scholarly journals Liquid argon characterization of the X-ARAPUCA with alpha particles, gamma rays and cosmic muons

2021 ◽  
Vol 16 (11) ◽  
pp. P11002
Author(s):  
H.V. Souza ◽  
E. Segreto ◽  
A.A. Machado ◽  
R.R. Sarmento ◽  
M.C.Q. Bazetto ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Liquid Argon ◽  
Alpha Particles ◽  
Cosmic Muons

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.

scholarly journals Characterization of gamma irradiation-induced mutations in Arabidopsis mutants deficient in non-homologous end joining

2020 ◽  
Vol 61 (5) ◽  
pp. 639-647
Author(s):  
Yan Du ◽  
Yoshihiro Hase ◽  
Katsuya Satoh ◽  
Naoya Shikazono
Keyword(s):  
Gamma Rays ◽  
Wild Type ◽  
End Joining ◽  
Complex Type ◽  
Single Base ◽  
In The Wild ◽  
Non Homologous End Joining ◽  
Dna Ends ◽  
Wild Type Control

Abstract To investigate the involvement of the non-homologous end joining (NHEJ) pathway in plant mutagenesis by ionizing radiation, we conducted a genome-wide characterization of the mutations induced by gamma rays in NHEJ-deficient Arabidopsis mutants (AtKu70−/− and AtLig4−/−). Although both mutants were more sensitive to gamma rays than the wild-type control, the AtKu70−/− mutant was slightly more sensitive than the AtLig4−/− mutant. Single-base substitutions (SBSs) were the predominant mutations in the wild-type control, whereas deletions (≥2 bp) and complex-type mutations [i.e. more than two SBSs or short insertion and deletions (InDels) separated by fewer than 10 bp] were frequently induced in the mutants. Single-base deletions were the most frequent deletions in the wild-type control, whereas the most common deletions in the mutants were 11–30 bp. The apparent microhomology at the rejoined sites of deletions peaked at 2 bp in the wild-type control, but was 3–4 bp in the mutants. This suggests the involvement of alternative end joining and single-strand annealing pathways involving increased microhomology for rejoining DNA ends. Complex-type mutations comprising short InDels were frequently detected in the mutants, but not in the wild-type control. Accordingly, NHEJ is more precise than the backup pathways, and is the main pathway for rejoining the broken DNA ends induced by ionizing radiation in plants.

Characterization of the response of Perovskite solar cells to gamma rays and neutrons

2019 ◽  
Author(s):  
Robert McTaggart ◽  
Ryan Michel ◽  
Qiquan Qiao ◽  
Ashish Dubey ◽  
Khan Mamun Reza ◽  
...  
Keyword(s):  
Solar Cells ◽  
Gamma Rays ◽  
Perovskite Solar Cells

Recoil proton, alpha particle, and heavy ion impacts on microdosimetry and RBE of fast neutrons: analysis of kerma spectra calculated by Monte Carlo simulation

2001 ◽  
Vol 79 (2) ◽  
pp. 189-195 ◽  
Author(s):  
Jean-Philippe Pignol ◽  
Jakobus Slabbert
Keyword(s):  
Monte Carlo ◽  
Recoil Proton ◽  
Clinical Results ◽  
Heavy Ion ◽  
Alpha Particles ◽  
Fast Neutrons ◽  
Monte Carlo Code ◽  
Powerful Method ◽  
Biological Effectiveness

Fast neutrons (FN) have a higher radio-biological effectiveness (RBE) compared with photons, however the mechanism of this increase remains a controversial issue. RBE variations are seen among various FN facilities and at the same facility when different tissue depths or thicknesses of hardening filters are used. These variations lead to uncertainties in dose reporting as well as in the comparisons of clinical results. Besides radiobiology and microdosimetry, another powerful method for the characterization of FN beams is the calculation of total proton and heavy ion kerma spectra. FLUKA and MCNP Monte Carlo code were used to simulate these kerma spectra following a set of microdosimetry measurements performed at the National Accelerator Centre. The calculated spectra confirmed major classical statements: RBE increase is linked to both slow energy protons and alpha particles yielded by (n,α) reactions on carbon and oxygen nuclei. The slow energy protons are produced by neutrons having an energy between 10 keV and 10 MeV, while the alpha particles are produced by neutrons having an energy between 10 keV and 15 MeV. Looking at the heavy ion kerma from <15 MeV and the proton kerma from neutrons <10 MeV, it is possible to anticipate y* and RBE trends.Key words: fast neutron, kerma, microdosimetry, RBE, Monte Carlo.

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