Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 2 of 2

Full-Text Articles in Physics

Radiation Dose Distributions In Three Dimensions From Tomographic Optical Density Scanning Of Polymer Gels: Ii. Optical Properties Of The Bang Polymer Gel, Yevgeniya Zastavker, Marek Maryanski, John Gore Jun 2012

Radiation Dose Distributions In Three Dimensions From Tomographic Optical Density Scanning Of Polymer Gels: Ii. Optical Properties Of The Bang Polymer Gel, Yevgeniya Zastavker, Marek Maryanski, John Gore

Yevgeniya V. Zastavker

A newly developed method of radiation dosimetry makes use of the optical properties of polymer gels. The dose-response mechanism relies on the production of light-scattering polymer micro-particles in the gel at each site of radiation absorption. The scattering produces an attenuation of transmitted light intensity that is directly related to the dose and independent of dose rate. For the BANG polymer gel (bis, acrylamide, nitrogen, and gelatin) the shape of the dose-response curve depends on the fraction of the cross-linking monomer in the initial mixture and on the wavelength of light. At 500 nm the attenuation coefficient (μ) increases by …


Solving Ill-Posed Problems With Artificial Neural Networks, Arun D. Kulkarni Dec 1990

Solving Ill-Posed Problems With Artificial Neural Networks, Arun D. Kulkarni

Arun Kulkarni

With many physical problems, measurement of spectral distribution, cosmic radiation, aerial and satellite imaging indirect sensing/recording devices are used. In many of these cases, the recording systems can be modeled by a Fredholm integral equation of the first kind. An inversion of the kernel representing a system, in the presence of noise, is an ill-posed problem. The direct inversion often yields an unacceptable solution. In this paper, we suggest an artificial neural network (ANN) architecture to solve certain kinds of ill-posed problems. The weights in the model are initialized using eigen-vectors and eigen-values of the kernel matrix that characterize the …