摘要:

A new sensitive x‐ray monochromator and detector system for performing extended x‐ray absorption fine structure (EXAFS) measurements in the laboratory is described. The monochromator combines x‐ray focusing optics with rapid elemental tunability. The detection system effectively removes glitches from the data stream, regardless of whether they are due to impurity lines from the x‐ray source or if they are due to random instabilities in the incident beam. Used together with a high intensity rotating anode x‐ray source, this system can provide synchrotronlike photon intensities, flexibility and resolution, with the easy access and control possible only in the laboratory.

ISSN:0034-6748    

DOI:10.1063/1.1136199

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

An electronic system for processing and recording some very important parameters of acoustic emission signals at a relatively high speed is described. The system is applicable to almost any process in which acoustic emission is implemented for quality control. Data processing is done in real time. The processed data are ring‐down count (threshold crossing), energy, duration, and time of occurrence of each acoustic emission burst.

ISSN:0034-6748    

DOI:10.1063/1.1136200

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A small rail gun with a barium electrode can be operated at higher than one shot per second to produce more than 2×1016barium ions with energy 10–20 eV. The operation of the gun takes advantage of the external magnetic field for cross‐field plasma injection into a trap. Up to 7 kG of the magnetic field examined, the gun performance improves with the increased magnetic field strength.

ISSN:0034-6748    

DOI:10.1063/1.1136201

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Using a triple‐pass plane and a confocal Fabry–Pe´rot interferometers in tandem, we have constructed a Brillouin spectrometer with a frequency resolution of 108and a contrast of more than 1010. Our system is controlled and fully stabilized by a desktop calculator, allowing efficient data collection for very long integration times.

ISSN:0034-6748    

DOI:10.1063/1.1136202

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A prototype framing x‐ray camera has been developed for photographic studies of inertial confinement fusion (ICF) targets irradiated by charged particle beams. Electron images from five, independently gated, microchannel plates are transported out of the radiation field by means of a toroidal magnetic field and are permanently recorded on film. The calculated, effective exposure time is ⩽5 ns (FWHM), and the resolution at the object is presently limited by the x‐ray pinhole optics to ∼0.5 mm. Time‐resolved photographic studies have been made of luminous targets irradiated by pulsed electron and ion beams. The camera has also been adapted for single frame, x‐radiographic studies of nonluminous imploding targets.

ISSN:0034-6748    

DOI:10.1063/1.1136203

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

An interface which enables data transfer to or from a microcomputer is described. Data transfer from an analyser uses the printer output under interface control. To put the processed data into a form acceptable to the analyser, the output of the microcomputer is converted by the interface into pulses the number of which is proportional to the binary‐coded data.

ISSN:0034-6748    

DOI:10.1063/1.1136204

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A method for measuring the thickness of a very thin oxide layer by secondary electron emission is described. The secondary electron signals are measured for an oxide‐covered silicon surface and a reference surface by using the line mode of scanning electron microscope. Then, their ratio correlates well with the thickness of oxide layer, and it is demonstrated that the thickness of an oxide layer can be obtained by measuring the ratio &ggr;. At the beam energy of 2 keV, the measurable thickness lies within the range of 15–150 A˚. The lower limit is due to the natural oxide remaining on the reference‐silicon surface and the upper limit to charging effects of oxide layers. A remarkable feature of this method is that an oxide thickness localized in a very small area is measurable, and the measurement is carried out for an oxide deposided in 0.1‐mm‐wide ditches.

ISSN:0034-6748    

DOI:10.1063/1.1136205

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A complete system is described for the measurement of the distribution of energy emanating from laser-produced plasmas in the form of (1) plasma blowoff (ions, electrons, neutral particles, and x rays), and (2) scattered laser light. The detectors consist of small modules containing two differential calorimeters in one package, one for each form of energy. Modular autozeroing amplifiers enable the slowly varying signals to be measured by computer with the aid of CAMAC analog to digital converters. The computer is also capable of absolutely calibrating the unitsinsitu. The programs used to record and display the data, and to calculate the fraction of laser energy absorbed, are described.

ISSN:0034-6748    

DOI:10.1063/1.1136206

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

We have designed an inexpensive instrument for automatically measuring time of flight for repetitive signals. It is stable in the presence of noise resembling the real signal. Specific peaks in a multipeak signal can be timed to an accuracy of about 10 ns with the present design. The output is either a digital word or an analog voltage. Computer control is simple and would make it possible to time several signals with the same instrument.

ISSN:0034-6748    

DOI:10.1063/1.1136207

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The standing vortices behind a circular cylinder have been visualized by means of direct shadows produced in glycerin–water solutions, and the length of the vortices has been measured. It has been thereby confirmed that the method is applicable to visualize the closed regions of standing vortices correctly. The shadow pattern over the whole flow field, however, seems to correspond to none of the patterns of common hydrodynamic lines.

ISSN:0034-6748    

DOI:10.1063/1.1136208

出版商:AIP    

年代:1980

数据来源: AIP