First measurement of surface nuclear recoil background for argon dark matter searches

One major background in direct searches for weakly interacting massive particles (WIMPs) comes from the deposition of radon progeny on detector surfaces. A dangerous surface background is the Pb206 nuclear recoils produced by Po210 decays. In this paper, we report the first characterization of this...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. D 2017-09, Vol.96 (6), Article 061101
Main Authors: Xu, Jingke, Stanford, Chris, Westerdale, Shawn, Calaprice, Frank, Wright, Alexander, Shi, Zhiming
Format: Article
Language:English
Subjects:
Argon
Dark matter
Energy measurement
NUCLEAR PHYSICS AND RADIATION PHYSICS
PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Progeny
Pulse shape
Radon
Recoil
Searching
Weakly interacting massive particles
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:One major background in direct searches for weakly interacting massive particles (WIMPs) comes from the deposition of radon progeny on detector surfaces. A dangerous surface background is the Pb206 nuclear recoils produced by Po210 decays. In this paper, we report the first characterization of this background in liquid argon. The scintillation signal of low energy Pb recoils is measured to be highly quenched in argon, and we estimate that the 103 keV Pb206 recoil background will produce a signal equal to that of a ∼5  keV (30 keV) electron recoil (Ar40 recoil). In addition, we demonstrate that this dangerous Po210 surface background can be suppressed, using pulse shape discrimination methods, by a factor of ∼100 or higher, which can make argon dark matter detectors near background-free and enhance their potential for discovery of medium- and high-mass WIMPs. We also discuss the impact on other low background experiments.
ISSN:2470-0010
2470-0029
DOI:10.1103/PhysRevD.96.061101