摘要:

The 240 MeV storage ring at the Physical Science Laboratory of the University of Wisconsin has been used as a source of radiation for extreme uv spectroscopy in the 40–400 Å wavelength range. The characteristics of the synchrotron radiation emitted by this machine are summarized. The experimental setup with a 2 m grazing spectrometer and the data acquisition system is described along with some of the procedures used for thin film photoabsorption measurements.

ISSN:0034-6748    

DOI:10.1063/1.1684793

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The efficiency of an electron multiplier for detecting fast hydrogen atoms has been measured by a coincidence technique employing Lyman &agr; photons from the induced decay of metastable hydrogen atoms. Results reported are for the energy range 3–20 keV.

ISSN:0034-6748    

DOI:10.1063/1.1684794

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The design and construction of an apparatus for domain observation and for the measurement of magneto‐optic rotation and coercivity of thin magnetic films, by means of the Faraday effect, are described. A spatial resolution of 5 &mgr; is achieved, allowing scanning of magneto‐optic properties across the film. Gas flow cooling and heating of the samples result in a temperature range of −120 to +200°C. A special sampling detector allows continuous recording of magneto‐optic rotation and coercivity as a function of temperature and wavelength.

ISSN:0034-6748    

DOI:10.1063/1.1684795

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The value which most affects the accuracy of the hydrogen maser is the experimental determination of the frequency shift produced by the collision of the atoms with the surface of the storage bulb. In the current method of using different bulbs with various sizes in order to determine the frequency shift, a large amount of uncertainty is due to the unreproducibility of the FEP Teflon coatings from one bulb to another. A way to get rid of this error is to use a single deformable bulb whose volume can be changed while the same surface is retained. Such a bulb has been developed which can be adapted to any regular maser.

ISSN:0034-6748    

DOI:10.1063/1.1684796

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The use of an autodyne oscillating NMR detector is discussed with particular reference to experimental situations where signal averaging or magnet field locking are involved. A frequency locking scheme which has proved very useful in this connection is described. Some additional circuits used in this locking scheme are discussed as applied to a Robinson circuit.

ISSN:0034-6748    

DOI:10.1063/1.1684797

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The theory of the hot wire anemometer is reviewed with emphasis on low velocity flow with relatively high turbulence intensity. A constant temperature linearized method is developed specifically for such measurements. Results for turbulence intensity as high as 90% are presented.

ISSN:0034-6748    

DOI:10.1063/1.1684798

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A practical technique is described for high sensitivity recording of input signals having a large dynamic range. The circuit senses when the input signal exceeds preset limits and applies a precise and stable baseline shift in the correct sense to maintain the output within these limits. The circuit may be regarded as a black box to be inserted between an analog signal source and a recording device and requiring no alteration to either. A system is presented in detail which permits recording of signals within the range −5.4 to +6.1 V on a recorder at 1.0 V full scale sensitivity. The drift introduced by this system is maintained at less than 1 mV/°C over a wide ambient temperature range. A discussion of the sources of error is presented and techniques for reducing these errors are described.

ISSN:0034-6748    

DOI:10.1063/1.1684799

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A Hall effect regulated electromagnet system can be locked to an NMR resonance by applying the NMR error signal to a small bias coil on the field sensor. The method requires no modification of the magnet regulator circuitry, produces negligible inhomogeneity near the center of the magnet, and reduces long term field drift to less than 1 mG if the NMR frequency is crystal controlled.

ISSN:0034-6748    

DOI:10.1063/1.1684800

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The sampled‐cw ultrasonic technique is applied to the study of highly attenuated waves in gases. Phase velocity and attenuation are obtained from a measurement of the reflection coefficient at the solid‐gas interface of a gas‐immersed crystal resonator.

ISSN:0034-6748    

DOI:10.1063/1.1684801

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A biased silicon transistor chain is used as the heart of a temperature stable circuit which will linearize the usual range of power law characteristics of hot wire and thin film constant temperature anemometers. In addition, this device can be used for characteristics which include segments with reverse curvature, a feature which has been found in some probes used to measure blood flow velocities in the aorta.

ISSN:0034-6748    

DOI:10.1063/1.1684802

出版商:AIP    

年代:1970

数据来源: AIP