Formation of ultra slow positron beam and upgrading of material evaluation by using it

The Electrotechnical Laboratory had developed a technique to form and control slow positron beam with high intensity by using high energy electron beam of an electron beam accelerator (LINIAC), succeeded in formation of positron ultra short pulse beam with the highest intensity in the world, developed measuring technique like positron annihilation excitation Auger electron spectroscopy by using positron life and flight time measurements and promoted some studies on their applications. For an aim at formation of ultra slow positron beam, in 1996 fiscal year, trial production of the positron ultra slow realization equipment and experiment of its application, experiment on high efficiency positron modulator, development of positron beam ultra short pulse making equipment for variable incident energy positron life measurement, and study on upgrading of flight time type high resolution positron annihilation excitation Auger electron spectrometer were conducted. As a result, it was confirmed to realize ultra slowness of positron as expected, but its efficiency was only about 20%. Then, a new positron converter modulator was designed and study on some modulator materials for this was conducted to select an optimum one. (G.K.)