摘要:

A focusing differential Cˇerenkov counter of high velocity resolution using a gas radiator has been developed and used in relativistic particle beams. The optical and mechanical features are described. The velocity &bgr; can be varied continuously from 0.81 to 1.00. These counters give a velocity resolution &Dgr;&bgr;/&bgr; of 0.0025 (half‐width at half‐maximum) at &bgr;=0.9985 and an average efficiency for a 4‐in. diameter particle aperture of 0.7 in a particle beam collimated to ±1°. The sources of spurious response and the ultimate limitations of counters of this type are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1717292

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Two techniques have been developed for the measurement of the infrared absorption of glasses at room temperature and of their melts up to 1000°C. In a vertical film apparatus, dehydration and the control of sample thickness may be carried out simultaneously. At high temperatures, the breakage of the film through flow is circumvented by a horizontal film arrangement. By the formation of suitable thin filmsin situ, rapid absorption of water is prevented. These methods are thus particularly suitable for highly hygroscopic materials where the conventional KBr disk technique is unsatisfactory. The advantages of the two techniques are demonstrated by measurements carried out on glassy and liquid B2O3up to 1000°C.

ISSN:0034-6748    

DOI:10.1063/1.1717293

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

This paper presents an explorative circuit system functioning as a highly stabilized and sensitive reactance meter with a wide range of application in various fields of scientific research and industrial operation. With a measuring range of 10−3to 10+6pf, it has a sensitivity of 5–10 &mgr;a/0.001 pf when measured through an ammeter with a full scale of 100 &mgr;a, and a stability of less than 1&mgr;a in terms of zero drift during several hours. Some experimental data are given for the appreciation of its characteristics.

ISSN:0034-6748    

DOI:10.1063/1.1717294

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A conductance cell assembly is reported of the capillary design with a cell constant sufficiently high to permit precise electrical conductance measurements with the standard type precision conductance bridge circuits. Important features are the use of single crystal grade MgO for construction of the capillaries that determine the resistance for the electrolyte in the conductance cell, and the use of such materials as gold, or gold‐palladium alloy to construct the various other components of the cell that contact the molten salts. The suspension of the MgO crystal capillaries is of a novel design which permits removal of the capillaries from the assembly for inspection or cleaning, and yet holds these firmly and securely in position during measurements. It is shown that recently published values of electrical conductance for molten KCl and KNO3may be used as standards for calibration of such cells at high temperatures.

ISSN:0034-6748    

DOI:10.1063/1.1717295

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A new method is described by which a plated quartz crystal oscillator is used for the measurement of sputtering. The crystal is placed in a molecular beam and sputtering of its plating is measured by the frequency change of the oscillator. The relationship between the frequency change of the oscillator and the change in plating mass of the crystal is given. The method is extremely sensitive. Sputtering of less than a millimicrogram of plating can be measured. A wide range of material can be used to plate the crystal. A crystal oscillator sputtering gauge was built by using a frequency counter with a digital readout to record the oscillator frequency. The operation of the gauge is illustrated by preliminary measurements on the sputtering rates of gold in an argon beam between 0 and 100 ev. Other uses of the gauge, such as a neutral beam detector, are also discussed.

ISSN:0034-6748    

DOI:10.1063/1.1717296

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An instrument was developed for the rapid and accurate measurement of small diameters. The operating procedure consists of placing the test fiber between two optically flat surfaces and, using the fiber as a fulcrum, adjusting the upper flat until the surfaces are parallel and utilizing the absence of interference fringes between the surfaces to indicate parallelism. Controlled tilting of the upper flat is obtained by adjusting, with a micrometer screw, a sliding wedge under a lever attached to the upper flat. Fiber diameter is a linear function of wedge position as indicated by micrometer screw setting.

ISSN:0034-6748    

DOI:10.1063/1.1717297

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A piezoelectric probe has been devised for use in plasma work, where one wishes to measure phenomena of short time duration (microseconds) giving rise to moderately small pressures (fractions of an atmosphere). Some of the response characteristics of such a probe and a method for its calibration are also presented.

ISSN:0034-6748    

DOI:10.1063/1.1717298

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The resonant extraction method previously proposed for the normally constant gradient synchrotron has been extended to alternate gradient accelerators. It is found that perturbation field gradients which contain circular functions of arguments 2&ngr;x, 2&ngr;x+1, 2&ngr;x+2 are particularly effective in causing the radial betatron oscillations to grow exponentially at a particular azimuthal position. The analytical procedure for predicting which perturbations give optimum results, and digital computer calculations verifying these predictions, are presented.

ISSN:0034-6748    

DOI:10.1063/1.1717299

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A convenient matrix method for calculating properties of magnetic deflection systems is presented. This method is applicable to particle beams of small spatial and angular extent, and small energy spread. Equations for quadrupole lenses and for deflecting magnets are given. Examples are given to show the procedure for calculating the parameters of magnet systems.

ISSN:0034-6748    

DOI:10.1063/1.1717300

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Henry's profile for shaped pole caps has been adapted to a 4‐in. magnet. The fields obtained at a pole cap separation of 2.6 cm have been examined in some detail. A region of constant ∂B2/∂xis obtained which is 1 cm in length at low fields and 1.4 cm at high fields. For excitation currents of 40×103amp turns the value ofB∂B/∂xis about 24×106gauss2/cm.

ISSN:0034-6748    

DOI:10.1063/1.1717301

出版商:AIP    

年代:1961

数据来源: AIP