Concentration of Atmospheric 7Be in Tsukuba, Japan

Concentration of 7Be in surface air was measured at Tsukuba Science City(36deg. 03min. N, 140deg. 07min. E), Japan, during the period of Jan. 1987 to Oct. 1992. Aerosol samples were collected by glass fiber filters using a high volume air sampler. Radioactivity was determined by 477-KeV gamma-ray with HPGe. The air concentration of 7Be ranged from 1 -> 6mBq/m3. Seasonal variation was observed: high concentration appeared in spring and in fall.The "two-peak" variation pattern observed for 7Be concentration is similar to the seasonal variation pattern of atmospheric ozone concentration observed on the summit of Mt. Tsukuba(868m).