METHOD OF EXCITING DOSIMETRIC SIGNAL OF OPTICALLY STIMULATED LUMINESCENCE OF IONISING RADIATION DETECTORS BASED ON ALUMINIUM OXIDE

FIELD: physics. SUBSTANCE: invention can be used to increase reliability and accuracy of a method and measurements taken using said method. The method of exciting a dosimetric signal of optically stimulated luminescence of ionising radiation detectors based on aluminium oxide involves putting a detector into an opaque housing between a optical stimulation source made in form of a light-emitting diode and a dividing optical filter at a distance of 1-2 mm from their surfaces inside the said housing. Stimulation is carried out in 30-50 seconds using radiation from the light-emitting diode with a continuous spectrum in the 450-900 nm range. EFFECT: shorter reading time, high sensitivity, accuracy and reliability of measuring doses, and effective destruction of dosimetric traps in TLD-500K detectors before their use in thermoluminescent dosimetry which replaces thermal treatment of detectors. 8 dwg.Изобретение относится к способам возбуждения дозиметрического сигнала в оптически стимулированной люминесцентной дозиметрии ионизирующих излучений и может быть использовано для повышения надежности, точности и достоверности метода и проводимых с его помощью измерений. Способ возбуждения дозиметрического сигнала оптически стимулированной люминесценции детекторов ионизирующих излучений на основе оксида алюминия, включающий помещение детектора в светонепроницаемый корпус между расположенным в нем источником оптической стимуляции, выполненным в виде светоизлучающего диода, и разделительным оптическим фильтром на расстоянии 1-2 мм от их поверхностей, при этом стимуляцию осуществляют в течение 30-50 с излучением светоизлучающего диода с непрерывным спектром в диапазоне 450-900 нм. Технический результат - сокращение времени считывания, повышение чувствительности, точности, надежности и достоверности измерений доз, а также эффективное опустошение дозиметрических ловушек в детекторах ТЛД-500К перед их применением в ТЛД дозиметрии, заменяющее термообработку детекторов. 8 ил

Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

WHAT EXTENSIVE READING IS, AND WHY IT IS A GOOD IDEA TO IMPLEMENT IT

&lt;p&gt;The article reviews the body of research on extensive reading and briefly explains main benefits, such as learners' overall language development, automated lower-level skills of word recognition and parsing processes, increased vocabulary knowledge without direct vocabulary instruction, improved writing skills, increased motivation for learning languages, and confidence in reading. Using extensive reading persistently in reading courses creates few demands and challenges for the teacher and doesn't involve time-consuming lesson preparation.&nbsp;&lt;/p&gt

Temperature conditions in the ventilation shaft lining and the space behind lining when reversing the main ventilation unit in winter

Using mathematical modeling methods, the authors studied the temperature changes in the ventilation shaft lining and the space behind lining under an alternating thermal effect of the ventilation flow (reversing the main ventilation unit in winter). We established the pattern of the temperature conditions created in the ventilation shaft, the lining, and the host rock mass when reversing the main ventilation unit at mines in the North. Our studies have shown that, in case of emergency at the mine, which requires reversing the air flow in the coldest period of the year, it will result in a change in the temperature conditions in the ventilation shaft, the concrete lining, and the host rock mass. The extent of such effect depends on the reverse duration. Thus, at an ambient temperature of -45°C, during the first 24 hours after the reverse, we can observe complete freezing of the concrete lining at a ventilation flow rate of over 2 m/s. The rock temperature drops below 0°C and, at air flow rates of up to 10 m/s, the frozen area thickness around the shaft will be no more than 7 cm. 48 hours after the reverse, the maximum freezing depth of the rock will be 30 cm

DECORATIVE SANDWICH CONCRETES WITH A PROTECTIVE POLYMER LAYER ENSURING IMPROVED FRACTURE STRENGTH

This paper covers the integrity of decorative sandwich materials; relations between relative deformations of the sandwich system and the length of contact between layers; thicknesses of the surface layer and relative deformations of the concrete base. Principles of the proposed technology are also provided in the article. The field study of the behaviour of decorative sandwich concrete products exposed to severe conditions of operation have proven that products collapse due to cracking and peeling of the polymer concrete layer in particular cases. Deformations of sandwich materials caused by temperature and humidity fluctuations were analyzed by strain-gauge resistance sensors placed onto the surface polymer concrete layer of a product fragment and on the concrete base in the course of their freezing. Deformations were measured at the temperature intervals of 4 to 5 degrees Celsius. Freezing represents the most severe condition. Mathematical method of experimental planning was employed to identify the dependence between relative deformations of sandwich system Исс and length of layer-to-layer contact L, thickness of surface layer h and relative deformations of the concrete base ɛ 105. As a result of the probabilistic and statistical processing of the experimental data a three-factor quadratic model of relative deformations of a sandwich system was generated. This equation is used to identify the most favourable conditions to assure the integrity of a sandwich product under the combined impact of the aforementioned factors. The analysis has proven that the surface layer made of polymer concrete does not crack irrespective of the contact length if deformations of the concrete base do not exceed the limit tensibility of the surface layer. In the event of substantial deformations of the concrete base, integrity of the sandwich system is to be assured by means of the right choice of thickness and length of the surface layer. Based on the dependence of relative deformations of the sandwich composite, made of a concrete matrix and a polymer concrete decorative and protective layer, analysis of their integrity was performed with the account for the thickness of the surface layer, contact length and relative deformations of the water saturated concrete base in the course of freezing. Pre-set theoretical provisions were applied to develop recommendations aimed at the optimization of the composition and characteristics of the technology of production of double-layer decorative and protective products based on polymer and mineral binders

Search for the rare hadronic decay Bs0→ppˉB_s^0\to p \bar{p}

A search for the rare hadronic decay Bs0→pp¯ is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6  fb-1. No evidence of the decay is found and an upper limit on its branching fraction is set at B(Bs0→pp¯)&lt;4.4(5.1)×10-9 at 90% (95%) confidence level; this is currently the world’s best upper limit. The decay mode B0→pp¯ is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be B(B0→pp¯)=(1.27±0.15±0.05±0.04)×10-8, where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel B0→K+π-. The combination of the two LHCb measurements of the B0→pp¯ branching fraction yields B(B0→pp¯)=(1.27±0.13±0.05±0.03)×10-8.A search for the rare hadronic decay $B_s^0\to p \bar{p}$ is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb$^{-1}$. No evidence of the decay is found and an upper limit on its branching fraction is set at ${\cal B}(B_s^0\to p \bar{p}) < 4.4~(5.1) \times 10^{-9}$ at 90% (95%) confidence level; this is currently the world's best upper limit. The decay mode $B^0\to p \bar{p}$ is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be ${\cal B}(B^0\to p \bar{p}) = \rm (1.27 \pm 0.15 \pm 0.05 \pm 0.04) \times 10^{-8}$, where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel $B^0\to K^+\pi^-$. The combination of the two LHCb measurements of the $B^0\to p \bar{p}$ branching fraction yields ${\cal B}(B^0\to p \bar{p}) = \rm (1.27 \pm 0.13 \pm 0.05 \pm 0.03) \times 10^{-8}$