Hornback, D. | Search NASA

DOE OSTI2017

Observation of coherent elastic neutrino-nucleus scattering

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. In this paper, we observed this process at a 6.7σ confidence level, using a low-background, 14.6-kilogram CsI[Na] scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Finally, improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2015

Event localization in bulk scintillator crystals using coded apertures

Not Available

Ziock, K. P.↗

DOE OSTI2015

Three-Dimensional Event Localization in Bulk Scintillator Crystals Using Optical Coded Apertures

Scintillator-based detectors are among the most commonly used methods for detecting ionizing radiation. Scintillators provide a reliable, cost-effective, and simple way to make large-volume detectors. Furthermore, localizing the position of the interactions in three dimensions within the crystals is useful to a wide array of fields. The most straightforward way of doing this is to pair the crystal with a position-sensitive phototransducer (PT). This allows for measurement of the shape of the light spot at the PT plane. Using this information, various methods exist to localize the gamma-ray interaction in the crystal; however, the position resolution worsens the farther the event occurs from the PT plane. To improve on the localization ability, this work uses an optical coded-aperture shadow mask between the crystal and the PT. In addition, the recorded detector response is used in reconstructing the event over the entire depth of the crystal, and the “sharpest” reconstructed image gives an event's depth. The lateral position is given from the standard coded-aperture image reconstruction. Lastly, experimental results obtained by emulating a 26-mm-thick crystal using a thin 1-mm-thick NaI(Tl) crystal and different amounts of light pipe between the crystal and the PT plane achieved ~ 1 to 2-mm resolution in all three dimensions throughout most of the 26-mm-thick crystal.

36 MATERIALS SCIENCE↗