Page 15 - Tlahuizcalli CB-30_Neat

Figure 9. Second Logic circuit layout. of muons detected in both scintillators diminished.
For a fixed separation of two detectors, the signal
from the upper one (converted to a logic pulse)
was used as the START of the TAC, while the signal
of the lower PMT was first introduced to a Gate and
Delay generator, where it was delayed a known
amount of time, and then it was used as the STOP
for the TAC. The MCA registered the amplitude of
the TAC in a specific channel or bin for each delay.
A curve fit was then made to find the relation
between the histogram bins and the actual time
separation of the pulses. The calibration curve is
shown in fig. (10).
Figure 10. MCA Calibration.
B3. Operation
Time measurements were made for two different
separation distances of the scintillators: 0.5m and
1m. As the separation was increased, the amount
Año 10 Núm. 30 septiembre-diciembre 2024
This was to be expected, as the more separated
the detectors are, the smaller is the solid angle
subtended by the areas of the scintillators, and
therefore, the amount of muons that actually go
through both scintillators is less. A consequence of
this, is that the experimental setup needed to run
for longer times as the separations increased in
order to get a time distribution of the same order as
for the smaller separations.
Table 1. Operation times.
Distance (meters) Time (days)
0.5 6
1 8
After enough measurements with each
separation
distance, a distribution of the time intervals was
obtained. A curve fit was then carried out to find
the mean value of the time interval for each
distance, which is given as the sum of the time for
the muon to go from one detector to the other, plus
the delay. This mean values for the time intervals for
each separation (eq. (9) and eq. (10)), were then
used to calculate the mean velocity of the
detected muons according to eq (12).
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