摘要:

A new electrostatic accelerator has been constructed and tested. The entire vacuum system including the accelerating tube and ion source is of bakable construction. The accelerating tube, corona tube, and support column are constructed of thin metal disks hard‐soldered to alumina ceramic rings and the insulation length of each is 5 ft. Without the accelerating tube the generator has been operated at potentials in excess of 7 Mv corresponding to gradients of over 1400 kv/ft. With flat disk molybdenum electrodes usable voltage was limited to 2.1 Mv. When these electrodes were replaced by flat disk steel electrodes having smaller beam apertures and provided with side pumpout holes, the accelerator was operated for short times at potentials in excess of 4 Mv corresponding to a tube gradient of over 800 kv/ft. There was no evidence of small discharges or electron loading in the tube. During the course of these tests three tube ceramics were cracked—probably by sparking—and it is now difficult to operate the machine at potentials much above 3.5 Mv. Voltage division is accomplished by a series of negative point‐to‐plane corona gaps which are enclosed in a tube. The charging belt is equipped with paper staples which are charged by induction. Accelerator voltage is very stable.

ISSN:0034-6748    

DOI:10.1063/1.1716367

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A gas Cˇerenkov counter is described which is suitable for charged‐particle detection in the Bev region (&bgr; from 0.980 to 0.999). Calibrations of the counting efficiency are included along with a table of indices of refraction of suitable gases. The use of this counter as a threshold detector to discriminate between elastic and inelastic pions in the momentum range of 1 to 2 Bev/c is discussed. Use of the counter to differentiate between charged particles of different mass in a momentum‐analyzed beam is also considered.

ISSN:0034-6748    

DOI:10.1063/1.1716368

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

By means of 20 and 35 Mev proton beams obtained from the University of Minnesota Linac, luminescent effects in Plexiglas Cˇerenkov detectors have been investigated. It was found that 1% of the protons entering the detector produced light pulses which overlapped the mu‐meson Cˇerenkov light distribution. These light pulses correspond to energy losses in a sodium iodide crystal of mainly less than 20 kev. Luminescent effects in the glass face of the particular photomultiplier employed were also studied and found to be quite large.

ISSN:0034-6748    

DOI:10.1063/1.1716369

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The use of beryllium copper and stainless steel in the construction of pressure vessels to contain 20 000 kg/cm2is described. Machine drawings are given for the construction of different types of pressure vessels, different types of seal, and methods of introducing electrical leads into the apparatus. Experience in the use of high‐pressure vessels and plugs beyond the elastic limit of the construction material is reviewed.

ISSN:0034-6748    

DOI:10.1063/1.1716370

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

An automatic device for tracing the wave form of a repetitive oscilloscope pattern has been developed. The wave form is accurately reproduced and enlarged by a conventional X‐Y recorder. Because optical and pulse techniques are used, the system is capable of reproducing signals displayed on even the fastest available oscilloscopes. When used with a high‐frequency traveling‐wave oscilloscope the method is applicable to phenomena in the millimicro‐second region and is capable of utilizing time resolution down to 0.1 m&mgr;sec. Deflections as small as one micron may be detected. In addition to making oscilloscope measurements faster and more convenient, certain distortions normally encountered in oscilloscopes are obviated.

ISSN:0034-6748    

DOI:10.1063/1.1716371

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A simple high‐temperature pressure‐vacuum furnace using a recrystallized alumina tube as the vessel with external resistance windings is described. Temperatures to 1900°C can be used in both strongly reducing and oxidizing atmospheres. Pressures to 28 atoms at 1200°C were obtained and no water cooling was required. Differential thermal analysis with continuous gas analysis of reaction products is made possible.

ISSN:0034-6748    

DOI:10.1063/1.1716372

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A lightweight, compact thermionic ionization gauge control is described which is simpler and more efficient than conventional units. Emission regulation is achieved by using a transistorized feedback amplifier to maintain constant emission current in the presence of variations in supply voltage and pressure. Ion current is measured from 10−8to 10−4amp, in a single range, using a Zener diode as a logarithmic element in the collector circuit. Two control units were successfully flown aboard the IGY Aerobee‐Hi rocket NN3.14F.

ISSN:0034-6748    

DOI:10.1063/1.1716373

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A method for the rapid determination of vacuum outgassing rates is described. Automatic range selection and automatic recording is used to accomplish this. Outgassing rates from 10−3 to 10−7 torr liter per second can be determined.

ISSN:0034-6748    

DOI:10.1063/1.1716374

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Experiments investigating the use of semiconductors for low‐pressure measurements proved that thermistors give the best results. These experiments led to the construction of thermistor systems consisting of miniature thermistors fixed to thin metal foils. With these systems it is possible to measure pressure changes in the range of 1 to 10−6mm Hg. The problem of temperature compensation is discussed and it is shown that in the case of thermistors this problem may be resolved by means of the voltagevscurrent characteristics. A detailed description of the apparatus, including the gauge head as well as the electric circuit and the calibration curves, is given.

ISSN:0034-6748    

DOI:10.1063/1.1716375

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A new high‐speed voltage comparator using a silicon capacitor bridge is described. For an input signal with a rate of change of 300 v/sec, the resolution is better than 1 mv. The performance of the circuit is discussed and results are given.

ISSN:0034-6748    

DOI:10.1063/1.1716376

出版商:AIP    

年代:1959

数据来源: AIP