Masatosi Imori

Performance of a photomultiplier high voltage power supply incorporating a piezoelectric ceramic transformer

The article describes a photomultiplier high voltage power supply incorporating a piezoelectric ceramic transformer. The ceramic transformer utilizes piezoelectric effect to generate high voltage and can be operated under a strong magnetic field. The high voltage power supply is intended to produce high voltage efficiently under a strong magnetic field. The high voltage power supply includes feedback to stabilize the output high voltage. Stability of the feedback is investigated from the viewpoint of beats. The circuit of a high voltage power supply is shown together with its performance. The high voltage power supply is capable of supplying a high voltage ranging from 1500 V to 2500 V against a load of less than 10 M/spl Omega/. The efficiency of the high voltage power supply is better than 50 percent.

A photomultiplier high-voltage power supply incorporating a ceramic transformer driven by frequency modulation

This paper describes the circuit and operation of a photomultiplier high-voltage power supply incorporating a ceramic transformer instead of a conventional magnetic one. The ceramic transformer, being constructed from a ceramic bar, utilizes the piezoelectric effect to generate high voltage. As no magnetic material is present, no leakage of magnetic flux occurs such that the power supply can be operated under a strong magnetic field. The transformer shows a sharp resonance, after which voltage amplification is dependent on frequency. Transformer output is stabilized by feedback utilizing frequency dependence, i.e., after rectification, the output high voltage is fed back to a voltage-controlled oscillator that adjusts the oscillation frequency according to the output voltage of an error amplifier that compares the output high voltage with a reference voltage. This photomultiplier high-voltage power supply provides high voltage from 1500 to 2500 V at a 20-M/spl Omega/; load, where the load is a breeder of the photomultiplier. The magnitude of voltage ripples is at a prescribed level when the load is 20 M/spl Omega/. Ripple magnitude is proportional to load current. Voltage ripples limit the load current to the photomultiplier.

Low power TAC & QVC circuits for balloon borne experiments

TAC (time-to-amplitude converter) and QVC (charge-to-voltage converter) circuits have been developed for balloon-borne experiments. The aim of the development is to reduce power consumption. The circuits were optimized by a simulation program on a workstation. The TAC measures a time interval and QVC measures an amount of charge. The time resolution of the TAC is 2 ns/count for a full scale of 8 mu s (12-b). The power consumption is 55 mW/channel. The QVC offers a resolution of 0.6 pC/count for a full scale of 1200 pC(11-b) and consumes 80 mW/channel. It is concluded that the design goals of the simulation have been achieved in the prototype TAC and QVC circuits. >

A high-voltage power supply operating under a magnetic field

The article describes a network of high voltage power supplies where the high voltage power supply incorporates a ceramic transformer utilizing piezoelectric effect to generate high voltage. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. So it is expected that the high voltage power supply can operate under a magnetic field. The high voltage power supply was tested under a magnetic field of 1.5 tesla. The performance of the power supply was almost intact in the magnetic field. The power supply includes feedback to stabilize the high voltage output, supplying from 1500 V to 2500 V with a load of more than 10M/spl Omega/ at a efficiency higher than 50%. From a supply voltage of 2 V, the power supply can provide about 3000 V at a load of 20 M/spl Omega/. A supply voltage of 5 V is large enough to provide 4000 V at the same load. The high voltage power supply is equipped with an interface chip with a network. Most functions of the high voltage power supply are kept under the control of the chip, and are then monitored and controlled through the network.

The line digraph of a regular and pancircular digraph is also regular and pancircular

This paper introduces thepancircularity property on digraphs: a digraphD is said to bepancircular if it contains circuits of every lengthL for all 1 ≦L ≦ # E(D). We discuss preservation of pancircularity under the line-digraph operation, and prove the theorem stated in the title. As a corollary, all DeBruijn graphs are proved to be pancyclic and pancircular.

A high voltage power supply utilizing a ceramic transformer with a large output current

The article describes a high voltage power supply utilizing a ceramic transformer with the capability of supplying about 1 mA at an output voltage of 4 kV. The power supply delivers a large output current, spanning a high voltage at output, with the efficiency of more than 80%. The ceramic transformer is newly developed for the power supply. The power supply includes feedback to stabilize the output voltage ranging from 2000 V to 4000 V with a load of more than 4 MOmega at the efficiency of about 80%. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. The transformer is free of leakage of magnetic flux. So the high voltage power supply can be operated under a strong magnetic field

A Factory Prototype of High Voltage Power Supply Module Incorporating Piezoceramic Transformer

The article describes a factory prototype of the high voltage power supply module incorporating a piezoelectric ceramic transformer. A Japanese company has developed a factory prototype of the module to verify performance, intending to manufacture commercial products for industrial use. The module is tested from the viewpoint of availability in LHC experiments. The module is capable of supplying stabilized high voltage from 2500 V to 4000 V to a load of more than 25 MΩ at efficiency of better than 50 percent from a supply voltage of 3 V under a magnetic field of 1.5 tesla. Ripples on the high voltage are a few tens of millivolts in peak-to-peak amplitude. The module is protected against short-circuiting. The module was irradiated by Co-60 source up to 2 krad without degradation in performance. The module is 110 mm in length, 100 mm in width and 15 mm in thickness. The module is provided with interface so that the module can be kept under external control. The modules are installed in a crate with a crate controller of network capability. The crates are networked and the modules in the crates are controlled through the network. I. HIGH VOLTAGE POWER SUPPLY MODULE The high voltage power supply module incorporates a ceramic transformer [1, 2, 3]. The ceramic transformer takes the place of the conventional magnetic transformer. The ceramic transformer utilizes piezoelectric effect to generate high voltage. The ceramic transformer generates high voltage efficiently. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. So the transformer is free of leakage of magnetic flux and can be operated efficiently under a magnetic field. The ceramic transformer can be operated under such strong magnetic field as 1.5 tesla [3]. An inductance element is required to obtain efficient high voltage generation, being implemented by an air-core coil. The transformer is shaped symmetrically in the lengthwise direction and operated in the longitudinal vibration mode. The power supply module is composed of divider resistors, an error amplifier, a voltage controlled oscillator (VCO), a driver circuit, the ceramic transformer and a Cockcroft-Walton (CW) circuit. The VCO generates a driving frequency of a sinusoidal voltage wave, which drives the ceramic transformer. The VCO supplies the driving frequency to the driver circuit where the sinusoidal voltage wave is generated synchronized with the driving frequency. The sinusoidal voltage wave is amplified in voltage by the transformer and then supplied to a Cockcroft-Walton (CW) circuit where the sinusoidal wave is amplified further in voltage and rectified. An output high voltage is produced at the output of the CW circuit.

A low power flash ADC system with fast data compression ASIC for a balloon-borne experiment

A low power multichannel flash analog-to-digital converters (FADC) system with fast data compression applications specific integrated circuits (ASICs) was developed for readout of drift chambers on a balloon-borne cosmic-ray superconducting spectrometer. The FADC system consists of up to 20 FADC modules, each of which has 32 input channels, and one interface module called crate controller. Each readout channel is equipped with a 30 Ms/s 8-bit FADC and a data compression ASIC. The data compression is executed synchronously with analog-to-digital conversion (ADC), thereby compressed data is ready for event building at almost the same time as the end of digitization. Thus, both event data size and data acquisition dead-time are reduced and the data of as many events as possible can be recorded onto a limited volume storage device on the balloon-borne apparatus. The main logic circuits of the interface module consist of one field programmable gate arrays (FPGAs), with the functions able to be changed flexibly depending on demand. The system is powered by batteries, and so special care is taken to reduce power consumption.

ONE STEP TRANSFORMATION OF PERIODIC SEQUENCES BY CELLULAR AUTOMATA

Consider a cellular automaton in one dimension, having m letters as the states of the constituent finite state automata, called cells. It is shown that, once the number of neighbors connected to each cell is fixed, there exist periodic sequences in m letters such that the cellular automaton is not capable of transforming them in one step into periodic sequences in

A high voltage system with 60 high voltage power supply channels in 2U height EURO crate

(m - 1)