摘要:

A method is described for the reliable production of reproducible multilayered targets for laser ablation rate studies using time‐resolved x‐ray spectroscopy. The targets consist of alternating layers of plastic and evaporated metals whose thickness and uniformity were examined by weighing and by SEM micrography to be suitable for experiments. The plastic layers are deposited by a dipping technique using various concentrations of polystyrene and Formvar solutions. The resulting thickness of the films versus the concentration of the solutions is reported. In addition, an application of submicrometer Formvar films for use as sub‐keV x‐ray filters is described.

ISSN:0034-6748    

DOI:10.1063/1.1139070

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Slowly changing signals will appear on an oscilloscope as a moving dot. A circuit is described which permits such waveforms to be fully displayed in real time. The oscilloscope screen functions as a window across which the signal scrolls at a user selectable rate.

ISSN:0034-6748    

DOI:10.1063/1.1139071

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We describe a scanning tunneling microscope which is extremely compact and rigid. Neither springs nor stacks of metal plates and rubber are necessary for vibration isolation. It can resolve the atomic structure of graphite at room and liquid‐helium temperatures. Its small size permits it to be dipped into a standard liquid‐helium storage Dewar.

ISSN:0034-6748    

DOI:10.1063/1.1139072

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A Faraday cup has been designed and tested to measure the ion current density in an intense ion beam immersed in a strong magnetic field. The ion flux is charge neutralized by a low‐energy codrifting electron beam. The codrifting electrons are deflected from the cup by use of an apertured magnetic plate at the entrance to the cup. Comparison of the integrated Faraday cup traces with the proton flux found from carbon activation measurements show that the ion Faraday cup consistently measured 59%±8% of the protons.

ISSN:0034-6748    

DOI:10.1063/1.1139073

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We describe a capacitive probe for the observation of high‐voltage fast pulses (1–100 kV, 1 to 10 ns) and we also show the results of some tests performed on a prototype. The probe is extremely simple and cheap, easy to build by small research groups. The attenuation factor can be adjusted through a simple operation which does not require substitution of components.

ISSN:0034-6748    

DOI:10.1063/1.1139074

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new single‐shot hydrogen pellet injector based on a simple ‘‘pipe gun’’ design is described. In the cryogenic gun block, the 4‐mm‐diam (nominal) pellet is frozeninsitudirectly from the gaseous hydrogen isotope and then accelerated in the gun barrel with a burst of high‐pressure (≤130‐bar) hydrogen gas to speeds of up to 1680 m/s.

ISSN:0034-6748    

DOI:10.1063/1.1139214

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Absolute temperature coefficients of the quantum efficiency of the bialkali photocathode in RCA 8850 photomultiplier tubes (PMTs) have been measured precisely as a function of wavelength over a range of 520–700 nm, using the photon‐counting technique. The measurements were greatly facilitated by particular features of the experimental apparatus and techniques employed.

ISSN:0034-6748    

DOI:10.1063/1.1139075

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The design and performance of a simple sputter ion gun is given. It uses a commercial Bayard–Alpert ionization gauge. A two‐stage extraction and acceleration system provides a variable beam profile as well as high currents at low energies (>1 &mgr;A above 200 eV). At a distance of 4 cm from the end of the gun a current density of more than 150 &mgr;A/cm2was obtained at 1.2 keV. A narrow energy distribution may also be obtained (≤1.6 eV FWHM at 1.2 keV).

ISSN:0034-6748    

DOI:10.1063/1.1139076

出版商:AIP    

年代:1986

数据来源: AIP