摘要:

The instrument described is a multichannel time interval analyzer with digital output for use in the millimicrosecond region. The analyzer consists of two circulating transmission lines with a single fast coincidence circuit between them and associated gating circuits. Each circulating line is a precisely trimmed coaxial cable with its ends joined by a two‐stage noninverting saturating amplifier. A circulating pulse delivers time marks to the input of the coincidence circuit. By making the circulation periods of the two lines slightly different, the time marks are made to arrive at slightly different frequencies. The instrument is a true vernier. To measure an interval it is only necessary to count the number of circulations before coincidence and multiply by the difference in circulation period of the lines. A commercial 256‐channel magnetic core memory is used for storage.The circuit of the instrument is described. A method is described for predicting circulation threshold, growth to equilibrium, and equilibrium amplitude of a circulating pulse from the amplifier transfer characteristic. Data are presented which indicate the linearity, stability, and time resolution of the instrument.

ISSN:0034-6748    

DOI:10.1063/1.1716500

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Using a concentric‐cylinder rotational viscometer, Weltmann has shown that automatic recording of flow curves in accordance with a predetermined program is important in the study of materials whose flow properties are shear‐dependent and time‐dependent. When the flow of such materials as greases was studied using the Ferranti‐Shirley cone‐plate viscometer, advantages of small sample size, ease of loading with minimum deformation, and uniform shear rate across the sample were apparent. However, time‐dependent properties of the grease could not be adequately described from data obtained in manual operation of the cone‐plate viscometer.An automatic control device for shear rate acceleration of the cone‐plate viscometer has been designed so that flow curves can be obtained automatically using anX‐Yrecorder. Flow curves of typical greases and other materials exhibiting non‐Newtonian and time‐dependent properties have been successfully obtained using this automatic control device. The cone‐plate viscometer as modified has distinct advantages for the study of non‐Newtonian and time‐dependent materials.

ISSN:0034-6748    

DOI:10.1063/1.1716501

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The relation between switching speed of a trigger circuit and the gain band width (GBW) of an amplifier is discussed. A special series connection of two tubes—referred to as a dynamic plate‐load amplifier (DPL)—is then presented and analyzed. A dc analysis shows that the DPL investigated has 18% of the output impedance, and 2.75 times the dc gain of a conventional amplifier. A transient analysis shows that the DPL may have 3 times the advantage in GBW over a conventional amplifier. This GBW improvement recommends its utilization in fast trigger circuits.

ISSN:0034-6748    

DOI:10.1063/1.1716502

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The cross‐spectral density of two functions may be determined by using two selective filters which have identical impulse responses except for a relative phase difference which should be 0° and 90° for the measurement of cosine and sine components, respectively. A technique is developed which is quite accurate and requires a minimum of special equipment. The operation of the system is checked by measuring the cross‐spectral density of two functions whose statistical properties are known.

ISSN:0034-6748    

DOI:10.1063/1.1716503

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A device for accurate measurement of diffraction patterns is described in detail. The accuracy of measurement is better than 0.01%. In addition, this device is useful for viewing photographic negatives and can also be used for other kinds of measurements.

ISSN:0034-6748    

DOI:10.1063/1.1716504

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The design and construction of a voltage graded vacuum spark gap is described. This gap is capable of switching currents as large as 106amp at voltages up to 75 kv. The effect of the insulating walls of the gap is briefly discussed.

ISSN:0034-6748    

DOI:10.1063/1.1716505

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

It is found that the temperature at any point below the surface of a helium bath, as deduced from pressure measurements over the surface corrected for hydrostatic head, does not agree with the temperature obtained using a vapor pressure bulb, the helium bath pressure invariably indicating a lower temperature, except below the &lgr; point. The discrepancy can be reduced but not eliminated by employing a heater at the bottom of the bath to provide a copious supply of vapor bubbles throughout the bath. A sharp temperature gradient at the surface of the bath is indicated. Below the &lgr; point no discrepancy is observed.

ISSN:0034-6748    

DOI:10.1063/1.1716506

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A high‐voltage, fixed frequency re‐entrant cavity of moderate power requirements designed for use in the Cornell 1.5‐Bev synchrotron is described. Design considerations and details of the cavity gap structure are presented. The problem of multipactoring is described. Advantages of coaxial gap construction using an internal insulator are given. In particular a dc bias to prevent multipactoring can easily be applied. A simplified analysis of the operation of the cavity in terms of equivalent circuits is also given.

ISSN:0034-6748    

DOI:10.1063/1.1716507

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Design considerations, description, and some data on the performance are given of a large pillbox‐shaped Stark cavity absorption cell for the 1.25‐cm wavelength region. The cavity can be used in anyTE0m1mode withmranging from about 5 to about 12 and its most prominent features are: high loadedQfactor (∼5×103−104), good electric insulation (at pressures below 4×10−2mm Hg Stark voltages up to 3000 v can be applied), low Stark field inhomogeneity (diameter to length ratio 15–20), large band width (from about 18 to about 28 kMc), and low mode density. No cross‐mode resonances occur and the only undesired modes excited appreciably are theTE2m1ones. When used in transmission only theTE0m1modes couple to the output.The cavity can be used at the same time as a reference cavity of a Pound‐type klystron frequency stabilizer. The klystron frequency will then automatically follow the resonance frequency of the cavity over a frequency interval up to 400 Mc.

ISSN:0034-6748    

DOI:10.1063/1.1716508

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A simple method is described for locating theCaxis of an uncut ruby crystal. The procedure involves measurement of the angular position of the ruby for zero light transmission when it is placed between crossed polarizer and analyzer. The precision is ±1°.

ISSN:0034-6748    

DOI:10.1063/1.1716509

出版商:AIP    

年代:1959

数据来源: AIP