance analysis of a high-Q resonant network with respect to variation in component values and its effect on amplitude and phase of magnet current, and the ac component reflected in the magnet current due to presence of ac and dc input source ripple is documented in detail. Design of a parallel , continuous ac excited resonant network for the QF2 magnet for the proposed 1 GeV Rapid Cycling Synchrotron is presented.  
 
THPMA047 Stair Current Output Power Supply for Switching Magnet controls, feedback, quadrupole, electron 691
 
  • S.-H. Jeong, J. Choi, H.-S. Kang, D. E. Kim, K.-H. Park
    PAL, Pohang, Kyungbuk
  The switching magnet for beam distribution to 5 beamlines of 20-MeV PEFP is served with DSP-controlled PWM switching-mode converter. This converter is employed IGBT module and a DSP (Digital Signal Processor) that is operated at ?350A, 2.5 Hz stair output. Current feedback and input voltage feed-forward control schemes are applied to improve the output current stability. Designed filter result in the good stability of each stair. Simulation and experimental results show that the implemented converter achieves stable repeat response at each stair and feasibility for versatile power supply.  
 
THPMA063 Energy Stabilization of 2.5 GeV Linac using DeQing linac, controls, feedback, klystron 717
 
  • S. H. Kim, Y. J. Han, J. Y. Huang, S.-C. Kim, S. H. Nam, S. S. Park
    PAL, Pohang, Kyungbuk
  The 2.5 GeV electron linac of Pohang Accelerator Laboratory (PAL) employs 80 MW klystrons with matching 200 MW modulators as RF sources. Beam voltage stability of the klystron is directly related to a PFN (pulse forming network) charging voltage of the modulator. Therefore, a good regulation of a PFN charging voltage is essential in the modulator. The regulation of the klystron pulse voltage amplitude is made by controlling the PFN charging voltage. In a conventional resonant charging pulse modulator, the regulation is usually achieved by using a deQing circuit. The required beam voltage regulation of less than ± 0.5 %, without deQing circuit, has been achieved by using a SCR phase controller with a voltage regulator. For further improvement of the beam voltage stability for the PAL XFEL (x-ray free electron laser) linac, PAL is studying a deQing circuit aiming at the stabilization of less than 0.02%. A new deQing circuit has been developed with a compensation function which can reduce a charge voltage fluctuation by about several times. The design concept and performance of the deQing circuit will be discussed.  
 
THPMA064 Development of a 200keV Linear Induction Accelerator induction, controls, acceleration, linac 720
 
  • K. V. Nagesh, S. Acharya, R. Agarwal, D. P. Chakravarthy, S. Mitra, K. C. Mittal, D. D. Praveen Kumar, R. N. Rajan, S. R. Raul, P. C. Saroj, A. S. Sharma, D. K. Sharma
    BARC, Mumbai
  Electron Linear Induction Accelerator (LIA) are for applications for applications in High Power Microwaves (HPM), high gradient accelerators, flash X-Ray radiography (FXR), flue gas clean-up, detoxification of chemicals, cross-linking of polymers, sterilization of food and medical devices, etc. The LIA-200 being developed at APPD/BARC consists of three main phases of pulse compression and voltage amplification, viz; (i)solid-state pulse modulator uses semiconductor devices, (ii)Pulse compression and voltage amplification stages, steps up to 200kV, 5 micro-seconds and compresses these pulses to 75kV, 10kA, 50ns in five stage and (iii)three induction cavities in ADDER mode for relativistic electron beam generation, with matched impedance of 5 ohms. Metglas cores have been used in the switches, cavities and pulse transformers. Deminaralized water capacitors and water transmission lines have been used for low impedance energy storage and compactness. The complete system has been assembled and ready for commissioning. LIA system will be operated from a PLC based control system which is under testing.  
 
THPMA070 Characterisation of Amorphous Magnetic Material with Multiple Pulse Excitation induction, impedance, linac 732
 
  • A. S. Sharma, S. Acharya, K. V. Nagesh
    BARC, Mumbai
  • U. Kumar, G. R. Nagabhushana
    IISC, Bangalore
  An experimental investigation for the understanding of magnetic core saturation behaviour under pulse excitation is presented in this paper. The effect of repetitive shots, after resetting, on the magnetic properties of toroidal amorphous core of size 160/240/25 mm is reported. This study is made using 20kV, 20, and 200ns square pulse source, to realize the various steps which an amorphous core undergoes on saturation as well as corresponding changes in magnetic parameters viz. magnetization force, total flux swing and relative permeability. The most significant effect of pulsing is seen at higher values of operating flux, compared to lower flux regimes. Effects of number of turns and input power level to the core are also shown in this paper. It has been shown that the total energy required to saturate the core in multiple pulses is less if peak input is smaller than that in case of higher peak pulse excitation. Keyword: amorphous core, multiple pulses, effect of turns, pulse excitation  
 
THPMA076 Development of the Klystron Modulator using a High-voltage Inverter Power Supply klystron, controls, cathode, linac 743
 
  • Y. G. Son, C. W. Chung, D. E. Kim, S. J. Kwon, J.-S. Oh
    PAL, Pohang, Kyungbuk
  The existing klystron modulator in the Linac use a 60 Hz high voltage power supply and adopt traditional L-C resonant charging scheme with De-Qing circuit. The stability of the output high voltage is not satisfactory especially when the AC line voltage fluctuations. If an inverter power supply is used as a HV generator, it will just meet the demands A high frequency inverter switching makes the overall system size small. The command-charging feature can guarantee the high reliability of switching function. In order to increase the stability, operating reliability and comply with the PLC (programming logic controller) and touch screen control system of PLS, an upgrading works is now in progress. This paper will discuss some inverter power supply design considerations and show the test results.  
 
THPMA100 Multipacting Study of Linac Prebuncher at CAMD electron, linac, focusing, storage-ring 785
 
  • Y. Wang
    LSU/CAMD, Baton Rouge, Louisiana
  Multipacting currents can absorb RF energy and produce breakdown in the prebuncher cavity of CAMD linac*. This phenomenon starts when the magnetic field to focus the electron beam is applied. The multipacting has been studied in different magnetic field and RF electric field, and can be eliminated by RF processing. In the paper, the theoretical and experimental results of multipacting study will be presented; moreover, the operability of the system will be analyzed.

* Y. Wang et al., “Upgrades of the Linac System at CAMD”. PAC2003, Portland, May 2003, p. 2892.

 
 
THPMA129 High Power Industrial Electron Accelerator controls, electron, vacuum, industrial-accelerators 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.  
 
THPMA130 Introduction of EPICS in VEC & SCC Control Systems controls, monitoring, simulation, cryogenics 827
 
  • T. Bhattacharjee, S. Bandyopadhyay, R. B. Bhole, Chaddha, N. Chaddha, A. De, Kundu, K. C. Kundu, J. Misra, S. Pal, A. Roy, B. Sarkar
    DAE/VECC, Calcutta
  As a part of computerization of the VEC and SCC Control System, using a standard open-source software tool for designing distributed control system named as EPICS (Experimental Physics and Industrial Control System), several IOCs' (I/O controller) have been developed to control and monitor the Main Magnet Power Supply (MPS), Beam line MPS, Deflector PS, Beam line instruments and LCW (Low Conductivity Water) system. The device layer of IOC, responsible for communication with MPS distributed among several multi-drop networks (RS485) ensures reliable and fast response while setting several MPS simultaneously. Process parameters e.g. water level, temperature and conductivity in different subsystems are measured using standard industrial sensors. An IOC has been developed for acquiring process data form sensors using Modbus-TCP based distributed DAQ modules on Windows platform. An IOC is being developed for affecting the necessary control for conditioning of the electrostatic deflector with facility for supervisory intervention. Application of EPICS in sub-systems will lead towards a unified distributed control architecture for auto beam tunning of the machines.