نتایج جستجو برای: neutron contamination

تعداد نتایج: 98839  

2001
V. B. Ignatiev A. G. Kuranov K. A. Postnov M. E. Prokhorov

Unresolved coalescing binary neutron stars in the Galaxy and beyond produce a stochastic gravitational wave background within the LISA frequency band, which can be potentially dangerous for possible detection of fundamentally more interesting relic cosmological backgrounds. Here we address the question what effects the unavoidable eccentricity of orbits of these systems should have on the prope...

Journal: :Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine 2001
J P Lin T C Chu S Y Lin M T Liu

This study involves the measurement of photoneutron contamination emitted from a Siemens Primus medical linear accelerator by using BD-PND bubble detectors. Various bubble detectors were arranged around the linac head with the interval of I m and at the same height as the isocenter to measure the dose equivalent distribution in the treatment room. The measurements were performed for 15 MV X-ray...

Journal: :iranian journal of radiation research 0
kakavand 1 department of physics, zanjan university, zanjan, iran ghafourian atomic energy organization of iran, tehran, iran haji-shafeieha 1 department of physics, zanjan university, zanjan, iran

background: miniature neutron sources with high neutron flux have abundant applications in medicine, industry and researches. the most important general characteristic of miniature neutron sources is their diameter which is 3mm in average. in this research, we have surveyed and designed an am-be miniature neutron source fabrication. materials and methods: this investigation resulted in creation...

Journal: :Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine 2015
A A Naqvi M Maslehuddin Khateeb Ur-Rehman O S B Al-Amoudi

The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete ...

2006
DAVID ELMORE T LEE

Determination of the more common light elements such as nitrogen and chlorine at trace levels is difficult because of their high abundance on sample surfaces, in materials used to build analysis instruments, and in the residual gas of the instrument vacuum. We present here a new approach to analysis of these elements: accelerator mass spectrometry (AMS) combined with neutron activation. The pro...

Journal: :Medical physics 1980
A M Kellerer J Rassow

Neutron beams for therapy always contain some gamma ray contamination that varies with depth and with distance from the beam axis. The problem therefore arises how the varying gamma ray contribution should be accounted for in dose specification. Not infrequently a "total effective dose" DE is quoted that is equal to the neutron dose plus the gamma ray dose divided by a constant weight factor ta...

Journal: :middle east journal of digestive diseases 0
maryam hashemian hossein poustchi akram pourshams masoud khoshnia john douglas brockman azita hekmatdoost

background in the golestan cohort study that was launched to investigate the causes of esophageal cancer, a complete biospecimen bank was established for storage of collected blood, urine, hair, and nail samples. the objective of this study was to evaluate the feasibility of nail samples as a biomarker of selected trace elements status. methods thirty toenail samples were selected randomly from...

Journal: :Physics in medicine and biology 2007
Myong-Seop Kim Byung-Chul Lee Sung-Yul Hwang Heonil Kim Byung-Jin Jun

The HANARO neutron irradiation facility for various applications in the boron neutron capture therapy (BNCT) field was developed, and its characteristics were investigated. In order to obtain the sufficient thermal neutron flux with a low level of contamination by fast neutrons and gamma rays, a radiation filtering method was adopted. The radiation filter was designed by using a silicon single ...

Journal: :basic and clinical cancer research 0
hoda darestani 1nuclear engineering department, science and research unit, azad university, tehran, i.r. iran hassan ali nedaie radiotherapy oncology department, cancer institute, tehran university of medical sciences, tehran, i.r. iran azim arbabi radiation oncology department, imam hussein medical center, faculty of medicine, shahid beheshti university of medical sciences, tehran, i.r. iran kheirollah mohammadi nuclear engineering department, amirkabir industrial university, tehran, i.r. iran mahmood allahverdi radiotherapy oncology department, cancer institute, tehran university of medical sciences, tehran, i.r. iran arjang shahvar agricultural, medical and industrial research school, karaj, i.r. iran

background : in spite of clinically useful photon and electron beams, high energy linacs produce secondary particles such as neutrons (photo-neutron production). neutrons have important roles during treatment with high energy photons in terms of protection and dose escalation. in this project, neutron dose equivalent of 18 mv varian accelerators is calculated by tld600 and tld700. materials and...

Journal: :iranian journal of radiation research 0
h.r. vega-carrillo unidad académica de estudios nucleares, universidad autonoma de zacatecas, zacatecas, zac. méxico r. barquero departamento de radiología del hospital universitario rio hortega, valladolid, spain g.a. mercado unidad academica de matematicas universidad autónoma de zacatecas, zacatecas, zac. méxico

background: in high-intensity, mixed and pulsed neutron fields the use of spectrometers or area monitors with active detectors is useless in these conditions neutron measuring devices must have a passive detector. here a passive neutron area monitor with cr39 track detector was designed and the response was calculated. materials and methods: the response of a passive neutron area monitor with c...

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