摘要:

The guide field for a low inductance (55×10−9H) air‐core plasma betatron is constructed by placing flux‐concentrators within the interior of a single‐turn solenoid. The betatron field coil is energized by the discharge of a 75 &mgr;F, 20 kV capacitor bank. The quarter period of the field‐coil capacitor bank system is 4 &mgr;sec and the peak magnetic and electric fields at the equilibrium orbit (r0=4.83 cm) are ≈3250 G and 60 V/cm, respectively. Techniques used to make accurate (±0.1%) measurements of transient magnetic field distributions are also described.

ISSN:0034-6748    

DOI:10.1063/1.1720648

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Several methods have been explored to produce gelatin‐free thin‐film plates of superior performance for the detection of positive ions. Of these methods, vacuum deposition of silver halides has been found to be the most flexible system and has been examined in an extended series of tests. Particle size, sensitivity, and shape of the response curve were studied as a function of various experimental parameters, such as evaporation temperature, thickness of layer, substrate temperature, ion energy, developing conditions, and others. The plates obtained by this technique have particle sizes of about 1 &mgr; and yield sensitivities, for 20 keV ions, approaching those of Ilford Q2 plates at 50% blackening. When blackeningBis plotted vs logE(E=exposure in coulombs), the slope of the resulting response curve is considerably steeper than that found for Q2 plates. The thin‐film plates produced have a number of advantages over the commercially available Schumann‐type plates: the background blackening of unexposed areas approaches that of clear glass and has an unusually low noise level; spectral line sharpness is greatly improved; the plates show practically no halation, have good conductivity and excellent vacuum properties; and there are no storage problems.

ISSN:0034-6748    

DOI:10.1063/1.1720649

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

To attempt a better understanding of the mechanism of ion detection with ion‐sensitive plates, a study was made of sensitivity as a function of ion energy, and of blackening as a function of exposure. Various commercially available and experimental plates used in mass spectrography were investigated. A dc beam of Cs+ions was used to expose evenly areas 0.1 by 0.25 cm on the plates, which were placed between the ion beam monitor collector and the magnetic sector entrance boundary of an AEI type MS7 double‐focusing mass spectrograph. Thus, after leaving the ion source, the ions traversed only the electrostatic sector portion of the instrument. For the sensitivity study, exposures were made with ion energies ranging from 0.1 to 20 keV on Ilford Q2, Kodak SWR, Kodak‐Pathe´ SC5, and RCA thin‐film plates made by the direct evaporation of AgBr onto glass (described in a companion paper by Honig, Woolston, and Kramer). In addition, blackening as a function of exposure was determined at various energies for each ion‐sensitive material. The relationship observed between sensitivity and ion energy, when plotted in double‐logarithmic fashion, is not a simple linear function, as has been stated by previous investigators, but exhibits a complex behavior.

ISSN:0034-6748    

DOI:10.1063/1.1720650

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A previously described suspension employing permanent magnets is shown to be a sensitive device for measuring magnetic viscosity. A large increase in viscosity concomitant to the loading of the suspended mass with nonmagnetic weights suggests that some of the observed viscosity originates in the mechanism of magnetic suspensionper se.

ISSN:0034-6748    

DOI:10.1063/1.1720651

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The detector is a Robinson limited oscillator with a single tuning control to which has been added an untuned ``transmitter'' coil orthogonal to the usual sample coil. Oscillation is maintained by a combination of Robinson feedback and weak mutual coupling of the two coils. The rf fields of the two coils are in time phase; the transmitter field is much the stronger. Dispersion signals were obtained in tests to 20 MHz at least as easily as were absorption signals with a conventional autodyne. The circuit is especially well suited to frequency‐swept searches for narrow, easily saturable lines (since the dispersion signal does not saturate) and those requiring highH1with unimpaired sensitivity (since the ``receiver'' sees the entire nuclear signal, but only a small fraction of the ``transmitter'' output).

ISSN:0034-6748    

DOI:10.1063/1.1720652

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The output power of the 6328 Å helium‐neon gas laser has been investigated as a function of capillary diameter, total pressure, and He‐Ne partial pressure ratio at optimum dc discharge currents. The optimum value ofpTd(total pressure × capillary diameter) remains constant, and the scaling laws, power ∝d, optimum current ∝dare approximately satisfied for the four diameters investigated. The results suggest that optimum laser output is always achieved at the same value of electron mean energy and at a constant fractional ionization. This study permits a clearer understanding of the relationship between various helium‐neon discharge parameters and the 6328 Å laser output power, and by extrapolation allows the prediction of optimum gas fill for other capillary diameters. These results should also be useful in analyzing the effect of gas cleanup on tube life.

ISSN:0034-6748    

DOI:10.1063/1.1720653

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A method is described for producing calibrated torques at low temperatures using the interaction between an applied magnetic field and a superconducting torus. The torque produced is proportional to the square of the applied magnetic field and can thus be varied continuously over a wide range by varying the current which produces the magnetic field. It can be used in a null method to measure any torques of interest, such as the torques produced by second sound on a Rayleigh disk or on a radiation balance. The principal advantages of this method are that a wider range of torques is available with a given assembly and that the null position is more easily obtained.

ISSN:0034-6748    

DOI:10.1063/1.1720654

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A solid state 9.4 GHz microwave refractometer has been developed using a new technique for phase measurement. Noise level in a passband of 0.3 to 30 Hz is about 0.03 N‐unit rms using a 10 mW microwave source with losses of 30 dB between source and sampling cavity. It is easily adapted to measuring multiple sampling cavities simultaneously, thus allowing absolute and relative refractive indices (in various combinations) to be observed at several locations.

ISSN:0034-6748    

DOI:10.1063/1.1720655

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A flash photolysis device is described which makes irradiation down to the LiF‐cutoff (∼1100 Å) in long reaction vessels feasible. The number of quanta per flash entering the reaction cell between ∼1100 and 1400 Å and ∼1100 to 1650 Å is measured by chemical actinometry. The light pulse has a 1/e duration of less than 2 &mgr;sec, largely independent of the discharge energy and the length of the light source.

ISSN:0034-6748    

DOI:10.1063/1.1720656

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Design parameter selection, block diagram, special circuit description, and calibration procedure are given for rocket instrumentation used to measure plasma resonances in the E‐region.

ISSN:0034-6748    

DOI:10.1063/1.1720657

出版商:AIP    

年代:1967

数据来源: AIP