It has recently been suggested that neutron stars inside the shells of young supernova remnants (SNR) are the sources of PeV cosmic rays and that the interaction of the particles with the radiation ...field in the SNR causes electron pair production, which has relevance to recent observations of "high" positron fluxes. Furthermore, the character of the interaction is such that the well-known knee in the cosmic ray energy spectrum can be explained. Our examination of the mechanism leads us to believe that the required parameters of SN and pulsars are so uncommon that the knee and positron fraction can only be explained if a single, local and recent SN - and associated pulsar - are concerned. In this case the mechanism can be valid.
We present a comparison of some characteristics of helium counters for measurements of low intensity neutron flux. We focus on neutron flux density measurements in low background laboratories. ...Because of an extremely low counting rate (few events per hour or less), we have concentrated on counter parameters which are sometimes meaningless under regular conditions, i.e. background from internal alpha radioactivity, percentage of events in full energy peak, and the width of this peak. The background depends on residual radioactivity of the counter tube material and can not be eliminated. The full energy peak characteristics can be specified by counter gas composition. We will present a comparison of four types of helium gas counters.
An analysis has been made of the world's data on very large extensive air showers with the object of deriving a `best-fit' primary energy spectrum.
It is reassuring that when the various, ...independently measured, spectra are standardised, using as a datum the well-known `dip' in the spectrum at about 3×10
18 eV, and a correction for inferred `noise', the measurements are all consistent.
The best-fit spectrum bears out the well-known problem with the lack of observation of a feature (a cut-off) due to interactions of the particles, commonly assumed to be extra-galactic protons, with the cosmic microwave background. However, we contend that a model involving extragalactic nuclei J. Phys. A 8 (1975) 1518; Astrophys. J. 205 (1976) 638; Astrophys. J. 512 (1999) 521 is satisfactory, although it is premature to be too prescriptive, due to the shortage of astronomical data.
A group of high school students (XII Liceum) in the framework of the Roland Maze Project has built a compact telescope of three Geiger-Muller counters. The connection between the telescope and a PC ...computer was also created and programmed by students involved in the Project. This has allowed students to use their equipment to perform serious scientific measurements concerning the single cosmic ray muon flux at ground level and below. These measurements were then analysed with the programs on the basis of current knowledge on statistics. An overview of the apparatus, methods and results have been presented at several student conferences and recently won the first prize in a national competition for high school students' scientific work. The telescope itself, in spite of its "scientific" purposes, is built in such a way that it can be hung on a wall in a school physics lab and count muons continuously. This can help to raise in interest in studying physics among others. At present a few (three) groups of young participants of the Roland Maze Project have already built their own telescopes for their schools and some others are working on it. This work is a perfect example of what can be done by young people when respective opportunities are created by more experienced researchers and a little help and advice is given.
The search for correlations between secondary cosmic ray detection rates and seismic effects has long been a subject of investigation motivated by the hope of identifying a new precursor type that ...could feed a global early warning system against earthquakes. Here we show for the first time that the average variation of the cosmic ray detection rates correlates with the global seismic activity to be observed with a time lag of approximately two weeks, and that the significance of the effect varies with a periodicity resembling the undecenal solar cycle, with a shift in phase of around three years, exceeding 6 σ at local maxima. The precursor characteristics of the observed correlations point to a pioneer perspective of an early warning system against earthquakes.
Variations of secondary cosmic ray detection rates are periodically correlated with future global earthquake magnitude sum.
•The local changes of the cosmic ray flux correlate with the global seismic activity.•The cosmic signal correlates with the future seismic activity.•The effect lasts a few years and occurs with periodicity similar to the solar cycle.
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