نتایج جستجو برای: pencil beam

تعداد نتایج: 116960  

2011
X. T. Li X. W. Zhao J. N. Wang M. H. Yin

Multi-beam antenna arrays have important applications in the field of communications and radar. The reconfigurable design problem is to find the element in a sector pattern main beam with side lobes. The same excitation amplitudes applied to the array with zero-phase should be in a high directivity, low side lobe pencil shaped main beam. This paper presents a new method of designing a reconfigu...

Journal: :Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics 2014
M Zarza-Moreno P Carreira L Madureira H Miras Del Rio F J Salguero A Leal N Teixeira A P Jesus G Mora

This study evaluates the dosimetric impact caused by an air cavity located at 2 mm depth from the top surface in a PMMA phantom irradiated by electron beams produced by a Siemens Primus linear accelerator. A systematic evaluation of the effect related to the cavity area and thickness as well as to the electron beam energy was performed by using Monte Carlo simulations (EGSnrc code), Pencil Beam...

2000
J. Bosser C. Dimopoulou A. Feschenko R. Maccaferri

A profile monitor is described that makes use of a low-intensity and low-energy ion beam to measure the transverse profile of a dense proton beam of small dimensions. Three techniques are considered based on the use of ion beams having a pencil, curtain, or cylindrical shape. The detector is almost non-interceptive for the proton beam and does not introduce disturbances in the machine environme...

2011
J. Nguyen M. Durante C. Bert

Irradiations of intra-fractionally moving organs with a scanned ion beam need to be performed with a dedicated motion mitigation technique to avoid cold-spots in the delivered dose distribution due to interplay [1]. One possible way to achieve this is beam tracking [2]. Beam tracking compensates organ motion by adjusting the position of the pencil beam in real-time during treatment delivery. Th...

Journal: :Monthly Notices of the Royal Astronomical Society 1969

Journal: :Monthly Notices of the Royal Astronomical Society 1966

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