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SCI-NaI-1
The Scintillator is a crystal that gives off a little light pulse (Cherenkov radiation) when hit by a particle. Gamma rays (X-ray photons) for example. The reason is that the particle is traveling faster than the speed of light (in the crystal where the speed of light is less than in the air outside the crystal). This is not allowed, so the particle has to slow down by dumping energy, and it does so by emitting photons (light) in the visible spectra. (Actually, the particle rattles the crystal lattice, and it sends out light as it relaxes.)
A sensitive detector (here below: a photo multiplier tube) picks up the light from the crystal and converts it into a small electric impulses, one for each photon! In the pulse in the left picture below, there is a "forest" of impulses, probably thousands per sweep, more than the detector can separate. To the eye, it looks like a burst of noise on the oscilloscope.
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A burst of 65 kV photons (X-rays) as detected --- and the LogProbe response
A simple X-ray machine, like a dental X-ray, has no rectifier built in. Every time the polarity of the line voltage is right, and the voltage is high enough, it does its job. 60 times/second here in the US. The sweep speed on the oscilloscope was 1 ms/cm, so the machine is only active about 1.6 ms every 16 ms or 10% of the time. Both pictures exposed for 1 s (~60 sweeps). PMT voltage = 1000 V. The vertical scale on the pictures are 2 V/cm on the left and 0.1 V/cm on the LogProbe output to the right.
On the left picture we can see how the intensity grows in a mostly exponential manner. On the right it looks like this is basically true (straight line going up = exponential growth) although it is "broken" halfway, so the coefficient of the exponential function changes. There is furthermore a small blip just before the main pulse. This is not even visible in the left picture. Then the power is virtually constant for 1.4 ms before dropping again. At 1.5 ms to the right of the center is a last pulse, the nature of which I do not know. Maybe some resonant phenomena in the high voltage transformer.
It is clear that LogProbe does a good job of interpreting this complex signal. With an output pulse of 0.25 V above its base line, it is barely started on its logarithmic output response of 0.05 - 9.25 V and much stronger signals could have been displayed.
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