摘要:

An electron model relativistic fixed‐frequency cyclotron of the azimuthally varying field type has been constructed for the purpose of testing the orbit dynamics of such a device. An iterative technique used in designing an acceptable magnetic field shape is described in some detail. A brief description of the various components of the device is given as well as an account of the beam phenomena observed in the initial period of operation. Results strongly indicate the feasibility, from an orbit dynamics standpoint, of large proton machines of this type.

ISSN:0034-6748    

DOI:10.1063/1.1716014

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A varying correction voltage is applied to the target which cancels beam energy fluctuations. This correction voltage is a known, constant multiple of a small, variable voltage which must be applied to the outer plate of an electrostatic analyzer to keep the beam centered at the analyzer image slits. The beam current at the analyzer image slits provides the signal which, when amplified by an electronic device called the Homogenizer, drives both the outer analyzer plate and the target. The energy spread is reduced to 250±120 ev and is probably due only to the ion source. If the HH+beam is put through the analyzer, the unlimited H+beam also has an energy spread of 250 ev. The 1.76‐Mev C13(p,&ggr;) and 0.992‐Mev Al27(p,&ggr;) resonances were used to test performance. Our data are consistent with &Ggr;(C13) = 75 ev and &Ggr;(Al27) = 100 ev. The upper limit for the C13width is 150 ev.

ISSN:0034-6748    

DOI:10.1063/1.1716015

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The ion phase in the internal beam of the Birmingham cyclotron at distances from the ion source from 8 mm up to 69 cm has been determined by measurements of the target current waveform. The equipment consisted of a screened target and a specially built oscilloscope based on the sampling technique. The results obtained are discussed and compared with theory.Ions are grouped in phase at early stages of acceleration over approximately 20 electrical degrees, which is about 5 times larger than predicted by the uniform electric field approximation. At later stages the measured phase changes are in good agreement with Rose's equation.

ISSN:0034-6748    

DOI:10.1063/1.1716016

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

An analog method is described for computing the Gaussian integral transformation which arises in the problem of making resolution corrections. Only apparatus which is readily available has been used. The basic element is a photomultiplier which views light flashes produced on an oscilloscope screen. A multichannel kicksorter is used to analyze, sum, and record pulses. Making a resolution correction is equivalent to inverting the integral transformation. A trial‐and‐error procedure is outlined for doing this.

ISSN:0034-6748    

DOI:10.1063/1.1716017

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Small explosively activated presses have been used as research tools in the study of the behavior of powdered materials under impulsive loads. Both single‐ and double‐acting presses have provided positive retention of the test specimen. The double‐acting press, which is of a sandwich‐type construction, uses two explosive charges fired simultaneously to drive two opposed pistons together into a central steel cylinder in which the specimen material has been placed. Estimates of the pressures which can be obtained are on the order of several million pounds per square in. By modifying the working faces of the pistons, materials can be formed into specimens of various shapes by the press action. Operation of these presses and their application to the study of several materials are described.

ISSN:0034-6748    

DOI:10.1063/1.1716018

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

It is shown that ion current stabilization for surface ionization mass spectrometers offers many advantages over the conventional methods of regulation which effectively stabilize the sample temperature. A technique is described which allows accurate measurement of very small relative isotopic abundances. A number of problems associated with the design of circuits for emission stabilization of surface ionization sources are considered. A successful stabilizer which maintains the ion current from such a source at a constant value by variation of the source filament temperature is described and the performance when used for the control of potassium positive ion sources is discussed. The stabilizer is capable of reducing ion current drifts, such as those due to exhaustion of the sample, by a factor of 130.

ISSN:0034-6748    

DOI:10.1063/1.1716019

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Special optical, mechanical, and electronic techniques have been combined in a new instrument—the microdeviometer—in which a beam of light and two optical gratings are used to obtain a very accurate scale of distance. The location, with respect to this distance scale, of the salient periodic features in the structure being measured is established through the interception of a second light beam by the structure. Electronic circuitry automatically stores and processes the position information and feeds the processed information, in the form of deviations from the corresponding ideal structure, to a pen recorder. A measuring accuracy of ±1 &mgr; has been consistently obtained, and measurements which formerly required nearly 2 man‐days are accomplished in less than 10 min.

ISSN:0034-6748    

DOI:10.1063/1.1716020

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A cryostat was constructed for the production of free radicals by electron bombardment of condensed gases at liquid helium and liquid hydrogen temperature. Provisions were made for simultaneous investigations of the bombardment products by electron diffraction and optical spectroscopy.

ISSN:0034-6748    

DOI:10.1063/1.1716021

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A high‐speed framing camera designed to investigate problems requiring a time coverage of from 6 to 20 milliseconds has been developed. Sixty pictures at framing rates up to 15 000 frames a second are possible. Unique to this system are the large image size (⅝×1¼ inches or ⅜×1¼ inches, depending on the framing rate required), and the very short exposure times (0.2 microsecond). The short exposure time has made this instrument useful in a number of applications.

ISSN:0034-6748    

DOI:10.1063/1.1716022

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Techniques are described for constructing cavity resonators atXband from low‐thermal expansion ceramics. A variety of mechanical arrangements is discussed.Qvalues as high as 14 000 and frequency‐temperature coefficients as low as 1 part in 100 million per °C have been obtained using simple processes.

ISSN:0034-6748    

DOI:10.1063/1.1716023

出版商:AIP    

年代:1958

数据来源: AIP