Abstract
We studied the light yield of a pure polystyrene slide
coated with wavelength-shifter molecules, coupled to a
photomultiplier, using
β
-
particles from a
90
Sr
source, as a possible ...easy-to-build, low-cost plastic scintillator
detector. Comparison measurements were performed with an uncoated
polystyrene slide as well as with uncoated and coated PMMA slides,
the latter which can only produce Cherenkov light when being
traversed by charged particles. The results with the single (double)
coated polystyrene slides show about 4.9 (6.3) times higher detected
photon yield compared to the uncoated slide. For comparison, the
light yield of a polystyrene-based extruded plastic scintillator
material doped with PTP and POPOP was measured as well. The
absolute detected light yield motivates future studies for
developing easy-to-build, low-cost polystyrene-based plastic
scintillator detectors.
Abstract
We measured the surface tension of linear alkylbenzene (LAB)
HYBLENE 113 mixed with Diphenyloxazole (PPO) as well as of pure LAB
HYBLENE 113 as part of material studies for the ...liquid-scintillator
based surround background tagger (SBT) in the proposed SHiP
experiment. The measurement was performed using the iron wire method
and the surface tension for linear alkyl benzene HYBLENE 113 plus
PPO was found to be (30.0 ± 0.6) mN/m 22.0 ± 0.5°C and
for pure HYBLENE 113, (29.2 ± 0.6) mN/m at
21.0 ± 0.5°C.
Abstract As a prototype detector for the SHiP Surrounding Background Tagger (SBT), we constructed a cell (120 cm × 80 cm × 25 cm) made from corten steel that is filled with liquid scintillator (LS) ...composed of linear alkylbenzene (LAB) and 2,5-diphenyloxazole (PPO). The detector is equipped with two Wavelength-shifting Optical Modules (WOMs) for light collection of the primary scintillation photons. Each WOM consists of an acrylic tube that is dip-coated with a wavelength-shifting layer on its surface. Via internal total reflection, the secondary photons emitted by the molecules of the wavelength shifter are guided to a ring-shaped array of 40 silicon photomultipliers (SiPMs) coupled to the WOM for light detection. The granularity of these SiPM arrays provides an innovative method to gain spatial information on the particle crossing point. Several improvements in the detector design significantly increased the light yield with respect to earlier proof-of-principle detectors. We report on the performance of this prototype detector during an exposure to high-energy positrons at the DESY II test beam facility by measuring the collected integrated yield and the signal time-of-arrival in each of the SiPM arrays. The resulting detection efficiency and reconstructed energy deposition of the incident positrons are presented, as well as the spatial and time resolution of the detector. These results are then compared to Monte Carlo simulations.
We studied the light yield of a pure polystyrene slide coated with wavelength-shifter molecules, coupled to a photomultiplier, using beta particles from a 90-Sr source, as a possible easy-to-build, ...low-cost plastic scintillator detector. Comparison measurements were performed with an uncoated polystyrene slide as well as with uncoated and coated PMMA slides, the latter which can only produce Cherenkov light when being traversed by charged particles. The results with the single (double) coated polystyrene slides show about 4.9 (6.3) times higher detected photon yield compared to the uncoated slide. For comparison, the light yield of a polystyrene-based extruded plastic scintillator material doped with PTP and POPOP was measured as well. The absolute detected light yield motivates future studies for developing easy-to-build, low-cost polystyrene-based plastic scintillator detectors.
As a prototype detector for the SHiP Surrounding Background Tagger (SBT), we constructed a cell (120 cm x 80 cm x 25 cm) made from corten steel that is filled with liquid scintillator (LS) composed ...of linear alkylbenzene (LAB) and 2,5-diphenyloxazole (PPO). The detector is equipped with two Wavelength-shifting Optical Modules (WOMs) for light collection of the primary scintillation photons. Each WOM consists of an acrylic tube that is dip-coated with a wavelength-shifting layer on its surface. Via internal total reflection, the secondary photons emitted by the molecules of the wavelength shifter are guided to a ring-shaped array of 40 silicon photomultipliers (SiPMs) coupled to the WOM for light detection. The granularity of these SiPM arrays provides an innovative method to gain spatial information on the particle crossing point. Several improvements in the detector design significantly increased the light yield with respect to earlier proof-of-principle detectors. We report on the performance of this prototype detector during an exposure to high-energy positrons at the DESY II test beam facility by measuring the collected integrated yield and the signal time-of-arrival in each of the SiPM arrays. The resulting detection efficiency and reconstructed energy deposition of the incident positrons are presented, as well as the spatial and time resolution of the detector. These results are then compared to Monte Carlo simulations.
We measured the surface tension of linear alkylbenzene (LAB) HYBLENE 113 mixed with Diphenyloxazole (PPO) as well as of pure LAB HYBLENE 113 as part of material studies for the liquid-scintillator ...based surround background tagger (SBT) in the proposed SHiP experiment. The measurement was performed using the iron wire method and the surface tension for linear alkyl benzene HYBLENE 113 plus PPO was found to be \((30.0\pm0.6)\) mN/m \(22.0\pm 0.5\) {\deg}C and for pure HYBLENE 113, \((29.2\pm 0.6)\) mN/m at \(21.0\pm 0.5\) {\deg}C.
Social, political, and economic changes in the former Soviet Union precipitated both the collapse of a once‐centralized medical education system in the region and the development of individual models ...in its place. In the context of rapid globalization and international concerns about health, this development of “nation‐based” models for the structure, content, language, and duration of instruction generated concerns about regional accreditation; workforce planning; student qualifications; residency training; continuing education; and infrastructure, such as access to literature, an adequate clinical training base, and links to certification and licensure. The World Health Organization acknowledges that the development of human resources for health is a complex and key element in reforming health systems. In Central Asia, international donor agencies facilitated the development of a regional council of rectors and a partnership consortium of medical academies as reform vehicles. International medical education organizations provide counsel and share their organizations' models, greatly facilitating the reform progress. The groups work to address both the political and regulatory environment and the professional and academic environment that affect the quality of medical schools. The council of rectors is establishing credibility as a regional nongovernmental organization that can advise governments about workforce planning, budgeting, admissions policies, accreditation, and licensure. The group sponsors faculty development workshops, bringing together regional educators around educational and institutional issues of mutual concern. Partnership academies collaborate to develop institutional and individual professional capacity, focusing on standardized evaluation, structure and content of the curriculum, pedagogy, and leadership development.
Involving Family Advisory Councils in decisions that impact pediatric healthcare demonstrates hospitals’ commitment to child- and family-centered care. Yet, reliance on advisors as the sole source of ...family input has several limitations: infrequent meetings impedes the council’s capacity to address emerging concerns in a timely manner; feedback obtained from a small number of highly-engaged family members may not represent the perspectives of “typical” patients and families; advisors provide feedback in a reactive manner and are generally not equitably involved in problem identification or the initial development of solutions. In recognition of the need to strengthen and advance family partnerships, the Children’s Hospital of Philadelphia made significant structural and operational changes to advance and expand the family centered care model. The Family Partners Program, a component of the broader family centered care portfolio, is a centralized institution-wide resource that enables practitioners, researchers, and healthcare leaders to collaborate with trained family representatives. This paper describes the Family Partner Program infrastructure; approaches to recruiting, onboarding, training, and mentoring parents and caregivers; and the many ways that Family Partners promote the core principles of child- and family-centeredness in clinical care, quality improve, and research contexts.
ABSTRACT Recent evidence supporting reionization ending at redshift $z \lesssim 6$ includes the rapid redshift evolution of the mean free path, $\lambda _{\rm mfp}$, for Lyman-limit photons through ...the intergalactic medium (IGM) at $5\lt z\lt 6$. Here, we investigate $\lambda _{\rm mfp}$ predicted by the Sherwood–Relics suite of hybrid radiation hydrodynamical simulations. Simulations with comoving volumes of $40^{3}\, h^{-3}\rm \, cMpc^{3}$ ($160^{3}\, h^{-3}\rm \, cMpc^{3}$), calibrated to match the observed Ly $\alpha$ forest transmission with a late end to reionization at $z\lt 6$, are consistent with recent $\lambda _{\rm mfp}$ measurements at $z\lt 5.9$, and are $1.2\sigma$ ($1.8\sigma$) above the highest redshift $\lambda _{\rm mfp}$ measurement at $z=5.93$. The majority of the Lyman-limit opacity at the end of reionization is attributable to highly ionized Ly $\alpha$ forest absorbers with neutral hydrogen column densities $N_{\rm HI} \leq 10^{16}$–$10^{17}\rm \, cm^{-2}$. Resolving these systems is critical for capturing the redshift evolution of $\lambda _{\rm mfp}$ during the final stages of reionization. After reionization completes, overdense gas will reduce $\lambda _{\rm mfp}$ by up to 20 per cent around haloes with masses $M_{\rm h}\sim 10^{9}$–$10^{11}h^{-1}\, {\rm M}_{\odot }$, but during reionization ionized bubbles will instead boost $\lambda _{\rm mfp}$ around haloes by up to an order of magnitude when the IGM is as much as 90 per cent neutral by volume. This effect will play an important role in the visibility of Ly $\alpha$ emitting galaxies at $z\gtrsim 10$ discovered with JWST.
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