AMoRE: A search for neutrinoless double-beta decay of 100Mo using low-temperature molybdenum-containing crystal detectors

The AMoRE is an experiment to search for neutrinoless double-beta decay of 100Mo in molybdate crystal scintillators using a cryogenic detection technique. The crystals are equipped with metallic magnetic calorimeter sensors that detect both phonon and photon signals at temperatures of a few tens of mK. Simultaneous measurements of thermal and scintillation signals produced by particle interactions in the crystals by MMC sensors provide high energy resolution and efficient particle discrimination. AMoRE-Pilot, an R&D phase with six 48deplCa100MoO4 crystals and a total mass of ~1.9 kg in the final configuration, operated at the 700 m deep Yangyang underground laboratory (Y2L). After completion of the AMoRE-Pilot run at the end of 2018, AMoRE-I with a ~6 kg crystal array comprised of thirteen 48deplCa100MoO4 and five Li2100MoO4 crystals is currently being assembled and installed at Y2L. We have secured 110 kg of 100Mo-isotope-enriched MoO3 powder for the production of crystals for the AMoRE-II phase, which will have ~200 kg of molybdate crystals and operate at Yemilab, a new underground laboratory located ~1,100 m deep in the Handeok iron mine that is currently being excavated and with a scheduled completion date of December 2020. AMoRE-II is expected to improve the upper limit on the effective Majorana neutrino mass to cover the entire inverted hierarchy neutrino mass region: 20-50 meV, in the case when no such decays are observed. Results from AMoRE-Pilot and progress of the preparations for AMoRE-I and AMoRE-II are presented.Comment: 10 pages, 4 figures, INSTR'20 conference (Novosibirsk, Feb. 24-28, 2020

A facility for mass production of ultra-pure NaI powder for the COSINE-200 experiment

COSINE-200 is the next phase of the ongoing COSINE-100 experiment. The main purpose of the experiment is the performance of an unambiguous verification of the annual modulation signals observed by the DAMA experiment. The success of the experiment critically depends on the production of a 200 kg array of ultra-pure NaI(Tl) crystal detectors that have lower backgrounds than the DAMA crystals. The purification of raw powder is the initial but important step toward the production of ultra-pure NaI(Tl) detectors. We have already demonstrated that fractional recrystallization from water solutions is an effective method for the removal of the problematic K and Pb elements. For the mass production of purified powder, a clean facility for the fractional recrystallization had been constructed at the Institute for Basic Science (IBS), Korea. Here, we report the design of the purification process, material recovery, and performance of the NaI powder purification facility.Comment: Proceeding for INSTR20, accepted in JINS

Transcriptional Regulator TonEBP Mediates Oxidative Damages in Ischemic Kidney Injury

TonEBP (tonicity-responsive enhancer binding protein) is a transcriptional regulator whose expression is elevated in response to various forms of stress including hyperglycemia, inflammation, and hypoxia. Here we investigated the role of TonEBP in acute kidney injury (AKI) using a line of TonEBP haplo-deficient mice subjected to bilateral renal ischemia followed by reperfusion (I/R). In the TonEBP haplo-deficient animals, induction of TonEBP, oxidative stress, inflammation, cell death, and functional injury in the kidney in response to I/R were all reduced. Analyses of renal transcriptome revealed that genes in several cellular pathways including peroxisome and mitochondrial inner membrane were suppressed in response to I/R, and the suppression was relieved in the TonEBP deficiency. Production of reactive oxygen species (ROS) and the cellular injury was reproduced in a renal epithelial cell line in response to hypoxia, ATP depletion, or hydrogen peroxide. The knockdown of TonEBP reduced ROS production and cellular injury in correlation with increased expression of the suppressed genes. The cellular injury was also blocked by inhibitors of necrosis. These results demonstrate that ischemic insult suppresses many genes involved in cellular metabolism leading to local oxidative stress by way of TonEBP induction. Thus, TonEBP is a promising target to prevent AKI

Measurement of the Background Activities of a 100Mo-enriched powder sample for AMoRE crystal material using a single high purity germanium detector

The Advanced Molybdenum-based Rare process Experiment (AMoRE) searches for neutrino-less double-beta (0{\nu}\b{eta}\b{eta}) decay of 100Mo in enriched molybdate crystals. The AMoRE crystals must have low levels of radioactive contamination to achieve low background signals with energies near the Q-value of the 100Mo 0{\nu}\b{eta}\b{eta} decay. To produce low-activity crystals, radioactive contaminants in the raw materials used to form the crystals must be controlled and quantified. 100EnrMoO3 powder, which is enriched in the 100Mo isotope, is of particular interest as it is the source of 100Mo in the crystals. A high-purity germanium detector having 100% relative efficiency, named CC1, is being operated in the Yangyang underground laboratory. Using CC1, we collected a gamma spectrum from a 1.6-kg 100EnrMoO3 powder sample enriched to 96.4% in 100Mo. Activities were analyzed for the isotopes 228Ac, 228Th, 226Ra, and 40K. They are long-lived naturally occurring isotopes that can produce background signals in the region of interest for AMoRE. Activities of both 228Ac and 228Th were < 1.0 mBq/kg at 90% confidence level (C.L.). The activity of 226Ra was measured to be 5.1 \pm 0.4 (stat) \pm 2.2 (syst) mBq/kg. The 40K activity was found as < 16.4 mBq/kg at 90% C.L.Comment: 20 pages, 6 figures, 5 table

Radon Concentration Measurement with a High-Sensitivity Radon Detector at the Yemilab

The radiation emitted from radon is a critical background in rare event search experiments conducted at the Yemi Underground Laboratory (Yemilab) in Jeongseon, Korea. A Radon Reduction System(RRS) has been developed and installed in Yemilab to reduce radon concentration in the air. The RRS primarily provides a purified air of 50 m3/h to the cleanroom used to assemble crystal detectors in the AMoRE, a neutrinoless double beta decay search experiment. RRS can reduce the radon level by a factor of 300, so a high-sensitivity radon detector was required. A highly sensitive radon detector was constructed using a 70 L chamber with a large PIN photodiode to measure radon concentration in the purified air. The radon detector shows an excellent resolution of 72 keV (FWHM) for 6.003 MeV alphas from 218Po decay and a sensitivity down to 23.8 +- 2.1 mBq/m3 with a boil-off N2 gas sample. The radon concentration level from the RRS measured by the radon detector was below 0.29 Bq/m3 with a reduction factor of about 300.Comment: 16 pages, 12 figures, 2 tables, to be published in JINS

The Neuroprotective Effect of Methanol Extract of Gagamjungjihwan and Fructus Euodiae on Ischemia-Induced Neuronal and Cognitive Impairment in the Rat

Gagamjungjihwan (GJ), a decoction consisting of five herbs including ginseng, Acori Graminei Rhizoma, Uncariae Ramulus et Uncus, Polygalae Radic and Frustus Euodiae (FE), has been widely used as herbal treatment for ischemia. In order to investigate the neuroprotective action of this novel prescription, we examined the influence of GJ and FE on learning and memory using the Morris water maze and studied their affects on the central cholinergic system in the hippocampus with neuronal and cognitive impairment. After middle cerebral artery occlusion was applied for 2 h, rats were administered GJ (200 mg kg−1, p.o.) or FE (200 mg kg−1, p.o.) daily for 2 weeks, followed by training and performance of the Morris water maze tasks. Rats with ischemic insults showed impaired learning and memory of the tasks. Pre-treatment with GJ and FE produced improvement in the escape latency to find the platform. Pre-treatments with GJ and FE also reduced the loss of cholinergic immunoreactivity in the hippocampus. The results demonstrated that GJ and FE have a protective effect against ischemia-induced neuronal and cognitive impairment. Our results suggest that GJ and FE might be useful in the treatment of vascular dementia