摘要:

The use of a pair of prisms to achieve precise pointing of an optical axis is analyzed. A sextant using prism pairs having an accuracy of 0.2″ is comfortably within the present state of the art. Even higher accuracies can be achieved at the expense of a limited maximum range in the sextant.

ISSN:0034-6748    

DOI:10.1063/1.1719546

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The operation of spark chambers with gaps of up to 40 cm has been studied. By applying electric fields of the order of 10 kV/cm particle spark tracks suitable for accurate curvature measurements have been obtained. The uniformity of the electric field represents a very important factor in determining the limit of accuracy of curvature measurements. By comparing two 40‐cm chambers located in a magnetic field against each other, it is found that the momentum of a 1‐BeV/ccosmic ray can be measured to an accuracy of ±1.4% with one 40‐cm chamber located in a 13.3‐kG magnetic field. Sensitive times of 5 &mgr;sec are typical.

ISSN:0034-6748    

DOI:10.1063/1.1719549

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

An application is considered where a beam of charged particles is passed through a large gap spark chamber. It is shown that the use of helium gas contained in a thin plastic bag in the region of the beam can reduce the efficiency of the spark chamber, in that region, to as little as 10−6or less. The efficiency for track detection outside this region is maintained at 100% with the use of a gas mixture of 89% neon, 10% helium, and 1% argon.

ISSN:0034-6748    

DOI:10.1063/1.1719550

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A calculation has been made of both the first‐ and second‐order optics of a uniform‐field circular‐pole magnet, using the impulse approximation for the fringe‐field effects. From this, the first‐ and second‐order resolution has been derived over the entire focal plane of the magnet as a function of the angle of deflection and the momentum of the particle.

ISSN:0034-6748    

DOI:10.1063/1.1719551

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A differential‐heat‐capacity calorimeter suitable for measuring the heats of thermally induced transition reactions of polymer solutions is described. The sensitivity of the calorimeter is such that an effect of 0.200 calories can be measured with a precision of ±1% on top of a large amount of heat (approximately 300 cal) needed to raise the temperature of the calorimeter 10°C.

ISSN:0034-6748    

DOI:10.1063/1.1719552

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Electrical and sputtering characteristics of a 10‐cm‐diam inverted magnetron configuration have been investigated in the transition region from positive to negative space‐charge modes. Radial voltage and ion energy distributions were obtained for both modes. The positive space‐charge mode resulted in the most efficient transport of sputtered material from cathode to anode. Dependence of space‐charge sign reversal on apparatus dimensions and magnetic field strength are discussed showing that operation in the 10−5Torr range can be expected for a 40‐cm‐diam configuration. The deposition profile at the anode was in good agreement with the calculated profile showing that ion current and hence sputtering is uniform over the effective cathode area.

ISSN:0034-6748    

DOI:10.1063/1.1719553

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

An apparatus has been built to determine the energy of each photon in a bremsstrahlung spectrum which produces an interaction of interest in a hydrogen target. The technique was applied specifically to charged pion photoproduction with photons of 2 to 5 BeV. The tagging system utilized a monoenergetic (to ± 1%) positron beam which produced photons and associated recoil positrons in a thin radiator. The recoil positrons were momentum analyzed and detected by a 19‐counter hodoscope. The difference between the energies of an incident and a recoil positron is the photon energy, and this was determined to ±2.5%. Since the photon beam is relatively weak, the interactions it produces must be detected with good efficiency. Such a large‐solid‐angle spark chamber, magnet, and counter system, which was used to measure the photoproduced pions, is also described.

ISSN:0034-6748    

DOI:10.1063/1.1719554

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A simple resistance‐heated furnace has been developed for operation at temperatures up to 2400°C in oxidizing as well as neutral or reducing atmospheres. The sample to be heated is placed in a dense zirconia tube, which is mounted inside a vertical split‐tube tantalum heating element. Any desired atmosphere may be used inside the zirconia tube without damaging the heating element, which is operated in argon. The heating element, which is also protected by the zirconia tube from attack by vapors from the sample, is surrounded by tantalum heat shields in a water‐cooled outer shell. A temperature of 2400°C was reached in a 2.22‐cm‐i.d. zirconia tube at a power level of 8 kW, and 2200°C was reached in a 3.5‐cm tube using 6.5 kW.

ISSN:0034-6748    

DOI:10.1063/1.1719555

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The hysteresis loop tracer described in this paper has two unique features: first, the pickup coil leaves one face of the film exposed thus allowing the film to be deposited while the pickup coil is in place; secondly, the high sensitivity (noise equivalent to 5×10−13Wb) allows measurements to be made on very thin films or on films having a very small saturation magnetization. The construction of the hysteresis loop tracer is discussed in detail and its effectiveness evaluated.

ISSN:0034-6748    

DOI:10.1063/1.1719556

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Five simple microwave cavities for producing discharges in gases were tested in He and H2at pressures from 1 &mgr; to 1 atm. Three of the cavities are commonly used, and two have been recently designed. One of the newly designed cavities offered a considerable improvement over early models with respect to compactness, ease of attachment to the system, and efficiency.

ISSN:0034-6748    

DOI:10.1063/1.1719557

出版商:AIP    

年代:1965

数据来源: AIP