摘要:

Multichannel systems for pulse‐height and time‐of‐flight analysis based on the original development of Hutchinson and Scarrott are described. The equipment can be divided into three basic categories:(a) A time channel analyzer using serial storage and arithmetic operations. This unit provides approximately 500 2‐&mgr;sec time channels each having a capacity of 10 binary digits. It is now being used for slow neutron time‐of‐flight spectroscopy.(b) A pulse‐height‐to‐time converter which when used in conjunction with the above or similar unit forms a multichannel pulse‐height analyzer with 200 useful channels.(c) Data display systems of two types, one for continuous visual monitoring and one for permanent recording in chart form.

ISSN:0034-6748    

DOI:10.1063/1.1715606

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The design of an apparatus for applying uniaxial compression to specimens with cross sections up to ¼ inch square is described. One feature of the apparatus is the construction of the force transmitting linkage. This linkage was designed to minimize the transmission of shear forces, and thus to avoid bending moments on the samples. The apparatus enables the compressive forces acting on the samples to be determined to within 0.1&percent;.

ISSN:0034-6748    

DOI:10.1063/1.1715607

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The control circuit described utilizes a logarithmic difference amplifier to measure the ratio of the positive ion current to the electron current drawn by the gauge. This eliminates the necessity of stabilizing the electron current within close limits and permits direct readings of pressures ranging from 10−3to 10−7mm of mercury on a single logarithmic scale.

ISSN:0034-6748    

DOI:10.1063/1.1715608

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A microwave interferometer has been developed for measuring the phase retardation of a wave passing through a radome wall. The instrument is used to analyze radomes which are subsequently corrected so that the phase retardations are of the desired values everywhere. High accuracy is required in the measurements. Automatic balancing of the interferometer is employed so that continuous measurements can be made.

ISSN:0034-6748    

DOI:10.1063/1.1715609

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The problem of the atmospheric infrared heat balance has been solved graphically and analytically, but almost no experimental evidence exists to verify the calculations. The ``Black Ball'' is a device which can be flown on an ordinary radiosonde and indicates a temperature which is related to the total incident infrared flux at any point. The actually observed temperatures must be corrected for convection effects and thermal time constants. Construction and correction data are presented in this paper.

ISSN:0034-6748    

DOI:10.1063/1.1715610

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A neutron energy spectrometer is described, suitable for the region 50 kev to 1 Mev. Hydrogen recoils from CH4in a proportional counter are collimated and enter a second counter. The sum of the pulse heights is analyzed whenever a coincidence occurs. A third counter in anticoincidence discriminates against cases in which all the energy is not lost in the first two. With the collimation used the energy spread is∼10&percent;and the efficiency an approximately linear function of energy, being 10−5at 180 kev.

ISSN:0034-6748    

DOI:10.1063/1.1715611

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A proton‐recoil telescope with thin polyethylene radiator has been designed for neutron spectroscopy and for neutron detection with known efficiency in the energy region from about 2 to 20 Mev. Five radiator thicknesses may be chosen over this energy region. Protons recoiling near zero degrees from the radiator pass through two proportional counters and terminate in a NaI(Tl) crystal. Triple coincidences gate an analyzer for observing the spectrum from the crystal. A spectrum of 13.7‐Mev neutrons was observed with a width at half‐maximum of 5.3&percent; and 6&percent; background. The efficiency with this resolution at 13.7 Mev is 3.6×10−6.

ISSN:0034-6748    

DOI:10.1063/1.1715612

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A linear amplifier with a 1.2‐&mgr;sec clipping time and a gain of 50 000 suitable for scintillation spectrometry is described. Low‐energy photoelectric peaks can be resolved under conditions in which the unwanted background has a rate in excess of 100 000 cps and has components 40 times more energetic than the desired spectrum. No shift in the energy axis is observed under these conditions.The amplifier consists of a White cathode follower preamplifier, three feedback groups, and a White cathode follower output stage. Each of the three feedback groups contains four stages, three of which are amplifiers. Blocking is eliminated by the use of grid resistors low in value compared to the preceding stage plate load resistors. This feedback group configuration is also more linear by an order of magnitude than the conventional configuration. It is shown howRLCcoupling between White cathode follower halves can conserve power supply voltage.It is shown how a cable correctly terminated at the transmitting end rather than at the receiving end can eliminate the difficulties usually associated with the use of a long cable between preamplifier and main amplifier.

ISSN:0034-6748    

DOI:10.1063/1.1715613

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

It is shown that the optimum pulse shape for driving a Schmitt trigger circuit is one in which the peak of the pulse occurs near the leading edge, followed by a linear decay to the trailing edge. The magnitude of the decay should be less than the trigger hysteresis. The circuit for obtaining such a pulse shape is shown.

ISSN:0034-6748    

DOI:10.1063/1.1715614

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

As part of the program to develop high current accelerators several model Thomas cyclotrons employing three‐phase rf were built. The three phase signal was produced by a phase generator which was excited by a crystal oscillator. Each phase was amplified and applied to the corresponding dee, which was kept in tune by means of servomechanisms. Balanced dee voltages require a symmetrical resonator with equal inter‐dee capacitances; stability of the servomechanism requires that the effective inter‐dee capacitances be zero. This last condition was fulfilled by means of neutralizing transmission lines connected from dee stem to dee stem. Thomas cyclotrons appear to be capable of producing megawatts of beam power with an rf efficiency in excess of 70&percent;.

ISSN:0034-6748    

DOI:10.1063/1.1715615

出版商:AIP    

年代:1956

数据来源: AIP