منابع مشابه
Analytical methods using a positron microprobe.
Positrons have been used for material analysis not only because of their novel characteristics, such as an ability to detect open-volume type defects in materials, but also because interactions with solids differ from those of electrons in such processes as scattering and diffraction. Monoenergetic positron beams and microbeams were developed in the 1980s, and positron experiments have made pro...
متن کاملA High Current, High Gradient, Laser Excited, Pulsed Electron Gun
This paper describes a pulsed electron gun that can be used as an FEL, as an injector for electron linear accelerators or for rf power generation. It comprises a 1 to 5 MeV, 1 to 2 ns pulsed power supply feeding a single diode, photoexcited acceleration gap. Beam quality of a ~ 1nC charge in ~ 1 GV/m field was studied. Computations of the beam parameters as a function of electrode configuration...
متن کاملProduction of a positron microprobe using a transmission remoderator.
A production method for a positron microprobe using a beta+-decay radioisotope (22Na) source has been investigated. When a magnetically guided positron beam was extracted from the magnetic field, the combination of an extraction coil and a magnetic lens enabled us to focus the positron beam by a factor of 10 and to achieve a high transport efficiency (71%). A 150-nm-thick Ni(100) thin film was ...
متن کاملHigh Current Density Pulsed Cathode Experiments at Slac
A 1.9 microperveance beam diode has been constructed to test high current density cathodes for use in klystrons. Several standard and specially coated dispenser cathodes are being tested. Results of tests to date show average cathode current densities in excess of 25 amps/cm, and maximum electric field gradients of more than 450 kV/ cm. for pulses of the order of 1 /'sec.
متن کاملDevelopment of a high-efficiency pulsed slow positron beam for measurements with orthopositronium in vacuum
We have developed a high-efficiency pulsed slow positron beam for experiments with orthopositronium in vacuum. The new pulsing scheme is based on a double-gap coaxial buncher powered by an RF pulse of appropriate shape. The modulation of the positron velocity in the two gaps is used to adjust their time-of-flight to a target. This pulsing scheme allows to minimize non-linear aberrations in the ...
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ژورنال
عنوان ژورنال: Materials Science Forum
سال: 1997
ISSN: 1662-9752
DOI: 10.4028/www.scientific.net/msf.255-257.644