نتایج جستجو برای: photon and neutron flux

تعداد نتایج: 16868852  

Journal: :Health physics 1996
X Mao K R Kase W R Nelson

This paper characterizes the functional dependence of the giant dipole resonance neutron yield produced by electrons in terms of the atomic number (Z) and thickness (T) of the target. The yields were calculated by integrating, over the photon energy, the product of the differential photon track length and published photoneutron cross sections. The EGS4 Monte Carlo code and analytical formulas w...

2015
S. Barros I. Bergström

In 2014 a new vertical flight path was installed at the neutron time-of-flight facility, n TOF, at CERN. The beam line optimization of this second experimental area (EAR2) was performed by FLUKA simulations with a detailed model of the facility, including the spallation target, neutron beam line, magnet, collimators and beam dump. The beam profile as well as neutron and gamma fluxes were calcul...

2006
E. J. Axton

The NBS Standard Thermal Neutron Flux has been calibrated in terms of the B(n, a) cross section [De Juren and Rosenwasser, 1954] and of the gold thermal neutron capture cross section [Mosburg and Murphey, 1961]. The present calibration, based on absolute counting of Au activity by the 4:ir@-y coincidence method, represents part of a program of international comparisons of thermal neutron flux d...

ژورنال: سنجش و ایمنی پرتو 2020

Neutron is one of the products of the interaction of high energy protons with light nuclei. Using computational Monte Carlo codes, it is possible to calculate and predict the neutron spectrum, neutron flux, and doses by simulating the system. But the use of different hadronic models in this process can influence the results of these calculations. In this research, the response of the four hadro...

Journal: :Radiation protection dosimetry 2007
D J Thomas N P Hawkes L N Jones P Kolkowski N J Roberts

Bonner sphere (BS) sets which use activation foils as the central thermal neutron sensor have advantages over active BS systems in certain environments, for example, pulsed fields, or fields with high photon components. In such environments, they may be the only type of neutron spectrometer which can be used. This paper describes work, using both measurements and calculations, to validate the r...

2017
M.M. Firoozabadi Gh. Izadi Vasafi K. Karimi-sh

BACKGROUND In neutron interaction with matter and reduction of neutron energy due to multiple scatterings to the thermal energy range, increasing the probability of thermal neutron capture by neutron captures makes dose enhancement in the tumors loaded with these materials. OBJECTIVE The purpose of this study is to evaluate dose distribution in the presence of 10B, 157Gd and 33S neutron captu...

2000
Christian Wernli Annette Fiechtner Jukka Kahilainen

INTRODUCTION A new type of personal dosimeter has been developed by RADOS Technology Oy. This system is based on a novel detector type, an ionisation chamber with so-called Direct Ion Storage (DIS). Ionisation chambers are sensitive to both neutrons and photons. Therefore, the application of the DIS principle to neutron dosimetry requires a double-chamber system for separating photon from neutr...

2002
J. S. FINDLAY N. P. HAWKES M. R. SENk

Measurements are presented of the photofission cross section and the mean number fi of neutrons per fission for 232Th made using bremsstrahlung from the Harwell electron linear accelerator HELIOS and a high efficiency neutron detector to record neutron multiplicity distributions. The cross section is interpreted in terms of a fission barrier with shallow wells in two separate outer barriers. In...

A. Antoniadis, J.G. Fantidis,

Background: A Boron Neutron Capture Therapy (BNCT) facility, based on a DT neutron generator, with the final goal to find out a potential, alternative, solution to existing BNCT treatment facilities which are based on nuclear reactors is examined. Materials and Methods: With the aim of the MCNP4B Monte Carlo code different beam-shaping assembly (BSA) configurations were considered. Lead was sel...

2005
Dong Lai

We present a theoretical study of radiative transfer in strongly magnetized electron-ion plasmas, focusing on the effect of vacuum polarization due to quantum electrodynamics. This study is directly relevant to thermal radiation from the surfaces of highly magnetized neutron stars, which have been detected in recent years. Strong-field vacuum polarization modifies the photon propagation modes i...

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