[en] A set of stabilized DC power supplies for energizing the windings of the electron model of the circular cyclotron is described. The set comprises three power supplies with current ratings 100 A, 300 A and 600 A (respective voltage ratings 10 V, 15 V and 25 V). The current instability and ripple are below 10^-3. Block diagrams of the set and its individual parts and circuit diagrams of some blocks are given. (author)

[en] Highly stable (±3 x 10^-5 - 10^-3) direct-current power supplies intended predominantly for cyclotron-type accelerators are discussed. All power supplies considered are based on the circuit of the compensated dc stabilizer. Versions of silicon -controlled rectifiers, filters, transducers, and other basic units of the power supplies in question are proposed. Block diagrams of the units discussed are presented. Recommendations on using the units for making power supplies with the necessary characteristics for any particular case are given. Block diagrams of power suppliers with several different combinations of their main parameters are presented. (authors)

[en] Non-Evaporable Getter (NEG) coating is an efficient method of pumping for the accelerators. It is very useful for evacuating the conductance limited insertion device chambers. In our experiments, Ti- Zr-V film has been deposited onto the inner face of the extruded aluminium-alloy pipes with elliptical profile. The chamber cross-section is 86mm x 36mm with 400mm length. Due to the elliptical profile, double target assembly was used for coating. DC magnetron sputtering system was used for coating this low gap elliptical chamber. This paper presents the target assembly, film deposition, and preliminary vacuum performance -ultimate vacuum and RGA analysis. Samples have been investigated by Scanning Electron Microscope (SEM), Profilometer and XRF to determine film structure, thickness and composition respectively. (author)

[en] In the past years. the idea of smart material has been interesting to the researchers and engineers as a new category of physical material that has integrated sensor, actuator, power electronics and microprocessor. Among all the smart materials. piezoelectric and electrostrictive materials are considered to especially promising due to their unique physical properties such as higher accuracy, higher response speed. lower power requirements etc., compared to other materials. As a result. actuator, transducer, and sensor made jim of these two materials have been widely used in piezoelectric transformers, and many other applications such as ultrasonic motors. deformable mirrors, active vibration cancellation, mechanical micro positioners etc. (author)

[en] Two DC glow discharge plasma sources, whose cathode and anode diameters were 70 mm and 2 mm respectively, and operating at a neutral pressure of 0.1 mbar, have been deployed for synchronization experiments. In each of the chambers, a Langmuir probe was placed for measuring floating potential fluctuations. Plasma was produced in both the chambers and floating potential frequencies were monitored. It has been observed that floating potential fluctuation frequencies in both the chambers were increasing linearly with increase in the discharge voltage. For the synchronization experiment we have kept fixed the discharge voltage of one of the systems to an oscillation frequency (f) and coupled the oscillation of frequencies of the other system with an increase in the discharge voltage. Nonlinear phenomenon like frequency entrained states were observed when oscillation frequencies of two coupled systems were close to the harmonic frequencies like f/2, 2f, 3f and 4f and far from this region frequency pulling and chaos were observed. Experimental results of frequency entrainment, frequency pulling and chaos have produced a very nice picture of the Arnold tongue between the two coupled glow discharge plasma systems. Some region of the experimental results was modeled by numerical simulation of two coupled asymmetric Van der Pol type equations and these results were found to be in good agreement. (author)

[en] Plasma position and shape control is very crucial for the overall performance of the fusion reactor such as Tokamak. The quality of the discharge in the Saskatchewan TORus-Modified (STOR-M) tokamak is strongly related to the position of the plasma column within the discharge vessel. If the plasma column approaches too near the wall, then either minor or complete disruption occurs. Consequently it is necessary to be able to control dynamically the position of the plasma column throughout the entire discharge. Now a day's most fusion reactor employs the traditional PID controller for the confinement of plasma layer. Fuzzy logic is used for the control of Plasma layer. In this paper we have used the hybrid of PSO-ANFIS technique to control the speed of a DC motor. We have used two input parameters like speed, torque and output is firing angle. In our work first order Sugeno fuzzy model is taken with three rules and the parameters of Gaussian membership function is controlled by the PSO technique. PSO-ANFIS speed controller obtains better dynamic behavior and superior performance of the DC motor speed control. Similar approach can be correlated to the control of plasma layer. For the plasma control two inputs can be taken as plasma position ΔH and the plasma current and the single output, the control decision u(t). (author)

[en] India Based Neutrino Observatory (INO) is planning to use ∼ 30,000 Resistive Plate Chamber (RPC) detectors of size 2m x 2m. Each resistive plate chamber is made up of glass or Bakelite whose resistance is of the order 10"1"2 Ω/cm"2, and two pick-up panels. Both glass electrodes of the detector have one side (outer) painted with thin and uniform coating of graphite paint. This provides the resistivity of range 100 - 300 kΩ per square. This range of resistivity provides distribution of voltage over the surface of glass electrodes. Uniform coating will provide uniform electric field inside the glass plate chamber and high resistivity value will help in confining the induced charge on the surface. It is one of the necessary criteria for good RPC detector that the coating of graphite paint should be uniform. Therefore it is required to measure the resistivity for the verification of uniformity. Last few years we have been focusing our efforts in this direction. In this connection, we made sequential improvement from the previous work. The present system is cost effective, automatically recording measurement in the computer, fast and accurate. Earlier MOTOR BEE ver. 5.0 microcontroller was used which was an imported and costly material. After massive search in the local market Arduino microcontroller was discovered, which controls the movement of all motors and it also saves the value of resistivity in the computer automatically

[en] A 3 MeV, 30 kW dc industrial electron beam Accelerator is being developed at EBC, Kharghar, Navi Mumbai. The 3 MV dc is generated by parallel coupled voltage multiplier operating at 120 kHz. This requires an input voltage of 150 kV-0-150 kV at 120 kHz. This is achieved by 50 kW/120 kHz power oscillator in conjunction with a tuned air-core step-up transformer. Input primary voltage of 6 kV-0-6 kV at 120 kHz is generated by an oscillator using BW1121J2 water cooled triodes in push-pull Colpitts configuration. The tank circuit for the oscillator is formed by the secondary winding inductance of the step-up transformer and capacitance formed by RF feeder electrodes of the voltage multiplier column. Grid feedback for the oscillator is derived by arranging a set of electrodes in the feeder assembly in a capacitive divider configuration. The oscillator is operated in class-C mode with grid leak bias for better efficiency which also has the advantages of self-adjustment with varying load conditions. High power test has been conducted in a simulated test set-up on dummy load up to 30kW. Subsequently, the power oscillator has been tested with HV multiplier at 1MeV level satisfactorily. This paper describes the design, test results and operational experiences of the oscillator. (author)

[en] Undergraduate students often encounter great difficulties in understanding Ohm’s law and electrical circuits. Considering the widespread students’ beliefs and their common mistakes, as they come out from the literature and our teaching experience, we think that a relevant source of these problems comes from the fact that electrical circuits are generally treated separately from the other topics of electromagnetism, with poor reference to the circulation of the electric field. We present here a way to deal with electrical circuits that could help students to overcome their difficulties. In our approach, the electric field is the protagonist and the mathematical tool the students are asked to use is its circulation. In the light of the circulation of the electric field, the experimental Ohm’s law is revisited, the concept of electromotive force is discussed and some suggestions to eliminate common misconceptions about the role of a battery in a circuit are presented. (paper)

[en] Experiments on non-neutral plasmas in SMARTEX-C (SMallAspect Ratio Toroidal Electron plasma EXperiment – C) are being pursued at Institute for Plasma Research. Trapping mechanism is similar to Penning-Malmberg trap which creates non-neutral plasma in cylindrical geometry. Basic trap operation is carried out in inject-hold-dump sequence which requires fast pulsing of potential voltage of electrodes and control sequence varying on a wide range of time scales. All the required sequential and combinational logic functions are described using VHDL, the user interface software is developed in Labview and the communication interface and command encoding is done in ‘C’ language for the soft processor. This report gives hardware and software description of the FPGA based high voltage trigger circuit with variable time spans along with test results