1. 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

2. 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

3. 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

4. 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

5. Using JSparc
Requesting a session: Includes giving an and school, as well as choosing the cluster of stations you want to use
Confirmation and 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
Title: KEHS293
Pin:

6. Using JSparc
(𝜒² is the error)

7. 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.

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

9. Further Results

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

11. 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

12. 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 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