摘要:

A technique is described for measuring the Bragg ionization curve of a certain kind of particle in the presence of a disturbing beam contamination. The pulses of the undesired particles are eliminated electronically by the applied counter telescope. The ionization values are gained from the pulse height spectra which the beam produces in a NaI (Tl) scintillator. The pulse train of the multichannel analyzer used and a program written in FORTRAN II supply the data for the ionization curve. Measurements with 150 MeV protons are compared with curves in the literature.

ISSN:0034-6748    

DOI:10.1063/1.1720162

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

Attempts have been made to study the homogeneous dissociation kinetics of N2F4and OF2by means of an adiabatic compression apparatus attached to the fast reaction cell of a Bendix time‐of‐flight mass spectrometer. It was found that, if helium is used for the reaction medium, temperatures sufficiently high for reaction to occur are not obtained, nor is the maximum temperature obtained constant for a significant period of time; i.e., the high thermal conductivity of helium does not permit an approach to adiabatic operation. A further bar to successful experimentation (assuming that the nonadiabaticity could have been overcome by using an inert medium of lower thermal conductivity) was the self‐destructiveness of the light weight apparatus and the damage to the ion source of the mass spectrometer, brought about by the impact of the piston at the end of the compression stroke. The experimental data obtained in this system with helium, argon, and nitrogen are critically examined and possible theoretical limits of mechanical adiabatic compression, proposed by Vernotte, are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1720163

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A kinematic locator with one rotational degree of freedom is described. This device allows the transfer of aligned crystals within 2″.

ISSN:0034-6748    

DOI:10.1063/1.1720164

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

The total number of electrons has been calculated as a function of depth in air, glass, and iron absorbers. The nuclear interactions have been described by the model of Cocconi, Koester, and Perkins. The results help in the design of ionization spectrometers for the measurement of the total energy of ultrahigh energy particles. In particular, a correlation is established between the maximum number of electrons and the primary energy. Also, the amount of energy lost from ionization spectrometers due to limited depth can be derived from the results presented here.

ISSN:0034-6748    

DOI:10.1063/1.1720165

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

An energy monitor for electron beams has been developed which makes use of the elastic scattering of electrons caused by a foil placed in the beam path. The scattered electrons are magnetically analyzed and detected by measuring the direct current from a plastic scintillator. During use of the beam the sweep of the magnetic field is repeated automatically, and the energy spectrum is displayed on a storage oscilloscope. Performance of the monitor constructed for a 15 MeV linear electron accelerator is presented.

ISSN:0034-6748    

DOI:10.1063/1.1720166

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A resonance type reversed bending, high temperature fatigue machine for operation at constant bending amplitude in vacuum has been developed. The vibration frequency is maintained at resonance by means of a feedback circuit employing a capacitance pickup. Another circuit maintains a constant amplitude of vibration. As fatigue cracks are developed, the resonant frequency decreases. Curves of resonant frequency versus time at 800°C for materials of high damping, such as type 316 stainless steel, and for materials of low damping, such as Inconel X, illustrate the development of fatigue damage.

ISSN:0034-6748    

DOI:10.1063/1.1720167

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A new type of pile‐up rejector, using a pulse overlap to pulse height converter, is described. It is operated at the output of a double delay line clipped amplifier and has a resolving time better than 20 nsec.

ISSN:0034-6748    

DOI:10.1063/1.1720168

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A simple omegatron, without guard rings and side plates, for measuring partial pressures has been studied. The factors influencing the collected ion and electron currents are discussed. Deviations and variations in omegatron collection efficiency are eliminated by using partial pressure ratios and the ionization gauge reading corrected for the gas mixture. Curves of ion versus electron currents are obtained. Possible effects from a hot tungsten filament are investigated. Fragmentation pattern and principal ion production are measured and discussed. The omegatron sensitivity is a function of secondary electron emission from the electron collector. Only one characteristic peak of each gas is necessary for residual gas analysis, when the fragmentation pattern is known.

ISSN:0034-6748    

DOI:10.1063/1.1720169

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

The apparatus described was developed to measure length changes in germanium due to electron irradiation and subsequent isochronal annealing at low temperatures. Similar techniques would be applicable to other experiments. Length changes of the sample produced changes in spacing of a system of three‐terminal capacitors. These capacitors were measured by an ac ratio bridge capable of detecting changes in capacitance of 4 parts in 107. The irradiated portion of the sample, the surrounding framework, and one plate of each of the parallel plate capacitors were all part of the same monolithic germanium single crystal. A system of six capacitors was used to eliminate extraneous effects. The sensitivity and long term stability was on the order of 0.1 Å which corresponds to 2 parts in 109for an irradiated sample length of ½ cm.

ISSN:0034-6748    

DOI:10.1063/1.1720170

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A reliable, inexpensive timing device has been constructed for use with the Kentron microhardness tester. This device, which consists of a photoelectric switch coupled to an electric timer, enables the duration of loading to be precisely controlled, provides a convenient method for measuring the loading rate, and facilitates adjustment of the tester. The use of this timing accessory increases the efficiency of operation of the microhardness tester and reduces operator error, thereby improving the accuracy and reproducibility of microhardness testing results. The device should be adaptable to other hardness testers.

ISSN:0034-6748    

DOI:10.1063/1.1720171

出版商:AIP    

年代:1966

数据来源: AIP