4 research outputs found
Gadolinium concentration measurement with an atomic absorption spectrophotometer
Because gadolinium (Gd) has the highest thermal neutron capture cross
section, resulting in an 8 MeV gamma cascade upon capture, it has been proposed
for dissolution in water Cherenkov detectors to achieve efficient neutron
tagging capabilities. While metallic Gd is insoluble in water, several
compounds are very easy to dissolve. Gadolinium sulfate, Gd(SO),
has been thoroughly tested and proposed as the best candidate. Accurate
measurement of its concentration, free of doubt from impurities in water, is
crucial. An atomic absorption spectrophotometer (AAS) is a device that suits
this purpose and is widely used to measure the concentration of many elements.
In this study, we describe three different approaches to measure Gd sulfate
concentrations in water using an AAS: doping samples with potassium and
lanthanum, and employing tantalum and tungsten platforms
Combined Pre-Supernova Alert System with Kamland and Super-Kamiokande
International audiencePreceding a core-collapse supernova, various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande via inverse beta decay interactions. Once these pre-supernova neutrinos are observed, an early warning of the upcoming core-collapse supernova can be provided. In light of this, KamLAND and Super-Kamiokande have been monitoring pre-supernova neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and Super-Kamiokande on pre-supernova neutrino detection. A pre-supernova alert system combining the KamLAND detector and the Super-Kamiokande detector is developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-supernova neutrino signal from a 15 M star within 510 pc of the Earth, at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hours in advance