نتایج جستجو برای: scintillation index
تعداد نتایج: 401329 فیلتر نتایج به سال:
The earth’s ionosphere can cause serious problems for many radio applications: DOD C31 and navigation systems and commercial applications such as communications, radio astronomy and navigation. They can all be seriously affected by ionospheric disturbances. Disturbance effects such as amplitude fading and phase scintillation limit the ability to coherently integrate weak signals. One solution, ...
A bidirectional horizontal-path optical link was demonstrated between Strawberry Peak (SP), Lake Arrowhead, California, and the JPL Table Mountain Facility (TMF), Wrightwood, California, during June and November of 1998. The 0.6-m telescope at TMF was used to broadcast a 4-beam 780-nm beacon to SP. The JPL-patented Optical Communications Demonstrator (OCD) at SP received the beacon, performed f...
Rapid fluctuations in the amplitude and phase of the GPS satellite signals caused by scattering from ionospheric irregularities can degrade GPS performance in a number of ways. These signal fluctuations are referred to as scintillations. Severe scintillations may result in loss of lock, and even when lock is maintained, they may cause errors decoding the GPS data messages and corrupt estimation...
The scintillation yield and decay time of LaBr3 doped with 0.2%, 0.5%, and 5% cerium were studied between 80 K and 600 K. LaBr3 :5%Ce 3+ on a photomultiplier tube shows at 300 K a very high scintillation yield of 22 800 photoelectrons per MeV 64 000 photons per MeV with a decay time of 16 ns. At 600 K the yield decreases by 15%. The scintillation yield of LaBr3 :0.2%Ce3+ is 19 800 photoelectron...
Pacific Northwest National Laboratory has recently opened a shallow underground laboratory intended for measurement of low-concentration levels of radioactive isotopes in samples collected from the environment. The development of a low-background liquid scintillation counter is currently underway to further augment the measurement capabilities within this underground laboratory. Liquid scintill...
Together, the Global Positioning System (GPS) and the Wide Area Augmentation System (WAAS) can guide aircraft down to 200 ft above the runway. This approach procedure is referred to as Localizer Performance with Vertical guidance (LPV)-200. Approach guidance using GPS and WAAS has many advantages over traditional precision approach guidance using the Instrument Landing System (ILS) and the numb...
The half-life of 87Rb was measured by a liquid scintillation method according to the efficiency tracing method. The measuring sample of rubidium chloride was dissolved in a scintillation cocktail of Insta-gel, and the rubidium was determined by gravimetry as tetraphenylborate. The result was (5.56 +/- 0.025) x 10(10) years.
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