摘要:

A description of a thin aluminum foil spark chamber spectrometer is given. The magnet has two sets of slots to allow 90° stereo views for photography. A discussion is presented on its characteristics as well as its possible use for the measurement of high‐energy &ggr; rays.

ISSN:0034-6748    

DOI:10.1063/1.1720911

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A simple gating method for photomultipliers is presented. The very high cutoff efficiency of the gate, its linearity, and the absence of spurious effect are shown by measurements taken on a RCA 7265 tube by using a pulsed and a cw light source in the S‐11 spectrum. This method has been found to be very useful in experiments of molecular physics where a weak spontaneous radiation to be detected is associated with a very intense pulse of stimulated radiation arising from a laser induced, coherent excitation of the medium.

ISSN:0034-6748    

DOI:10.1063/1.1720912

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A fiber optic window has been fitted to a stainless steel field ion microscope permitting the use of direct contact photography for recording the image. The elimination of intermediate optics coupled with the use of large format sheet film results in shorter exposure times and increased quality of the field ion micrograph. The fiber optic window itself is briefly described along with some experimental results.

ISSN:0034-6748    

DOI:10.1063/1.1720913

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A simple cell in combination with a mass spectrometer and multichannel recorder provides interesting approaches to the study of gas diffusion and electrical phenomena in solids. The apparatus permits (1) studies of the directional dependence of gas diffusion in a solid, (2) observation of the effect of electric fields on gas diffusion in solids, and (3) simultaneous measurements of electrical conduction and gas diffusion in solids. It also appears that this apparatus may yield information about the energy states occupied by rare gas impurity atoms in ionic crystals.

ISSN:0034-6748    

DOI:10.1063/1.1720914

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A large cloud‐chamber‐ion‐chamber stack has been designed and operated to measure the properties of the interactions in light materials of cosmic‐ray protons and pions in the energy range greater than 140 GeV. The usable flux of these particles at sea level is limited to the measured value of (1.3±0.1)×10−4m−2ster−1sec−1by the requirement that each particle be unaccompanied by time‐coincident particles in the aperture of the apparatus of 0.22 m2‐ ster. With the use of this flux and the apparatus described, an interaction cross section for protons in carbon can be measured for energies up to 300 GeV in about a year. In the use of the ionization spectrometer, large fluctuations in the absorption curve have been observed that preclude the use of the shape of the curve alone to measure the energy of individual events.

ISSN:0034-6748    

DOI:10.1063/1.1720915

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Spatial separation of undesired particle components from high energy kaon, pion, and antiproton beams is achieved by means of an rf separator consisting of two transverse deflectors, set 40 m apart and operated at 2.856 GHz. Elimination of two contaminants is possible if their difference in transit time between deflectors equals a multiple of one rf cycle. In the system described this occurs, for example, at 12.80, 9.04, and 7.38 GeV/c if kaons are desired. The actual useful beam system involves the magnetic optics necessary to form a momentum analyzed beam with &Dgr;p/p=1% and to transport the particles over 129 m between an external target at the Brookhaven Alternating‐Gradient Synchrotron and the 80 Inch Bubble Chamber. The design of the magnetic optics for the momentum analysis section, the separator stage, and the post analysis section is discussed. For proper operation, the rf beam separator described requires deflectors which are capable of imparting a transverse momentumpT≥18 MeV/c to traversing particles. A 3 m long iris‐loaded structure operating in a backward wave hybrid mode with dipole character was selected. The necessary multi‐MW rf pulses are generated by a microwave system which consists of a phase locked source, TWT, triode, and klystron amplifiers, as well as associated modulators. A phase servo maintains the prescribed phase relationship between deflectors. The separated beam has been tested and run as kaon and pion beams. The system has, in general, performed according to expectations. Preliminary performance data indicate for example at 12.8 GeV/c an average yield of eight K−mesons per pulse with 0±15% background.

ISSN:0034-6748    

DOI:10.1063/1.1720916

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Two types of phase sensitive detection systems which have been used up to 130 Mc are described. The first utilizes a wideband amplifier and a single phase detector to provide a system which is continuously tuneable between 1 and 130 Mc. The second uses two phase detectors in quadrature to obtain the vector representation of a wave, and extends by three orders of magnitude the frequency range of previously available apparatus. Below 100 Mc, the equivalent input noise of these systems is less than 5×10−8V rms.

ISSN:0034-6748    

DOI:10.1063/1.1720917

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

It is shown that any bilateral voltage divider may be operated backwards as a current divider in the Ayrton shunt mode (Julie element). The use of Poggendorff's second ``compensation'' method in the construction of constant resistance potentiometers is surveyed. A design of a constant resistance potentiometer (Julie nanovolt potentiometer) using a constant current source in conjunction with a Kelvin‐Varley slide operating as a current divider is described and its advantages discussed. Applications are suggested for constant current sources used with current dividers. These are (a) simplified potentiometers, (b) defection potentiometers, (c) self balancing potentiometers, (d) servo error detectors, and (e) current balances. The symmetry of Poggendroff's two methods is indicated.

ISSN:0034-6748    

DOI:10.1063/1.1720918

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The highly convergent fringing field produced by a 100 kVA C‐magnet has been used to guide electrons emitted at a source around a 90° arc to a Si(Li) detector. This source‐detector configuration is often desirable because it enables the electron detector to be effectively shielded from other radiations emitted at the source. The electron motion in this device consists of a superposition of a trochoidal motion and a vertical oscillation through the magnet symmetry plane. The high detection efficiency of the system (∼5%) makes it particularly well suited for applications in electron coincidence experiments. Utilization of the device in a study of internal conversion in coincidence with fission is described, and several other applications are suggested.

ISSN:0034-6748    

DOI:10.1063/1.1720919

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

An apparatus utilizing a photocell detection system was designed and built to measure the force required to crush a spherical particle 0.05 to 0.5 mm in diameter. The force applied to the particle causes a variation in light area on two matched photocells. The signal from the unbalance in the photocells is recorded without amplification on a millivolt recorder as the particle is crushed. Standardization is accomplished by placing known weights on the apparatus and measuring the displacement on a recorder. The apparatus can be used to measure crush strengths from 0.080 to 2500 g.

ISSN:0034-6748    

DOI:10.1063/1.1720920

出版商:AIP    

年代:1967

数据来源: AIP