FALL-OUT IS TWICE PREVIOUS BLAST

Press, Volume CV, Issue 31057, 12 May 1966, Page 19

FALL-OUT IS TWICE PREVIOUS BLAST

t-V z. Press Association—Copyright)

TOKYO, May 11. Radioactive fall-out described as twice as strong as that recorded alter China’s second atomic blast was reported today on the Japan Sea coast opposite the China mainland.

Scientists at Japan’s Niigata University, on the northern sea coast, said the fall-out reached Japan half a day earlier than expected.

This morning the scientists detected more than 20 giant particles whose maximum Geiger count was an estimated 500.000 counts a minute, against the maximum of 15.000 counts a minute recorded after China’s second nuclear blast on May 14 last vear.

They said the fallout was believed to have been carried to Japan by an eastward jet stream four to five miles above the earth.

Radioactive particles of less counts were also detected in other parts of Japan such as Akita, northern Japan, and Osaka, western Japan.

Scientists said they had detected zirconium 97, niobium (columbium) 97, molybdenum 99 and neptunium 239 but added it would take about two weeks before determining what kind of bomb China had exploded.

The readings came less than 48 hours after the

Chinese exploded their third nuclear bomb which they claimed contained “thermonuclear elements.” The scientists said that one of the giant particles collected overnight registered a radioactivity of between 30,000 and 100,000 micromicrocuries. Dust Collector The ordinary radioactive content of a litre of rainwater is between lOf and 1000 micro-microcuries. Professor Takao Kosaka, of Niigata University’s public [health department, said an i electric dust collector and [other instruments were set [up on the roof of the univerIsity to collect debris from [the bomb. i Nine rabbits and 60 mice i were exposed to the radioi active atmosphere.

They will be dissected to check their blood and bone chemistry. Higher Yield As atomic experts analysed the still preliminary information on the Chinese explosion today it became apparent that the United States had underestimated the force of the explosion. The initial estimate, offered yesterday by the State Department in announcing the Chinese test, was that the

explosion was “in the same general range” as the two earlier tests, which had yields of about 20 kilotons, or the equivalent of 20,000 tons of T.N.T. But on re-examination of the initial data and on the basis of additional information on the test, United States analysts concluded today that the yield was between 100 and 200 kilotons and probably around 130 kilotons. Later Analysis The initial estimates are based on measurements, made by instruments hundreds or thousands of miles away from the test site in Sinkiang province in north-western China, of the seismic, acoustical and electromagnetic waves generated by the explosion. Until radioactive debris picked up by United States planes in the next few days is analysed, United States officials will have no certain '•answer to the type of bomb.