Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe updated SANAE neutron monitor
105
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Neutron monitors have been the premier ground-based instruments for monitoring the near-Earth cosmic ray flux for more than 70 years. It is essential to continue with such measurements in order to extend this unique long-term time series. Moreover, with the recent interest of the aviation industry to space weather effects, and especially the radiation risk posed by solar energetic particles and galactic cosmic rays, it is vital to extend the current neutron monitor network in order to provide near-real-time measurements to the space weather community. In this paper we discuss a new electronics system that was retrofitted to the SANAE neutron monitor in Antarctica. We present initial results from this system, featuring very high temporal resolution and discuss the techniques applied to the data analysis. Based on these successful upgrades, we are confident that this system can be used to rejuvenate the aligning neutron monitor network, and even possibly to revive some of the decommissioned instruments.
rate research
Read More
A ground-based neutron monitor is a standard tool to measure cosmic ray variability near Earth, and it is crucially important to know its yield function for primary cosmic rays. Although there are several earlier theoretically calculated yield functions, none of them agrees with experimental data of latitude surveys of sea-level neutron monitors, thus suggesting for an inconsistency. A newly computed yield function of the standard sea-level 6NM64 neutron monitor is presented here separately for primary cosmic ray protons and $alpha-$particles, the latter representing also heavier species of cosmic rays. The computations have been done using the GEANT-4 Planetocosmics Monte-Carlo tool and a realistic curved atmospheric model. For the first time, an effect of the geometrical correction of the neutron monitor effective area, related to the finite lateral expansion of the cosmic ray induced atmospheric cascade, is considered, that was neglected in the previous studies. This correction slightly enhances the relative impact of higher-energy cosmic rays (energy above 5--10 GeV/nucleon) in neutron monitor count rate. The new computation finally resolves the long-standing problem of disagreement between the theoretically calculated spatial variability of cosmic rays over the globe and experimental latitude surveys. The newly calculated yield function, corrected for this geometrical factor, appears fully consistent with the experimental latitude surveys of neutron monitors performed during three consecutive solar minima in 1976--77, 1986--87 and 1996--97. Thus, we provide a new yield function of the standard sea-level neutron monitor 6NM64 that is validated against experimental data.
This paper describes the Plateau de Bure Neutron Monitor (PdBNM), an instrument providing continuous ground-level measurements of atmospheric secondary neutron flux resulting from the interaction of primary cosmic rays with the Earths atmosphere. The detector is installed on the Plateau de Bure (Devoluy mountains, south of France, latitude North 44{deg} 38 02, longitude East 5{deg} 54 26, altitude 2555 m) as a part of the ASTEP Platform (Altitude Single-event effects Test European Platform), a permanent installation dedicated to the study of the impact of terrestrial natural radiation on microelectronics circuit reliability. The present paper reports the neutron monitor design, its operation since August 2008 and its complete numerical simulation using the Monte Carlo codes GEANT4 and MCNPX. We particularly detail the computation of the neutron monitor detection response function for neutrons, muons, protons and pions, the comparison between GEANT4 and MCNPX numerical results and the evaluation of the PdBNM counting rate a function of both the nature and flux of the incident atmospheric particles.
The Radiation Monitor (RADMON) on-board Aalto-1 CubeSat is an energetic particle detector that fulfills the requirements of small size, low power consumption and low budget. Aalto-1 was launched on 23 June 2017 to a sun-synchronous polar orbit with 97.4{deg} inclination and an average altitude of somewhat above 500 km. RADMON has been measuring integral particle intensities from October 2017 to May 2018 with electron energies starting at low-MeV and protons from 10 MeV upwards. In this paper, we present first electron and proton intensity maps obtained over the mission period. In addition, the response of RADMON measurements to magnetospheric dynamics are analyzed, and the electron observations are compared with corresponding measurements by the PROBA-V/EPT mission. Finally, the we describe the RADMON data set, which is made publicly available.
A prototype quasi-parasitic thermal neutron beam monitor based on isotropic neutron scattering from a thin natural vanadium foil and standard $^3$He proportional counters is conceptualized, designed, simulated, calibrated, and commissioned. The European Spallation Source designed to deliver the highest integrated neutron flux originating from a pulsed source is currently under construction in Lund, Sweden. The effort to investigate a vanadium-based neutron beam monitor was triggered by a list of requirements for Beam Monitors permanently placed in the ESS neutron beams in order to provide reliable monitoring at complex beamlines: low attenuation, linear response over a wide range of neutron fluxes, near to constant efficiency for neutron wavelengths in a range of 0.6-10 r{A}, calibration stability and the possibility to place the system in vacuum are all desirable characteristics. The scattering-based prototype, employing a natural vanadium foil and standard $^3$He proportional counters, was investigated at the V17 and V20 neutron beamlines of the Helmholtz-Zentrum in Berlin, Germany, in several different geometrical configurations of the $^3$He proportional counters around the foil. Response linearity is successfully demonstrated for foil thicknesses ranging from 0.04 mm to 3.15 mm. Attenuation lower than 1% for thermal neutrons is demonstrated for the 0.04 mm and 0.125 mm foils. The geometries used for the experiment were simulated allowing for absolute flux calibration and establishing the possible range of efficiencies for various designs of the prototype. The operational flux limits for the beam monitor prototype were established as a dependency of the background radiation and prototype geometry. The herein demonstrated prototype monitors can be employed for neutron fluxes ranging from $10^3-10^{10}$ n/s/cm$^2$.
We present the scientific motivation for future space tests of the equivalence principle, and in particular the universality of free fall, at the $10^{-17}$ level or better. Two possible mission scenarios, one based on quantum technologies, the other on electrostatic accelerometers, that could reach that goal are briefly discussed.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
