Author: Edward Joseph Dowdy
Publisher:
ISBN:
Category :
Languages : en
Pages : 132

View

Book Description

Author: R. C. Greenwood
Publisher:
ISBN:
Category : Gamma rays
Languages : en
Pages : 910

View

Book Description

Author: R. E. Chrien
Publisher: Springer Science & Business Media
ISBN: 146132940X
Category : Science
Languages : en
Pages : 875

View

Book Description
The post World War II era witnessed a tremendous growth in the research carried out in neutron-induced reactions and especially in neutron capture y-ray studies. This growth was stimulated by the availability of neutron sources, such as reactors and accelerators, and by the development of high resolution y-ray and conversion electron detectors. Today the combination of high flux reactors and precise instrumentation has produced spectral data of exceptional quality, as the pages of these proceedings illustrate. The world-wide community of the practioners of the art of cap ture y-ray spectroscopy has met three times in the last decade: the first international symposium on this subject was held at Studsvik, Sweden in 1969, and the second at Petten, The Netherlands in 1974. A smaller meeting, of mostly u. S. and some European parti cipation, was held at Argonne National Laboratory in 1966. A perusal of the proceedings of these meetings shows the striking ad vances in this now mature field of physics over the last dozen years. Each meeting has seen a small but perceptible increase in the number of papers presented and the number of laboratories repre sented. More importantly, each meeting has documented the increasing impact of (n,y) reasearch, not only on other areas of basic physics, but also on commercial and medical applications of this technology. A total of 29 invited papers and 97 contributed papers were presented at this symposium.

Author: Sidney M. Dancoff
Publisher:
ISBN:
Category : Gamma rays
Languages : en
Pages : 40

View

Book Description

Author: Brian Joseph Quiter
Publisher:
ISBN:
Category :
Languages : en
Pages : 510

View

Book Description
This dissertation examines the measurement of nuclear resonance fluorescence gamma-rays as a technique to non-destructively determine isotopic compositions of target materials that are of interest for nuclear security applications. The physical processes that can result in non-resonant background to nuclear resonance fluorescence measurements are described and investigated using a radiation transport computer code that relies on the Monte Carlo technique, MCNPX. The phenomenon of nuclear resonance fluorescence is discussed with consideration of the angular distributions of resonance emissions, the effects of nuclear recoil, and the influence of thermal motion. Models describing two ways of measuring nuclear resonance fluorescence rates in materials are considered. First the measurement of back-scattered photons is considered. In this type of measurement, the portion of the interrogating photon beam that is scattered into large relative angles is measured. When the radioactivity of the target can be overcome by shielding or by use of intense photon sources, direct measurement of gamma-rays, emitted during nuclear resonance fluorescence can provide quantitative signatures that appear to be useful for applications such as forensic age-dating of large radiological sources. However, if the target radioactivity is too intense, as in the case for most spent nuclear fuel, a second measurement type, where indirect measurement of transmitted resonant-energy photons can also provide quantitative information. This method allows radiation detectors to be better-shielded from target radioactivity, but suffers from a slower accrual rate of statistical confidence. The models described herein indicate that very intense photon sources and large high-resolution detector arrays would be needed to measure 239Pu content in spent fuel to precisions desired by nuclear safeguards organizations. However, the rates at which statistics accrue are strongly proportional to the strengths of the resonances, and measurement of a plutonium isotope with stronger resonances may provide more practical measurement rates. The model for predicting relative detection rates of nuclear resonance fluorescence gamma-rays in the transmission measurement was experimentally tested using the 238U in a mixture of depleted uranium and lead as a surrogate for 239Pu in spent fuel. The experiment indicated that the model was approximately correct, but that the process of notch refilling, which was excluded from the initial model, appears to be visible. Data files of the computer code, MCNPX, were modified to allow for nuclear resonance fluorescence to be simulated and a bug in the code was repaired to allow the code to more accurately simulate non-resonant elastic photon scattering. Simulations using this modified version of MCNPX have indicated that the magnitude of the notch refill process is comparable to that of the difference between the analytical model and the experimental data.

Author: Herbert Goldstein
Publisher:
ISBN:
Category : Gamma rays
Languages : en
Pages : 324

View

Book Description

Author:
Publisher:
ISBN:
Category : Neutron capture gamma ray spectroscopy
Languages : en
Pages : 742

View

Book Description

Author: Shankarnarayan Ramchandran
Publisher:
ISBN:
Category :
Languages : en
Pages : 254

View

Book Description

Author: F. E. Throw
Publisher:
ISBN:
Category : Gamma ray spectrometry
Languages : en
Pages : 628

View

Book Description

Author: Reginald C. Greenwood
Publisher:
ISBN:
Category : Gamma rays
Languages : en
Pages :

View

Book Description