Dual-phase xenon detectors lead the search for keV-scale nuclear recoil signals expected from the scattering of weakly interacting massive particle (WIMP) dark matter, and can potentially be used to ...study the coherent nuclear scattering of MeV-scale neutrinos. New capabilities of such experiments can be enabled by extending their nuclear recoil searches down to the lowest measurable energy. The response of the liquid xenon target medium to nuclear recoils, however, is not well characterized below a few keV, leading to large uncertainties in projected sensitivities. In this work, we report a new measurement of ionization signals from nuclear recoils in liquid xenon down to the lowest energy reported to date. At 0.3 keV, we find that the average recoil produces approximately one ionization electron; this is the first measurement of nuclear recoil signals at the single-ionization-electron level, approaching the physical limit of liquid xenon ionization detectors. We discuss the implications of these measurements on the physics reach of xenon detectors for nuclear-recoil-based WIMP dark matter searches and the detection of coherent elastic neutrino-nucleus scattering.
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The social sustainability transition in the construction sector seeks to improve safety and health of workers, gainful employment and total inclusiveness. However, it is novel in the Nigerian ...construction industry and a less debated domain within this framework is how employment requirements provide opportunities for the socially disadvantaged such as the poorly educated, youths, immigrants and disabled individuals to be employed in the construction industry. In Nigeria alone, there are over 27 million disabled human species, most of who are living in extreme poverty with poor quality of life. Furthermore, there are evidence of development projects designed and built in developing countries that have failed socially and many mass housing scheme in Nigeria suffices as examples. Drawing on a systematic review of relevant literature, this research qualitatively examines social sustainability practices in the Nigerian construction industry, and highlight strategies for diffusing the approach at each phase of the project life cycle. The outcome of the result will initiate a novel research domain and promote sound academic debate towards improving total inclusiveness in Nigerian and Africa’s built environment. The potential impact of this research is that it will contribute to the knowledge base of the social sustainability concept and provide an alternative solution to the increasing shortage of skilled labour force in the construction industry. Its conclusion surmises that social procurement is a strategic tool for creating employment for the disadvantaged in the construction sector.
Abstract
We present results of several measurements of CsINa
scintillation response to 3–60 keV energy nuclear recoils
performed by the COHERENT collaboration using tagged neutron elastic
scattering ...experiments and an endpoint technique. Earlier results,
used to estimate the coherent elastic neutrino-nucleus scattering
(CEvNS) event rate for the first observation of this process
achieved by COHERENT at the Spallation Neutron Source (SNS), have
been reassessed. We discuss corrections for the identified
systematic effects and update the respective uncertainty values. The
impact of updated results on future precision tests of CEvNS is
estimated. We scrutinize potential systematic effects that could
affect each measurement. In particular we confirm the response of
the H11934-200 Hamamatsu photomultiplier tube (PMT) used for the
measurements presented in this study to be linear in the relevant
signal scale region.
The non-linear energy response of the plastic scintillator EJ-260 is measured with the MicroCHANDLER detector, using neutron beams of energy 5 to 27 MeV at the Triangle Universities Nuclear ...Laboratory. The first and second order Birks' constants are extracted from the data, and found to be kB=(8.70±0.93)×10−3g/cm2/MeV and kC=(1.42±1.00)×10−5(g/cm2/MeV)2. This result covers a unique energy range that is of direct relevance for fast neutron backgrounds in reactor inverse beta decay detectors. These measurements will improve the energy non-linearity modeling of plastic scintillator detectors. In particular, the updated energy response model will lead to an improvement of fast neutron modeling for detectors based on the CHANDLER reactor neutrino detector technology.
We report on the preparation of and calibration measurements with a 83mKr source for the CENNS-10 liquid argon detector. 83mKr atoms generated in the decay of a 83Rb source were introduced into the ...detector via injection into the Ar circulation loop. Scintillation light arising from the 9.4 keV and 32.1 keV conversion electrons in the decay of 83mKr in the detector volume were then observed. This calibration source allows the characterization of the low-energy response of the CENNS-10 detector and is applicable to other low-energy-threshold detectors. The energy resolution of the detector was measured to be 9% at the total 83mKr decay energy of 41.5 keV. We performed an analysis to separately calibrate the detector using the two conversion electrons at 9.4 keV and 32.1 keV.
COHERENT Experiment: current status Akimov, D; Albert, J B; Awe, C ...
Journal of physics. Conference series,
01/2017, Volume:
798, Issue:
1
Journal Article
Peer reviewed
Open access
The COHERENT Collaboration is realizing a long term neutrino physics research program. The main goals of the program are to detect and study elastic neutrino-nucleus scattering (CE NS). This process ...is predicted by Standard Model but it has never been observed experimentally because of the very low energy of the recoil nucleus. COHERENT is using different detector technologies: CsINa and NaI scintillator crystals, a single-phase liquid Ar and a Ge detectors. The placement of all the detector setups is in the basement of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The current status of the COHERENT experimental program is presented.
The building and construction industry (BCI) is made of diverse professionals and despite its emphasis on quality project delivery, the essentials of site meetings have not been adequately explored. ...The study examined the fundamental aspects of Site Meetings and their impact on the execution of construction projects in the building sector, specifically focusing on higher education institutions in Ekiti State, Nigeria. An online survey questionnaire was used and administered to the Consultants and Contractors, within Higher Institutions in Ekiti State, and only seventy-four (74) Respondents filled out the questionnaire and submitted it. The results indicated that 67.6% and 31.1% strongly agreed and agreed respectively that site minutes are important to project implementation. 50% each strongly agreed and agreed that the agenda is a critical tool for project implementation. 37.7% of respondent do not have a definite time for sending notice of a meeting while 10.8% do not have an agenda for their site meetings, also, 52.7% make the minutes of site meetings available before the meeting and 47.3% during the meeting. The study recommended that all stakeholders should take the essentials seriously. Notice of meetings, agendas, and Minutes should be prepared and sent ahead of site meeting dates.
The COHERENT experiment is well poised to test sub-GeV dark matter models using detectors sensitive to coherent elastic neutrino-nucleus scattering (CEvNS) in the π+ decay-at-rest (π-DAR) neutrino ...beam produced by the Spallation Neutron Source. We show a planned 750-kg single-phase liquid argon scintillation detector would place leading limits on scalar light dark matter models for dark matter particles produced through vector and leptophobic portals in the absence of other effects beyond the standard model. The characteristic timing profile of a π-DAR beam allows a unique opportunity for constraining systematic uncertainties on the standard model background using a time window where dark matter signal is not expected, enhancing expected sensitivity. Additionally, we discuss future prospects which show that an on-axis CEvNS detector would probe the thermal abundance for a scalar dark matter candidate for all couplings α′ ≤ 1 for 15 MeV dark matter with just 1.0 tonne-yr of exposure with increased exposure testing a wider range of dark matter masses and spins.
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