摘要:

A proportional counter has been designed to detect soft beta‐emitters in the gas phase. Data is presented to illustrate the applicability of the counters to the detection of C14, S35, and H3. Various partial pressures of C14O2have been investigated to determine the effects on the counter properties. Corrections have been made for the counter ends and the memory effects are described. An energy spectrum is presented for H3to determine the low energy limit of the instrument.

ISSN:0034-6748    

DOI:10.1063/1.1745517

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A new technique of neutron energy measurement not requiring neutron collimation is described. The method employs the nuclear reaction Li6(n,&agr;)H3(Q=4.64 Mev) observed within photographic emulsions impregnated with enriched Li6. Results on monoenergetic neutrons indicate a resolution of at least ±0.1 Mev in the region studied (from thermal energies up to 1.3 Mev). To extend the method to measurement of continuous neutron spectra, both the excitation function and the angular distribution of the Li6disintegration process should be known. However, for immediate practical application, the method may be calibrated with a well‐known spectrum. The Li6technique is particularly well suited to energy measurements on neutrons within a material medium where perturbations introduced by the detector must be minimized and where collimation is clearly impossible.

ISSN:0034-6748    

DOI:10.1063/1.1745518

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An electronic switch has been developed which eliminates the difficulties with frequency adjustments usually encountered in existing electronic switches. This is done by developing a switching square wave synchronized by either input signal. Therefore this switch is very much easier to use as the control settings are not critical.

ISSN:0034-6748    

DOI:10.1063/1.1745519

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An instrument designed to measure and record a small difference in frequency between two cavity resonators is described. A sweep frequency technique is used to generate the resonance responses of the cavities. These responses are sharpened and made to control the operating time of a trigger circuit, whose average output is metered. A sensitivity equal to 200 c.p.s. is obtained in the measurement of the frequency difference between two highQcavities, whose resonance frequencies are equal to 9000 Mc. Applications of this instrument are discussed, especially those relating to measuring changes in dielectric constant. A simple extension of the present instrument is suggested for simultaneously recording changes in dielectric constant and loss.

ISSN:0034-6748    

DOI:10.1063/1.1745520

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A simple circuit is described which integrates approximately beam currents of 10−14amp. or larger. It consists of a d.c. amplifier, which converts the current into a voltage signal, and a voltage integrator circuit. Integration is approximate primarily because of slow circuit response to fluctuations; under usual conditions of high voltage accelerator work, one can expect integration accuracy of about one to five percent.

ISSN:0034-6748    

DOI:10.1063/1.1745521

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

It has long been established that variable‐&mgr; tubes of types such as the 6SK7 were capable of outputs which were proportional to the logarithm of the input over a specified range of bias voltages. The use of inverted triodes, and related circuits, is also widely known. It was decided to combine these two older techniques in the hope of developing a new one. Accordingly, a 6SK7 was hooked up as an inverted triode, i.e., the plate was used as the controlling element, and the control grid was employed as the output element; the results obtained with this arrangement were then plotted and investigated. As reported herein, a circuit capable of extracting antilogarithms over a fairly extended range of input voltages was developed.

ISSN:0034-6748    

DOI:10.1063/1.1745522

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A magnetic suspension for small rotors has been developed which employs scattered light to regulate the vertical height of the rotor. Upon entering a horizontal beam of light the rotor scatters or reflects light into a photo‐electron multiplier cell. This cell actuates an electronic circuit which in turn regulates the current through the supporting solenoid in such a way as to maintain the ferromagnetic rotor at the desired vertical position. Rotors with diameters down to 0.004″ have been stably supported. A164′′rotor was spun to an estimated speed of 800,000 r.p.s. which gave a centrifugal field in excess of one‐half billion times gravity. Besides providing a support for rotors, the apparatus may be used as an analytical balance for weighing materials inside a vacuum chamber. It detects changes in mass of from 10−8to 10−9gram. Other uses also are indicated.

ISSN:0034-6748    

DOI:10.1063/1.1745523

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A method is described by which a commercial x‐ray diffraction powder camera, designed to take rod or tubular mounts, may be easily adapted to accommodate small, flat mounts. Provision is made to change the customary continuous rotation to that of 10° rotary oscillation. A diffraction pattern of the core of a large renal calculus is shown as being illustrative of the patterns obtained from this modified camera.

ISSN:0034-6748    

DOI:10.1063/1.1745524

出版商:AIP    

年代:1950

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745525

出版商:AIP    

年代:1950

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745527

出版商:AIP    

年代:1950

数据来源: AIP