摘要:

An extension of familiar techniques in magnetic measurements has been made enabling the direct measurement of magnetization cuves,M vs H, in high pulsed magnetic fields (H≳ 100 koe.). The sample is placed in the most spatially uniform region of the available field, inside one of a pair of balanced and opposing pickup coils. Their output is integrated and displayed on the vertical deflection plates of an oscilloscope asM, while the integrated output of the empty coil appears on the horizontal plates asH. As presently operated, a magnetization M of ∼30 emu or a volume susceptibility of ∼5×10−4can be detected with reasonable but not high accuracy. The method is better suited to nonlinear magnetization curves than those methods which involve placing the sample in an inhomogeneous field, and hence may be useful in studying metamagnetics and weak antiferromagnetics.

ISSN:0034-6748    

DOI:10.1063/1.1716304

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A 33‐cps resistance thermometer bridge, suitable for precise temperature measurements in the liquid helium range, has been designed as a completely self‐contained unit. The amplifier has a gain of 120 db, band width of 0.3 cps, and input impedance of 10 kohms. With a power dissipation of 2×10−8watts in the thermometer, resistance changes of 0.1 ohm can be detected. For a typical resistance thermometer this corresponds to a temperature change of 4×10−6°K at 2°K. Other features include high rejection of line‐frequency pickup, short recovery time after saturation, and a combination gain band‐width control which shortens the response time during preliminary balancing operations.

ISSN:0034-6748    

DOI:10.1063/1.1716305

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A simple device for rapid measurement of the intensities of microwave absorption lines has been constructed. It requires only a small electromagnet and power supply and utilizes a free electron resonance to provide a standard comparison line at any frequency from 0 to 40 kMc. Preliminary tests carried out on ammonia atKband indicate reproducible results with errors of less than ±30% in most cases. Suggestions are made for improving the accuracy of the measurements.

ISSN:0034-6748    

DOI:10.1063/1.1716306

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The extraction of particles from the nonlinear magnetic field of a synchrocyclotron by a single magnetic perturbation is studied by use of a general approximation to the magnetic field and a calculation technique closely tied to the physical process. The analysis is useful for extraction amplitudes of several inches. Regenerator strengths are computed as an illustrative example.

ISSN:0034-6748    

DOI:10.1063/1.1716307

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

An improved double reflection x‐ray camera is described in which both the crystal and the film rotate simultaneously. It registers x‐ray reflections from crystals in form of a line, and shows the double reflections on this line. Some examples of double reflections taken with this apparatus are shown.

ISSN:0034-6748    

DOI:10.1063/1.1716308

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A device is described which records and prints data which can be represented by the decimal system of numbers. The register section can be arranged to handle several groups of figures containing any number of digits and has a total capacity of 16 digits. The registers automatically return to zero before the beginning of each recording period.

ISSN:0034-6748    

DOI:10.1063/1.1716309

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Radio‐frequency oscillators used as detectors of nuclear paramagnetic resonance absorption employ an auxiliary source at audio frequency to modulate the static magnetic field. A small component of voltage at this frequency is usually induced into the tank coil of the oscillator. If this voltage is permitted to appear at the grid of the oscillator, mixing with the rf voltage will occur. This produces a false signal indistinguishable from the resonance signal. A simple LC filter put between tank circuit and oscillator tube is found to be extremely effective in removing false resonances. The response of the oscillator to signals generated by a Watkins calibrator is measured in the range from 5 to 25 Mc. Results of these and ``Q'' measurements show the oscillator sensitivity to be unimpaired by the addition of the LC network.

ISSN:0034-6748    

DOI:10.1063/1.1716310

出版商:AIP    

年代:1958

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1716312

出版商:AIP    

年代:1958

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1716313

出版商:AIP    

年代:1958

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1716314

出版商:AIP    

年代:1958

数据来源: AIP