While scintillation dosimetry has been around for decades, the need for a dosimeter tailored to the reality of modern radiation therapy-in particular a real-time, water-equivalent, energy-independent dosimeter with high spatial resolution-has generated renewed interest in scintillators over the last 10 years. With the advent of at least one commercial plastic scintillation dosimeter and the eve...

Scintillation counting is one of the most important developments in the application of radioisotopes to procedures needed by scientists, physicians, engineers, and technicians from many diverse discipline for the detection and quantitative measurement of radioactivity. In fact, Scintillation is the most sensitive and versatile technique for the detection and quantification of radioactivity. Par...

Numerical simulations of scintillation measurements within the NetLander Geodesy and Ionosphere Experiment (NEIGE) are presented. The multiple phase screen scintillation model is used, allowing for vertical variations of the background ionosphere (atmosphere) parameters. It is shown that ionospheric scintillation at 400 MHz is weak due to a small electron concentration and ionosphere thickness....

We present observations of the 22 GHz water vapor megamasers in the Circinus galaxy made with the Tidbinbilla 70 m telescope. These observations confirm the rapid variability seen earlier by Greenhill et al. (1997). We show that this rapid variability can be explained by interstellar scintillation, based on what is now known of the interstellar scintillation seen in a significant number of flat...

Satellite communication channels are affected by ionospheric scintillation phenomenon, causing signal attenuation. This paper presents the performance of a WaveletBased Multi-Carrier Code Division Multiple Access (WBMC-CDMA) under flat scintillation channels, in comparison with the Fourier-Based method. With scintillation, as the scintillation index S4 increases, the performance of communicatio...

Besides their intended use in radionavigation, global positioning system (GPS) satellite signals provide convenient radio beacons for ionospheric studies. Among other propagation phenomena, the ionosphere affects GPS signal propagation through amplitude scintillations that develop after radio waves propagate through ionospheric electron density irregularities. This paper outlines the design, te...

The energy density of high frequency waves propagating in highly oscillatory random media is well approximated by solutions of deterministic kinetic models. The scintillation function determines the statistical instability of the kinetic solution. This paper analyzes the single scattering term in the scintillation function. This is the term of the scintillation function that is linear in the po...

Aircraft landing using the Global Positioning System (GPS) in equatorial regions is more difficult than in other regions because ionospheric scintillation is prevalent. Ionospheric scintillation causes amplitude fades of 20 dB or more and an increase in the phase jitter. This research evaluates techniques to enhance a GPS receiver for overcoming ionospheric scintillation. To validate the design...

Radio wave scintillations are rapid fluctuations in both amplitude and phase of signals propagating through the atmosphere. GPS signals can be affected by these disturbances which can lead to a complete loss of lock when the electron density strongly fluctuates around the background ionization level at small spatial scales. This paper will present recent improvements to the theoretical Global I...

High-precision fast photometry from ground-based observatories is a challenge due to intensity fluctuations (scintillation) produced by the Earth’s atmosphere. Here we describe a method to reduce the effects of scintillation by a combination of pupil reconjugation and calibration using a comparison star. Because scintillation is produced by high-altitude turbulence, the range of angles over whi...