Scintillation crystals Gd
Al
Ga
O
(GAGG) are considered for the application in ionizing-radiation detectors because of their high radiation resistance, density and light yield. These crystals can be ...used in addition to lead tungstate (PbWO
or PWO) crystals for the development of a new generation electromagnetic calorimeter with good spatial and energy resolutions in a broad energy range. PWO crystals enable an accurate detection of high energy photons, while the addition of GAGG crystals makes it possible to precisely measure photon energies down to a few MeV units. Different options of composite electromagnetic calorimeter based on PWO and GAGG crystals are considered to optimize spatial and energy resolutions in a broad energy range (from 1 MeV to 100 GeV). The optimization is based on Geant4 simulations taking into account light collection as well as using different photodetectors and noise of electronics. The simulations are verified with the help of light yield measurements of GAGG samples obtained using radioactive sources and test beam measurements of PWO based photon spectrometer of the ALICE experiment at CERN.
The ALICE experiment is optimized to study the properties of hot quark–gluon plasma produced in ultrarelativistic heavy-ion collisions. One of the electromagnetic calorimeters of ALICE, the Photon ...Spectrometer (PHOS), is designed for measuring direct photons and neutral mesons spectra. The possibility of increasing the working area of the PHOS detector by using PbWO
4
crystals of the CMS experiment is currently under consideration. It is possible to change the kinematic range by varying pseudo-rapidity, with a constant azimuthal angle, or azimutal angle, with the same pseudorapidity. It is also possible to move apart the detector modules without adding additional crystals. The proton collisions at energy of 13 TeV have been simulated by the Monte Carlo method using the PYTHIA software package. On the basis of the simulation results, it can be stated that for measurements in the low
p
T
region increasing the azimuthal angle is the most optimum, since it becomes possible to investigate the
p
T
region down to 25 MeV/
c
for π
0
. This makes it possible to measure direct photons in the very low energy range (tens of MeV) and possibly verify the Low theorem for soft photons. At the same time, the available range for measuring—the η meson also significantly increases (down to 50 MeV/
c
).
Experimental studies of the collisions of heavy nuclei at relativistic energies have established the properties of the quark–gluon plasma (QGP), a state of hot, dense nuclear matter in which quarks ...and gluons are not bound into hadrons1–4. In this state, matter behaves as a nearly inviscid fluid5 that efficiently translates initial spatial anisotropies into correlated momentum anisotropies among the particles produced, creating a common velocity field pattern known as collective flow. In recent years, comparable momentum anisotropies have been measured in small-system proton–proton (p+p) and proton–nucleus (p+A) collisions, despite expectations that the volume and lifetime of the medium produced would be too small to form a QGP. Here we report on the observation of elliptic and triangular flow patterns of charged particles produced in proton–gold (p+Au), deuteron–gold (d+Au) and helium–gold (3He+Au) collisions at a nucleon–nucleon centre-of-mass energy \\sqrt {s_{{\mathrm{NN}}}\ = 200 GeV. The unique combination of three distinct initial geometries and two flow patterns provides unprecedented model discrimination. Hydrodynamical models, which include the formation of a short-lived QGP droplet, provide the best simultaneous description of these measurements.
A statistical method for extracting the η → γγ signal upon rejecting those γ clusters that form pairs with invariant masses close to that of the π
0
meson is proposed. The η selection efficiency (the ...ratio between the numbers of selected and produced η mesons) and the signal-to-background ratio as a function of the η transverse momentum are obtained using a template of proton–proton collisions at
= 13 TeV simulated with PYTHIA 8.2 (with Monash-2013 tuning). The proposed method provides for an η → γγ selection efficiency of ~80% and for a 20–50% increase in the signal-to-background ratio compared to currently implemented techniques.
Recently, multiparticle-correlation measurements of relativistic p/d/^{3}He+Au, p+Pb, and even p+p collisions show surprising collective signatures. Here, we present beam-energy-scan measurements of ...two-, four-, and six-particle angular correlations in d+Au collisions at sqrts_{NN}=200, 62.4, 39, and 19.6 GeV. We also present measurements of two- and four-particle angular correlations in p+Au collisions at sqrts_{NN}=200 GeV. We find the four-particle cumulant to be real valued for d+Au collisions at all four energies. We also find that the four-particle cumulant in p+Au has the opposite sign as that in d+Au. Further, we find that the six-particle cumulant agrees with the four-particle cumulant in d+Au collisions at 200 GeV, indicating that nonflow effects are subdominant. These observations provide strong evidence that the correlations originate from the initial geometric configuration, which is then translated into the momentum distribution for all particles, commonly referred to as collectivity.
In this paper, we report results from an investigation studying the purification of Co-filled carbon nanotubes (CNTs) using Thermogravimetric analysis (TGA). The as-grown CNTs were prepared using ...Microwave Plasma Chemical Vapour Deposition (MPCVD). Transmission electron microscopy (TEM), Fourier Transform Infrared (FTIR) and Raman spectroscopy were used to characterise the CNT samples. The CNTs produced by MPCVD were filled with cobalt and consisted of thick multi-walls. After TGA purification at 900 °C, 30 wt.% Co-filled CNTs remained in the TGA pan. However, while investigating the un-filled commercial CNTs (thin multiwalled), the sample completely burnt out at around 650 °C in the TGA furnace. The high thermal stability and the ability of thick-walled CNTs to act as an effective protective shield which prevents the oxidation of encapsulated cobalt have been demonstrated.
Objective Cystic fibrosis (CF) can be difficult to diagnose, even when newborn screening (NBS) tests yield positive results. This challenge is exacerbated by the multitude of NBS protocols, ...misunderstandings about screening vs diagnostic tests, and the lack of guidelines for presumptive diagnoses. There is also confusion regarding the designation of age at diagnosis. Study design To improve diagnosis and achieve standardization in definitions worldwide, the CF Foundation convened a committee of 32 experts with a mission to develop clear and actionable consensus guidelines on diagnosis of CF with an emphasis on screened populations, especially the newborn population. A comprehensive literature review was performed with emphasis on relevant articles published during the past decade. Results After reviewing the common screening protocols and outcome scenarios, 14 of 27 consensus statements were drafted that apply to screened populations. These were approved by 80% or more of the participants. Conclusions It is recommended that all diagnoses be established by demonstrating dysfunction of the CF transmembrane conductance regulator (CFTR) channel, initially with a sweat chloride test and, when needed, potentially with newer methods assessing membrane transport directly, such as intestinal current measurements. Even in babies with 2 CF-causing mutations detected via NBS, diagnosis must be confirmed by demonstrating CFTR dysfunction. The committee also recommends that the latest classifications identified in the Clinical and Functional Translation of CFTR project http://www.cftr2.org/index.php should be used to aid with CF diagnosis. Finally, to avoid delays in treatment, we provide guidelines for presumptive diagnoses and recommend how to determine the age of diagnosis.
A statistical method for extracting the eta right arrow gammagamma signal upon rejecting those gamma clusters that form pairs with invariant masses close to that of the pi.sup.0 meson is proposed. ...The eta selection efficiency (the ratio between the numbers of selected and produced eta mesons) and the signal-to-background ratio as a function of the eta transverse momentum are obtained using a template of proton-proton collisions at Formula omitted = 13 TeV simulated with PYTHIA 8.2 (with Monash-2013 tuning). The proposed method provides for an eta right arrow gammagamma selection efficiency of ~80% and for a 20-50% increase in the signal-to-background ratio compared to currently implemented techniques.
We report on the nuclear dependence of transverse single-spin asymmetries (TSSAs) in the production of positively charged hadrons in polarized p↑+p, p↑+Al, and p↑+Au collisions at sNN=200 GeV. The ...measurements have been performed at forward rapidity (1.4<η<2.4) over the range of transverse momentum (1.8<pT<7.0 GeV/c) and Feynman x (0.1<xF<0.2). We observed positive asymmetries for positively charged hadrons in p↑+p collisions, and significantly reduced asymmetries in p↑+A collisions. These results reveal a nuclear dependence of TSSAs for charged-hadron production in a regime where perturbative techniques are applicable. These results provide new opportunities to use p↑+A collisions as a tool to investigate the rich phenomena behind TSSAs in hadronic collisions and to use TSSAs as a new handle in studying small-system collisions.
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