Melissa Chung and Jieyi Li King Edward VI High School for Girls HiSPARC Student Conference 2016 Using the JSPARC analysis software to investigate the energy spectrum of primary cosmic rays Melissa Chung and Jieyi Li King Edward VI High School for Girls

Air Showers Primary cosmic rays consist of charged particles & electromagnetic radiation Collision of primary particles and atoms in the atmosphere High-energy reactions creates secondary particles (e.g. pions and muons) Number of particles increases until the kinetic energy of the secondary particles is too low and they can only be scattered

Energy Spectrum Flux (y-axis) is related to the number of primary particles The flux depends on the energy of the particles (x-axis) Logarithmic scale used As energy increases, the flux decreases rapidly Therefore particles with a higher kinetic energy are a lot less frequent ‘knee’ and ‘ankle’ points where the gradient of the graph changes

What is JSparc? Software which uses the data from the HiSPARC public database to analyse air showers which have been detected by several HiSPARC stations Calculates the energy of a primary particle from the number of muons detected at each station

Using JSparc Requesting a session: Includes giving an email and school, as well as choosing the cluster of stations you want to use Confirmation email and email containing title and pin of required to get data Use these to log in. Clicking “Get Data” loads information of a different coincidence each time http://data.hisparc.nl/media/jsparc/jsparc.html Title: KEHS293 Pin: 4309

Using JSparc (𝜒² is the error)

How JSparc Works NKG (Nishimura-Kamata-Greisen) Function Calculates flux intensity/particle density S(r) is the particle density r is the distance to the shower core k is related to the energy The rest are constants S(r) is proportional to r Calculates the energy Shows the relationship between the particle density 600m from the shower core, and the energy.

Results Used about 100 results from the Amsterdam Science Park, ordered them by energy and created a histogram

Further Results

Further Results (Cont.) Range of energies: 1.59x1015eV to 1.36x1018eV Energies used at CERN in 2015 were only 1.31013 eV!

Evaluation Jsparc assumes the zenith angle is zero (i.e. the cosmic ray is approaching perpendicular to the detectors) so is not entirely accurate Equations used in Jsparc are formed from a different experiment (AGASA), so different values of constants may be used Detectors may be more sensitive to particles of 1x10^15 resulting in a higher frequency of them Need to carry out the process on a much larger scale in order to reproduce the knee This requires writing software Therefore manually continuing the process is not feasible or practical Repeating with different times and station clusters

Sources of Cosmic Radiation Relatively low energy levels have a solar origin, and are found in the solar winds. These create aurorae when they interact with the Earth’s magnetic field Particles with an energy below 5x109eV won’t reach the Earth’s surface so are not detected Particles with an energy of around 1015 eV come from our own galaxy, the Milky Way Those with an extremely high energy (1019eV) interact with and lose energy to Cosmic Microwave Background Radiation from the Big Bang. The GZK limit (Greiser-Zatsepin-Kuzmin) is the limit to the highest energy a cosmic ray can have due to this Particles with such energies should therefore not be detected unless physics is wrong or they are from an unknown local source