학술논문

Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment
Document Type
article
Source
European Physical Journal C. 75(11)
Subject
Nuclear and Plasma Physics
Particle and High Energy Physics
Synchrotrons and Accelerators
Physical Sciences
astro-ph.IM
physics.ins-det
Atomic
Molecular
Nuclear
Particle and Plasma Physics
Quantum Physics
Nuclear & Particles Physics
Astronomical sciences
Atomic
molecular and optical physics
Particle and high energy physics
Language
Abstract
The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410 has been developed by Hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. We present the results from the joint effort between the XENON collaboration and the Hamamatsu company to produce a highly radio-pure photosensor (version R11410-21) for the XENON1T dark matter experiment. After introducing the photosensor and its components, we show the methods and results of the radioactive contamination measurements of the individual materials employed in the photomultiplier production. We then discuss the adopted strategies to reduce the radioactivity of the various PMT versions. Finally, we detail the results from screening 286 tubes with ultra-low background germanium detectors, as well as their implications for the expected electronic and nuclear recoil background of the XENON1T experiment.