Scintillation

About: Scintillation is a research topic. Over the lifetime, 14022 publications have been published within this topic receiving 187694 citations.

Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter

Abstract: We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al.. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well-described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.

Dynamics of equatorial F region irregularities from spaced receiver scintillation observations

Abstract: Spaced receiver observations of amplitude scintillations on a 244 MHz signal, at an equatorial station, have been used to study random temporal changes associated with the scintillation-producing irregularities and the variability of their motion. The computed drift of the scintillation pattern shows the presence of velocity structures associated with equatorial bubbles in the early phase of their development. On magnetically quiet days, after 22:00 LT, the estimated drifts fall into a pattern which is close to that of the ambient plasma drift. There is considerable decorrelation between the two signals until 22:00 LT. The power spectra of the most highly correlated scintillations recorded by spaced receivers indicate that the associated irregularities are confined to a thin layer on the bottomside of the equatorial F region. This suggests that the convection pattern associated with bottomside irregularities is stable due to the dominance of ion-neutral collisions over ion inertia.

Development of lithium yttrium borate glass doped with Dy 3 + for laser medium, W-LEDs and scintillation materials applications

Abstract: Lithium yttrium borate glasses doped with dysprosium ion (Dy3 +) were synthesized by a melt-quenching technique. Glasses were studied the physical properties such as density, molar volume and refractive index. The absorption, excitation and emission spectra, including decay curve were monitored to study the luminescence properties. The X-ray induced luminescence and temperature dependence luminescence spectra was also investigated. The experimental results show that Dy3 + probably acts as modifier in this glass because molar volume increased with increasing of Dy3 + doped content. Glasses absorbs photon in visible light and near-infrared region with Dy3 + transition from 6H15/2 ground state. Glass performs the strongest emission at 575 nm (4F9/2 → 6H13/2) with 388 nm excitation wavelength. The intensity of emission increases with increasing of Dy2O3 concentration until 1.00 mol% after that it decreases by resonance energy transfer and cross-relaxation processes. The photoemission is white light confirmed by CIE 1931 chromaticity and UV lamp excitation. Decay curve, fitted by Inokutie-Hirayama model (S = 6), shows the non-exponential pattern which indicates a dipole-dipole interaction between Dy3 + donor and acceptor in glass. Judd-Ofelt analysis exhibits an interesting potential for using glass as laser medium with 575 nm emitting. X-ray induced luminescence spectra perform the sharp emission band of Dy3 + after accepted energy transfer from host glass. This is a good sign for scintillation potential. Temperature dependence luminescence spectra show the strong emission at low temperature condition. Emission intensity relates linearly with the temperature change. This Dy3 + doped glass can be developed for using as photonic materials in the display, white-light emitting diode, laser device, scintillation detector and even temperature sensor.

Long-Term Scintillation Studies of Pulsars. I. Observations and Basic Results

Abstract: We report long-term scintillation observations of 18 pulsars in the dispersion measure range 3-35 pc cm-3 carried out from 1993 January to 1995 August using the Ooty Radio Telescope at 327 MHz. These observations were made with the aim of studying refractive effects in pulsar scintillation and obtaining reliable estimates of diffractive and refractive scintillation properties. Dynamic scintillation spectra of pulsars were regularly monitored at 10-90 epochs spanning 100-1000 days. Significant changes are observed in the dynamic spectra over timescales as short as a few days. Large-amplitude fluctuations are observed in quantities such as decorrelation bandwidth, scintillation timescale, drift rate, and flux density. Several pulsars show organized features, such as drifting bands in a highly pronounced manner. For some pulsars, gradual and systematic variations are seen in the drift rate of patterns that undergo several sign reversals during the observing time spans. Anomalous behavior, such as persistent drifts lasting over many months, is seen for PSRs B0834+06 and B1919+21. Four pulsars were studied for 2-4 well-separated observing sessions, each lasting over ~100 days. In some cases, significant variations are seen in the average scintillation properties and/or flux densities between successive observing sessions. From our data, we have been able to obtain more accurate and reliable estimates of scintillation properties and flux densities than those from the earlier observations by averaging out the fluctuations due to refractive scintillation effects. These measurements are used to derive parameters such as the strength of scattering and scintillation speeds. The scintillation speed estimates are found to be reasonably good indicators of proper-motion speeds of pulsars. The present measurements are compared with earlier measurements and the long-term stability of scintillation properties and flux densities is discussed.

GPS scintillation in the high arctic associated with an auroral arc

Abstract: A rapid signal-fading event produced by diffractive scintillations was observed around 0123 UT on 8 November 2004 by three closely sited (less than 250 m apart) GPS scintillation receivers in northern Norway. The entire duration of the event was about 10 s and was recorded by all three receivers. Intense, short duration events such as these are not clearly observable in the 1-min scintillation index (S4) because they do not necessarily last for the entire minute. In spite of their short duration they can cause a receiver to lose lock because of their intensity. The geomagnetic conditions were disturbed at this time with the interplanetary magnetic field southward for a period of several hours. Magnetometers from the IMAGE network in Scandinavia showed evidence of a 2000 nT substorm. The GPS measurements are compared with all-sky camera (ASC) data to show that the signal fades can be attributed to the GPS ray paths crossing electron density structures associated with the aurora. The ASC images reveal moving auroral structures at the same time as the GPS signals show movement of the ionospheric regions causing fading. The results indicate that at high latitudes low-elevation GPS signals can suffer sudden fading due to E-region auroral events. This is the first time that a direct connection has been established between the loss of lock on a GPS receiver and diffractive fading caused by auroral precipitation.