摘要:

The construction and operation of a molecular beam maser spectrometer, similar to the ammonia maser, is described. The observed linewidths are of the order of 5 kc at microwave frequencies, thereby allowing high resolution hyperfine spectroscopy on a number of molecules. The major factors affecting the resolution and sensitivity are examined. A brief survey of possible experiments is given.

ISSN:0034-6748    

DOI:10.1063/1.1717169

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The preparation of artificial &bgr;‐eucryptite (Li2O Al2O32SiO2) as a filament coating for the emission of Li+ions is discussed. Two ion sources with their initial focusing gaps are described.

ISSN:0034-6748    

DOI:10.1063/1.1717170

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A system diagram and the circuit for each of the components of an automatic conductance plotting machine are presented. Conventional circuitry using vacuum tubes is used throughout. The circuit impresses a small 5‐kc incremental voltage of controlled amplitude upon the dc bias of the diode under test and senses the magnitude and sign of the in‐phase component of the resulting current.

ISSN:0034-6748    

DOI:10.1063/1.1717171

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A current monitor suitable for use with continuous or pulsed high energy electron beams is described. It functions by collecting slow secondary electrons emitted on passage of high energy electrons through a thin foil in vacuum. The secondary current is a linear function of primary current at average primary currents up to at least 120 &mgr;a (peak current density −150 ma/cm2), and is independent of energy at least in the range 6–30 Mev. With design modifications, the device should be capable of monitoring current at energies as low as 1 Mev with negligible beam absorption.

ISSN:0034-6748    

DOI:10.1063/1.1717172

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Apparatus has been developed for producing a molecular N2beam covering the energy range 5–1000 ev. The technique includes ionization by electron impact, acceleration and focusing, and neutralization by charge transfer. Energy spread is 0.5 ev. The beam intensity ranges from 108molecules per second at low energy to 1010at high energy. The absolute beam intensity can be determined within 20%. Charge transfer efficiency, beam intensity monitoring, and adaptability of the apparatus to the studies of ionization cross sections and surface phenomena are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1717173

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A general set of standing wave relations, applicable to the rf‐ and i.f.‐substitution techniques, are derived and used in the subsequent development of curves appropriate to measurements made around the pattern minimum. Although the experimental results using the rf‐substitution procedure have not been recorded for a VSWR in excess of 200:1, there appears to be no limit on the magnitude of standing wave ratio that can be measured, if suitable equipment is available. An analysis of errors reveals that the principal factor which influences the accuracy attainable is the precision with which the attenuator can be determined.

ISSN:0034-6748    

DOI:10.1063/1.1717174

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The transfer of electrically‐supplied heat from a copper thermal link into single‐crystal slabs of chromium potassium alum has been measured in the temperature range from 0.03 to 0.15°K. Temperature differences produced by heating were less than 6% of the average temperature. The heat transfer rate per unit temperature difference is characteristic of two thermal conductances in series with a heat sink. One of the conductances is characteristic of electrical‐purity copper and is ascribed to the copper thermal link. The second corresponds to a heat transfer rate per unit temperature difference and per unit contact area of 3×105T3erg/sec cm2K°4. Comparison with other experiments leads to the conclusion that heat flow rates into single crystals of ferric alum and chrome alum are proportional to the contact area with the thermal link and are reasonably reproducible from experiment to experiment. In the present experiments it is likely that classical thermal diffusion does not determine the flow of heat within the alum crystals. Instead, the experiments suggest that theT3thermal conductance is a boundary effect and that the phonon mean free path within the chrome alum crystals is sufficiently long to insure that the crystal temperature is homogeneous.

ISSN:0034-6748    

DOI:10.1063/1.1717175

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A balance with a weighing range between 9 and 24 kg has been tested. The use of radiation resistant sensing devices makes it acceptable for use in hot cell applications. With an unrefined read‐out method the system sensitivity, including resolution of chart reading by eye, at 65% confidence limits is ±10 g in 2.5‐kg intervals. Over the entire 9 to 24 kg range the linearity of the system is such that the sensitivity is reduced to ±17 g. It is predicted that digital indication of weight and use of a low inertia, low friction indicating system will double the system sensitivity.

ISSN:0034-6748    

DOI:10.1063/1.1717176

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The theory and operation of a device that makes the beam in the Cosmotron come onto a target in about 5 &mgr;sec instead of the usual 3 msec are described. The magnetic field in a two‐turn coil, pulsed with a condenser bank, deflects the internal beam enough to throw the beam onto a target during the rise time of the perturbing field. The system has an inductance of 2 &mgr;h and a capacitance of 11 &mgr;f, giving a ringing frequency of 34 kc, a peak current of 47 000 amp at 20 kv and a peak field of 1100 gauss. The ejector can also be used to put only a small fraction of the beam onto a target, permitting the rest of the beam to continue on the normal accelerating cycle.

ISSN:0034-6748    

DOI:10.1063/1.1717177

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A high‐temperature calorimeter has been built to measure the heats of formation of certain refractory compounds (by direct reaction of the elements) at temperatures in excess of 1000°C. The standard heat of formation of TiB2was found to be −50±5 kcal/mole. A known heat of formation, that of TiC, was also measured, yielding reasonable agreement with the literature value.

ISSN:0034-6748    

DOI:10.1063/1.1717178

出版商:AIP    

年代:1961

数据来源: AIP