摘要:

A new variation of the duoPIGatron ion source, the coaxial duoPIGatron ion source, has been built and tested. A distinctive feature of this source is the coaxially‐shaped intermediate electrode formed by a magnetic center pole and an intermediate electrode chamber. The source generated a dense and uniform plasma over a grid of 18.5 cm diameter and produced ion beams of 30 A at 30 kV stably and efficiently. The coaxial intermediate electrode worked well at a fixed ratio between the center pole coil current and source coil current, indicating that the magnetic nozzle has successfully connected the cathode with source plasma region. An increase of the applied magnetic field did not affect the density profile, and it raised the arc efficiency. The arc efficiency reached 1.5 A/kW at the source coil current of 30 A when the operation of the source was most stable. The ion species fraction was measured and the proton ratio was increased to 70% from 60% of the modified duoPIGatron.

ISSN:0034-6748    

DOI:10.1063/1.1136627

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A simple fluorescence decay‐time measuring system with single photon counting technique is described which uses, besides an undumped cw mode‐locked laser as an exciting source, a compact side‐on photomultiplier and IC comparators instead of a head‐on photomultiplier and a constant‐fraction discriminator. This system gives time behavior of fluorescence in the subnanosecond region or less with sufficient accuracy within a time as short as several seconds. The performance of this system is studied and factors to broaden the response time are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1136628

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A temperature‐controlled cell has been constructed for laser‐induced fluorescence studies of UF6and other corrosive gases. The temperature stability achieved in our UF6fluorescence investigation was ±0.1 °C from −30° to 0 °C and ±0.05 °C from 0° to 80 °C. The cell has also been used in UF6absorption measurements at temperatures as high as 100 °C with comparable stability.

ISSN:0034-6748    

DOI:10.1063/1.1136629

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The design and operation of a stable ultrashort light pulse generator using a GaAlAs single heterostructure laser diode is presented. The unit is capable of generating optical pulses at a wavelength of 820 nm as narrow as 60 ps full width at half maximum (FWHM) at pulse repetition rates up to 10 kHz with a peak power of 3 W. The light pulses are emitted from a flexible light pipe with relatively small jitter of less than ±10 ps. Single pulses without any subpulses were confirmed by direct measurements using a streak camera system having a temporal resolution of better than 10 ps. This generator will find applications in the study and evaluation of time characteristics of fast photodetectors, optoelectronic devices, etc.

ISSN:0034-6748    

DOI:10.1063/1.1136630

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A continuously balanced impedance bridge under computer control constructed for a cryogenic thermometry application provides a few ppm resolution in resistance ratio measurements. The use of IEEE‐488 computer bus‐compatible commercial equipment reduces the design mainly to that of software and permits flexibility in the balancing procedure.

ISSN:0034-6748    

DOI:10.1063/1.1136641

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

New calorimetric detectors for measurements of enthalpies of formation of liquid ionic and metallic systems in the temperature range 1000°–1500 °C have been designed and assembled. Much attention was paid in designing these new detectors in order to obtain reliable data. The mixing method, used with a stirring device, allows avoidance of parasitic thermal effects, and therefore improves the accuracy of the measured heat of mixing. The acquisition and treatment system of the calorimetric data is described.

ISSN:0034-6748    

DOI:10.1063/1.1136642

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A new method of quickly and precisely measuring the surface tension of liquids and solutions is described. Utilizing the fact that the size of the bubbles formed from a gas flowing out of a nozzle is dependent on the nozzle diameter and the surface tension of the liquid used, the surface tension of a liquid can be determined by simply counting the number of bubbles formed from a gas flowing out at a constant flow rate or by measuring the period of bubble formation. The expected accuracy of the method is below 0.1% of variance. An evident correlation between the period of bubble formation and the surface tension was shown with several kinds of liquids which differ in surface tension. Changes in surface tension with varied degree of neutralization were determined in an aqueous solution of polyacrylic acid (PAA), 20–30 points of measurement with an accuracy of about 0.1% could be easily obtained within one hour.

ISSN:0034-6748    

DOI:10.1063/1.1136626

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A high‐resolution, particle‐velocity gauge system was developed to obtain a hydrodynamic streamline in the flow field associated with shock waves or detonation products. The system is composed of a passive current loop (stirrup probe) embedded in the host material, a magnetic field generator to establish a Lorentz force, and a computer‐controlled, analog‐to‐digital transient recorder to monitor the gauge response. The operation principle is that the motion of one side of a rectangular loop in a magnetic field produces a current proportional to the velocity of that leg. System tests were conducted with 50‐mm diam. by 50‐mm long cylinders of 1,3,5‐triamino–2,4,6‐trinitrobenzene (TATB) explosive and explosive‐driven polytetrafluoroethylene (PTFE). The velocity profiles obtained have a time resolution of a few nanoseconds with an amplitude uncertainty of approximately 2% based on a system error analysis. Detailed descriptions of the gauge system components are included.

ISSN:0034-6748    

DOI:10.1063/1.1136643

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A circuit capable of dividing 250 kV pulses by a ratio of 100,000 has been built and tested. It permits use of standard oscilloscopes to view high‐speed transients that have components between 200 kHz and 200 MHz. The design is an adaptation of the guard ring principle, commonly used in electrostatic measurements.

ISSN:0034-6748    

DOI:10.1063/1.1136644

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

An accurate yet inexpensive technique for measuring time constants of fast exponentially‐decaying signals is described. Two discriminators are set at different levels and the difference between the corresponding triggering times gives the time constant.

ISSN:0034-6748    

DOI:10.1063/1.1136645

出版商:AIP    

年代:1981

数据来源: AIP