[1] Using an eight-station time of arrival (TOA) network composed of NaI(Tl) scintillation detectors and wideband electric field derivative (dE/dt) antennas covering approximately 1 km on the ground, we have located both the sources of X-ray emissions and electric field changes produced during the leader phase of both downward negative natural and rocket-triggered lightning strokes. We show tha...

In the studies of radiological assessment, 137Cs is the most important radioactive contaminant, produced from the atmospheric bomb tests, discharges from nuclear reprocessing plants and the Chernobyl reactor accident. The systems most commonly used for the in situ monitoring of γ-radiation in seawater, are based on NaI(Tl) detectors, which are characterized by high detection efficiency and low ...

The main detectors used for clinical dosimetry are ionisation chambers and semiconductors. Thermoluminescent (TL) dosimeters are also of interest because of their following advantages: i) wide useful dose range, ii) small physical size, iii) no need for high voltage or cables, i.e. stand alone character, and iv) tissue equivalence (LiF) for most radiation types. TL detectors can particularly be...

[1] Terrestrial gamma-ray flashes (TGFs)-very short, intense bursts of electrons, positrons, and energetic photons originating from terrestrial thunderstorms-have been detected with satellite instruments. TGF and Energetic Thunderstorm Rooftop Array (TETRA), an array of NaI(Tl) scintillators at Louisiana State University, has now been used to detect similar bursts of 50 keV to over 2 MeV gamma-...

Measurements have been performed with a 2.85 MeV mono-energetic neutron beam of relative scintillation efficiency and pulse-shape for nuclear and electron recoils in NaI(Tl) and CaF2(Eu). Scintillation efficiencies in NaI(Tl) relative to 60 keV gamma events were found to be 27.5 ± 1.8 % for Na recoils (recoil energy Erec > 4 keV) and 8.6 ± 0.7 % for I recoils (Erec > 10 keV). Relative scintilla...

The purpose of this study was to improve the performance of a small gamma camera, utilizing a NaI(Tl) plate and a 5" position sensitive PMT. We attempted to build a NaI(Tl) plate crystal system which retained all its advantages, while at the same time integrating some of the advantages inherent in an array-type scintillation crystal system. Flood images were obtained with a lead hole mask, and ...

[1] We report the observation of an intense gamma-ray burst observed on the ground at sea level, produced in association with the initial-stage of rocket-triggered lightning at the International Center for Lightning Research and Testing at Camp Blanding, FL. The burst was observed simultaneously on three NaI(Tl)/photomultiplier tube detectors that were located 650 m from the triggered lightning...

Small organic scintillators that exhibit pulse shape dflierences (PSD) in response to charged particles have been investigated as possible neutron detectors in the energy range from 1 to 200 MeV. Neutrons in this energy range can induce reactions such as (up) and (n,alpha) in these scintillators, and the cross sections for these reactions vary with energy. Pulse-height and PSD dktributions were...