摘要:

The voltage measuring system described in this current paper is based on the electro‐optical Kerr effect,viz, variations in the voltage magnitude will result in respective changes in the intensity of a light beam passing through the Kerr cell perpendicularly to the applied field. The proposed measuring system has the advantages of a fast response of the Kerr effect substance to the application of voltage transients‐better than 2×10−8sec; and also high voltage pulses, with peak magnitude of the order of 105V, may be applied directly across the cell. The complete separation of the measuring circuit from the pulse circuit eliminates the electric noise from reaching the measuring circuit without any screening of this circuit. However, its major limitation is that the recorded pulse has the ``rectified'' form of the original pulse waveform.

ISSN:0034-6748    

DOI:10.1063/1.1718316

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

This fully automatic single‐crystal diffractometer employs the Eulerian hoop geometry. It is under punchedtape control and the three independent shafts are set simultaneously for each reflection to an accuracy of 0.03° using a moire´ fringe positioning system. The reflection is then measured by moving the crystal in steps across the reflecting position. The time on each step is variable, being determined by a monitoring counter, and the number of steps is under program control. Results are both printed in plain language and punched on a paper tape, ready for direct processing in a computer.

ISSN:0034-6748    

DOI:10.1063/1.1718317

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

An electronic device for automatically plotting the second derivative of probe curves is described in detail. A small sinusoidal signal is superimposed on the dc probe voltage which is swept manually. The second harmonic in the probe current is filtered, amplified by a low noise cascode amplifier, rectified by a phase‐true rectifier, and plotted by an X‐Y recorder. The components, the critical points in their wiring, and the performance of the system are described. A quantitative comparison is made with related devices. The system described here is somewhat simpler than the competing ones and has the advantage of being applicable to the first and the third derivatives as well.

ISSN:0034-6748    

DOI:10.1063/1.1718318

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The high‐resolution proton‐stabilized, and frequency‐swept spectrometer of Baker and Burd was limited to proton spectra. A modification of this instrument suitable for all magnetic nuclei is described, based upon the use of a Rhode and Schwarz frequency synthesizer. This modification provides generation and detection of an unmodulated signal at the frequency of another nuclear species, while retaining the features of proton stabilization and precalibration on a frequency scale of the older instrument. Frequency scans from 10 cps to 2 kc may be shifted in precise increments by means of crystal oscillators and the lock‐on features of the synthesizer. In going from one nuclear species to another, ratios of magnetogyric ratios are given automatically to high precision. Examples of spectra are given.

ISSN:0034-6748    

DOI:10.1063/1.1718319

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

A proton‐stabilized, frequency‐swept, high resolution NMR spectrometer using a frequency synthesizer was described previously by E. B. Baker and L. W. Burd. The addition of a second synthesizer and suitable power amplification allows a variety of nuclear spin decoupling experiments to be carried out with any pair of nuclear species, including INDOR experiments. For INDOR experiments a dispersion signal lock‐on provides extra stability for resting on the peak of a very sharp absorption line. A P31INDOR spectrum of trimethyl phosphite is shown as an example.

ISSN:0034-6748    

DOI:10.1063/1.1718320

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

A framing camera has been built based upon a very simple image multiplier. The image multiplier consisted of two layers of ¼‐in.‐diam glass rod (glass blowers' cane) crossed at right angles. At each intersection a real image of the event was produced. A 6×6 in. image multiplier produced some 576 separate images of the event. A transfer lens allowed these images to be projected on to a sheet of 8×10 in. film. A Nipkov disk was used to scan the image multiplier to produce a framing sequence up to a rate of 50 000 pictures/sec. It was considered that this framing rate could easily be extended beyond 106pictures/sec using a Jacob's optical focal plane shutter. The camera has the faults of parallax and optical distortion, but in the present application of the camera these are minimized by using a grid stationed at the event. It is considered that the camera is superior to those based upon image dissection devices. The camera was designed to be continuously available for approximately 3 msec, and was fitted with a crudely synchronized shut‐off shutter to prevent overwriting when used in the present application.

ISSN:0034-6748    

DOI:10.1063/1.1718321

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

A completely transistorized direct current electrometer voltmeter with an input impedance greater than 108&OHgr;, the accuracy and stability of which is virtually independent of moderate changes in transistor characteristics, has been developed. The high input impedance was attained because transistors with high current gain at very low collector currents are now available.

ISSN:0034-6748    

DOI:10.1063/1.1718322

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The widths of the time‐resolution curves of scintillation counters (Philips 56 AVP, plastic, and stilbene scintillators) are measured as a function of the height at which the timing pulse is derived from the rising edge of the scintillation pulse. A very small fraction of this leading edge is used to create a timing signal in a biased two‐stage limiter circuit. The arrangement agrees closely with a timing method discussed by Gatti and Svelto and the results are compared to their theoretical predictions.

ISSN:0034-6748    

DOI:10.1063/1.1718323

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Following a previously proposed method for producing short intense monoenergetic ion bunches, a complete variable‐path magnetic ion buncher was constructed. Tests in 1958 showed that bunching did occur, but available ion beam intensity and instrumental resolution were too low for detailed measurements at that time. Reconstruction of the available accelerator to give a high current (≥100 &mgr;A), well‐focused ion beam, and correspondingly high resolution pulse measuring equipment permitted meaningful resumption of testing by late 1960. Bunching performance in accordance with design predictions was then observed. Measurements with ½‐MeV protons indicated pulse lengths ≤1 m&mgr;sec, peak currents ≥4 mA, and a bunching ratio of ≥40. Average bunched current was >30 &mgr;A. Although tested with ½‐MeV protons, the design permits operation with protons or deuterons to more than 1 MeV. Bunching is accomplished by deflecting successive portions of a continuous monoenergetic ion beam from an electrostatic accelerator over progressively shorter paths between foci of a multifocusing 103° deflection magnet in a manner such that all ions come together essentially simultaneously at one focal point in high intensity short duration ion pulses. Sinusoidal electrostatic deflection at 8.8 Mc, linearized by cylindrical electrostatic lenses, or through harmonic synthesis, provides the required sweep.

ISSN:0034-6748    

DOI:10.1063/1.1718324

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

It is shown that by use of a multistage technique in which electrons are drawn from a cathode by a high potential and decelerated to the required final energy, guns can be designed capable of forming beams in which the current is limited only by space charge in the beam itself. The design principles and procedures are given and illustrated by two examples of electron guns giving highly collimated beams and operating at energies of 30 and 500 eV. The measured currents obtained are somewhat greater than the space charge limited beam maximum because of ion neutralization.

ISSN:0034-6748    

DOI:10.1063/1.1718325

出版商:AIP    

年代:1963

数据来源: AIP