skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity

Abstract

With the aid of a novel combination of existing equipment – JYFLTRAP and the TASISpec decay station – it is possible to perform very clean quantum-state selective, high-resolution particle-γ decay spectroscopy. We intend to study the determination of the branching ratio of the ℓ = 9 proton emission from the I{sup π} = 19/2{sup −}, 3174-keV isomer in the N = Z − 1 nucleus {sup 53}Co. The study aims to initiate a series of similar experiments along the proton dripline, thereby providing unique insights into “open quantum systems”. The technique has been pioneered in case studies using SHIPTRAP and TASISpec at GSI. Newly available radioactive decay modes in Geant4 simulations are going to corroborate the anticipated experimental results.

Authors:
;  [1]
  1. Department of Physics, Lund University, 22100 Lund (Sweden)
Publication Date:
OSTI Identifier:
22608517
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1753; Journal Issue: 1; Conference: Latin American symposium on nuclear physics and applications, Medellin (Colombia), 30 Nov - 4 Dec 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BRANCHING RATIO; COBALT 53; ISOMERS; KEV RANGE; NEUTRON EMISSION; NEUTRONS; NUCLEAR DECAY; PROTONS; QUANTUM STATES; QUANTUM SYSTEMS; RADIOACTIVITY; RESOLUTION; SIMULATION; SPECTROSCOPY

Citation Formats

Sarmiento, L. G., E-mail: Luis.Sarmiento@nuclear.lu.se, and Rudolph, D.. Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity. United States: N. p., 2016. Web. doi:10.1063/1.4955370.
Sarmiento, L. G., E-mail: Luis.Sarmiento@nuclear.lu.se, & Rudolph, D.. Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity. United States. doi:10.1063/1.4955370.
Sarmiento, L. G., E-mail: Luis.Sarmiento@nuclear.lu.se, and Rudolph, D.. 2016. "Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity". United States. doi:10.1063/1.4955370.
@article{osti_22608517,
title = {Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity},
author = {Sarmiento, L. G., E-mail: Luis.Sarmiento@nuclear.lu.se and Rudolph, D.},
abstractNote = {With the aid of a novel combination of existing equipment – JYFLTRAP and the TASISpec decay station – it is possible to perform very clean quantum-state selective, high-resolution particle-γ decay spectroscopy. We intend to study the determination of the branching ratio of the ℓ = 9 proton emission from the I{sup π} = 19/2{sup −}, 3174-keV isomer in the N = Z − 1 nucleus {sup 53}Co. The study aims to initiate a series of similar experiments along the proton dripline, thereby providing unique insights into “open quantum systems”. The technique has been pioneered in case studies using SHIPTRAP and TASISpec at GSI. Newly available radioactive decay modes in Geant4 simulations are going to corroborate the anticipated experimental results.},
doi = {10.1063/1.4955370},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1753,
place = {United States},
year = 2016,
month = 7
}
  • Purpose: Proton therapy exhibits several advantages over photon therapy due to depth-dose distributions from proton interactions within the target material. However, uncertainties associated with protons beam range in the patient limit the advantage of proton therapy applications. To quantify beam range, positron-emitting nuclei (PEN) and prompt gamma (PG) techniques have been developed. These techniques use de-excitation photons to describe the location of the beam in the patient. To develop a detector system for implementing the PG technique for range verification applications in proton therapy, we studied the yields, energy and angular distributions of the secondary particles emitted from a PMMAmore » phantom. Methods: Proton pencil beams of various energies incident onto a PMMA phantom with dimensions of 5 x 5 x 50 cm3 were used for simulation with the Geant4 toolkit using the standard electromagnetic packages as well as the packages based on the binary-cascade nuclear model. The emitted secondary particles are analyzed . Results: For 160 MeV incident protons, the yields of secondary neutrons and photons per 100 incident protons were ~6 and ~15 respectively. Secondary photon energy spectrum showed several energy peaks in the range between 0 and 10 MeV. The energy peaks located between 4 and 6 MeV were attributed to originate from direct proton interactions with 12C (~ 4.4 MeV) and 16O (~ 6 MeV), respectively. Most of the escaping secondary neutrons were found to have energies between 10 and 100 MeV. Isotropic emissions were found for lower energy neutrons (<10 MeV) and photons for all energies, while higher energy neutrons were emitted predominantly in the forward direction. The yields of emitted photons and neutrons increased with the increase of incident proton energies. Conclusions: A detector system is currently being developed incorporating the yields, energy and angular distributions of secondary particles from proton interactions obtained from this study.« less
  • Purpose: A major concern in proton therapy is the production of secondary neutrons causing secondary cancers, especially in young adults and children. Most utilized Monte Carlo codes in proton therapy are Geant4 and MCNP. However, the default versions of Geant4 and MCNP6 do not have suitable cross sections or physical models to properly handle secondary particle production in proton energy ranges used for therapy. In this study, default versions of Geant4 and MCNP6 were modified to better handle production of secondaries by adding the TENDL-2012 cross-section library. Methods: In-water proton depth-dose was measured at the “The Svedberg Laboratory” in Uppsalamore » (Sweden). The proton beam was mono-energetic with mean energy of 178.25±0.2 MeV. The measurement set-up was simulated by Geant4 version 10.00 (default and modified version) and MCNP6. Proton depth-dose, primary and secondary particle fluence and neutron equivalent dose were calculated. In case of Geant4, the secondary particle fluence was filtered by all the physics processes to identify the main process responsible for the difference between the default and modified version. Results: The proton depth-dose curves and primary proton fluence show a good agreement between both Geant4 versions and MCNP6. With respect to the modified version, default Geant4 underestimates the production of secondary neutrons while overestimates that of gammas. The “ProtonInElastic” process was identified as the main responsible process for the difference between the two versions. MCNP6 shows higher neutron production and lower gamma production than both Geant4 versions. Conclusion: Despite the good agreement on the proton depth dose curve and primary proton fluence, there is a significant discrepancy on secondary neutron production between MCNP6 and both versions of Geant4. Further studies are thus in order to find the possible cause of this discrepancy or more accurate cross-sections/models to handle the nuclear interactions of protons with energy ranges used for therapy. NSERC-CRSNG’ CREATE Medical Physics Research Training Network compute calcul CANADA; McGill University health center research institute the fast foundation; LM acknowledges partial support by the CREATE Medical Physics Research Training Network grant of the Natural Sciences and Engineering; Research Council Grant number 432290.« less
  • Application of isotopic-invariance principles to light nuclei yields a very simple relation between the neutron ard proton binding energies in distant mirror nuclei. On the basis of this relation the limits of stability of neutrondeficient isctopes of light nuclei with respect to proton emission can be established and the existence and properties of approximately 90 such isotopes can be predicted. Nuclei are indicated for which proton radioactivity or the very specific phenomenon of two-proton radioactivity can be observed. The chief properties of tbis interesting phenomenon are analyzed. (auth)
  • Proton radioactivity of {sup 117}La, was measured with much improved statistics, but no evidence is observed for the isomeric proton decay. Prompt {gamma}-rays were identified in proton emitters {sup 117}La, {sup 151}Lu, and beta-delayed proton precursor {sup 117}Ba using recoil decay tagging method by coupling the Gammasphere Ge array at the target position with the Argonne Fragment Mass Analyzer (FMA)
  • The unbound nucleus {sup 18}Na, the intermediate nucleus in the two-proton radioactivity of {sup 19}Mg, is studied through the resonant elastic scattering {sup 17}Ne(p,{sup 17}Ne)p. The spectroscopic information obtained in this experiment is discussed and put in perspective with previous measurements and the structure of the mirror nucleus {sup 18}N.