摘要:

A laboratory vacuum furnace with a glass envelope has been developed, using as a heater a cylindrical grid of tungsten wire enclosed by radiation shields.The furnace is suitable for physicochemical measurements in the range 1000–2000°C.

ISSN:0034-6748    

DOI:10.1063/1.1745635

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A high intensity ultraviolet continuous spectrum d.c. source emitting between 50 and 100 times as much light as comparable commercial sources has been designed and constructed. Transitions between two molecular energy states of hydrogen are induced to produce a continuum from 1850A to 6000A. The arc is run at approximately 14 amperes and 90 volts from a 220‐volt d.c. line. A hydrogen pressure of 3 mm of mercury is used. Lifetimes greater than 40 hours have been obtained.

ISSN:0034-6748    

DOI:10.1063/1.1745636

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The use of the sensitive McLeod gauge is limited by its fragility, bulk, and lack of portability. A new type of McLeod gauge is described which greatly reduces these difficulties. A helix of several turns of glass tubing provides the volume through which the gas is compressed by a small quantity of mercury as the gauge is rotated upon its rotary seal. A model has been constructed which is 16×16×21 cm in over‐all dimensions and weighs less than 1 kg. Its gauge constant with a 0.8 mm capillary is 1.4×10−6mm−1.

ISSN:0034-6748    

DOI:10.1063/1.1745637

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The need for new ultra‐high speed photographic techniques in studies of brief transient phenomena has led to the development of a multiple Kerr‐cell camera designed to take a sequence of three photographs at submicrosecond exposure times. This camera uses shutters of the electro‐optical type utilizing the Kerr effect in nitrobenzene. Pulsing networks for the Kerr cells and synchronizing networks for the entire system are described. The system has shown itself to be capable of high shutter speed, high sequence rate, and very good stability of timing. With this camera, studies of electrical discharages at effective exposure times of 0.04 microsecond and framing rates corresponding to 40,000,000 frames per second have routinely been made. It is felt that cameras of this type are valuable research tools that will help open the way for further important studies.

ISSN:0034-6748    

DOI:10.1063/1.1745638

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A counter was excited by a series of x‐ray pulses of short duration occurring at regular intervals. Spurious counts were then easily recognized since they occur between the x‐ray pulses. The counter pulses were displayed on an oscilloscope screen with a synchronized sweep and the counter deadtime, recovery time, and number of spurious counts determined by inspection. More quantitative information of the time distribution was obtained with an electronic circuit that recorded counts in a small arbitrarily chosen interval. It was found that the interval distribution shows at least two maxima. A mechanism is suggested for the appearance of the second maximum in terms of negative ions formed at the cathode by positive‐ion bombardment.

ISSN:0034-6748    

DOI:10.1063/1.1745639

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An arrangement is described which gives a continuous measurement of the relative magnetic field strength in a nuclear spectrometer with an accuracy of about 0.1 percent. The method consists of balancing the a.c. voltage picked up by a coil rotating in the field of the spectrometer against that picked up in a standard Helmholtz field.

ISSN:0034-6748    

DOI:10.1063/1.1745640

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The construction and manipulation of two diffusion cells, one of glass and the other of stainless steel, are described. In both cells the initially sharp boundary is formed by allowing solution and solvent to flow together into a narrow horizontal exit slit in the side wall of the diffusion channel. These cells have been tested by diffusion measurements with the aid of the Gouy interference method. Moreover, in the case of the metal cell which is provided with a reference channel in close proximity to that in which diffusion occurs, an interference method that gives the refractive index directly as a function of the height has also been studied.

ISSN:0034-6748    

DOI:10.1063/1.1745641

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A description is given of balloon‐borne proportional counters and circuitry for telemetering and recording cosmic‐ray neutron intensities. The preamplifier, amplifier, scaler, and trigger circuit described all use low drain directly heated battery‐type tubes. Methods and reasons for pressurization of high voltage circuits are discussed. Included is a description of a multiple‐level flight technique using single large plastic balloons for long time intervals at pre‐set altitudes.

ISSN:0034-6748    

DOI:10.1063/1.1745642

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An experiment was performed with Ilford TypeC2nuclear emulsion to determine the usefulness of photographic plates for measuring neutron fluxes and spectra by proton recoils in the region of the low energy limit of the emulsion. The results show that the plates give valid data for neutron flux determinations and energy distributions down to a neutron energy of about 0.5 Mev. Below 0.5 Mev the proton recoils give low values for the number of incident neutrons but approximate results can be obtained down to 0.3 Mev by applying a correction factor in this energy region. The experimental results permit a range‐energy curve for protons inC2emulsion to be determined for the energy region from 0.2 to 1.5 Mev. Finally, recoil proton energy distributions obtained from neutron irradiations ofC2plates at various low energy values are presented and discussed.

ISSN:0034-6748    

DOI:10.1063/1.1745643

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A relatively inexpensive 180° magnetic focusing beta‐ray spectrometer has been constructed, having a principle orbit radius of 15 cm. A radially inhomogeneous field provides essentially perfect focusing of electrons leaving the source within a 33° angle. In operation, with a 1‐mm wide source, the transmission is 0.2 percent, the full width at half‐maximum of an internal conversion line is 0.4 percent, and the effects of background and scattering are generally inappreciable.

ISSN:0034-6748    

DOI:10.1063/1.1745644

出版商:AIP    

年代:1950

数据来源: AIP