First underground results with NEWAGE-0.3a direction-sensitive dark matter detector

A direction-sensitive dark matter search experiment at Kamioka underground laboratory with the NEWAGE-0 3a detector was performed The NEWAGE-0 3a detector is a gaseous micro-time-projection chamber filled With CF4 gas at 152 Torr. The fiducial Volume and target mass are 20 x 25 x 31 cm(3) and 0 0115 kg. respectively. With an exposure of 0 524 kg days, improved spin-dependent weakly interacting massive particle (WIMP)-proton cross section limits by a direction-sensitive method were achieved Including a new record of 5400 pb for 150 GeV/c(2) WIMPs We studied the remaining background and found that ambient gamma-rays contributed about one-fifth of the remaining background and radioactive contaminants inside the gas chamber contributed the rest. (C) 2010 Elsevier B V All rights reserved