نتایج جستجو برای: detectors

تعداد نتایج: 33248  

Journal: :journal of biomedical physics and engineering 0
b amanat department of physics, payame noor university, po box 19395-3697, tehran, iran mr kardan radiation application school, nuclear sciences and technology institute, tehran, iran r faghihi radiation research center, shiraz university, shiraz, iran sm hosseini pooya radiation application school, nuclear sciences and technology institute, tehran, iran

background: radon and its daughters are amongst the most important sources of natural exposure in the world. soil is one of the significant sources of radon/thoron due to both radium and thorium so that the emanated thoron from it may cause increased uncertainties in radon measurements. recently, a diffusion chamber has been designed and optimized for passive discriminative measurements of rado...

Journal: :iranian journal of radiation research 0
b. amanat department of physics, payame noor university, tehran, iran m.r. kardan radiation application school, nuclear sciences and technology institute, tehran, iran r. faghihi radiation research center, shiraz university, shiraz, iran m. taheri iran nuclear regulatory authority, tehran, iran

background: separate radon and thoron measurements in soil are very important in assessment of internal exposure due to inhalation of such radioactive gases. materials and methods: in this study, a low cost, small size, passive diffusion chamber has been developed for simple measurement of radon-222 and radon-220(thoron) gases separately in soil. the diffusion chamber consists of two films and ...

ژورنال: سنجش و ایمنی پرتو 2016

The aim of this paper is to design, manufacture and test the first triple RETGEM detector. Using resistive electrode in RETGEM detectors made them more robust against the electrical discharge with respect to THGEM detectors. However, even these robust detectors are not protected against electrical discharge at gains higher than 105. Studying the role of dimensions of the triple RETGEMS detector...

Journal: :رادار 0
محمدرضا تابان آرش شیخ مظفری

in this paper, we deal with the problem of adaptive coherent signal detection in gaussian interference (clutter plus noise) for surveillance pulse radars. some of the adaptive radar detectors exploit the ar model for clutter. most of these detectors have been obtained using the glr test. this test relies on the maximum likelihood estimation whose accuracy depends on the number of data. whereas,...

Journal: :iranian journal of medical physics 0
m. taghizadeh dabbagh m.sc. in medical physics, medical imaging center, imam hosein hospital, shahrood college of medical sciences, shahrood, iran. m. allahverdi assistant professor, medical physics dept., cancer institute, imam khomeini hospital, tehran university of medical sciences, tehran, iran. m. esfahani m.sc. in medical physics, cancer institute, imam khomeini hospital, tehran university of medical sciences, tehran, iran. p. haddad associate professor, radiation therapy dept., cancer institute, imam khomeini hospital, tehran university of medical sciences, tehran, iran.

introduction: during radiotherapy, high accuracy in the dose delivery is required because there is a strong  relationship between the absorbed dose, local tumor control and particularly the normal tissue damage. in  many institutions, in vivo dosimetry using diodes is performed to check the actual dose delivered. in general,  the uncertainty in the dose delivered should fall within  ± 5% of the...

and G. Mirjalily, M. Ghaffari, M.M. Nayebi, M.R. Taban,

In this paper, two suboptimum detectors are proposed for coherent radar signal detection in K-distributed clutter. Assuming certain values for several initial moments of clutter amplitude, the characteristic function of the clutter amplitude is approximated by a limited series. Using the Pade approximation, it is then converted to a rational fraction. Thus, the pdf of the clutter amplitude is o...

and G. Mirjalily, M. Ghaffari, M.M. Nayebi, M.R. Taban,

In this paper, two suboptimum detectors are proposed for coherent radar signal detection in K-distributed clutter. Assuming certain values for several initial moments of clutter amplitude, the characteristic function of the clutter amplitude is approximated by a limited series. Using the Pade approximation, it is then converted to a rational fraction. Thus, the pdf of the clutter amplitude is o...

Journal: :iranian journal of radiation research 0
m. allahverdi department of medical physics, cancer institute, tehran university of medical sciences, tehran, iran m.r. taghizadeh department of radiotherapy, imam khomeini hospital, tehran university of medical sciences, tehran, iran

abstract background: in vivo measurements of applied dose during radiotherapy treatment, is important to ensure accurate dose delivery to patients. uncertainty in dose delivery should fall within ±5% of the prescribed dose as recommended by icru. assessment of dose for radiotherapy applications performed with various types of detectors. in this study, semiconductor diodes were used which have s...

and A. Sheikhi, M. Farzan Sabahi, M. Modarres Hashemi,

In this paper, radar detection based on Monte Carlo sampling is studied. Two detectors based on Importance Sampling are presented. In these detectors, called Particle Detector, the approximated likelihood ratio is calculated by Monte Carlo sampling. In the first detector, the unknown parameters are first estimated and are substituted in the likelihood ratio (like the GLRT method). In the sec...

and A. Sheikhi, M. Farzan Sabahi, M. Modarres Hashemi,

In this paper, radar detection based on Monte Carlo sampling is studied. Two detectors based on Importance Sampling are presented. In these detectors, called Particle Detector, the approximated likelihood ratio is calculated by Monte Carlo sampling. In the first detector, the unknown parameters are first estimated and are substituted in the likelihood ratio (like &#10the GLRT method). In the s...

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