Boron autoradiography of botanical specimens

1972 ◽  
Vol 50 (1) ◽  
pp. 245-246 ◽  
Author(s):  
Robert H. Stinson
Keyword(s):  
Neutron Source ◽  
Gamma Rays ◽  
Neutron Capture ◽  
Plant Material ◽  
Alpha Particles ◽  
Photographic Film

Boron autoradiographs of plant material may be obtained on a new commercially available "film." Samples and film are placed in a neutron source. The film records the location of boron atoms by detecting alpha particles emitted from boron after neutron capture. The film is completely insensitive to gamma rays, which usually cause undesirable darkening when this technique is used with conventional photographic film. Variation in content of boron in sunflowers grown at varying boron concentrations was easily detected. Boron tends to accumulate at the tip and along the margins of the leaf.

LOGGING OF DRILL HOLES BY THE NEUTRON, GAMMA METHOD, AND GAMMA RAY SCATTERING

Geophysics ◽  
1951 ◽  
Vol 16 (2) ◽  
pp. 260-276 ◽  
Author(s):  
Henry Faul ◽  
C. W. Tittle
Keyword(s):  
Gamma Radiation ◽  
Neutron Source ◽  
Gamma Rays ◽  
Hydrogen Content ◽  
Neutron Capture ◽  
Gamma Ray ◽  
Drilling Mud ◽  
Favorable Conditions ◽  
Drill Holes ◽  
Gamma Intensity

The intensity distribution of secondary gamma radiation resulting from neutron capture has been measured in simulated drill holes, of various types such as cased and uncased, empty and water‐filled. The intensity of neutron‐capture gamma rays depends on the hydrogen content of the rock. In a six‐inch well, it increases with hydrogen content at points within about 16 inches of the neutron source and decreases at more distant points. The absolute gamma intensity is greatly reduced when non‐hydrogenous gamma‐ray or neutron absorbers, e.g., lead or boron are introduced between logging probe and formation. The slope of logarithmic gamma ray intensity vs. distance remains virtually constant. It changes with the hydrogen content of the formation and offers a means of quantitatively estimating porosity behind casing despite extraneous absorption. The slope can be measured automatically in the well by two gamma detectors placed in a probe at fixed distances from a neutron source. Hydrogenous material between probe and rock increases the slope. Two or three inches of drilling mud seriously impair the sensitivity. Gamma radiation scattered by the walls of drill holes necessitates proper shielding for detectors used in (n, γ) logging with a radium‐beryllium source. A shielded detector is predominantly sensitive to the hard neutron‐capture gamma rays and tends to discriminate against the softer scattered radiation. The scattered intensity decreases with increasing bulk density of the formation. Under favorable conditions, continuous logs of formation density as a function of depth can be obtained.

New Particles

2018 ◽  
Author(s):  
Roger H. Stuewer
Keyword(s):  
Gamma Rays ◽  
Atomic Hydrogen ◽  
Nuclear Physics ◽  
Hydrogen Isotope ◽  
Alpha Particles ◽  
Cloud Chamber ◽  
Ernest Rutherford ◽  
James Chadwick ◽  
Theoretical Foundations ◽  
New Particles

In December 1931, Harold Urey discovered deuterium (and its nucleus, the deuteron) by spectroscopically detecting the faint companion lines in the Balmer spectrum of atomic hydrogen that were produced by the heavy hydrogen isotope. In February 1932, James Chadwick, stimulated by the claim of the wife-and-husband team of Irène Curie and Frédéric Joliot that polonium alpha particles cause the emission of energetic gamma rays from beryllium, proved experimentally that not gamma rays but neutrons are emitted, thereby discovering the particle whose existence had been predicted a dozen years earlier by Chadwick’s mentor, Ernest Rutherford. In August 1932, Carl Anderson took a cloud-chamber photograph of a positron traversing a lead plate, unaware that Paul Dirac had predicted the existence of the anti-electron in 1931. These three new particles, the deuteron, neutron, and positron, were immediately incorporated into the experimental and theoretical foundations of nuclear physics.

Nuclear Electrons and Nuclear Structure

2018 ◽  
Author(s):  
Roger H. Stuewer
Keyword(s):  
Nuclear Structure ◽  
Beta Decay ◽  
Gamma Rays ◽  
Alpha Particle ◽  
Continuous Distribution ◽  
Alpha Particles ◽  
Light Nuclei ◽  
Coincidence Method ◽  
Wolfgang Pauli ◽  
Beta Particles

Serious contradictions to the existence of electrons in nuclei impinged in one way or another on the theory of beta decay and became acute when Charles Ellis and William Wooster proved, in an experimental tour de force in 1927, that beta particles are emitted from a radioactive nucleus with a continuous distribution of energies. Bohr concluded that energy is not conserved in the nucleus, an idea that Wolfgang Pauli vigorously opposed. Another puzzle arose in alpha-particle experiments. Walther Bothe and his co-workers used his coincidence method in 1928–30 and concluded that energetic gamma rays are produced when polonium alpha particles bombard beryllium and other light nuclei. That stimulated Frédéric Joliot and Irène Curie to carry out related experiments. These experimental results were thoroughly discussed at a conference that Enrico Fermi organized in Rome in October 1931, whose proceedings included the first publication of Pauli’s neutrino hypothesis.

Accelerator-based neutron source for boron neutron capture therapy

2021 ◽  
Author(s):  
Alexander A. Ivanov ◽  
Artem N. Smirnov ◽  
Sergei Yu. Taskaev ◽  
Boris F. Bayanov ◽  
Yurii I. Belchenko ◽  
...  
Keyword(s):  
Neutron Source ◽  
Boron Neutron Capture Therapy ◽  
Neutron Capture ◽  
Neutron Capture Therapy ◽  
Boron Neutron Capture

Analysis of primary electric dipole gamma rays from slow-neutron capture by Ca isotopes

1987 ◽  
Vol 36 (2) ◽  
pp. 533-542 ◽  
Author(s):  
S. Kahane ◽  
J. E. Lynn ◽  
S. Raman
Keyword(s):  
Gamma Rays ◽  
Electric Dipole ◽  
Neutron Capture ◽  
Slow Neutron

The Feasibility Research for Detecting the Nitrogen Content in Sewage with NIPGA Method

2014 ◽  
Vol 602-605 ◽  
pp. 2445-2448
Author(s):  
Fu Quan Jia ◽  
Zhu Jun Tian
Keyword(s):  
Nitrogen Content ◽  
Neutron Source ◽  
Total Nitrogen ◽  
Gamma Rays ◽  
Neutron Generator ◽  
Limit Of Detection ◽  
Total Nitrogen Content ◽  
Feasibility Research ◽  
Type Water

NIPGA technology is used in order to detect the total nitrogen content in sewage quickly. D-D neutron generator is used as the neutron source and BGO detector is used to detect gamma rays of nitrogen. The simulated result of MCNP shows the nitrogen’s limit of detection is 0.2 mg/L and the total nitrogen in V-type water can be detected. So this method can be used to detect the total nitrogen content in sewage quickly.

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