The initial beam diameter (4 mm) was reduced to 80 Î¼m. However, this spatial resolution is not high enough. To focus beam more, a small positron source should be fabricated. In this work, we developed a positron microbeam by a small source, a solid neon moderator, magnetic lenses and a SEM optics. In addition, a beam pulsing system was also developed which allows the positron annihilation lifetime spectroscopy (PALS) measurement.
The first American to orbit the Earth, John Glenn made history again when, at the age of 77, he became the oldest person to travel in space. But before he was nationally recognized as a hero, he had put his life on the line for his country many times.
John Glenn became the first American to orbit the Earth when he blasted off from Floridaâs Cape Canaveral on February 20, 1962. Seven years later, Neil Armstrong became the first man to walk on the moon after Apollo 11 was launched from the nearby Kennedy Space Center on July 16, 1969.