(The Knowledge Showers) Spataru Anamaria Supervisor: G.A. Shelkov - - PowerPoint PPT Presentation

Cosmic ray study using air shower time coincidence arrays (“The Knowledge Showers”)

Spataru Anamaria Supervisor: G.A. Shelkov

Table of contents

Cosmic rays Setup Zenith angular dependence of muon intensity The dependence on the thickness of the material

On 7 August 1912, Victor Hess, discovered the cosmic rays Cosmic ray – the flux of particles arriving

• n Earth from outer space

Composition: *80% protons *15% alpha particle *5 % heavier elements and antimatter

After entering the atmosphere, the primary cosmic rays interact with the nuclei and the molecules in the air creating pions, muons, beta particles, and gammas Muons are the main component of cosmic rays observed at the sea level

Setup

• 3 Counters: scintillater detectors ( consists of a material that

luminates when is ionized) photomultiplier tubes (multiplies the photon and convert it to an electric pulse)

• QuarkNet DAQ board: takes the signal from the counters and

produces the output data

Zenith angular dependence of muon intensity

• the intensity is decreasing as the angle is increasing
• can be expressed as I (θ) = I (0◦)cos^2(θ)

Measurements:

θ(◦)

• No. of

counts (N) Time (s) Rate (counts/s) 118 ± 11 6460 1.826 30 85 ± 9 6430 1.321 45 54 ± 7 6840 0.789 60 372 ± 19 68105 0.546 90 172 ± 13 82265 0.209

the flux is decreasing with the zenith angle

Material Thickness (mm)

• No. of

particles Time (s) Rate (counts/ s) 9078 3865 2.35 Pb 1.9 2997 1210 2.48 Pb 4.6 3212 1205 2.67 Pb 7.65 3189 1230 2.59 Pb 10.65 3068 1220 2.51 Pb 15.35 2977 1225 2.43 Pb 45 2904 1370 2.12 Pb 98.65 2615 1220 2.14

The dependence on the thickness of the material Measurements:

Material Thickness (mm)

• No. of

particles Time (s) Rate (counts/ s) 3047 1215 2.51 Al 1.35 3475 1360 2.56 Al 5.4 3361 1250 2.69 Al 9.1 3415 1250 2.73 Al 16.5 6026 2295 2.63 Al 31.5 3252 1220 2.67 Al 40.5 3177 2.64 1205 Al 125 3322 2.53 1315

Thank you for

your attention!