Abstract / Description of output
The DRIFT-IId dark matter detector is a m3-scale low-pressure
TPC with directional sensitivity to WIMP-induced nuclear recoils. Its
primary backgrounds were due to alpha decays from contamination on the
central cathode. Efforts to reduce these backgrounds led to replacing
the 20 μm wire central cathode with one constructed from 0.9 μm
aluminized mylar, which is almost totally transparent to alpha
particles. Detailed modeling of the nature and origin of the remaining
backgrounds led to an in-situ, ppt-sensitive assay of alpha decay
backgrounds from the central cathode. This led to further improvements
in the thin-film cathode resulting in over 2 orders of magnitude
reduction in backgrounds compared to the wire cathode. Finally, the
addition of O2 to CS2 gas was found to produce
multiple species of electronegative charge carriers, providing a method
to determine the absolute position of nuclear recoils and reject all
known remaining backgrounds while retaining a high efficiency for
nuclear recoil detection.
Original language | English |
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Pages (from-to) | 130-137 |
Journal | Physics Procedia |
Volume | 61 |
Publication status | Published - 2014 |
Keywords / Materials (for Non-textual outputs)
- Radon
- Dark Matter
- TPC
- DRIFT