08/2016 Rev. 1.0
Page 5
SiPM
Eval Kit
4 Measurements with Scintillator
•
With bright scintillators typically the charge released by the SiPM exceeds the dynamic range of the
preamplifier. In this case, the Monitor output is used. The charge released by the SiPM is a measure
for the detected number of scintillating photons and thus a measure for the deposited energy in the
scintillator.
•
Note:
Alternatively the preamplifier can be disconnected to connect the Signal output directly to the oscillo
-
scope
(50 Ω DC)
. This is an option in case timing is not measured.
•
For simultaneous measurements of timing and energy, the Amplified Signal is used for timing and the
Monitor output for the energy measurement.
•
Note:
Even though the preamplifier may be in saturation, timing can still be measured at the steep rising edge
of the Amplified Signal close to the baseline.
•
Usually the monitor output is used to measure the charge released by the SiPM corresponding to the
deposited energy in the scintillator.
•
Evaluation Kits can be ordered either with unmounted or premounted LYSO crystals on the SiPMs:
•
For PM11 (1.2 x 1.2 mm² active area) LYSO with 1.2 x 1.2 x 4.0 mm³
•
For PM33 (3.0 x 3.0 mm² active area) LYSO with 3.0 x 3.0 x 5.0 mm³
•
For PM66 (6.0 x 6.0 mm² active area) LYSO with 5.0 x 5.0 x 5.0 mm³
4.1 Energy Spectrum
•
In analogy to section 3.1, at the oscilloscope the trigger has to be set to the SiPM signal above the base
-
line and the pulse area as a measure for the energy is histogrammed.
•
Figure 3 shows an example energy spectrum of a ²²Na source measured with the Monitor output. The
used scintillator is LYSO with 3 x 3 x 5 mm³.
Fig. 3 Example of an Energy Spectrum
Measured with PM3350 at 4 V overvoltage, ²²Na source and LYSO 3.0 x 3.0 x 5.0 mm³
0
50
100
150
200
250
300
350
0
250
500
750
1000
1250
Energy [keV]
Coun
ts [a.u.]
Energy Resolution
11.9% FWHM at 511 keV
(corrected for saturation)
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