||Experimental setup of each
Tupi detector, showing the scintillator
(bottom) within a pyramidal box, and the
photomultiplier and the preamplifier box (top).
The telescopes array is defined here
|General layout of each telescope.
The logic implemented in the data acquisition
system was made using the virtual instruments
technique within the LabVIEW software.
The card of acqusition (for all telescopes) works
at a rate of 0.4 MHz. With exception of the vertical
and inclined (45 degree West) telescopes work at a
rate of 40 MHz. The telescope counts the number of
coincident signals in the top and bottom detector.
In addition, each telescope uses a veto or
anti-coincidence guard system of a third detector
close to the two telescope. This system allows only
the detectionof muons traveling close to the axis of
||Photograph of the vertical Tupi telescope,
located at sea level (22S, 43W) and close to SAA central
region. The Tupi telescopes are inside a building under
two flagstones of concrete, allowing registration of muons
with energy threshold Eth = 0.1 GeV, required to penetrate
the twoflagstones. Also the flagstones constitute an efficient
absorption medium for the soft cosmic ray background. The Tupi
experiment has a fully independent power supply, with an autonomy
of up to six hours to guard against eventual local power failures.
As a result, the data acquisition is carried out 24 hours a
day, giving a duty cycle greater than 90%.