摘要:

A pressure gauge for the range from several mm Hg down to the micron region is described. The new gauge, based on the properties of alternating gas discharges, measures pressure in terms of the frequency of a relaxation oscillator incorporating as the nonlinear element a glow discharge between electrodes immersed in the gas, the pressure of which is to be determined. A stability of 1% has been obtained; the robustness and simplicity of the instrument render it particularly suitable for rocket‐borne measurements at high altitude.

ISSN:0034-6748    

DOI:10.1063/1.1717255

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A measurement is reported of individual bubble locations along tracks of high‐energy protons in a very small, short time scale pentane bubble chamber. Track distortions of the usual kind are greatly reduced in this system, so that one is measuring, to a precision of a few microns, the deviation of the true centers of the bubbles from the particle path. The average deviation in bubble position measurement is found from second differences to be 3.8 &mgr; in space, most of which is shown to be accounted for by measurement errors. The average bubble is thus found to be centered on the track to better than 4 &mgr; in hydrocarbons; however, an occasional bubble will be off by many times the average deviation. Arguments are advanced to show that a similar precision should obtain in hydrogen. This result is shown to be in general agreement with the bubble‐chamber theory of Seitz.

ISSN:0034-6748    

DOI:10.1063/1.1717256

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A diffuse, highly reflecting coating for use with Cˇerenkov counters is described. This coating can be used to advantage inside inorganic‐liquid Cˇerenkov counters, or can be used externally when bonded to the inside surface of the light‐tight radiator cover.

ISSN:0034-6748    

DOI:10.1063/1.1717257

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The use of a bidirectional square wave for frequency modulation of a radio‐frequency spectrometer offers certain advantages, the principal one being that the background signal due to incidental amplitude modulation can be effectively eliminated by appropriate adjustment of the relative amplitudes of the positive‐ and negative‐going excursions. A quadrupole resonance spectrometer employing this principle has given excellent sensitivity and faithful line shape presentation. The oscillator, of the regenerative type, is based on a circuit recently published by Knight. The frequency modulation method should be widely applicable to other types of spectrometers.

ISSN:0034-6748    

DOI:10.1063/1.1717258

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A spectrometer of the marginal oscillator type has been designed and constructed to operate over the range 100 to 300 Mc. The salient features of this spectrometer are that it may be frequency swept over a wide band, it is frequency modulated, and the extraneous amplitude modulation, often known as ``potato,'' is kept to a minimum and made largely independent of frequency. The spectrometer has been used with considerable success to study the nuclear resonance of Co59in various ferromagnetic environments.

ISSN:0034-6748    

DOI:10.1063/1.1717259

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A simple, transistorized circuit is described which analyzes the frequency composition of the photomultiplier current pulse from a phoswich scintillation counter. The circuit generates a gate waveform from the fast current pulse of an organic scintillator, but not from the slower pulse from an inorganic crystal. Such a circuit finds application when the phoswich is used to provide an anticoincidence particle shield around a &ggr;‐ray spectrometer.

ISSN:0034-6748    

DOI:10.1063/1.1717260

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A demagnifying image intensifier is proposed using parallel converging electric and magnetic fields. The design of such a tube is considered and the results of calculations for the particular case of conical fields are presented; the diameter of a typical disk of confusion for a linear demagnification of 5:1 and minimum flux density of 10−2weber/m2is found to be <0.004 cm. Suggestions are made for a tube incorporating an intermediate stage of electron multiplication.

ISSN:0034-6748    

DOI:10.1063/1.1717261

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A gas target with a very thin cylindrical window has been developed for use with the new M. I. T. multiple‐gap, broad‐range spectrograph. This gas target permits observation of reaction particles at all angles, except zero and 180°. It has been used with a window thickness of 0.5 &mgr; and a gas pressure of 1 cm Hg for (d,p) angular‐distribution experiments with a 7.5‐Mev, 0.5‐&mgr;a deuteron beam.

ISSN:0034-6748    

DOI:10.1063/1.1717262

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The presence of columnar electron‐ion recombination luminescence from &agr; particles and fission fragments in an argon gas scintillation counter having a few percent N2as waveshifter has been established. A decrease in luminescence yield with applied electric field indicates a loss of recombination luminescence by ion collection. For a U235fission counter at two atmospheres pressure, a reduction in mean scintillation pulse height of 40% for fission fragments and 3% for background U234alphas resulted at 1200 v/cm. It is concluded that columnar electron‐ion recombination luminescence accounts for the considerable nonlinearity of energy response previously reported in gas scintillation counters for heavily ionizing particles.

ISSN:0034-6748    

DOI:10.1063/1.1717263

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1717264

出版商:AIP    

年代:1961

数据来源: AIP