36 research outputs found
Development of low-threshold detectors for low-mass dark matter searches with a p-type germanium detector operated at cryogenic temperature
This study investigates new technology for enhancing the sensitivity of
low-mass dark matter detection by analyzing charge transport in a p-type
germanium detector at 5.2 K. To achieve low-threshold detectors, precise
calculations of the binding energies of dipole and cluster dipole states, as
well as the cross-sections of trapping affected by the electric field, are
essential. The detector was operated in two modes: depleted at 77 K before
cooling to 5.2 K and cooled directly to 5.2 K with various bias voltages. Our
results indicate that the second mode produces lower binding energies and
suggests different charge states under varying operating modes. Notably, our
measurements of the dipole and cluster dipole state binding energies at zero
fields were meV and meV, respectively. These
findings have strong implications for the development of low-threshold
detectors for detecting low-mass dark matter in the future.Comment: 7 pages, 8 figures. arXiv admin note: substantial text overlap with
arXiv:2302.0841
Development of Low-Threshold Detectors for Low-Mass Dark Matter Searches Using an N-Type Germanium Detector at 5.2 K
We investigated charge transport in an n-type germanium detector at 5.2 K to
explore new technology for enhancing low-mass dark matter detection
sensitivity. Calculations of dipole and cluster dipole state binding energies
and electric field-dependent trapping cross-sections are critical to developing
low-threshold detectors. The detector operates in two modes: depleting at 77K
before cooling, or directly cooling to 5.2 K and applying different bias
voltages. Results indicated lower binding energy of charge states in the second
mode, at zero field and under an electric field, suggesting different charge
states formed under different operating modes. Measured cluster dipole and
dipole state binding energies at zero field were 7.8840.644 meV and
8.3690.748 meV, respectively, signifying high low-threshold potential for
low-mass dark matter searches in the future.Comment: 7 pages, 8 figure
Olfactory deficit: a potential functional marker across the Alzheimer’s disease continuum
Alzheimer’s disease (AD) is a prevalent form of dementia that affects an estimated 32 million individuals globally. Identifying early indicators is vital for screening at-risk populations and implementing timely interventions. At present, there is an urgent need for early and sensitive biomarkers to screen individuals at risk of AD. Among all sensory biomarkers, olfaction is currently one of the most promising indicators for AD. Olfactory dysfunction signifies a decline in the ability to detect, identify, or remember odors. Within the spectrum of AD, impairment in olfactory identification precedes detectable cognitive impairments, including mild cognitive impairment (MCI) and even the stage of subjective cognitive decline (SCD), by several years. Olfactory impairment is closely linked to the clinical symptoms and neuropathological biomarkers of AD, accompanied by significant structural and functional abnormalities in the brain. Olfactory behavior examination can subjectively evaluate the abilities of olfactory identification, threshold, and discrimination. Olfactory functional magnetic resonance imaging (fMRI) can provide a relatively objective assessment of olfactory capabilities, with the potential to become a promising tool for exploring the neural mechanisms of olfactory damage in AD. Here, we provide a timely review of recent literature on the characteristics, neuropathology, and examination of olfactory dysfunction in the AD continuum. We focus on the early changes in olfactory indicators detected by behavioral and fMRI assessments and discuss the potential of these techniques in MCI and preclinical AD. Despite the challenges and limitations of existing research, olfactory dysfunction has demonstrated its value in assessing neurodegenerative diseases and may serve as an early indicator of AD in the future
US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report
This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in
Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Evaluation of cosmogenic production of and for rare-event physics using underground argon
Underground argon (UAr) with lower cosmogenic activities of and
has been planned as a detector in detecting scintillation light and
charge collection using time projection chambers for dark matter searches and
as a veto detector in suppressing backgrounds for neutrinoless double beta
decay (0) experiments. Long-lived radioactive isotopes,
and , can also be produced on the surface when UAr is pumped
out from a deep well. Understanding the production of long-lived isotopes in Ar
is important for utilizing UAr for dark matter and 0 experiments
in terms of its production, transportation, and storage. Ar exposure to cosmic
rays at sea-level is simulated using Geant4 for a given cosmic ray muon,
neutron, and proton energy spectrum. We report the simulated cosmogenic
production rates of , , and other long-lived isotopes at
sea-level from fast neutrons, high energy muons, and high energy protons. Total
production rates of 938.53/kgday and
5.8110/kgday for Ar and Ar are found
from our simulation. Utilizing these production rates, we set a time limit of
954 days constrained by the production of Ar for UAr to be on the
surface before it compromises the sensitivity for a dark matter experiment.
Similarly, a time limit of 1702 days constrained by the production of Ar
is found for a 0 experiment.Comment: 12 pages, 3 figures, and 2 table
The characteristics of the complete chloroplast genome of Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae)
Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae) is an important ornamental herb mainly distributed in the southern region of China, including Fujian, Guangdong, Hainan, and Taiwan provinces. However, the complete chloroplast genome of S. concinnula, which could serve as a genetic resource for studies on its taxonomy and evolution, is poorly studied at present. In this study, we reported the complete chloroplast genome of S. concinnula that was assembled using high-throughput sequencing data. The chloroplast genome was 153,783 bp long, with a typical quadripartite structure containing a small single-copy region (SSC; 17,855 bp), a large single-copy region (LSC; 84,636 bp) and a pair of inverted repeats (IRs; each 25,646 bp). The overall GC content of the chloroplast genome was 38.04%. A total of 86 protein-coding genes (PCGs), 8 rRNA genes, and 37 tRNA genes were predicted. Phylogenetic analysis based on the combined sequences of 86 PCGs with the other 16 closely related species of Acanthaceae indicated that S. concinnula is closely related to Avicennia marina. The genomic data and finding from the phylogenetic studies of S. concinnula could provide useful information and give light to in-depth studies on the evolution pattern of the understudied species, as well as Staurogyne
The characteristics of the complete chloroplast genome of <i>Staurogyne concinnula</i> (Hance) O. Kuntze (Acanthaceae)
Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae) is an important ornamental herb mainly distributed in the southern region of China, including Fujian, Guangdong, Hainan, and Taiwan provinces. However, the complete chloroplast genome of S. concinnula, which could serve as a genetic resource for studies on its taxonomy and evolution, is poorly studied at present. In this study, we reported the complete chloroplast genome of S. concinnula that was assembled using high-throughput sequencing data. The chloroplast genome was 153,783 bp long, with a typical quadripartite structure containing a small single-copy region (SSC; 17,855 bp), a large single-copy region (LSC; 84,636 bp) and a pair of inverted repeats (IRs; each 25,646 bp). The overall GC content of the chloroplast genome was 38.04%. A total of 86 protein-coding genes (PCGs), 8 rRNA genes, and 37 tRNA genes were predicted. Phylogenetic analysis based on the combined sequences of 86 PCGs with the other 16 closely related species of Acanthaceae indicated that S. concinnula is closely related to Avicennia marina. The genomic data and finding from the phylogenetic studies of S. concinnula could provide useful information and give light to in-depth studies on the evolution pattern of the understudied species, as well as Staurogyne.</p