Roy, A.

Paper	Title	Page
WEPMA144	High Power Microwave Generation From Coaxial Virtual Cathode Oscillator	523
	A. Roy, RM. Menon, S. Mitra, K. C. Mittal, J. Mondal, D. D. Praveen Kumar, A. S. Sharma BARC, Mumbai
	A coaxial virtual cathode oscillator (VIRCATOR) has been designed to generate Relativistic Electron Beams and High Power Microwaves. Coaxial virtual cathode oscillators are known for better efficiency compared to the axial virtual cathode oscillators. This Coaxial VIRCATOR has been designed for the KALI-5000 (1MeV, 60kA, 100 ns) pulse power system. Provision for a large anode cathode gap has been kept to avoid the prepulse effect during the electron beam generation from the KALI-5000 system. Experimental studies are carried out to generate and characterize Relativistic Electron Beams and High Power Microwaves. Relativistic Electron Beams are generated by the Coaxial Explosively emitted graphite cathodes. Electron beam voltage has been measured by a copper sulphate voltage divider and beam current by a B-dot probe. High Power Microwaves are detected by the glow of neon lamps placed closed to the output window.
THPMA016	Median Plane Magnetic Field Mapping for Superconducting Cyclotron (SCC) in VECC	652
	A. Roy, T. Bhattacharjee, R. B. Bhole, U. Bhunia, Chaddha, N. Chaddha, J. Debnath, M. K. Dey, A. Dutta, C. Mallik, C. N. Nandi, Z. A. Naser, G. P. Pal, S. Pal, S. Paul, J. Pradhan DAE/VECC, Calcutta
	The magnetic field upto 29 inch radius on median plane of SCC Magnet (Peak field 5.8T) is measured over its operating range. A client-server system is developed to minimise mapping time and human intervention. The magnetic field is mapped at radial interval of 0.1 inch and angular interval of 1 degree. The complete map of 360 degree comprised of about 100K field points is obtained in less than 100 minutes. The field mapping system is designed to work as PC based TCP Client-Server to reduce the design complexity, system overload and debugging effort. The Server program is developed as windows console in ‘C’ and the Client is developed using LabView to provide a user friendly operation console along with online preliminary display and analysis of field data. This architecture provides a reliable and easily modifiable control s/w. The correctness of the magnet assembly is calculated from the acquired data, which in-turn represents the correctness of measurement system. A detailed study of the magnet characteristic is done. The first harmonics of the fields at different radii are obtained at all magnet excitation and corrected by coil-centering and shims placement.
THPMA130	Introduction of EPICS in VEC & SCC Control Systems	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.
WEPMA078	HTS-ECRIS and Low Energy Beam Transport System of the High Current Injector	434
	G. Rodrigues, R. Ahuja, D. Kanjilal, P. Kumar, P. S. Lakshmy, A. Mandal, Y. Mathur, D. Naik, A. Roy, U. Unnam IUAC, New Delhi
	A high performance electron cyclotron resonance ion source (ECRIS) called PKDELIS capable of operation at 14.5 and 18 GHz and which uses High Temperature Superconducting (HTS) coils designed jointly by IUAC, Delhi (earlier called NSC), Pantechnik, Caen and ISN, Grenoble is presently in operation. The source is very suitable for operation on a 400 kV high voltage platform for injecting beams from the High Current Injector (HCI) into the Superconducting Linear Accelerator Booster. In the low energy beam transport (LEBT) system of the HCI, the beam extraction and transport becomes more and more challenging. In order to avoid the losses of the beam, the complete transport system is being made as short as possible. In addition, due to the high currents (~10 mA) extracted, the extraction system needs proper cooling requirements and possibility of movement of the electrodes for tuning various A/q beams. Typical axial and radial bremstraahlung spectra have been measured from the ECR plasma. Details will be discussed and further measurements are being explored to obtain a better understanding.
WEPMA132	Superconducting Niobium Resonator Fabrication And Testing At IUAC	500
	P. N. Prakash, D. Kanjilal, K. K. MISTRI, A. Roy, S. S.K. Sonti, J. Zacharias IUAC, New Delhi
	Superconducting niobium resonator fabrication and testing facilities have been developed at Inter-University Accelerator Centre. The facilities are used to construct niobium resonators for the superconducting booster linac as well as for future accelerator development projects. In the first phase a single quarter wave resonator (QWR) was successfully fabricated and tested. In the second phase two completely indigenously built QWRs were constructed. In cold tests at 4.5 K one of them performed at 3.5 MV/m with 3.5 W RF input power, exceeding the nominal design goal. After the successful completion of this project production of fifteen QWRs for the 2nd and 3rd linac modules began. This work has progressed sufficiently and we plan to complete the production by mid ‘2007. In addition to resonator fabrication the facilities have been used for other developments such as a new design of niobium-stainless steel transition assembly, slow tuner modifications, and repairing of the existing QWRs. Details of the activities and performance of the resonators will be presented.
THYMA04	Development of Quarter Wave Resonators	554
	A. Roy IUAC, New Delhi
	The accelerating structure for the superconducting linac booster for the 15 UD Pelletron at IUAC is a Nb QWR cavity, designed and fabricated as a joint collaboration between IUAC and ANL, USA. Initial cavities required for the first linac module were fabricated at ANL. For fabrication of cavities required for future modules a Superconducting Resonator Fabrication Facility has been set up at IUAC. Three quarter wave resonator (QWR) cavities have been fabricated and fifteen more resonators for the second and third linac modules are in advanced stage of completion. This facility has allowed us to undertake repairs on some of the resonators which sprung leaks. First experiment with the accelerated Si beam through the first linac module having eight resonators along with a superconducting solenoid have been conducted recently.
	Slides
THPMA050	Performance of Cryomodule and Cryogenic Network System for the Superconducting Linac at IUAC. Delhi	697
	T. S. Datta, J. Antony, S. Babu, J. Chacko, A. Choudhury, S. Kar, M. Kumar, R. S. Meena, A. Roy IUAC, New Delhi
	The Superconducting Linear Accelerator as a booster of existing 15 UD Pelletron accelerator is under construction at IUAC. The heart of superconducting linac is three cryomodules, each one housing eight quarter wave niobium cavities. At present the first linac module along with superbuncher and rebuncher cryostat are integrated with zero degree beam line. Design and fabrication of two more linac modules under progress. A VME based CRYO-DACS has been developed to monitor and control parameters of cryostat. The total load at 4.2 K for complete system including locally developed liquid helium distribution line as well as break up load for each cryomodules has been measured. The measured load in linac module is higher than the design value. A detailed thermal analysis has been carried out using temperature profile for each component of cryomodules. Extra load is mainly contributed by aluminum structure,drive coupler and additional radiation load. The present paper will be highlighting the operating experience on cool down of linac as well as thermal performance of each cryo module. Scope of improvement on future linac cryo module to reduce the static load will also be covered.