Jane MacGibbon - Academia.edu (original) (raw)
Papers by Jane MacGibbon
Radiation Protection Dosimetry, 2010
The use of Monte Carlo track structure is a choice method in biophysical modelling and calculatio... more The use of Monte Carlo track structure is a choice method in biophysical modelling and calculations. To precisely model 3D and 4D tracks, the cross section for the ionisation by an incoming ion, double differential in the outgoing electron energy and angle, is required. However, the double differential cross section cannot be theoretically modelled over the full range of parameters. To address this issue, a database of all available experimental data has been constructed. Currently, the database of Experimental Double Differential Ionisation Cross sections (EDDIX) contains over 1200 digitalised experimentally measured datasets from the 1960s to present date, covering all available ion species (hydrogen to uranium) and all available target species. Double differential cross sections are also presented with the aid of an eight parameter functions fitted to the cross sections. The parameters include projectile species and charge, target nuclear charge and atomic mass, projectile atomic mass and energy, electron energy and deflection angle. It is planned to freely distribute EDDIX and make it available to the radiation research community for use in the analytical and numerical modelling of track structure.
Astroparticle Physics, 2015
In theories with cosmic strings, a small fraction of string loops may collapse to form black hole... more In theories with cosmic strings, a small fraction of string loops may collapse to form black holes. In this Letter, various constraints on such models involving black holes are considered. Hawking radiation from black holes, gamma and cosmic ray flux limits and constraints from the possible formation of stable black hole remnants are reanalyzed. The constraints which emerge from these considerations are remarkably close to those derived from the normalization of the cosmic string model to the cosmic microwave background anisotropies.
The theoretical maximum time variation in the electronic charge permitted by the Generalized Seco... more The theoretical maximum time variation in the electronic charge permitted by the Generalized Second Law of Thermodynamics applied to black holes radiating and accreting in the cosmic microwave background matches the measured cosmological variation in the fine structure constant claimed by Webb et al.. Such black holes cannot respond adiabatically to a varying fine structure constant.
Several authors have claimed that the observable Hawking emission from a microscopic black hole i... more Several authors have claimed that the observable Hawking emission from a microscopic black hole is significantly modified by the formation of a photosphere or chromosphere around the black hole due to QED or QCD interactions between the emitted particles. Analyzing these models we identify a number of physical and geometrical effects which invalidate them. In all cases, we find that the observational signatures of a cosmic or Galactic background of black holes or an individual black hole remain essentially those of the standard Hawking model, with little change to the detection probability.
Primordial black holes (PBHs) are hypothetical black holes that may have formed from extreme dens... more Primordial black holes (PBHs) are hypothetical black holes that may have formed from extreme densities of matter present during the early universe. Hawking showed that due to quantum-gravitational effects, a black hole possesses a temperature inversely proportional to its mass and emits with a thermal spectrum all species of fundamental particles. PBHs with initial masses of 5:0 10 14 g should be expiring now with bursts of high- energy particles, including gamma rays in the MeV - TeV energy range, making them candidate gamma ray burst (GRB) progenitors. A number of detectors have searched for these events and reported upper limits. The upcoming High Altitude Water Cherenkov (HAWC) observatory is a next generation water Cherenkov telescope located in Mexico at 4100 m above sea level. HAWC is sensitive to gamma-rays in the energy range 50 GeV to 100 TeV. Due to its wide field-of-view and high duty-cycle, HAWC will become the prime observatory for either detecting a PBH burst or setti...
The Twelfth Marcel Grossmann Meeting, 2012
AIP Conference Proceedings
Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015)
Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015)
AIP Conference Proceedings
Phys Rev Lett, Nov 6, 2008
] on the application of the Generalized Second Law of Thermodynamics to derive limits on the vari... more ] on the application of the Generalized Second Law of Thermodynamics to derive limits on the variation of fundamental constants, for example the fine structure constant.
Phys Rev D, 1993
We calculate the flux of ultra high energy photons from individual ordinary (i.e. non-superconduc... more We calculate the flux of ultra high energy photons from individual ordinary (i.e. non-superconducting) cosmic strings and compare the results with the sensitivity of current and proposed TeV and EeV telescopes. Our calculations give only upper limits for the gamma ray flux, since the source of the photons, jets from particle production at cusps, may be weakened by back reaction effects. For the usual cosmic distribution of strings, the predicted bursts from strings with the value of mass per unit length associated with galaxy formation or light strings may just be detectable. A diffuse gamma ray background from light strings may also be seen by the Fly's Eye detector at above 7times10107 \times 10^{10}7times1010 GeV.
AIP Conference Proceedings, 1999
The idea of blending a modern object-oriented graphics-based analysis program with a Monte Carlo ... more The idea of blending a modern object-oriented graphics-based analysis program with a Monte Carlo radiation transport code for space-based applications is being assessed. This is part of an ongoing effort to restructure the FLUKA physics radiation transport simulation code for ...
New Worlds in Astroparticle Physics Ii, 1999
Radiation Protection Dosimetry, 2010
The use of Monte Carlo track structure is a choice method in biophysical modelling and calculatio... more The use of Monte Carlo track structure is a choice method in biophysical modelling and calculations. To precisely model 3D and 4D tracks, the cross section for the ionisation by an incoming ion, double differential in the outgoing electron energy and angle, is required. However, the double differential cross section cannot be theoretically modelled over the full range of parameters. To address this issue, a database of all available experimental data has been constructed. Currently, the database of Experimental Double Differential Ionisation Cross sections (EDDIX) contains over 1200 digitalised experimentally measured datasets from the 1960s to present date, covering all available ion species (hydrogen to uranium) and all available target species. Double differential cross sections are also presented with the aid of an eight parameter functions fitted to the cross sections. The parameters include projectile species and charge, target nuclear charge and atomic mass, projectile atomic mass and energy, electron energy and deflection angle. It is planned to freely distribute EDDIX and make it available to the radiation research community for use in the analytical and numerical modelling of track structure.
Astroparticle Physics, 2015
In theories with cosmic strings, a small fraction of string loops may collapse to form black hole... more In theories with cosmic strings, a small fraction of string loops may collapse to form black holes. In this Letter, various constraints on such models involving black holes are considered. Hawking radiation from black holes, gamma and cosmic ray flux limits and constraints from the possible formation of stable black hole remnants are reanalyzed. The constraints which emerge from these considerations are remarkably close to those derived from the normalization of the cosmic string model to the cosmic microwave background anisotropies.
The theoretical maximum time variation in the electronic charge permitted by the Generalized Seco... more The theoretical maximum time variation in the electronic charge permitted by the Generalized Second Law of Thermodynamics applied to black holes radiating and accreting in the cosmic microwave background matches the measured cosmological variation in the fine structure constant claimed by Webb et al.. Such black holes cannot respond adiabatically to a varying fine structure constant.
Several authors have claimed that the observable Hawking emission from a microscopic black hole i... more Several authors have claimed that the observable Hawking emission from a microscopic black hole is significantly modified by the formation of a photosphere or chromosphere around the black hole due to QED or QCD interactions between the emitted particles. Analyzing these models we identify a number of physical and geometrical effects which invalidate them. In all cases, we find that the observational signatures of a cosmic or Galactic background of black holes or an individual black hole remain essentially those of the standard Hawking model, with little change to the detection probability.
Primordial black holes (PBHs) are hypothetical black holes that may have formed from extreme dens... more Primordial black holes (PBHs) are hypothetical black holes that may have formed from extreme densities of matter present during the early universe. Hawking showed that due to quantum-gravitational effects, a black hole possesses a temperature inversely proportional to its mass and emits with a thermal spectrum all species of fundamental particles. PBHs with initial masses of 5:0 10 14 g should be expiring now with bursts of high- energy particles, including gamma rays in the MeV - TeV energy range, making them candidate gamma ray burst (GRB) progenitors. A number of detectors have searched for these events and reported upper limits. The upcoming High Altitude Water Cherenkov (HAWC) observatory is a next generation water Cherenkov telescope located in Mexico at 4100 m above sea level. HAWC is sensitive to gamma-rays in the energy range 50 GeV to 100 TeV. Due to its wide field-of-view and high duty-cycle, HAWC will become the prime observatory for either detecting a PBH burst or setti...
The Twelfth Marcel Grossmann Meeting, 2012
AIP Conference Proceedings
Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015)
Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015)
AIP Conference Proceedings
Phys Rev Lett, Nov 6, 2008
] on the application of the Generalized Second Law of Thermodynamics to derive limits on the vari... more ] on the application of the Generalized Second Law of Thermodynamics to derive limits on the variation of fundamental constants, for example the fine structure constant.
Phys Rev D, 1993
We calculate the flux of ultra high energy photons from individual ordinary (i.e. non-superconduc... more We calculate the flux of ultra high energy photons from individual ordinary (i.e. non-superconducting) cosmic strings and compare the results with the sensitivity of current and proposed TeV and EeV telescopes. Our calculations give only upper limits for the gamma ray flux, since the source of the photons, jets from particle production at cusps, may be weakened by back reaction effects. For the usual cosmic distribution of strings, the predicted bursts from strings with the value of mass per unit length associated with galaxy formation or light strings may just be detectable. A diffuse gamma ray background from light strings may also be seen by the Fly's Eye detector at above 7times10107 \times 10^{10}7times1010 GeV.
AIP Conference Proceedings, 1999
The idea of blending a modern object-oriented graphics-based analysis program with a Monte Carlo ... more The idea of blending a modern object-oriented graphics-based analysis program with a Monte Carlo radiation transport code for space-based applications is being assessed. This is part of an ongoing effort to restructure the FLUKA physics radiation transport simulation code for ...
New Worlds in Astroparticle Physics Ii, 1999