Perspectives of High Pressure Xenon Gamma-Ray Spectrometers to Detect and Identify Radioactive and Fissile Materials

2007 ◽  
pp. 155-172
Author(s):  
V. V. Dmitrenko ◽  
S. E. Ulin ◽  
V. M. Grachev ◽  
K. F. Vlasik ◽  
Z. M. Uteshev ◽  
...  
Keyword(s):  
High Pressure ◽  
Gamma Ray

A new coplanar-grid high-pressure xenon gamma-ray spectrometer

2005 ◽  
Vol 52 (6) ◽  
pp. 2932-2939 ◽  
Author(s):  
S.D. Kiff ◽  
Zhong He ◽  
G.C. Tepper
Keyword(s):  
High Pressure ◽  
Gamma Ray ◽  
Gamma Ray Spectrometer ◽  
Coplanar Grid

scholarly journals In Vitro Protein Disappearance of Raw Chicken as Dog Foods Decreased by Thermal Processing, but Was Unaffected by Non-Thermal Processing

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1256
Author(s):  
Hansol Kim ◽  
Ah Hyun Jung ◽  
Sung Hee Park ◽  
Yohan Yoon ◽  
Beob Gyun Kim
Keyword(s):  
High Pressure ◽  
Electron Beam ◽  
Thermal Processing ◽  
Gamma Ray ◽  
Light Emitting Diode ◽  
High Pressure Processing ◽  
Chicken Meat ◽  
In Vitro Assays ◽  
Uv Led

The objectives of the present study were to determine the influence of thermal and non-thermal processing procedures on in vitro ileal disappearance (IVID) of dry matter (DM) and crude protein (CP) in chicken meat as dog foods using 2-step in vitro assays. In thermal processing experiments, IVID of DM and CP in chicken meat thermally processed at 70, 90, and 121 °C, respectively, with increasing processing time was determined. For non-thermal processing experiments, IVID of DM and CP in chicken meat processed by high-pressure, ultraviolet-light emitting diode (UV-LED), electron-beam, and gamma-ray was determined. Thermal processing of chicken meat at 70, 90, and 121 °C resulted in decreased IVID of CP (p < 0.05) as heating time increased. In non-thermal processing experiment, IVID of CP in chicken meat was not affected by high-pressure processing or UV-LED radiation. In vitro ileal disappearance of CP in electron-beam- or gamma-ray-irradiated chicken meat was not affected by the irradiation intensity. Taken together, ileal protein digestibility of chicken meat for dogs is decreased by thermal processing, but is minimally affected by non-thermal processing methods.

scholarly journals Secondary gamma rays excited by the passage of neutrons through matter

1935 ◽  
Vol 150 (871) ◽  
pp. 637-668 ◽  
Keyword(s):  
High Pressure ◽  
Gamma Rays ◽  
Alpha Particle ◽  
Ionization Chamber ◽  
Gamma Ray ◽  
Beta Particle ◽  
Nuclear Excitation ◽  
Ionization Chambers ◽  
Scattering Material ◽  
Pass Through

It is well known that the absorption of neutrons in their passage through matter is due to nuclear collisions, and not appreciably to interaction with extranuclear electrons. A collision of a neutron with a nucleus may result in the scattering of the neutron, or in the disintegration of the nucleus. The experiments of Feather and of Harkins, Gans, and Newson§ have shown that several light elements, C, N, O, F, Ne are disintegrated, the mechanism probably being absorption of the neutron and emission of an alpha particle. Fermi|| has reported that a variety of elements when bombarded by neutrons show the phenomenon of induced radioactivity, emitting beta rays. He suggests that the disintegration process takes place usually by absorption of a neutron and emission of an alpha particle or proton, the resulting nucleus being an unstable radio element, transforming into a stable body by emission of a beta particle. The experiments here to be described show that when neutrons pass through various substances, gamma rays are produced. The origin of this radiation has not definitely been established; nuclear excitation appears to be the most plausible explanation in most cases. 2—Experimental Method The general method consisted in measuring the ionization current produced by a Po + Be source (usually of about 10-15 millicuries) placed above a high pressure ionization chamber, and observing the increased ionization when a block of scattering material was placed immediately above the source. A correction was applied for the diminution of the natural effect caused by the scatterer. The increase in ionization amounted usually to 2-3%, and thus to obtain even a rough measurement of the effect, accurate measurements of the ionization currents were required. For this reason the high pressure ionization chamber was usually used in preference to the counter, since measurements to one part in a thousand are impracticable with the latter. The ionization method has, however, the disadvantage that both gamma rays and neutrons are detected. To distinguish between the two radiations, two similar ionization chambers were used, one containing argon at a pressure of 90 atmospheres, the other hydrogen at about 60 atmospheres. The former is more sensitive to gamma radiation, the latter to neutrons. The ionization chambers were of steel and had cylindrical walls 1 cm thick; the radiations entered through the roofs of the chambers, which were 2·5 cm thick. The inside dimensions were 16 cm high and 12 cm diameter, with a 2-cm diameter central electrode. Collecting potentials of 250-500 volts were used. Measurements were made by a balance method and followed standard practice. From the measurements of ionization currents in argon and hydrogen estimates may be made of the neutron ( n ) and gamma ray (γ) intensities separately. The method by which this is achieved is described in § 11.

Measurement of Electron Drift Velocities in the Mixture of Xe and He for a New High-Pressure Xe Gamma-Ray Detector

2003 ◽  
Vol 42 (Part 1, No. 1) ◽  
pp. 333-334 ◽  
Author(s):  
Shingo Kobayashi ◽  
Valery V. Dmitrenko ◽  
Tadayoshi Doke ◽  
Victor M. Grachev ◽  
Nobuyuki Hasebe ◽  
...  
Keyword(s):  
High Pressure ◽  
Gamma Ray ◽  
Electron Drift ◽  
Gamma Ray Detector

Measurement of the gamma-ray lines with high-pressure xenon spectrometer on board the orbital station MIR

1993 ◽  
Author(s):  
Yu. T. Yurkin ◽  
Aleksey E. Bolotnikov ◽  
I. V. Chernycheva ◽  
Valery V. Dmitrenko ◽  
A. M. Galper ◽  
...  
Keyword(s):  
High Pressure ◽  
Gamma Ray ◽  
Orbital Station

Physical Properties of Shales and Possible Origin of High Pressures

1980 ◽  
Vol 20 (05) ◽  
pp. 341-348 ◽  
Author(s):  
William C. Pritchett
Keyword(s):  
High Pressure ◽  
Cross Sections ◽  
Neutron Capture ◽  
Gamma Ray ◽  
Gulf Coast ◽  
Capture Cross ◽  
Neutron Lifetime ◽  
Ray Density ◽  
Depth Of Investigation ◽  
Capture Cross Sections

Introduction Laboratory and borehole measurements of shale properties may be unreliable because of modification during or after drilling or coring. The borehole gravimeter is an ideal tool for measuring the bulk density of thick shale units because of its great depth of investigation and negligible sensitivity to shale in the vicinity of the borehole, which may have been modified in drilling. By contrast, the scatter gamma ray density log has an extremely shallow depth of investigation and its response may be dominated by modified shale surrounding a borehole. A comparison of bulk densities measured by these two methods in both sands and shales was made in three U.S. gulf coast wells. In all three wells the two methods yielded comparable densities for the sands. But in two wells, which were drilled with fresh muds, the density log yielded shale bulk densities significantly less than those shown by the borehole gravimeter. These data indicate that shale adjacent to the borehole in these two wells had been modified by drilling and the modified shale densities had been reduced significantly. In the well drilled with a saline mud, bulk densities from the two methods were in close agreement in both sands and shales, which indicates that shales adjacent to the borehole in this well were not modified significantly. High-pressure shales are particularly susceptible to modification during drilling since they are relatively permeabble and soft. Sometimes they even flow. Density log data in high-pressure shales are unreliable due to probable shale modification. Unfortunately, we have no borehole gravimeter data in high. pressure shales and, therefore, no reliable measurements of bulk densities in their natural state. The best data available for studying high-pressure shales are some neutron lifetime logs. The effective depth of investigation of the neutron lifetime log is considerably greater than that of the scatter gamma ray density log.1,2 Therefore, neutron lifetime log measurements should be affected much less by any modified shale near the borehole than would measurements made with a density log. Neutron lifetime logs show a progressive decrease in macroscopic neutron capture cross section with increasing depth for U.S. gulf coast shales with normal pore pressures. This decrease in neutron capture cross section is the result of increased compaction of shales with depth. If high-pressure shales are shales that were not compacted normally with increasing depth of burial, then they should have physical properties comparable with relatively uncompacted shales at much shallower depths of a few thousand feet (1000 to 1500 m). In particular, they should have high neutron capture cross sections as compared with normally pressured shales at slightly shallower depths. However, our logs show neutron capture cross sections for U.S. gulf coast high-pressure shales that range from normal to less than normal for their depths. These data indicate that these high-pressure shales are not shales that were never compacted. The data are consistent with an alternate hypothesis for the generation of high pore pressures in shales.

High-pressure xenon gamma-ray spectrometers: recent developments and applications

1999 ◽  
Author(s):  
Gary C. Tepper ◽  
Robert L. Palmer ◽  
Jon R. Losee
Keyword(s):  
High Pressure ◽  
Gamma Ray ◽  
Recent Developments
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