Cosmic Ray Laboratory in Lodz (Poland) - Underground muon telescope


Teleskope - photo+info
Muon telescope
(larger photo only
format JPEG, 294x300, 71kB)
The muon telescope is placed in the underground laboratory at the depth of 13 m. It is registering directions of muons which have minimum energy of 5 GeV at the ground level. These muons originate from interactions of cosmic rays (mainly protons) of energy from 20 to 1000 GeV in the Earth atmosphere. The variability of Solar activity leads to variation of cosmic ray proton flux entering the atmosphere and - in consequence - the variation of the flux of created muons. We are studying these effects using our underground muon telescope.
A decrease of cosmic ray intensity is registered when the solar particles (solar wind) and related magnetic fields push away galactic cosmic ray particles, which have entered our Interplanetary space. The variation of solar activity (11 years cycle) causes in the Earth vicinity a decrease of cosmic ray intensity of energies below several GeV (1 gigaelectronvolt = 1.E9 electronvolt) at the time of higher solar activity. More information together with results of many years of cosmic ray intensity observation are given by The Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation. There are also available results of current registrations and many addresses to other experiments involved in cosmic ray variation studies.

Muon telescope in Lodz has registered 3 rapid decreases of cosmic ray intensity (Forbush decreases):
17 September 2000,
28 October 2000,
26 November 2000.
Observed muon flux variations were caused by the change of intensity of cosmic ray protons of energy above 20 GeV (probably up to about 50-100 GeV) at the Earth vicinity.
17-IX-2000 plot+caption

Plot of muon counting rate
for the period of 14 - 20 September 2000
(format GIF, 600x464, 12kB)
Muon counting rate registration for the period of 14 - 20 September 2000.
Points connected by the blue line represent counting rate of the Lodz muon telescope (per 2 hours) - left axis; for comparison: red line represents counting rate of the neutron monitor in Apatity (the North-Western Russia) per 0.5 hour - right axis. The Forbush decrease of 17th September 2000 has been registered.
28-X-2000 plot+caption

Data 26 October - 2 November 2000 (format GIF, 600x464, 13kB)
Muon counting rate registration for the period of 26 October - 2 November 2000.
Points connected by the blue line represent counting rate of the Lodz muon telescope (per 2 hours) - left axis; for comparison: red line represents counting rate of the neutron monitor in Apatity (the North-Western Russia) per 0.5 hour - right axis. The rapid decrease of 28th October 2000 has been registered.
26-XI-2000 plot+caption

Data 23 November - 1 December 2000 (format GIF, 600x464, 13kB)
Muon counting rate registration for the period of 23 November - 1 December 2000.
Points connected by the blue line represent counting rate of the Lodz muon telescope (per 2 hours) - left axis; for comparison: red line represents counting rate of the neutron monitor in Apatity (the North-Western Russia) per 0.5 hour - right axis. The rapid decrease of 26th November 2000 has been registered.
24-III-2001 plot+caption

Data 24 March - 13 April 2001 (format GIF, 600x464, 13kB)
Muon counting rate registration for the period of 24 March - 13 April 2001.
Points connected by the blue line represent counting rate of the Lodz muon telescope (per 4 hours) - left axis; for comparison: red line represents counting rate of the neutron monitor in Apatity (the North-Western Russia) per 0.5 hour - right axis. 5 rapid decreases have been registered in the Apatity detector.
17-VIII-2001 plot+caption

Data 3 August - 19 August 2001 (format GIF, 600x464, 15kB)
Muon counting rate registration for the period of 3 - 19 August 2001.
Points connected by the blue line represent counting rate of the Lodz muon telescope (per 4 hours) - left axis; for comparison: red line represents counting rate of the neutron monitor in Apatity (the North-Western Russia) per 0.5 hour - right axis. 5 rapid decreases have been registered in the Apatity detector.
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