摘要:

A Mathieu‐type pendulum magnetic balance is described that employs the Faraday principle for measuring the specific magnetization of ferromagnetic materials. The balance can be operated automatically, or deflections may be read optically. The sensitivity of the balance can be varied twenty‐fold by changing the weight distribution, and the calibration remains constant for years. Specific magnetizations are obtained with a precision of ±0.3%. Field strengths up to 10 000 oe can be held constant within ±0.3% for several hours. Specimens can be heated to 800°C or cooled to −180°C, and the temperature can be held constant to ±1.0°C for isothermal measurements. Automatic heating of the specimen at constant rate is provided.

ISSN:0034-6748    

DOI:10.1063/1.1717868

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A tunnel diode coincidence circuit which is versatile and simple is described. It is intended to serve as the elemental block for building up complicated fast logic schemes which are frequently required in high energy physics experiments. Performance results are given as well as discussions of numerous possible variations on the design.

ISSN:0034-6748    

DOI:10.1063/1.1717869

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A new technique for measuring temperatures by means of the velocity of sound in a gas is described. A closed‐end, gas‐filled pipe is excited to longitudinal acoustic resonance, and the resonant frequency is measured. The temperature of the gas is then determined from the well‐known relations between the temperature and the velocity of sound. The generation and detection of acoustic waves are carried out by a transceiver which is remote from the measuring region and which is connected to the cavity by a small‐diameter, gas‐filled tube. The technique is particularly well suited to high‐temperature studies in nuclear‐radiation environments.

ISSN:0034-6748    

DOI:10.1063/1.1717870

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A simple device consisting of an iron sphere constrained with fine copper wire and suspended in the field of a large permanent magnet is described. Weight changes of 2 parts in 106are measurable. The device was employed to measure the forces exerted on a magnetized object by other substances according to their magnetic susceptibility.

ISSN:0034-6748    

DOI:10.1063/1.1717871

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Apparatus is described which permits insulators to be zone melted by electron beam techniques. The primary feature is the use of secondary emission from the sample to prevent build‐up of an electrostatic charge. In addition to remelting solid rods, this procedure can be applied to the melting and zone refining of sintered polycrystalline rods and tubes.

ISSN:0034-6748    

DOI:10.1063/1.1717872

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

In positioning an x‐ray tube in an experiment in order to gain optimum usable power, the variables at the operator's control are the take‐off angle and the collimation (or slit) system. These variables should be fixed by consideration of sample size, focal‐spot size, target ``absorption shadow,'' and the amount of divergence to be permitted. Consideration of these factors leads to an uncommon collimator for simple large single‐crystal diffraction work.

ISSN:0034-6748    

DOI:10.1063/1.1717873

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

An instrument for transmitting a carrier frequency analog of atmospheric radio index of refraction is described. The signal transmitted is received at a remote point through the use of a phase lock type of receiver. It employs a ceramic coaxial cavity, one‐half wavelength long, as a sensor, and the nominal operating frequency is 403 Mc. The instrument, when operated with other cavities, offers the laboratory gas dielectric investigator a convenient tool for studying real components of gas dielectrics. Operation can be easily extended to higher frequencies by the use of suitable cavities and solid state multipliers.

ISSN:0034-6748    

DOI:10.1063/1.1717874

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

An analysis is made of a system utilizing modulation and synchronous detection. The signal after modulation is expressed both as a Taylor expansion and as a Fourier series. The evaluation of the coefficients and subsequent comparison show that the first derivative of the signal can be expressed asf′(x)=A−1[H1−3H3+5H5−7H7+…+(−1)n−1(2n−1)H2n−1+…),whereAis the amplitude of the cosine modulation andH1,H3, etc., are the amplitudes of the odd harmonics of the modulated signal.

ISSN:0034-6748    

DOI:10.1063/1.1717875

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A negative ion source is described which is capable of producing negative ion beams of moderate intensity, but with relatively narrow spread in ion energy. The source consists essentially of a jet of gas intersected by an electron beam. The pressure in the vicinity of the thermionic electron source is kept low by differential pumping. Although ion currents are not as high as those obtained with discharge sources, the present source produces ion beams particularly free of noise and instability.

ISSN:0034-6748    

DOI:10.1063/1.1717876

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A hot filament ion gauge with a calculated time constant of 130 &mgr;sec for D2at room temperature has been developed to measure neutral gas density near a magnetically confined plasma. The plasma contribution to the collector current is determined by operating the device with the filament cold. The influence of emission, gas pressure, and magnetic field on gauge sensitivity is given. Measurements taken on a stellarator demonstrate the use of the gauge.

ISSN:0034-6748    

DOI:10.1063/1.1717877

出版商:AIP    

年代:1962

数据来源: AIP