Author/Authors :
Acosta-Kane، نويسنده , , D. and Acciarri، نويسنده , , R. and Amaize، نويسنده , , O. and Antonello، نويسنده , , M. and Baibussinov، نويسنده , , B. and Baldo-Ceolin، نويسنده , , M. and Ballentine، نويسنده , , C.J. and Bansal، نويسنده , , R. and Basgall، نويسنده , , L. and Bazarko، نويسنده , , A. and Benetti، نويسنده , , P. and Benziger، نويسنده , , J. and Burgers، نويسنده , , A. and Calaprice، نويسنده , , F. and Calligari، نويسنده ,
Abstract :
We report on the first measurement of 39Ar in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of 39Ar. The ratio of 39Ar to stable argon was measured to be ⩽ 4 × 10 - 17 (84% C.L.), less than 5% the value in atmospheric argon ( 39 Ar / Ar = 8 × 10 - 16 ). The total quantity of argon currently stored in the National Helium Reserve is estimated at 1000 tons. 39Ar represents one of the most important backgrounds in argon detectors for WIMP dark matter searches. The findings reported demonstrate the possibility of constructing large multi-ton argon detectors with low radioactivity suitable for WIMP dark matter searches.
