208 research outputs found
The SABRE South Experiment at the Stawell Underground Physics Laboratory
The SABRE (Sodium iodide with Active Background REjection) experiment aims to
detect an annual rate modulation from dark matter interactions in ultra-high
purity NaI(Tl) crystals in order to provide a model independent test of the
signal observed by DAMA/LIBRA. It is made up of two separate detectors; SABRE
South located at the Stawell Underground Physics Laboratory (SUPL), in regional
Victoria, Australia, and SABRE North at the Laboratori Nazionali del Gran Sasso
(LNGS). SABRE South is designed to disentangle seasonal or site-related effects
from the dark matter-like modulated signal by using an active veto and muon
detection system. Ultra-high purity NaI(Tl) crystals are immersed in a linear
alkyl benzene (LAB) based liquid scintillator veto, further surrounded by
passive steel and polyethylene shielding and a plastic scintillator muon veto.
Significant work has been undertaken to understand and mitigate the background
processes, that take into account radiation from the detector materials, from
both intrinsic and cosmogenic activated processes, and to understand the
performance of both the crystal and veto systems. SUPL is a newly built
facility located 1024 m underground (about 2900 m water equivalent) within the
Stawell Gold Mine and its construction has been completed in mid-2022. The
laboratory will house rare event physics searches, including the upcoming SABRE
dark matter experiment, as well as measurement facilities to support low
background physics experiments and applications such as radiobiology and
quantum computing. The SABRE South commissioning is expected to occur in 2023.
This paper describes the setup and projections for the experiment, and the
description of the underground laboratory.Comment: Proceedings of the 15th Asia Pacific Physics Conferenc
Gamma astronomy with ARGO-YBJ
ARGO-YBJ, an extensive air shower detector located at Yangbajing (Tibet, China) at 4300m a.s.l., is made by a full coverage carpet plus a guard ring (∼ 6700m2) of resistive plate chambers. Its structure, and the high altitude allow exhaustive studies of γ astronomy with energy range in the TeV region. In this paper some of the ARGO-YBJ results in γ astronomy are discussed. In particular
the TeV emissions of the blazar Mrk 421, the analysis of its last two flares and the comparison with Cherenkov telescopes results are presented
Examining the Prevalence Rates, Demographic Differences, and Concurrent Validity Associated with a Universal Bidimensional Mental Health Screener for Youth in Schools
When using a bidimensional mental health (BDMH) model, psychological distress and wellbeing are measured. This study used a mental health screening measure, with equal number of items measuring each mental health dimension (i.e., wellbeing and distress) to classify students into one of four possible mental health groups: mentally healthy (MH), mentally unhealthy (MU), symptomatic but content (SBC), and asymptomatic but discontent (ABD). First, prevalence rates for each group in a sample of youth from the 2009–10 Health Behavior in School-aged Children Survey in the United States (N = 6,345) were explored; about a quarter of the population experienced mixed mental health (i.e., SBC or ABD). The second purpose was to investigate how demographic variables (e.g., gender, ethnicity) influenced a student’s BDMH; these variables did not have a practically meaningful relationship to BDMH. The third purpose was to investigate the effect of BDMH classification (i.e., MH, MU, SBC, or ABD) on relevant student behavior variables (i.e., school performance perceptions, class climate, bullying victimization and perpetration, family support, life satisfaction, somatic symptoms, alcohol, cigarette, and marijuana use). Results indicated that MH students experienced the most advantageous, and MU students the most deleterious, concurrent outcomes. However, ABD students (not identified by a traditional screener) experienced concurrent outcomes worse than or similar to their MU peers. Taken together, the results suggest that measuring wellbeing has value-added in differentiating students with varying levels of risk, and identifying students with potential need for intervention. Implications of these results and considerations regarding measurement of psychological wellbeing in mental health screening procedures in schools are discussed
Differential Effects of Mindful Breathing and Loving-Kindness Meditation Exercises on College Students\u27 Mental Health
Mindfulness and loving-kindness are two concepts with associated meditation exercises that have been evaluated as part of mindfulness-based treatment approaches (MBTAs) to improve mental health. A common MBTA, Mindfulness Based Stress Reduction (MBSR) includes multiple component exercises including mindful breathing meditation (MBM), and loving-kindness meditation (LKM). The purpose of the present study was to examine differential effects of MBM and LKM on the proposed process variables of social connectedness, cognitive fusion and experiential avoidance, present moment awareness, affect, and compassion for self and others, as well as across outcomes measures of general anxiety, social anxiety, depression, and wellbeing. Additionally the study determined if changes in outcomes were predicted by changes in theoretically related process variables. Differences in, and effects of, previous meditation experience (PME), treatment integrity (TI), and treatment acceptability (TA) by condition were also explored. The research design was a randomized controlled trial with four conditions: MBM, LKM, Combined (MBM and LKM), and Relaxation. The interventions consisted of a once daily 10-minute audio-assisted exercise, completed for two weeks. Findings revealed a statistically significant therapeutic effect of time regardless of condition. Consideration of effect sizes further indicated that MBM and LKM had greater therapeutic effects than Combined and Relaxation, with therapeutic differences between conditions ranging from small to large. Results for the total sample also showed that changes in process variables predicted changes in various outcomes. Finally, although PME, TI, and TA did not differ between conditions, TA did predict changes in depression. Implications for future research and practice are discussed
222Rn daughters influence on scaler mode of the ARGO-YBJ detector
The ARGO-YBJ experiment is a full coverage air shower array; its lowest
energy threshold is reached using the "scaler mode technique". Working in this
mode, the signals generated by any particle hitting each cluster are put in
coincidence every 150 ns and read by four independent scaler channels, giving
the counting rates of multiplicity \geq1, \geq2, \geq3 and \geq4 (C1, C2, C3
and C4, respectively). The study of these counting rates pointed out a
different behaviour of C1 respect to C2, C3 and C4, suggesting that C1 is
detecting not only cosmic rays. This work shows that the radon (222Rn) gamma
emitter daughters present in the ARGO-YBJ building air are contributing to C1
counts at the level of 1 Hz each Bq/m3 of radon. The uncertainty about this
contribution is great, because of the high variability of 222Rn concentration
and the building ventilation. The radon monitoring will allow the C1 correction
improving the sensitivity of the ARGO-YBJ experiment at its lowest energy
threshold.Comment: 4 pages, 3 figures, Proceedings of the 32nd International Cosmic Ray
Conference (ICRC
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