نتایج جستجو برای: background radiation
تعداد نتایج: 1052985 فیلتر نتایج به سال:
Potential biological damage from radiation received during fluoroscopy procedures is of particular concern because of the high volume and variety of procedures performed and the increasing length of radiation exposure. This article focuses on the effects of low-level radiation, gaps in education and skills among personnel performing and assisting with fluoroscopy, the certification and privileg...
An increase in radiation dose exposure In 2006, the average annual effective dose per individual in the US was 6.2 mSv1, a figure that has almost doubled over the last 25 years [1]. Approximately 50% of the dose currently received stems from background radiation [1], but varies depending on where you live (for example, in Australia dose levels are about half of levels in the US) [2]. The other ...
The in situ measured average outdoor absorbed dose rate in air was found to vary from 108.4 to 1596.4 nGy h at Homa Mountain area in southwestern Kenya. Rock and soil samples collected gave average values of the radioactivity concentrations of K, Ra and Th of 915.6, 195.3 and 409.5 Bq kg, respectively. The range of the annual effective dose for a person living in Homa Mountain area calculated v...
OBJECTIVE To compare the total work-related radiation dose in our department of radiology with the dose in Dutch residences, taking x-ray radiation, external natural radiation and radon into account. METHODS Annual doses due to exposure to x-rays and external natural radiation were derived from the measured personal dose equivalent [H(p)(10)] of 144 workers. Additionally, departmental (222)Rn...
We experimentally demonstrate ultrafast polarization switching of terahertz (THz) radiation generated by dual-color driving pulses composed of orthogonally polarized fundamental and second-harmonic waves, which can be controlled by field-free molecular alignment in air by modulating the relative phase between the two field components as a transient dynamic wave plate. By fine-tuning the time de...
A national radon survey is still lacking for Greece. Some groups have carried out several more or less local or extended radon surveys and valuable experience has been gained. After the first preliminary survey carried out by our group, where 500 Kodak LR-115 etched track detectors were placed in Greek schools and dwellings for one year, indoor radon measurements were continued by placing the s...
The calculations of Guang-Wen Ma’s recent Letter [Phys.Lett. A239, (1998) 209] contain an easily detectable error which makes his conclusions irrelevant. ∗E-mail: [email protected]
Blazar emission of gamma rays and cosmic ray production of gamma rays in gas-rich clusters have been proposed recently as alternative sources of the high energy extragalactic diffuse gamma ray background radiation. We show that these sources also produce a very different high energy extragalactic diffuse neutrino background radiation. This neutrino background may be detected by the new generati...
An epoch of accelerated expansion, or inflation, in the early universe solves several cosmological problems. While there are many models of inflation only recently has it become possible to discriminate between some of the models using observations of the cosmic microwave background radiation and large-scale structure. In this talk, we discuss inflation and its observational consequences, and t...
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